Subject: Re: My broken DataQ AD converter From: "tchannel" tchannel@.............. Date: Sat, 31 Mar 2007 13:29:46 -0600 Well Chris, You did it again! I hope your head doesn't get too = big.....But facts are facts. From way over there, in the UK?, you were = able to help me fix this silly AD board, here in Boise Idaho, USA....... I do believe you were correct at every turn.... 1 I do think this is an older 194 8 bit board, from your physical = description. 2 The resistor numbers on the surface mount components were 1003, and = 2003. Of course the two missing ones had no numbers. But there was a = pattern as the resistors were in a row, something like = 1003,2003,1003,2003,1003,2003,xxxx,2003, so I figured the xxxx was the = 1003, 100K 3 The other missing resistor was near others which had the 2003, so I = figured the xxxx would be a 200K, the way it is built I could not see = where these resistors were in the circuit. I soldered in the two = missing resistors, and it is now working!!!!!!! 4 I did go to AmaSeis .ini files but did not see any "Channel # listed" = so maybe it is always going to be Channel 1. and never Channel 2,3, or 4. 5 I do think you are correct about someone modifying the board to run = as a +5v and a -0, as these two missing resistors just did not fail and = fall off, they look like they were purposely popped off, small scratch = marks in their place. Again, Many Thanks, Ted ----- Original Message -----=20 From: ChrisAtUpw@.......... To: psn-l@................. Sent: Saturday, March 31, 2007 12:00 PM Subject: Re: My broken DataQ AD converter In a message dated 2007/03/31, tchannel@.............. writes: Hi All, Looking closely at the board I see two resistors which are = "Open" "cracked" Its a wonder it works at all, but some parts of it do work. Channel = 1, only puts out + voltage, just a small amount of - I think that account for the AmaSeis trace showing only the top part = of an earthquake. Hi Ted, The input resistors are two 200 K in series. The offset line is = 100 K to the centre point. If any of them are damaged, it should not be = difficult to replace them. Alternatively, could you unsolder the = resistors on CH4 and replace the ones on CH1? The resistor values are = printed on them eg 2003. I get about -0.59 V on the offset line and about 90 mV on the = input. I suspect that this is because the ADC is not in operating mode. = The offset line should be -5V for +/-10V input. Check the voltage on the = offset line while the channel is switched on? However Channel, 2,3,4 all seem to work showing both positive and = negative movement "In DataQ Software Only", in this software Channel 1, = only shows positive trace movement, and, no negative. You could get this with failed resistors. Is the range 5V or = 10V? I suspect that the ADC may have been 'modified' for a single = polarity 5V signal? Can the friend who gave it to you provide any = information?=20 When I connected my Sensor to Channel 2,3 or 4 Using DataQ, I was = thinking it would then work in AmaSeis, but it does not. It looks as if = AmaSeis will not read any Channel except Channel 1. Even though in DataQ = Channel 2,3,4 all seem to work fine. If I connect the sensor to Channel = 3, AmaSeis shows a trace, but the trace does not move in either = direction if I stimulate the sensor. This is true for Channel, 2,3,4. = Only Channel 1, moves the trace in AmaSeis. I think you can change the com port, in AmaSeis, but is there = anywhere you can or need to change for Channel selection? In DataQ I closed all the Channels except Ch. 3 and saved before = closing. So If I were just using DataQ software, I would be = operational. Amaseis normally uses CH1 only. However there are two setup = files Amaseis.ini and AS1.ini. It may be possible to set a different = channel by editing and then saving the file, but I am not sure. I know = that you get your different sample rates this way. If you use a Dataq = and Amaseis without editing the ini file, you just get 6 SPS. This information is taken from an old 8 bit DI-194 board, which = I suspect that you have. Regards, Chris Chapman
Well Chris, You did it again!  I = hope your=20 head doesn't get too big.....But facts are facts. From way over there, = in the=20 UK?, you were able to help me fix this silly AD board, here in Boise = Idaho,=20 USA.......
 
I do believe you were correct at every=20 turn....
 
1  I do think this is an older 194 = 8 bit=20 board, from your physical description.
2  The resistor numbers on the = surface mount=20 components were 1003, and 2003.  Of course the two missing ones had = no=20 numbers.  But there was a pattern as the resistors were in a row, = something=20 like 1003,2003,1003,2003,1003,2003,xxxx,2003, so I figured the xxxx was = the=20 1003, 100K
3  The other missing resistor was = near others=20 which had the 2003, so I figured the xxxx would be a 200K, the way it is = built I=20 could not see where these resistors were in the circuit.  I = soldered in the=20 two missing resistors, and it is now working!!!!!!!
 
4  I did go to AmaSeis .ini files = but did not=20 see any "Channel # listed"  so maybe it is always going to be = Channel=20 1.
and never Channel 2,3, or = 4.
5  I do think you are correct = about someone=20 modifying the board to run as a +5v and a -0, as these two missing = resistors=20 just did not fail and fall off, they look like they were purposely = popped off,=20 small scratch marks in their place.
 
Again, Many Thanks, Ted
 
----- Original Message -----
From:=20 ChrisAtUpw@.......
To: psn-l@..............
Sent: Saturday, March 31, 2007 = 12:00=20 PM
Subject: Re: My broken DataQ AD = converter

In a=20 message dated 2007/03/31, tchannel@..............=20 writes:

Hi All, Looking closely at the board I see two resistors = which=20 are "Open" "cracked"
Its a wonder it works at all, but some parts of it = do work.=20 Channel 1, only puts out + voltage, just a small amount of = -
I think that = account for the=20 AmaSeis trace showing only the top part of an = earthquake.

Hi=20 Ted,

       The input resistors = are two=20 200 K in series. The offset line is 100 K to the centre point. If any = of them=20 are damaged, it should not be difficult to replace them. = Alternatively, could=20 you  unsolder the resistors on CH4 and replace the ones on CH1? = The=20 resistor values are printed on them eg=20 2003.
       I get about -0.59 V on = the=20 offset line and about 90 mV on the input. I suspect that this is = because the=20 ADC is not in operating mode. The offset line should be -5V for +/-10V = input.=20 Check the voltage on the offset line while the channel is switched=20 on?

 However Channel, 2,3,4 all seem to work showing both = positive=20 and negative movement "In DataQ Software Only", in this software = Channel 1,=20 only shows positive trace movement, and, no negative.

       You=20 could get this with failed resistors. Is the range 5V or 10V? I = suspect that=20 the ADC may have been 'modified' for a single polarity 5V signal? Can = the=20 friend who gave it to you provide any information?

When I connected my Sensor to Channel 2,3 or 4 Using=20 DataQ,  I was thinking it would then work in AmaSeis, but it = does=20 not.  It looks as if AmaSeis will not read any Channel except = Channel=20 1. Even though in DataQ Channel 2,3,4 all seem to work fine.  = If I=20 connect the sensor to Channel 3,  AmaSeis shows a trace, but = the trace=20 does not move in either direction if I stimulate the sensor.  = This is=20 true for Channel, 2,3,4.  Only Channel 1, moves the trace in=20 AmaSeis.
I think you can change the com port, in AmaSeis, = but is there=20 anywhere you can or need to change for Channel = selection?
In DataQ I = closed all the=20 Channels except Ch. 3 and saved before closing.  So If I were = just=20 using DataQ software, I would be operational.

       Amaseis = normally uses=20 CH1 only. However there are two setup files Amaseis.ini and AS1.ini. = It may be=20 possible to set a different channel by editing and then saving the = file, but I=20 am not sure. I know that you get your different sample rates this way. = If you=20 use a Dataq and Amaseis without editing the ini file, you just get 6=20 SPS.

       This information is = taken=20 from an old 8 bit DI-194 board, which I suspect that you=20 have.

      =20 Regards,

       Chris = Chapman=20 Subject: Large earthquake near Solomon Islands From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@......... Date: Sun, 01 Apr 2007 21:33:40 +0000 Hi all At 20:39 there was a Mw7.6 earthquake according to automatic data near Solomon Islands. But based on how the earthquake is appearing on plots around the world, I assume it is at least 0.5 magnitude bigger then automatic system assume. Regards. --=20 J=F3n Fr=EDmann http://www.jonfr.com http://www.simnet.is/jonfr500/earthquake/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: My broken DataQ AD converter From: "Geoffrey" gmvoeth@........... Date: Sun, 1 Apr 2007 14:38:28 -0700 Someone who has reworked a PWB (printed wiring board) will most always leave signs like scratch marks or noticibly different solder work. Resistors will be cut and left in place rather than unsoldering them because a PWB can only take so much heat before the foil starts to peal away. No sense in doing unnecessary soldering. You must look with a magnifying glass at the solder joints to make sure they are well wetted and no fine hairs of conductive materials are where they are not wanted. No resistor should ever be burnt or the board under them. You really must have a schematic because the job of tracing out one yourself can be next to impossible. In past years the manufacturers would almost always provide schematics but today since most US industry has gone overseas these forign places will refuse to let you get the schematic thill the equipment is old and obsolete. It is not practicle for the common man to work on surface mounted technology you need to work on the new boards is expensive and medical like tools require fine skills. If you like electronics as a hobby it is best to go to a university and become an engineer. Technologist or if all else fails a Technician. Without the proper tools throw the old one away and buy a new one. You will waste your life/monies in trivial pursuits. ----- Original Message ----- From: "tchannel" To: Sent: Saturday, March 31, 2007 12:29 Subject: Re: My broken DataQ AD converter Well Chris, You did it again! I hope your head doesn't get too big.....But facts are facts. From way over there, in the UK?, you were able to help me fix this silly AD board, here in Boise Idaho, USA....... I do believe you were correct at every turn.... 1 I do think this is an older 194 8 bit board, from your physical description. 2 The resistor numbers on the surface mount components were 1003, and 2003. Of course the two missing ones had no numbers. But there was a pattern as the resistors were in a row, something like 1003,2003,1003,2003,1003,2003,xxxx,2003, so I figured the xxxx was the 1003, 100K 3 The other missing resistor was near others which had the 2003, so I figured the xxxx would be a 200K, the way it is built I could not see where these resistors were in the circuit. I soldered in the two missing resistors, and it is now working!!!!!!! 4 I did go to AmaSeis .ini files but did not see any "Channel # listed" so maybe it is always going to be Channel 1. and never Channel 2,3, or 4. 5 I do think you are correct about someone modifying the board to run as a +5v and a -0, as these two missing resistors just did not fail and fall off, they look like they were purposely popped off, small scratch marks in their place. Again, Many Thanks, Ted ----- Original Message ----- From: ChrisAtUpw@....... To: psn-l@.............. Sent: Saturday, March 31, 2007 12:00 PM Subject: Re: My broken DataQ AD converter In a message dated 2007/03/31, tchannel@.............. writes: Hi All, Looking closely at the board I see two resistors which are "Open" "cracked" Its a wonder it works at all, but some parts of it do work. Channel 1, only puts out + voltage, just a small amount of - I think that account for the AmaSeis trace showing only the top part of an earthquake. Hi Ted, The input resistors are two 200 K in series. The offset line is 100 K to the centre point. If any of them are damaged, it should not be difficult to replace them. Alternatively, could you unsolder the resistors on CH4 and replace the ones on CH1? The resistor values are printed on them eg 2003. I get about -0.59 V on the offset line and about 90 mV on the input. I suspect that this is because the ADC is not in operating mode. The offset line should be -5V for +/-10V input. Check the voltage on the offset line while the channel is switched on? However Channel, 2,3,4 all seem to work showing both positive and negative movement "In DataQ Software Only", in this software Channel 1, only shows positive trace movement, and, no negative. You could get this with failed resistors. Is the range 5V or 10V? I suspect that the ADC may have been 'modified' for a single polarity 5V signal? Can the friend who gave it to you provide any information? When I connected my Sensor to Channel 2,3 or 4 Using DataQ, I was thinking it would then work in AmaSeis, but it does not. It looks as if AmaSeis will not read any Channel except Channel 1. Even though in DataQ Channel 2,3,4 all seem to work fine. If I connect the sensor to Channel 3, AmaSeis shows a trace, but the trace does not move in either direction if I stimulate the sensor. This is true for Channel, 2,3,4. Only Channel 1, moves the trace in AmaSeis. I think you can change the com port, in AmaSeis, but is there anywhere you can or need to change for Channel selection? In DataQ I closed all the Channels except Ch. 3 and saved before closing. So If I were just using DataQ software, I would be operational. Amaseis normally uses CH1 only. However there are two setup files Amaseis.ini and AS1.ini. It may be possible to set a different channel by editing and then saving the file, but I am not sure. I know that you get your different sample rates this way. If you use a Dataq and Amaseis without editing the ini file, you just get 6 SPS. This information is taken from an old 8 bit DI-194 board, which I suspect that you have. Regards, Chris Chapman __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Info on Volksmeter....? From: "Geoffrey" gmvoeth@........... Date: Sun, 1 Apr 2007 14:50:59 -0700 I intend to call the company monday mst and see what they have to say. Since they post no prices I fear their attitude to be if you must ask you cant afford it. ----- Original Message ----- From: To: Sent: Saturday, March 31, 2007 01:25 Subject: Re: Info on Volksmeter....? > In a message dated 2007/03/31, mckimzey@........... writes: > >> I remain very interested in the "volksmeter"...but there has been little >> talk about it...only the PDF sheet on Larry's site. I did a web search, and >> >> there seems now to be a bit more information...and nice pictures! It was >> found at http://www.rllinstruments.com/ >> >> Does anyone have any more information? > > HI Mike, > > What further information do you want? > > Regards, > > Chris Chapman > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: My broken DataQ AD converter From: "tchannel" tchannel@.............. Date: Sun, 1 Apr 2007 16:06:18 -0600 Geoffrey, Good advise, indeed.... Thanks, Ted ----- Original Message ----- From: "Geoffrey" To: Sent: Sunday, April 01, 2007 3:38 PM Subject: Re: My broken DataQ AD converter > Someone who has reworked a PWB (printed wiring board) will most always > leave signs like scratch marks or noticibly different solder work. > Resistors will be cut and left in place rather than unsoldering them > because a PWB can only take so much heat before the foil starts > to peal away. No sense in doing unnecessary soldering. You must look > with a magnifying glass at the solder joints to make sure they are > well wetted and no fine hairs of conductive materials are where they > are not wanted. No resistor should ever be burnt or the board under them. > You really must have a schematic because the job of tracing out one > yourself > can be next to impossible. In past years the manufacturers would almost > always > provide schematics but today since most US industry has gone overseas > these forign places will refuse to let you get the schematic thill the > equipment > is old and obsolete. > It is not practicle for the common man to work on surface mounted > technology you > need to work on the new boards is expensive and medical like tools require > fine skills. > If you like electronics as a hobby it is best to go to a university and > become an engineer. > Technologist or if all else fails a Technician. > Without the proper tools throw the old one away and buy a new one. > You will waste your life/monies in trivial pursuits. > > > ----- Original Message ----- > From: "tchannel" > To: > Sent: Saturday, March 31, 2007 12:29 > Subject: Re: My broken DataQ AD converter > > > Well Chris, You did it again! I hope your head doesn't get too > big.....But facts are facts. From way over there, in the UK?, you were > able to help me fix this silly AD board, here in Boise Idaho, USA....... > > I do believe you were correct at every turn.... > > 1 I do think this is an older 194 8 bit board, from your physical > description. > 2 The resistor numbers on the surface mount components were 1003, and > 2003. Of course the two missing ones had no numbers. But there was a > pattern as the resistors were in a row, something like > 1003,2003,1003,2003,1003,2003,xxxx,2003, so I figured the xxxx was the > 1003, 100K > 3 The other missing resistor was near others which had the 2003, so I > figured the xxxx would be a 200K, the way it is built I could not see > where these resistors were in the circuit. I soldered in the two missing > resistors, and it is now working!!!!!!! > > 4 I did go to AmaSeis .ini files but did not see any "Channel # listed" > so maybe it is always going to be Channel 1. > and never Channel 2,3, or 4. > 5 I do think you are correct about someone modifying the board to run as > a +5v and a -0, as these two missing resistors just did not fail and fall > off, they look like they were purposely popped off, small scratch marks in > their place. > > Again, Many Thanks, Ted > > ----- Original Message ----- > From: ChrisAtUpw@....... > To: psn-l@.............. > Sent: Saturday, March 31, 2007 12:00 PM > Subject: Re: My broken DataQ AD converter > > > In a message dated 2007/03/31, tchannel@.............. writes: > > > Hi All, Looking closely at the board I see two resistors which are > "Open" "cracked" > Its a wonder it works at all, but some parts of it do work. Channel 1, > only puts out + voltage, just a small amount of - > I think that account for the AmaSeis trace showing only the top part of > an earthquake. > > > Hi Ted, > > The input resistors are two 200 K in series. The offset line is > 100 K to the centre point. If any of them are damaged, it should not be > difficult to replace them. Alternatively, could you unsolder the > resistors on CH4 and replace the ones on CH1? The resistor values are > printed on them eg 2003. > I get about -0.59 V on the offset line and about 90 mV on the > input. I suspect that this is because the ADC is not in operating mode. > The offset line should be -5V for +/-10V input. Check the voltage on the > offset line while the channel is switched on? > > > However Channel, 2,3,4 all seem to work showing both positive and > negative movement "In DataQ Software Only", in this software Channel 1, > only shows positive trace movement, and, no negative. > > > You could get this with failed resistors. Is the range 5V or 10V? > I suspect that the ADC may have been 'modified' for a single polarity 5V > signal? Can the friend who gave it to you provide any information? > > > When I connected my Sensor to Channel 2,3 or 4 Using DataQ, I was > thinking it would then work in AmaSeis, but it does not. It looks as if > AmaSeis will not read any Channel except Channel 1. Even though in DataQ > Channel 2,3,4 all seem to work fine. If I connect the sensor to Channel > 3, AmaSeis shows a trace, but the trace does not move in either direction > if I stimulate the sensor. This is true for Channel, 2,3,4. Only Channel > 1, moves the trace in AmaSeis. > I think you can change the com port, in AmaSeis, but is there anywhere > you can or need to change for Channel selection? > In DataQ I closed all the Channels except Ch. 3 and saved before > closing. So If I were just using DataQ software, I would be operational. > > > Amaseis normally uses CH1 only. However there are two setup files > Amaseis.ini and AS1.ini. It may be possible to set a different channel by > editing and then saving the file, but I am not sure. I know that you get > your different sample rates this way. If you use a Dataq and Amaseis > without editing the ini file, you just get 6 SPS. > > This information is taken from an old 8 bit DI-194 board, which I > suspect that you have. > > Regards, > > Chris Chapman > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with the body of the > message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: My broken DataQ AD converter From: ChrisAtUpw@....... Date: Sun, 1 Apr 2007 20:39:18 EDT In a message dated 2007/04/01, gmvoeth@........... writes: > It is not practicle for the common man to work on surface mounted > technology you > need to work on the new boards is expensive and medical like tools require > fine skills. > If you like electronics as a hobby it is best to go to a university and > become an engineer. Hi Geoff, The same was probably said when we changed from hard wiring valves to transistor PCBs !! Sure, you need the tools for the job and it hasn't get any easier with time. The first requirements are a temperature controlled soldering iron, a solder sucker, SS tweezers and a head mounted magnifying glass. I agree that 'taking a circuit diagram' can take a lot of time and effort, but it can be done. You may only need to look at part of the circuit. I look for the earth connection and the power supply rails first. Since when did a degree in engineering equip you to deal with PCB electronics? Regards, Chris Chapman In a me= ssage dated 2007/04/01, gmvoeth@........... writes:

It is not practicle for the com= mon man to work on surface mounted technology you
need to work on the new boards is expensive and medical like tools require f= ine skills.
If you like electronics as a hobby it is best to go to a university and beco= me an engineer.


Hi Geoff,

       The same was probably said when we chan= ged from hard wiring valves to transistor PCBs !!

       Sure, you need the tools for the job an= d it hasn't get any easier with time. The first requirements are a temperatu= re controlled soldering iron, a solder sucker, SS tweezers and a head mounte= d magnifying glass.

       I agree that 'taking a circuit diagram'= can take a lot of time and effort, but it can be done. You may only need to= look at part of the circuit. I look for the earth connection and the power=20= supply rails first.

       Since when did a degree in engineering=20= equip you to deal with PCB electronics?

       Regards,

       Chris Chapman
 Subject: RE: My broken DataQ AD converter From: "Keith Payea" kpayea@........... Date: Sun, 1 Apr 2007 20:15:41 -0700 I must respectfully disagree with your statement about handling SMT boards. I, too, learned to solder by dis-assembling old tube (valve) radios, and building "Heath Kits" during the 70's. As technology marched on, I had to learn how to deal with smaller and smaller parts. I distinctly remember cartoons in the electronics hobbyist magazines of that era making fun of the tiny parts and losing them on the workbench. I'm sure they were talking about nothing smaller than 2N3904 transistors in TO-92 packages. I have typical 50 year old eyes and shaky hands, but I have successfully built and reworked many boards with 0402 SMT resistors and caps. While there are a few tools you need to work on SMT pc boards, they are neither hard to find nor expensive. Most electronics catalogs/websites have a decent soldering iron with a tip small enough to do the job. If you already have something better than a Radio Shack wood burner, you may be able to get a finer tip for a few bucks. Buy a roll or two of solder wick while you are at it and save your solder sucker for the big jobs. The way I install fine pitch, 100 pin ICs is to glob on the solder and then remove the excess with solder wick. One trick I use is to buy a pair of "drug store" reading glasses that are more powerful than the ones I use for just reading. For really tough jobs, I combine these with a magnifying lamp I got from Harbor Freight Tools. I would never buy their stuff through a catalog, without seeing it in person, but their magnifying lamp with flourescent lamp is a pretty good unit. Good tweezers can be found in the cosmetics section of most drug stores too. If the tip isn't fine enough, take a file and/or sandpaper to them. There are tons of tutorials on-line, complete with videos to show you how to do deal with small SMT parts. Here's a link to a pretty good one: http://www.epemag.wimborne.co.uk/solderfaq.htm I also highly recommend "MAKE" Magazine: www.makezine.com. I subscribe to their print and online versions. Oh, and lay off the quadruple latte's if you need to do some fine soldering work! I have to wait for the caffiene to wear off before I do any really fussy work.... Good Luck! Keith -----Original Message----- From: psn-l-request@.............. [mailto:psn-l-request@............... On Behalf Of Geoffrey Sent: Sunday, April 01, 2007 2:38 PM To: psn-l@.............. Subject: Re: My broken DataQ AD converter Someone who has reworked a PWB (printed wiring board) will most always leave signs like scratch marks or noticibly different solder work. Resistors will be cut and left in place rather than unsoldering them because a PWB can only take so much heat before the foil starts to peal away. No sense in doing unnecessary soldering. You must look with a magnifying glass at the solder joints to make sure they are well wetted and no fine hairs of conductive materials are where they are not wanted. No resistor should ever be burnt or the board under them. You really must have a schematic because the job of tracing out one yourself can be next to impossible. In past years the manufacturers would almost always provide schematics but today since most US industry has gone overseas these forign places will refuse to let you get the schematic thill the equipment is old and obsolete. It is not practicle for the common man to work on surface mounted technology you need to work on the new boards is expensive and medical like tools require fine skills. If you like electronics as a hobby it is best to go to a university and become an engineer. Technologist or if all else fails a Technician. Without the proper tools throw the old one away and buy a new one. You will waste your life/monies in trivial pursuits. ----- Original Message ----- From: "tchannel" To: Sent: Saturday, March 31, 2007 12:29 Subject: Re: My broken DataQ AD converter Well Chris, You did it again! I hope your head doesn't get too big.....But facts are facts. From way over there, in the UK?, you were able to help me fix this silly AD board, here in Boise Idaho, USA....... I do believe you were correct at every turn.... 1 I do think this is an older 194 8 bit board, from your physical description. 2 The resistor numbers on the surface mount components were 1003, and 2003. Of course the two missing ones had no numbers. But there was a pattern as the resistors were in a row, something like 1003,2003,1003,2003,1003,2003,xxxx,2003, so I figured the xxxx was the 1003, 100K 3 The other missing resistor was near others which had the 2003, so I figured the xxxx would be a 200K, the way it is built I could not see where these resistors were in the circuit. I soldered in the two missing resistors, and it is now working!!!!!!! 4 I did go to AmaSeis .ini files but did not see any "Channel # listed" so maybe it is always going to be Channel 1. and never Channel 2,3, or 4. 5 I do think you are correct about someone modifying the board to run as a +5v and a -0, as these two missing resistors just did not fail and fall off, they look like they were purposely popped off, small scratch marks in their place. Again, Many Thanks, Ted ----- Original Message ----- From: ChrisAtUpw@....... To: psn-l@.............. Sent: Saturday, March 31, 2007 12:00 PM Subject: Re: My broken DataQ AD converter In a message dated 2007/03/31, tchannel@.............. writes: Hi All, Looking closely at the board I see two resistors which are "Open" "cracked" Its a wonder it works at all, but some parts of it do work. Channel 1, only puts out + voltage, just a small amount of - I think that account for the AmaSeis trace showing only the top part of an earthquake. Hi Ted, The input resistors are two 200 K in series. The offset line is 100 K to the centre point. If any of them are damaged, it should not be difficult to replace them. Alternatively, could you unsolder the resistors on CH4 and replace the ones on CH1? The resistor values are printed on them eg 2003. I get about -0.59 V on the offset line and about 90 mV on the input. I suspect that this is because the ADC is not in operating mode. The offset line should be -5V for +/-10V input. Check the voltage on the offset line while the channel is switched on? However Channel, 2,3,4 all seem to work showing both positive and negative movement "In DataQ Software Only", in this software Channel 1, only shows positive trace movement, and, no negative. You could get this with failed resistors. Is the range 5V or 10V? I suspect that the ADC may have been 'modified' for a single polarity 5V signal? Can the friend who gave it to you provide any information? When I connected my Sensor to Channel 2,3 or 4 Using DataQ, I was thinking it would then work in AmaSeis, but it does not. It looks as if AmaSeis will not read any Channel except Channel 1. Even though in DataQ Channel 2,3,4 all seem to work fine. If I connect the sensor to Channel 3, AmaSeis shows a trace, but the trace does not move in either direction if I stimulate the sensor. This is true for Channel, 2,3,4. Only Channel 1, moves the trace in AmaSeis. I think you can change the com port, in AmaSeis, but is there anywhere you can or need to change for Channel selection? In DataQ I closed all the Channels except Ch. 3 and saved before closing. So If I were just using DataQ software, I would be operational. Amaseis normally uses CH1 only. However there are two setup files Amaseis.ini and AS1.ini. It may be possible to set a different channel by editing and then saving the file, but I am not sure. I know that you get your different sample rates this way. If you use a Dataq and Amaseis without editing the ini file, you just get 6 SPS. This information is taken from an old 8 bit DI-194 board, which I suspect that you have. Regards, Chris Chapman __________________________________________________________ Public Seismic Network Mailing List (PSN-L) __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Large earthquake near Solomon Islands From: "Dale Hardy" photon1@........... Date: Tue, 3 Apr 2007 09:55:07 +1000 According to Red Puma, 59 EQ's >5.0 in the Solomons in the last few days, definitely not a place to be, however am getting good traces on my Lehman http://www.daleh.id.au/Current_Lehman_trace.GIF regards Dale To: Sent: Monday, April 02, 2007 5:55 PM Subject: Re: Large earthquake near Solomon Islands > According to Red Puma, 59 EQ's >5.0 in the Solomons in the last few days, > definitely not a place to be, however > am getting good traces on my Lehman > http://www.daleh.id.au/Current_Lehman_trace.GIF > regards > Dale > > > > Solomon Islands. But based on how the earthquake is appearing on plots > around the world, I assume it is at least 0.5 magnitude bigger then > automatic system assume. > > Regards. > -- > Jón Frímann > http://www.jonfr.com > http://www.simnet.is/jonfr500/earthquake/ > > __________________________________________________________ > > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with the body of the > message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Large earthquake near Solomon Islands From: "Dale Hardy" photon1@........... Date: Tue, 3 Apr 2007 11:27:58 +1000 Thanks Ted, I am located near Newcastle NSW Australia, some 2800km from the Solomons Dale ----- Original Message ----- From: "tchannel" To: Sent: Tuesday, April 03, 2007 10:21 AM Subject: Re: Large earthquake near Solomon Islands > Hi Dale, Very impressive, where are you located? Thanks, Ted in Idaho > > > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: My broken DataQ AD converter From: ChrisAtUpw@....... Date: Mon, 2 Apr 2007 22:40:18 EDT In a message dated 2007/04/02, kpayea@........... writes: > While there are a few tools you need to work on SMT pc boards, they are > neither hard to find nor expensive. Most electronics catalogs/websites have > a decent soldering iron with a tip small enough to do the job. Buy a roll > or two of solder wick while you are at it and save your solder sucker for the > big jobs. Hi Keith, It can also be useful to get strips of 2 thou SS foil off an old shaver, or an old SS razor blade. You can heat the solder joint and slide the foil in between the component and the board to unsolder the joint. SS tweezers are also fairly essential. Regards, Chris Chapman In a me= ssage dated 2007/04/02, kpayea@........... writes:

While there are a few tools you= need to work on SMT pc boards, they are
neither hard to find nor expensive.  Most electronics catalogs/websites= have
a decent soldering iron with a tip small enough to do the job.  Buy a r= oll or two of solder wick while you are at it and save your solder sucker fo= r the big jobs.


Hi Keith,

       It can also be useful to get strips of=20= 2 thou SS foil off an old shaver, or an old SS razor blade. You can heat the= solder joint and slide the foil in between the component and the board to u= nsolder the joint. SS tweezers are also fairly essential.

       Regards,

       Chris Chapman Subject: Re: Large earthquake near Solomon Islands From: "Michael Kimzey" mckimzey@........... Date: Mon, 02 Apr 2007 22:41:58 -0400 There sure is a lot of activity! ...where there are usually circles on the IRIS map...around the Solomons there is just one big red circle. -Mike __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Large earthquake near Solomon Islands From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@......... Date: Tue, 03 Apr 2007 20:52:13 +0000 Hi all Besides all the aftershocks, the event appears to have sparked many earthquakes in nearby areas, many of them in mag 5.5 range or stronger. Regards. --=20 J=F3n Fr=EDmann http://www.jonfr.com http://www.simnet.is/jonfr500/earthquake/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Volksmeter.... From: ChrisAtUpw@....... Date: Tue, 3 Apr 2007 20:51:51 EDT In a message dated 2007/03/31, mckimzey@........... writes: > I had been waiting (like a kid at Christmas!) for some info on Larry's site > (he said that there would be more info around February) but I'm sure he is > busy. I'll probably > just give a call some time this week now that there is a phone number. > Thanks for the feedback. Hi Mike, The current (introductory) price of a 2-channel VolksMeter (model VMII-RU2) is US$1495.00. The GPS Time Standard option (VMII-GPS) is US$125.00. The universal AC power supply (VMII-UACA) is US$35.00 (now includes UK and EU AC adapter plugs) Time to raid your 'piggy bank' ! ! Regards, Chris Chapman In a me= ssage dated 2007/03/31, mckimzey@........... writes:

I had been waiting (like a kid=20= at Christmas!) for some info on Larry's site (he said that there would be mo= re info around February) but I'm sure he is busy.  I'll probably
just give a call  some time this week now that there is a phone number.=  
Thanks for the feedback.


Hi Mike,

       The current (introductory) price of a 2= -channel VolksMeter (model VMII-RU2) is US$1495.00.  The GPS Time Stand= ard option (VMII-GPS) is US$125.00.  The universal AC power supply (VMI= I-UACA) is US$35.00 (now includes UK and EU AC adapter plugs)

       Time to raid your 'piggy bank' ! !

       Regards,

       Chris Chapman

       Subject: Re: Large earthquake near Solomon Islands From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@......... Date: Wed, 04 Apr 2007 02:00:00 +0000 Hi all I have added a seismic station that USGS has a plot on from Solomon islands on my USGS plot webpage. The plot can be seen here. http://www.simnet.is/jonfr500/earthquake/tremorusgsen.htm Regards. --=20 J=F3n Fr=EDmann http://www.jonfr.com http://www.simnet.is/jonfr500/earthquake/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Volksmeter.... From: "Michael Kimzey" mckimzey@........... Date: Tue, 03 Apr 2007 23:08:12 -0400 Thanks for the update Chris. I actually wrote to Les LaZar and received the full 'draft' info sheet. I just may raid the piggy bank. Here are some questions and musings to the list, though... In the grand scheme of things, where does the Volksmeter fit? Certainly, a beginner starts with the AS1 or Lehman (I have constructed both). Is the next step an SG? How does the Volksmeter compare to a STM-8 that is homebuilt? Or even to some of the sensors that Mr. Allan Coleman has made? The info sheet states that the Volksmeter compares favorably (although a tab less sensitive...and expensive) to a STS-1, which, I guess, is one of the _de facto_ standards. I've read through the very nice PDF on the Volksmeter at Larry's site, but I will admit that some of the information has gone over my head. (Anyone else lost on some of the diagrams?) If I can't understand all of it, wound (or should) that preclude someone (me) from purchasing such a system? Maybe I'm just thinking way too much, but certainly the dollar amount would warrant it. - Mike __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re:webpage From: "Michael Kimzey" mckimzey@........... Date: Tue, 03 Apr 2007 23:22:14 -0400 Jon, I updated my site a little and my new plots are named mk1.gif and mk2.gif. You may need to update your page. http://mckimzey.homeip.net:8080/seismometer/mk1.gif http://mckimzey.homeip.net:8080/seismometer/mk2.gif As you can see from my other post, I'm thinking about the Volksmeter. If I get one, I'll let you know about those links also. Regards, - Mike Kimzey __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: GPS Based frequency reference From: Philip Schmidt pgschmidt@............... Date: Wed, 04 Apr 2007 21:18:52 +0930 Hello All Last month a Australian electronics magazine called Silicon Chip published the first of a two part article on a GPS-Based Frequency reference. I am not sure if it would come in handy to people on the list however at the very least I though it should get a mention. The article is available on line to purchase. An introduction is available to view at the following link http://www.siliconchip.com.au/cms/A_108508/article.html Hope it comes in handy to someone out there. Cheers Philip Schmidt __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Solomon Islands From: "Dale Hardy" photon1@........... Date: Wed, 4 Apr 2007 21:56:51 +1000 Another earthquake is occurring at the moment at the Loyalty Islands, = making 3 days of extreme activity in the area, does anyone know of = previous events comparable to this 'swarm', currently 12 earthquakes on = my Amaseis screen Dale
Another earthquake is occurring at the = moment at=20 the Loyalty Islands, making 3 days of extreme activity in the area, does = anyone=20 know of previous events comparable to this 'swarm', currently 12 = earthquakes on=20 my Amaseis screen
Dale
Subject: Re: Solomon Islands From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@......... Date: Wed, 04 Apr 2007 12:52:26 +0000 Hi I don't know about any comparision to this earthquake aftershock activite. But I do think that the area did be come unstable when the area was struck by mag 8.1 earthquake. At current rate it is going to be a long time until it slows down agen. Regards. --=20 J=F3n Fr=EDmann http://www.jonfr.com http://www.simnet.is/jonfr500/earthquake/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Solomon Islands From: Stephen & Kathy skmort@............ Date: Wed, 04 Apr 2007 09:19:56 -0700 I did a look up for 6+ events for the 2004 Sumatra quake and found 14 within about 48 hours! My count of 6+ events for this swarm is 9 within 48 hours! I was unable to find complete data for the 1960 Chile, and 1964 Alaska quakes???? Stephen PSN Station #55 Dale Hardy wrote: > Another earthquake is occurring at the moment at the Loyalty Islands, > making 3 days of extreme activity in the area, does anyone know of > previous events comparable to this 'swarm', currently 12 earthquakes > on my Amaseis screen > Dale I did a look up for 6+ events for the 2004 Sumatra quake and found 14 within about 48 hours!   My count of 6+ events for this swarm is 9 within 48 hours!    I was unable to find complete data for the 1960 Chile, and 1964 Alaska quakes????
  Stephen
  PSN Station #55
 

Dale Hardy wrote:
Another earthquake is occurring at the moment at the Loyalty Islands, making 3 days of extreme activity in the area, does anyone know of previous events comparable to this 'swarm', currently 12 earthquakes on my Amaseis screen
Dale
Subject: Tiltmeter progress From: George Bush ke6pxp@....... Date: Wed, 04 Apr 2007 10:01:45 -0700 Chris- I wanted to report on my recent activity with the tiltmeter (NOT the tiltometer!). Your last comment to me about the Linear LTC1043 circuit going unstable if the Cx is smaller than the Cref has opened a door and I am now proceeding. Knowing that the circuit was working was of great value and I stopped trouble-shooting and have attached the circuit to the tiltmeter yesterday! The instrument is amazingly stable, no apparent noise on the scope, no sensitivity to moving my hands near the un-shielded Hg pots and it seems to just simply work. I did a simple sensitivy check. The plate the two pots are mounted on is supported by screws in a triangle configuration (see http://ntweb.mcn.org/gbush/Tiltmeter/Construction/Construction.html). The pots are separated by 24" center-to-center, and the micrometer leveller leg is separated from the other end two suppoort screws by 27 1/2". When I adjusted the micrometer by .01" vertically, I got an output voltage change reading of 0.193v. If my trig is correct this is the voltage change for a tilt change of 6.347 -07 deg. I have no feeling if this is getting into the ball-park of sensitivity needed to detect Earth tides. What sensitivity do you think is needed? Since yesterday afternoon I have periodically recorded output voltage and time. This is the signal so far: Date Time Vout ---- ---- ---- 3-4-07 1:21p 1.625 3:45p 1.594 5:27p 1.605 6:30p 1.615 4-4-07 9:29a 1.654 Presently I am connecting the instrument to my Windaq DI-194 to try to plot daily signal variations. Then I will be able to see if I need to add another stage of gain. After that, a complete mechanical tear-down to shield the Hg cups and connecting tube and to build an insulated enclosure with a heater in the top. I can see light at the end of the tunnel and am really geting excited! George __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Tiltmeter progress From: "tchannel" tchannel@.............. Date: Wed, 4 Apr 2007 11:59:14 -0600 Hi George, This is interesting. Where can I find articles to read more about the basic principle. etc. Thanks, Ted ----- Original Message ----- From: "George Bush" To: Sent: Wednesday, April 04, 2007 11:01 AM Subject: Tiltmeter progress > Chris- > > I wanted to report on my recent activity with the tiltmeter (NOT the > tiltometer!). > > Your last comment to me about the Linear LTC1043 circuit going unstable if > the Cx is smaller than the Cref has opened a door and I am now proceeding. > Knowing that the circuit was working was of great value and I stopped > trouble-shooting and have attached the circuit to the tiltmeter yesterday! > The instrument is amazingly stable, no apparent noise on the scope, no > sensitivity to moving my hands near the un-shielded Hg pots and it seems > to > just simply work. > > I did a simple sensitivy check. The plate the two pots are mounted on is > supported by screws in a triangle configuration (see > http://ntweb.mcn.org/gbush/Tiltmeter/Construction/Construction.html). > The pots are separated by 24" center-to-center, and the micrometer > leveller > leg is separated from the other end two suppoort screws by 27 1/2". When I > adjusted the micrometer by .01" vertically, I got an output voltage change > reading of 0.193v. If my trig is correct this is the voltage change for a > tilt change of 6.347 -07 deg. I have no feeling if this is getting into > the > ball-park of sensitivity needed to detect Earth tides. What sensitivity do > you think is needed? > > Since yesterday afternoon I have periodically recorded output voltage and > time. This is the signal so far: > > Date Time Vout > ---- ---- ---- > 3-4-07 1:21p 1.625 > 3:45p 1.594 > 5:27p 1.605 > 6:30p 1.615 > 4-4-07 9:29a 1.654 > > Presently I am connecting the instrument to my Windaq DI-194 to try to > plot > daily signal variations. Then I will be able to see if I need to add > another stage of gain. After that, a complete mechanical tear-down to > shield the Hg cups and connecting tube and to build an insulated enclosure > with a heater in the top. > > I can see light at the end of the tunnel and am really geting excited! > > > George > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Tiltmeter progress From: ChrisAtUpw@....... Date: Wed, 4 Apr 2007 17:54:23 EDT In a message dated 2007/04/07, tchannel@.............. writes: > Hi George, This is interesting. Where can I find articles to read more > about the basic principle. etc. Hi Ted, See http://ntweb.mcn.org/gbush/Tiltmeter/tiltmeter%20Main.html for several references. This tiltmeter has two Perspex cups 2 ft apart on a baseplate, connected by plastic tube and part filled with Mercury. Two flat plates are suspended just above the Hg surfaces to form capacitative level detectors. The cup system is sealed to contain the Hg vapour, which is very poisonous and attacks electronic components, Cu wire, pcbs etc like fun. The original SciAm circuit used valves, a crystal oscillator and resonant tuned detectors followed by diode rectifiers. The oscillating voltages were quite high. The Nuts and Volts version was an adaptation of this to semiconductors, with lower voltages. The new N&V board seemed to suffer from AC hum from the on board PSU. A major problem with the whole concept is that the foreward voltage of rectifier diodes drifts by about 2.5 mV / C deg and the resonant circuits also drift with temperarure. So, unless you are very determined, you may end up with an expensive differential thermometer sensitive to random air movements and to any stray capacitance going. The work/satisfaction ratio may be discouraging. A good way around this ''problem'' is to redesign the circuit using a capacitative detector working at high audio frequencies, not at RF and to provide a FET phase sensitive detector. The LTC1043 IC has all the switching components on it. You can use the on chip oscillator, but I found that an external Crystal oscillator gave significantly better results. I used a 2.4576 M Hz AT cut crystal in a 4060 oscillator divider circuit, giving a 9.6 kHz drive. If you want to sense only earth tides and similar, severely damping the Hg flow will tend to reject any passing earthquakes, local delivery trucks, etc. Clamp a piece of cleaned iron wire centrally in the plastic tube containing the Hg, using an external clamp maybe 1" wide. Hg 'wets' the iron, but does not dissolve it, leaving two narrow triangular passages bounded by the plastic and the wire. Regards, Chris Chapman In a me= ssage dated 2007/04/07, tchannel@.............. writes:

Hi George,  This is intere= sting.  Where can I find articles to read more
about the basic principle. etc.


Hi Ted,

       See http://ntweb.mcn.org/gbush/Tiltmete= r/tiltmeter%20Main.html for several references.
       This tiltmeter has two Perspex cups 2 f= t apart on a baseplate, connected by plastic tube and part filled with Mercu= ry. Two flat plates are suspended just above the Hg surfaces to form capacit= ative level detectors. The cup system is sealed to contain the Hg vapour, wh= ich is very poisonous and attacks electronic components, Cu wire, pcbs etc l= ike fun.
       The original SciAm circuit used valves,= a crystal oscillator and resonant tuned detectors followed by diode rectifi= ers. The oscillating voltages were quite high. The Nuts and Volts version wa= s an adaptation of this to semiconductors, with lower voltages. The new N&am= p;V board seemed to suffer from AC hum from the on board PSU. A major proble= m with the whole concept is that the foreward voltage of rectifier diodes dr= ifts by about 2.5 mV / C deg and the resonant circuits also drift with tempe= rarure. So, unless you are very determined, you may end up with an expensive= differential thermometer sensitive to random air movements and to any stray= capacitance going. The work/satisfaction ratio may be discouraging.
       A good way around this ''problem'' is t= o redesign the circuit using a capacitative detector working at high audio f= requencies, not at RF and to provide a FET phase sensitive detector. The LTC= 1043 IC has all the switching components on it. You can use the on chip osci= llator, but I found that an external Crystal oscillator gave significantly b= etter results. I used a 2.4576 M Hz AT cut crystal in a 4060 oscillator divi= der circuit, giving a 9.6 kHz drive.
       If you want to sense only earth tides a= nd similar, severely damping the Hg flow will tend to reject any passing ear= thquakes, local delivery trucks, etc. Clamp a piece of cleaned iron wire cen= trally in the plastic tube containing the Hg, using an external clamp maybe=20= 1" wide. Hg 'wets' the iron, but does not dissolve it, leaving two narrow tr= iangular passages bounded by the plastic and the wire.

       Regards,

       Chris Chapman Subject: Re: Tiltmeter progress From: George Bush ke6pxp@....... Date: Wed, 04 Apr 2007 15:44:23 -0700 Ted- I want to apologize to you and the list for sending a message for Chris Chapman to the whole list (I just hit reply without seeing who it was replying to). I have been interested in Earth tides and have wanted to make an instrument to measure them. C. L. Strong originally had an article on making a tiltmeter based on two mercury-filled cups connected by a tube and measuring the level by a capacitance gauge, "A sensitive mercury tiltmeter that serves as a seismometer" Scientific American, November 1973, pp. 124-129. The electronics were updated by an article in Nuts & Volts by Ron Newton, "Measure Earth Tides with a Tiltometer" I ordered a board from Ron, but was unable to make it work. I have just completed a circuit suggested by Chris based on the Linear Technology LTC 1043 chip and the email to Chris was to let him know how it was working. Check my website at http://ntweb.mcn.org/gbush/Tiltmeter/tiltmeter%20Main.html for further info on my project and references. At 11:59 AM 4/4/2007 -0600, you wrote: >Hi George, This is interesting. Where can I find articles to read more >about the basic principle. etc. Thanks, Ted ....snip... George __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Tiltmeter progress From: "tchannel" tchannel@.............. Date: Wed, 4 Apr 2007 16:55:02 -0600 Hi George, Thanks for the reply, to me this is great stuff, new to me. How is it working for you? Do you have a larger picture of the unit as illustrated at the top of you wed page? I can't see it very well. Thanks, Ted ----- Original Message ----- From: "George Bush" To: Sent: Wednesday, April 04, 2007 4:44 PM Subject: Re: Tiltmeter progress > Ted- > > I want to apologize to you and the list for sending a message for Chris > Chapman to the whole list (I just hit reply without seeing who it was > replying to). I have been interested in Earth tides and have wanted to > make > an instrument to measure them. C. L. Strong originally had an article on > making a tiltmeter based on two mercury-filled cups connected by a tube > and > measuring the level by a capacitance gauge, "A sensitive mercury tiltmeter > that serves as a seismometer" Scientific American, November 1973, pp. > 124-129. The electronics were updated by an article in Nuts & Volts by Ron > Newton, "Measure Earth Tides with a Tiltometer" I ordered a board from > Ron, > but was unable to make it work. I have just completed a circuit suggested > by Chris based on the Linear Technology LTC 1043 chip and the email to > Chris was to let him know how it was working. > > Check my website at > http://ntweb.mcn.org/gbush/Tiltmeter/tiltmeter%20Main.html > for further info on my project and references. > > At 11:59 AM 4/4/2007 -0600, you wrote: >>Hi George, This is interesting. Where can I find articles to read more >>about the basic principle. etc. Thanks, Ted > ...snip... > George > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Tiltmeter progress From: "tchannel" tchannel@.............. Date: Wed, 4 Apr 2007 17:03:06 -0600 Hi Chris, Thanks for the explanation. Have they also use lasers, in = such devises? Ted ----- Original Message -----=20 From: ChrisAtUpw@.......... To: psn-l@................. Sent: Wednesday, April 04, 2007 3:54 PM Subject: Re: Tiltmeter progress In a message dated 2007/04/07, tchannel@.............. writes: Hi George, This is interesting. Where can I find articles to read = more=20 about the basic principle. etc.=20 Hi Ted, See http://ntweb.mcn.org/gbush/Tiltmeter/tiltmeter%20Main.html = for several references. This tiltmeter has two Perspex cups 2 ft apart on a baseplate, = connected by plastic tube and part filled with Mercury. Two flat plates = are suspended just above the Hg surfaces to form capacitative level = detectors. The cup system is sealed to contain the Hg vapour, which is = very poisonous and attacks electronic components, Cu wire, pcbs etc like = fun. The original SciAm circuit used valves, a crystal oscillator = and resonant tuned detectors followed by diode rectifiers. The = oscillating voltages were quite high. The Nuts and Volts version was an = adaptation of this to semiconductors, with lower voltages. The new N&V = board seemed to suffer from AC hum from the on board PSU. A major = problem with the whole concept is that the foreward voltage of rectifier = diodes drifts by about 2.5 mV / C deg and the resonant circuits also = drift with temperarure. So, unless you are very determined, you may end = up with an expensive differential thermometer sensitive to random air = movements and to any stray capacitance going. The work/satisfaction = ratio may be discouraging. A good way around this ''problem'' is to redesign the circuit = using a capacitative detector working at high audio frequencies, not at = RF and to provide a FET phase sensitive detector. The LTC1043 IC has all = the switching components on it. You can use the on chip oscillator, but = I found that an external Crystal oscillator gave significantly better = results. I used a 2.4576 M Hz AT cut crystal in a 4060 oscillator = divider circuit, giving a 9.6 kHz drive.=20 If you want to sense only earth tides and similar, severely = damping the Hg flow will tend to reject any passing earthquakes, local = delivery trucks, etc. Clamp a piece of cleaned iron wire centrally in = the plastic tube containing the Hg, using an external clamp maybe 1" = wide. Hg 'wets' the iron, but does not dissolve it, leaving two narrow = triangular passages bounded by the plastic and the wire. Regards, Chris Chapman
Hi Chris,  Thanks for the = explanation. =20 Have they also use lasers, in such devises?   Ted
----- Original Message -----
From:=20 ChrisAtUpw@.......
Sent: Wednesday, April 04, 2007 = 3:54=20 PM
Subject: Re: Tiltmeter = progress

In a=20 message dated 2007/04/07, tchannel@..............=20 writes:

Hi George,  This is interesting.  Where can I = find=20 articles to read more
about the basic principle. etc.=20

Hi = Ted,

       See=20 http:= //ntweb.mcn.org/gbush/Tiltmeter/tiltmeter%20Main.html=20 for several references.
       This = tiltmeter=20 has two Perspex cups 2 ft apart on a baseplate, connected by plastic = tube and=20 part filled with Mercury. Two flat plates are suspended just above the = Hg=20 surfaces to form capacitative level detectors. The cup system is = sealed to=20 contain the Hg vapour, which is very poisonous and attacks electronic=20 components, Cu wire, pcbs etc like=20 fun.
       The original SciAm = circuit used=20 valves, a crystal oscillator and resonant tuned detectors followed by = diode=20 rectifiers. The oscillating voltages were quite high. The Nuts and = Volts=20 version was an adaptation of this to semiconductors, with lower = voltages. The=20 new N&V board seemed to suffer from AC hum from the on board PSU. = A major=20 problem with the whole concept is that the foreward voltage of = rectifier=20 diodes drifts by about 2.5 mV / C deg and the resonant circuits also = drift=20 with temperarure. So, unless you are very determined, you may end up = with an=20 expensive differential thermometer sensitive to random air movements = and to=20 any stray capacitance going. The work/satisfaction ratio may be=20 discouraging.
       A good way = around this=20 ''problem'' is to redesign the circuit using a capacitative detector = working=20 at high audio frequencies, not at RF and to provide a FET phase = sensitive=20 detector. The LTC1043 IC has all the switching components on it. You = can use=20 the on chip oscillator, but I found that an external Crystal = oscillator gave=20 significantly better results. I used a 2.4576 M Hz AT cut crystal in a = 4060=20 oscillator divider circuit, giving a 9.6 kHz drive.=20
       If you want to sense only = earth tides=20 and similar, severely damping the Hg flow will tend to reject any = passing=20 earthquakes, local delivery trucks, etc. Clamp a piece of cleaned iron = wire=20 centrally in the plastic tube containing the Hg, using an external = clamp maybe=20 1" wide. Hg 'wets' the iron, but does not dissolve it, leaving two = narrow=20 triangular passages bounded by the plastic and the=20 wire.

      =20 Regards,

       Chris = Chapman=20 Subject: Re: Tiltmeter progress From: ChrisAtUpw@....... Date: Wed, 4 Apr 2007 20:54:56 EDT In a message dated 2007/04/05, tchannel@.............. writes: > Hi Chris, Thanks for the explanation. Have they also use lasers, in such > devises? Ted Hi Ted, Lasers have been used, but I don't know how successfully. In seismic applications you tend to be limited by 1/2 the wavelength of light for fringe counting - a step size of say ~0.3 micron = large. Fringe counting may sound simple, but it is not a 'cheap and easy technique'. Your average microseism may be ~2 microns. You want to measure seismic movements down to nano metres. Measuring to 1/100 of a wavelength tends to be very costly. Especially when a small filament bulb and a couple of Si photocells can give you an optical sensor with a noise level <15 nano metres! The intensity stability of semiconductor lasers in my experience is lousy. The huge open trough tiltmeters in Washington State use floats with 'free armature' LVDT magnetic sensors. See http://www.geodesy.cwu.edu/tilt/ The smaller ones at Walferdange use capacitative sensors of at least two types. There are also small bubble tiltmeters, which use AC fluid resistance measurement, but they do not have such a high resolution. They tend to be used for monitoring the tilts of buildings, bridges, roads, etc. See several des criptions at http://www.geomechanics.com/bibliography.cfm The Earth Tide tilts may be ~0.25 micro radian = 1/4 mm at 1 km = not very large. Regards, Chris Chapman In a me= ssage dated 2007/04/05, tchannel@.............. writes:

Hi Chris,  Thanks for the=20= explanation.  Have they also use lasers, in such devises?   T= ed


Hi Ted,

       Lasers have been used, but I don't know= how successfully. In seismic applications you tend to be limited by 1/2 the= wavelength of light for fringe counting - a step size of say ~0.3 micron=20= =3D large. Fringe counting may sound simple, but it is not a 'cheap and easy= technique'. Your average microseism may be ~2 microns. You want to measure=20= seismic movements down to nano metres. Measuring to 1/100 of a wavelength te= nds to be very costly. Especially when a small filament bulb and a couple of= Si photocells can give you an optical sensor with a noise level <15 nano= metres! The intensity stability of semiconductor lasers in my experience is= lousy.
       The huge open trough tiltmeters in Wash= ington State use floats with 'free armature' LVDT magnetic sensors. See http= ://www.geodesy.cwu.edu/tilt/  
       The smaller ones at Walferdange use cap= acitative sensors of at least two types. There are also small bubble tiltmet= ers, which use AC fluid resistance measurement, but they do not have such a=20= high resolution. They tend to be used for monitoring the tilts of buildings,= bridges, roads, etc. See several descriptions at http://www.geomechanics.co= m/bibliography.cfm
       The Earth Tide tilts may be ~0.25 micro= radian =3D 1/4 mm at 1 km =3D not very large.

       Regards,

       Chris Chapman Subject: Re: Tiltmeter designs From: George Bush ke6pxp@....... Date: Thu, 05 Apr 2007 09:57:01 -0700 Ted- The picture on the top of my website was from the Scientific American article I mentioned below. On my web you can see what my instrument looks like. My approach may not be the best route. I have been following the work of the FMES group (http://groups.yahoo.com/group/fmes) and the instrument designed by Dave Nelson (davefnelson@........ that is based on the resistance of water in a similar two-cup configuration. He uses circuits with hi-pass coupling, and I was wondering if dc-coupled circuits could possibly be used to detect earth tides? I am concentrating on getting my system working, but it might be fun if someone else wanted to look in to modifying Dave's instrument for ultra-low freq operation. Thank you for your interest. At 04:55 PM 4/4/2007 -0600, you wrote: >Hi George, Thanks for the reply, to me this is great stuff, new to me. > >How is it working for you? Do you have a larger picture of the unit as >illustrated at the top of you wed page? >I can't see it very well. Thanks, Ted > > > >----- Original Message ----- >From: "George Bush" >To: >Sent: Wednesday, April 04, 2007 4:44 PM >Subject: Re: Tiltmeter progress > > >> Ted- >> >> I want to apologize to you and the list for sending a message for Chris >> Chapman to the whole list (I just hit reply without seeing who it was >> replying to). I have been interested in Earth tides and have wanted to >> make >> an instrument to measure them. C. L. Strong originally had an article on >> making a tiltmeter based on two mercury-filled cups connected by a tube >> and >> measuring the level by a capacitance gauge, "A sensitive mercury tiltmeter >> that serves as a seismometer" Scientific American, November 1973, pp. >> 124-129. The electronics were updated by an article in Nuts & Volts by Ron >> Newton, "Measure Earth Tides with a Tiltometer" I ordered a board from >> Ron, >> but was unable to make it work. I have just completed a circuit suggested >> by Chris based on the Linear Technology LTC 1043 chip and the email to >> Chris was to let him know how it was working. >> >> Check my website at >> http://ntweb.mcn.org/gbush/Tiltmeter/tiltmeter%20Main.html >> for further info on my project and references. >> >> ...snip... > George __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: GPS and solarflairs From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@......... Date: Fri, 06 Apr 2007 00:18:10 +0000 Hi all I want to point out artical about solar flairs and how they can disrupt a gps signal.=20 http://www.reghardware.co.uk/2007/04/05/solar_flares_zap_gps/ It is worth tracking solar flares since most of us recording earthquakes use gps to keep track of time. Regards. --=20 J=F3n Fr=EDmann http://www.jonfr.com http://www.simnet.is/jonfr500/earthquake/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: My broken DataQ AD converter From: "Geoffrey" gmvoeth@........... Date: Fri, 6 Apr 2007 18:00:31 -0700 Personal experience has shown me only factories are properly equipped and funded to handle modern day electronics. The small business peoples and private individuals usually are not properly trained to do these things. It is mainly my personal preference speaking here. The only exception I make are with Engineering techs who make models for Engineers that have not yet been put into production. Unless they use special tools just about anyone with previous experience in the field should be able to reproduce and work on their designs. But as for final products after FAT Final Assembly and Test I would never recommend anyone trying to alter anything other than a minor field change/alt or replacement of a socketed chip. I would make no major changes to pre-built factory type devices. I once knew a tech who thought he could spudge a microwave oscillator without any special tools but later found out through personal experience in the field that thousand of dollars of special purpose tools were reqired to do the stuff that- that guy was trying to do blind. I was caught in a kind of trap that my senior would make me look like a sabatour because of his actions. I do not recommend wasting ones times with the unknown unless the results are possibly- significantly profitable. I dont necessarily mean money when I say this. The purpose is to have fun here. Or at least that is MY goal. ----- Original Message ----- From: To: Sent: Sunday, April 01, 2007 17:39 Subject: Re: My broken DataQ AD converter > In a message dated 2007/04/01, gmvoeth@........... writes: > >> It is not practicle for the common man to work on surface mounted >> technology you >> need to work on the new boards is expensive and medical like tools require >> fine skills. >> If you like electronics as a hobby it is best to go to a university and >> become an engineer. > > Hi Geoff, > > The same was probably said when we changed from hard wiring valves to > transistor PCBs !! > > Sure, you need the tools for the job and it hasn't get any easier with > time. The first requirements are a temperature controlled soldering iron, a > solder sucker, SS tweezers and a head mounted magnifying glass. > > I agree that 'taking a circuit diagram' can take a lot of time and > effort, but it can be done. You may only need to look at part of the circuit. I > look for the earth connection and the power supply rails first. > > Since when did a degree in engineering equip you to deal with PCB > electronics? > > Regards, > > Chris Chapman > > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: GPS and solarflairs From: Brad Douglas rez@.................. Date: Sat, 07 Apr 2007 05:05:06 +0000 On Fri, 2007-04-06 at 00:18 +0000, JĂłn FrĂ­mann wrote: > Hi all > > I want to point out artical about solar flairs and how they can disrupt > a gps signal. > > http://www.reghardware.co.uk/2007/04/05/solar_flares_zap_gps/ > > It is worth tracking solar flares since most of us recording earthquakes > use gps to keep track of time. Keep in mind that we're just now coming up from a solar minimum and this next cycle is supposed to be particularly strong (but solar modeling is far from diagnostic). Not only can solar flares disrupt propagation paths, but can also alter the atmospheric index of refraction and gas composition, further complication matters of spacial precision. Here's an overview of the effects on positioning due to medium (atmosphere) alteration by solar interaction: http://citeseer.ist.psu.edu/418582.html GPS is resistant to flares to a certain level, but has been demonstrated in the last cycle (where user density was much smaller and SA was on) that they can be knocked out for periods of time. The GLONASS and next gen GPS constellations should address these concerns. We have a few years to go before the solar maximum. Personally, I'm a little more concerned with ISS than satellites. It's impossible to do an EVA in those conditions and only limited areas of the ISS are shielded. -- 73, de Brad KB8UYR/6 __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: My broken DataQ AD converter From: ChrisAtUpw@....... Date: Sat, 7 Apr 2007 06:26:12 EDT In a message dated 2007/04/07, gmvoeth@........... writes: > I once knew a tech who thought he could spudge a microwave oscillator > without any special tools but later found out through personal experience in the > field that thousand of dollars of special purpose tools were reqired to do the > stuff that- > that guy was trying to do blind. Hi Geoff, What does 'spudge' involve, please? I don't know the term. What adjustements and measurements are involved in setting up and regulating this microwave oscillator? How does this relate to handling SIM ICs on a circuit board? Regards, Chris Chapman In a me= ssage dated 2007/04/07, gmvoeth@........... writes:

I once knew a tech who thought=20= he could spudge a microwave oscillator without any special tools but later f= ound out through personal experience in the field that thousand of dollars o= f special purpose tools were reqired to do the stuff that-
that guy was trying to do blind.


Hi Geoff,

       What does 'spudge' involve, please? I d= on't know the term.
       What adjustements and measurements are=20= involved in setting up and regulating this microwave oscillator?

       How does this relate to handling SIM IC= s on a circuit board?

       Regards,

       Chris Chapman Subject: Prior earthquake before a larger one From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@......... Date: Sat, 07 Apr 2007 13:32:34 +0000 Hi all Yesterday at 18:39 there was a mag 4.5 earthquake 285 km north of my location. I did record that earthquake really good on my system, the traces of this earthquake can be seen here. http://seismicnet.com/cgi-dos/makegif.exe?/quakes/0704/070406.184900.hvt1z.= psn http://seismicnet.com/cgi-dos/makegif.exe?/quakes/0704/070406.184900.hvt1n.= psn http://seismicnet.com/cgi-dos/makegif.exe?/quakes/0704/070406.184900.hvt1e.= psn I do belive that this earthquake is a prior earthquake to a much larger earthquake somewhere close to the location of this earthquake. I have seen activie in this region few weeks back with mag 3 - 4 earthquakes. The activite appears to be on the rise in that area. It is hard to tell when this earthquake is going to hit, but I do expect it hit sometimes in next two weeks. Regards. --=20 J=F3n Fr=EDmann http://www.jonfr.com http://www.simnet.is/jonfr500/earthquake/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Solomon island earthquake effect on the crust From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@......... Date: Sat, 07 Apr 2007 14:14:43 +0000 Hi all Here is a intresting news about what did happen in the Solomon Island earthquake. http://www.dnaindia.com/report.asp?NewsID=3D1089455 It appears that the earthquake did change the landscape in the island cluster and has in some areas lifted the crust up by many meters. So much that islands that where below the ocen are now on dry land. Regards. --=20 J=F3n Fr=EDmann http://www.jonfr.com http://www.simnet.is/jonfr500/earthquake/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Solomon island earthquake effect on the crust From: Roger Sparks rsparks@.......... Date: Sun, 08 Apr 2007 06:11:02 -0700 Good Morning All, Here is another Uplifting Article that describes effects from the Solomon Island Quake, Roger > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Earthquake swarm on the Reykjanes Ridge From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@......... Date: Mon, 09 Apr 2007 23:10:43 +0000 Hi all There has just started a earthquake swarm on the Reykjanes Ridge. This earthquake swarm appears to be bigger then the one I did obserive in Week 9 of 2007. At his moment there has been at least one mag 3.5 earthquake (size unkown when I write this message). There is a possiblitie that this is a volcano related earthquake swarms. But at the moment I don't know if this volcano related or not. I will send more info if I need to. Regards. --=20 J=F3n Fr=EDmann http://www.jonfr.com http://www.simnet.is/jonfr500/earthquake/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Earthquake swarm on the Reykjanes Ridge From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@......... Date: Tue, 10 Apr 2007 12:53:28 +0000 Hi all I have sent in the mag 3+ earthquakes I did record from the ongoing earthquake swarm on the Reykjanes Ridge. The largest earthquakes are in the order of mag 4 to 5. The swarm is still ongoing. Regards. --=20 J=F3n Fr=EDmann http://www.jonfr.com http://www.simnet.is/jonfr500/earthquake/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Earthquake swarm on the Reykjanes Ridge From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@......... Date: Wed, 11 Apr 2007 15:39:24 +0000 Hi all The Reykjanes Ridge earthquake swarm appears to be over. I did record well over 50 earthquakes in this swarm. Many of them are overlapping each other and others are less then 1 min apart. It is unknown at this time if it is volcano related or not. Last swarm in this area was in week 9, but at more distance from the shore. Regards. --=20 J=F3n Fr=EDmann http://www.jonfr.com http://www.simnet.is/jonfr500/earthquake/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: new additions From: Dave Nelson davenn@............... Date: Sun, 15 Apr 2007 15:48:53 +1000 Greetings Gang, a note to let you all know there are a couple of new additions to the PSN Station Map and Database. Ted Channel Boise, Idaho and Idaho Museum of Mining and Geology (station managed by Linda Channel) www.sydneystormcity.com/map.htm (USA section) thanks for adding your info and just a reminder to everyone else dont forget to email me with updates if you make changes to your station. Chers Dave Nelson Sydney, Australia www.sydneystormcity.com __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: A record week From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@......... Date: Sun, 15 Apr 2007 07:09:01 +0000 Hi all This week has been a record for me (Week 15). My station has recored 63+ earthquakes this week and I have not even finised reviewing all the earthquakes I got. I also have many overlapping events to go over. There is also one day left over this week and many things can happen in the time left. Regards. --=20 J=F3n Fr=EDmann http://www.jonfr.com http://www.simnet.is/jonfr500/earthquake/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: new additions From: John or Jan Lahr JohnJan@........ Date: Sun, 15 Apr 2007 07:01:33 -0700 Hi Dave, Nice maps! Thanks for this big effort! I'm running an IRIS "Seismographs in School" station in my basement. IRIS has provided more than 140 such stations to educators around the country, and the number increases by about 30 per year. See: http://www.iris.edu/edu/AS1.htm and: http://jclahr.com/science/psn/as1/ It would be great if amateurs living near a school or museum station would stop by to see if they could use any help in operating the equipment or interpreting their seismograms. Most of these stations are registered with SpiNet: http://www.scienceeducationsolutions.org/spinet/spinet_stations.php Unfortunately they don't have an interactive station map like the one you maintain for the PSN. Or, if your local school doesn't have a seismic station, but does have an interested teacher, it would be great to help the teacher set one up. They could apply to obtain one from IRIS, or apply for a small grant to purchase one for about $600. There are many sources of small grants for teachers. All of the IRIS teachers use an AS-1 with AmaSeis so that it's easy to compare records between schools. Some of the helicorder images are posted here: http://jclahr.com/science/psn/as1/heli/allas1.php Cheers, John Lahr Corvallis, Oregon At 10:48 PM 4/14/2007, you wrote: > Greetings Gang, > a note to let you all know there are a couple of new additions to the PSN >Station Map and Database. > > Ted Channel Boise, Idaho > and > Idaho Museum of Mining and Geology (station managed by Linda Channel) > > www.sydneystormcity.com/map.htm >(USA section) > thanks for adding your info >and just a reminder to everyone else dont forget to email me with updates >if you make changes to your station. > >Chers >Dave Nelson >Sydney, Australia >www.sydneystormcity.com > >__________________________________________________________ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: RE: new additions From: "Stephen Hammond" shammon1@............. Date: Sun, 15 Apr 2007 10:49:33 -0700 Welcome to the group and great work on the map Dave. Regards, Steve Hammond PSN San Jose, Aptos Calif. -----Original Message----- From: psn-l-request@.............. [mailto:psn-l-request@............... On Behalf Of Dave Nelson Sent: Saturday, April 14, 2007 10:49 PM To: psn-l@.............. Subject: new additions Greetings Gang, a note to let you all know there are a couple of new additions to the PSN Station Map and Database. Ted Channel Boise, Idaho and Idaho Museum of Mining and Geology (station managed by Linda Channel) www.sydneystormcity.com/map.htm (USA section) thanks for adding your info and just a reminder to everyone else dont forget to email me with updates if you make changes to your station. Chers Dave Nelson Sydney, Australia www.sydneystormcity.com __________________________________________________________ Public Seismic Network Mailing List (PSN-L) __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: new additions From: "tchannel" tchannel@.............. Date: Sun, 15 Apr 2007 12:43:10 -0600 Hi Folks, Just a note on our new station here in Boise Idaho. The IMMG, Idaho Museum of Mining and Geology, is a small, all volunteers group who run a Museum about 5 miles East of my other sensor TCID. The site is located at an Old Penitentiary. The building they are in is called the "Trusty Building" The whole area is very interesting. They have gardens tours of the Prison, and many activities during the summer. The Penitentiary looks like a set, from the 1930's gangster movies, guard towers old rusted security lights, and entirely made of blocks of local sandstone, quarried from the near by hills. Their wed site is __________________. Most of the volunteers are retired Earth Science folks, Miners, or rock hounds. Linda, my Wife, is retired from the USGS after 31 years. She and some others thought it would be great to have a Seismometer. I found your group and with all of your input and suggestions was able to help them out. They now have their new Station up and running, and each day is like Christmas for them. It is the greatest single display in their Museum. The volunteers and the visitors, young and old think it is the greatest. I wanted to thank the group and everyone who helped me over the months, with answers, diagrams, sources, parts, troubleshooting, and encouragement. Cheers, Ted ----- Original Message ----- From: "Stephen Hammond" To: Sent: Sunday, April 15, 2007 11:49 AM Subject: RE: new additions > Welcome to the group and great work on the map Dave. > Regards, Steve Hammond PSN San Jose, Aptos Calif. > > -----Original Message----- > From: psn-l-request@.............. [mailto:psn-l-request@............... > On Behalf Of Dave Nelson > Sent: Saturday, April 14, 2007 10:49 PM > To: psn-l@.............. > Subject: new additions > > Greetings Gang, > a note to let you all know there are a couple of new additions to > the PSN > Station Map and Database. > > Ted Channel Boise, Idaho > and > Idaho Museum of Mining and Geology (station managed by Linda > Channel) > > www.sydneystormcity.com/map.htm > (USA section) > thanks for adding your info > and just a reminder to everyone else dont forget to email me with > updates > if you make changes to your station. > > Chers > Dave Nelson > Sydney, Australia > www.sydneystormcity.com > > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. > > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: IMMG address From: "tchannel" tchannel@.............. Date: Sun, 15 Apr 2007 12:49:15 -0600 Sorry I forgot the IMMG address. They are in the process of updating = their page, so I hope it is avail. Ted, http://www.idahomuseum.org/
Sorry I forgot the IMMG address.  = They are in=20 the process of updating their page, so I hope it is avail.
 
 
Ted,          =         =20 http://www.idahomuseum.org/<= /SPAN>
Subject: Re: new additions From: "peter la plante" laplantep@............... Date: Mon, 16 Apr 2007 11:03:00 -0600 Hello: My name is Pete and I am located between Parma and Nyssa Oregon. I have been interested in seismology for many years and about a year ago I started to put together a monitoring station. I purchased a 3 channel board and other items from Larry Cockrin and constructed two sensors and purchased several vertical and horizontal sensors off ebay. I have not completed the sensors and my interests have moved on. I have been a amateur radio operator for may years and have been inactive for the past ten or so years. I am planning to get back into ham radio again and wish to sell all the seismic equipment that I have. If you know any one who might be interested my phone number is 208-722-7069. Thank you. Peter J. La Plante W7SOV. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Seislog From: "Steve Shufflebotham" Cellectronic@............. Date: Wed, 18 Apr 2007 17:58:40 +0100 Hi Everyone, Is anybody out there using "Mauro Mariotti, SADC" interface in = conjunction with "Seislog" ? I am experimenting with this setup and have an error message "Data has = been lost" this message just rolling up the screen, Everything else = seems to work ok, events detected and stopped etc but the events are = dumped. Many thanks in advance for any help. Steve
Hi Everyone,
Is anybody out there using "Mauro = Mariotti, SADC"=20 interface in conjunction with "Seislog" ?
I am experimenting with this setup and = have an=20 error message "Data has been lost" this message just rolling up the = screen,=20 Everything else seems to work ok, events detected and stopped etc but = the events=20 are dumped.
Many thanks in advance for any = help.
Steve
Subject: Re: Seislog From: Angel sismos@.............. Date: Wed, 18 Apr 2007 21:31:09 +0000

Hello Steve,


Seislog expects to get an exact number of samples in a one second package, let's say 50.  The SARA digitizer card mostly put out 50 but now and then maybe 49 or 51.  Seislog (for windows) throws out the packets that don't have the exact sample rate.  So what can you do?????


You can use the SARA acquisition software SeismowinPro.  You can use the Seislog for Linux which is smarter than the Seislog for windows.  It does not have the fancy GUI that other have but then it works real well.  You can use SeisComP from GFZ also for linux. 


Seismowin will make PSN, GSE and Seisan files it also has a LISS server so you can connect with earthworm systems. And you can use the Seisgram2k to look at the traces. 


Well I ramble, there are many options.


If I can help just write a note.


Angel


Wednesday, April 18, 2007, 4:58:40 PM, you wrote:


>

Hi Everyone,

Is anybody out there using "Mauro Mariotti, SADC" interface in conjunction with "Seislog" ?

I am experimenting with this setup and have an error message "Data has been lost" this message just rolling up the screen, Everything else seems to work ok, events detected and stopped etc but the events are dumped.

Many thanks in advance for any help.

Steve 





-- 

Best regards,

 Angel

Subject: Microquakes From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@......... Date: Wed, 18 Apr 2007 22:01:46 +0000 Hi all I have an access to a station located in Mosfellsb=E6 near Reykjav=EDk (I d= o not own it!). This station is located close to all the major active areas in south Iceland. SISZ is not far off and it is close to Reykjanes earthquakes areas and volcanoes. Also is a good chance of recording actitive in Myrdalsjokull volcano and Hekla volcano and other volcanoes that are close to SISZ. >From 16th today there has been microquakes close to the station. Most of those earthquakes have the size mag 0.42 to mag 1.4. At the range of 1km to 24 km. The smallest earthquakes and those how are closest to the station appear good on the station plot I that I currently have on my webpage. It is really intresting to see how the small earthquakes appears on this station. But the station is currently set on low gain (200). But it is going to increased in the end of this week I hope, but then I hopefully can record small earthquakes at bigger distance. The closest earthqauke that this station has recored was so close that p and s time diffrence is only 00.2 sec. Regards. --=20 J=F3n Fr=EDmann http://www.jonfr.com http://www.simnet.is/jonfr500/earthquake/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: whats up! From: "swollard" swollard@.......... Date: Wed, 18 Apr 2007 18:38:12 -0400 Whats up with these e-mails. I have been getting these e-mails from = people I don'nt even know, about some kind of product. Please stop = sending these e-mails. ----- Original Message -----=20 From: Angel=20 To: Steve Shufflebotham=20 Sent: Wednesday, April 18, 2007 5:31 PM Subject: Re: Seislog Hello Steve, Seislog expects to get an exact number of samples in a one second = package, let's say 50. The SARA digitizer card mostly put out 50 but = now and then maybe 49 or 51. Seislog (for windows) throws out the = packets that don't have the exact sample rate. So what can you do????? You can use the SARA acquisition software SeismowinPro. You can use = the Seislog for Linux which is smarter than the Seislog for windows. It = does not have the fancy GUI that other have but then it works real well. = You can use SeisComP from GFZ also for linux.=20 Seismowin will make PSN, GSE and Seisan files it also has a LISS = server so you can connect with earthworm systems. And you can use the = Seisgram2k to look at the traces.=20 Well I ramble, there are many options. If I can help just write a note. Angel Wednesday, April 18, 2007, 4:58:40 PM, you wrote: > Hi Everyone, Is anybody out there using "Mauro Mariotti, SADC" interface in = conjunction with "Seislog" ? I am experimenting with this setup and have an error message = "Data has been lost" this message just rolling up the screen, Everything = else seems to work ok, events detected and stopped etc but the events = are dumped. Many thanks in advance for any help. Steve=20 =20 --=20 Best regards, Angel
Whats up with these e-mails. I have = been getting=20 these e-mails from people I don'nt even know, about some kind of = product. Please=20 stop sending these e-mails.
----- Original Message -----
From:=20 Angel=20
Sent: Wednesday, April 18, 2007 = 5:31=20 PM
Subject: Re: Seislog

Hello Steve,


Seislog expects to get an exact number of samples in a one second = package,=20 let's say 50.  The SARA digitizer card mostly put out 50 but now = and then=20 maybe 49 or 51.  Seislog (for windows) throws out the packets = that don't=20 have the exact sample rate.  So what can you do?????


You can use the SARA acquisition software SeismowinPro.  You = can use=20 the Seislog for Linux which is smarter than the Seislog for windows. =  It=20 does not have the fancy GUI that other have but then it works real = well.=20  You can use SeisComP from GFZ also for linux. 


Seismowin will make PSN, GSE and Seisan files it also has a LISS = server so=20 you can connect with earthworm systems. And you can use the Seisgram2k = to look=20 at the traces. 


Well I ramble, there are many options.


If I can help just write a note.


Angel


Wednesday, April 18, 2007, 4:58:40 PM, you wrote:


>

Hi Everyone,

Is anybody out there using "Mauro = Mariotti, SADC"=20 interface in conjunction with "Seislog" ?

I am experimenting with this setup and = have an=20 error message "Data has been lost" this message just rolling up = the=20 screen, Everything else seems to work ok, events detected and = stopped=20 etc but the events are dumped.

Many thanks in advance for any = help.

Steve 





-- 

Best regards,

 Angel

Subject: Re: whats up! From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@......... Date: Wed, 18 Apr 2007 23:16:35 +0000 On Wed, 2007-04-18 at 18:38 -0400, swollard wrote: > Whats up with these e-mails. I have been getting these e-mails from > people I don'nt even know, about some kind of product. Please stop > sending these e-mails. Hi Please leave the PSN list if you have not registerd on it. You can do so here, http://seismicnet.com/maillist.html Regards. --=20 J=F3n Fr=EDmann http://www.jonfr.com http://www.simnet.is/jonfr500/earthquake/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Predictions From: "tchannel" tchannel@.............. Date: Fri, 20 Apr 2007 16:24:41 -0600 Hi Folks, Just curious about the subject of Earthquake Predictions. = We all can predict earthquakes, if we keep the "when" and "where" = nonspecific. But on a serious note, are there any scientific tools = used? Do the phases of the moon and the tides play a part? I have = asked this question to several people and received just as many = opinions. Thanks, Ted
Hi Folks,  Just curious about the = subject of=20 Earthquake Predictions.   We all can predict earthquakes, if = we keep=20 the "when" and "where" nonspecific.   But on a serious = note, are=20 there any scientific tools used?   Do the phases of the moon = and the=20 tides play a part?   I have asked this question to several = people and=20 received just as many opinions.
 
Thanks, Ted
Subject: Re: updates and additions From: Dave Nelson davenn@............... Date: Sat, 21 Apr 2007 11:04:17 +1000 Hi Gang :) Greetings from drought stricken Australia. Plans are afoot for a mass migration to New Zealand and USA ;) . Seriously tho ... its getting really bad here, as water supplies dry up for farms and cities alike. Sydney's water reserves are in the mid 30's % and Melbourne is somewhere ~ 15%. Back to the PSN .... thanks to those that have responded Pete Rowe ... dang mate dunno why you have been left off the list for so long thanks for the info :) John Lahr ... likewise. I have just put a link direct to your homepage 1999 seems so long ago when i got to visit you and the other guys in Golden, CO. at the NEIC HQ Dave Wolny ... Time flies doesnt it :) thanks buddy Michael Kimzey ... a new addition to the PSN, great to hear from you and welcome. Roger Sparks ... and how did you also get missed out in the early days of setting up the database and maps ... better late than never :) tnx mate There are several names of people that I see in the e-mail from time to time that I know are not on the map. Maybe they would like to get in touch with me at some stage and let me kow what gear they are running. Finally, dont forget, if you havent already, to update your bookmarks with my correct homepage address. main page = www.sydneystormcity.com or to get direct to the maps www.sydneystormcity.com/map.htm cheers Dave N Sydney Oz __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Predictions From: "Dave \(Santa Dave\)" kc6old@............. Date: Fri, 20 Apr 2007 19:16:58 -0700 (PDT) Back in the late 80s there was an "ham" (amateur radio) net which met and this group of hams did a whole bunch of record keeping of things like well head hight, lost dogs (via newspaper ads) Earthquake logging, and other "possables" . after more "man" hours than you can imagine the only correlation I ever heard of was one man logged EVERY known earthquake versus the position of the moon -- and found a Slight tendancy towards quakes in the northern hemisphere when the moon was high in the southern hemishere. This group was on two metters and was known as the PUBLIC SIESMIC NET. I only know of two people who were involved in that. Dave, Kc6old tchannel wrote: Hi Folks, Just curious about the subject of Earthquake Predictions. We all can predict earthquakes, if we keep the "when" and "where" nonspecific. But on a serious note, are there any scientific tools used? Do the phases of the moon and the tides play a part? I have asked this question to several people and received just as many opinions. Thanks, Ted
Back in the late 80s there was an "ham" (amateur radio) net which met and this group of hams did a whole bunch of record keeping of things like well head hight, lost dogs (via newspaper ads) Earthquake logging, and other "possables" . after more "man" hours than you can imagine the only correlation I ever heard of was one man logged EVERY known earthquake versus the position of the moon -- and found a Slight tendancy towards quakes in the northern hemisphere when the moon was high in the southern hemishere.
This group was on two metters and was known as the PUBLIC SIESMIC NET.
I only know of two people who were involved in that.
Dave, Kc6old

tchannel <tchannel@..............> wrote:
Hi Folks,  Just curious about the subject of Earthquake Predictions.   We all can predict earthquakes, if we keep the "when" and "where" nonspecific.   But on a serious note, are there any scientific tools used?   Do the phases of the moon and the tides play a part?   I have asked this question to several people and received just as many opinions.
 
Thanks, Ted

Subject: Re: Predictions From: ChrisAtUpw@....... Date: Fri, 20 Apr 2007 23:23:04 EDT In a message dated 2007/04/20, tchannel@.............. writes: > Just curious about the subject of Earthquake Predictions. But on a serious > note, are there any scientific tools used? Do the phases of the moon and the > tides play a part? I have asked this question to several people and received > just as many opinions. Hi Ted, Type Earthquake Prediction into Google? See http://www.nature.com/nature/debates/earthquake/equake_frameset.html Short answer is that we don't know. Strong quakes may be associated with parts of the tide cycle. The question is which cycle? The local background noise may decrease before a large quake. There may be physical movement before shallower quakes, but you are unlikely to get much observable effect at the surface if the rupture is 100 km down. About 1/3 of quakes show precursor quakes. There may be a few cycles of very long period precursor. There may be changes in the water table, changes in Radon emission, electric / RF field noise, animals seem to be able to sense 'something'..... One thing is certain. If you say we will never be able to predict quakes and no funds to experiment are allocated, we WON'T develop the / any ability!! Even if we could only get timely warning for a few quake locations / depths, the benefits could be very significant. A lot of the severe quakes are associated with subduction zones, like those off the west coast of the Americas, but the interval may be hundreds of years. Regards, Chris Chapman In a me= ssage dated 2007/04/20, tchannel@.............. writes:

Just curious about the subject=20= of Earthquake Predictions. But on a serious note, are there any scientific t= ools used? Do the phases of the moon and the tides play a part? I have asked= this question to several people and received just as many opinions.<= FONT COLOR=3D"#000000" BACK=3D"#ffffff" style=3D"BACKGROUND-COLOR: #ffffff"= SIZE=3D3 PTSIZE=3D12 FAMILY=3D"SANSSERIF" FACE=3D"Arial" LANG=3D"0">

Hi Ted,

       Type Earthquake Prediction into Google?=
       See http://www.nature.com/nature/debate= s/earthquake/equake_frameset.html

       Short answer is that we don't know. Str= ong quakes may be associated with parts of the tide cycle. The question is w= hich cycle? The local background noise may decrease before a large quake. Th= ere may be physical movement before shallower quakes, but you are unlikely t= o get much observable effect at the surface if the rupture is 100 km down. A= bout 1/3 of quakes show precursor quakes. There may be a few cycles of very=20= long period precursor. There may be changes in the water table, changes in R= adon emission, electric / RF field noise, animals seem to be able to sense '= something'.....
       One thing is certain. If you say we wil= l never be able to predict quakes and no funds to experiment are allocated,=20= we WON'T develop the / any ability!! Even if we could only get timely warnin= g for a few quake locations / depths, the benefits could be very significant= .. A lot of the severe quakes are associated with subduction zones, like thos= e off the west coast of the Americas, but the interval may be hundreds of ye= ars.

       Regards,

       Chris Chapman Subject: Re: Predictions From: Stephen & Kathy skmort@............ Date: Fri, 20 Apr 2007 23:12:44 -0700 FYI,, Following this little introduction, is a simple study I did a few years ago!! Since then I have tried to correlate the events to Solid Earth Tide,,, so far I have found no correlation!! My conclusion at this point is that I think there may be a moon and or sun tide connection, but like trying to predict the position in the bending cycle where a wire will finally break, that you bend with your fingers, there appears to be a similar problem with trying to tie a tidal phase point to quakes???? It simply breaks when it is ready, no matter where in the tidal cycle of bending it happens to be???? The complexity of water tides may also contribute to the problem for events that happen in the vicinity of ocean tides????? The reason I feel that there may be a phase connection, becomes clear from the following study where we see that the time of the new moon, where we have the greatest tidal motion, also favors the greatest number of quakes?????? I am open to correction, other studies, other data, and or other conclusions!!!! Stephen PSN Station #55 Subject: Large quakes (mag. 8 and above) and their relationship to Moon phases, using data found over the web at the following links: http://en.wikipedia.org/wiki/List_of_earthquakes http://www.fourmilab.ch/cgi-bin/uncgi/Earth/action?opt=-m&img=Moon.evif Using the top link to find quake times and mag., then using the bottom link to compare them to moon phases, I found 38 quakes of mag. 8 or greater since 1556, of which I used 35 because the first three did not have times listed. Where local times were listed I converted them to UTC time for compatibility with the Moon phase link. After finding the data, the next problem is determining how to illustrate it with statistics! Statistics can be used in many ways to manipulate data! Do we use only one or two days around the new and full moon and compare that to the total, or should we divide it into approx. 4 equal quadrants? For my simple analysis I will use 4 quadrants. The moon link above uses approx. 29.4 days for a complete cycle, so I will use approx. 7.35 days per quadrant, which when related to the phases works out to about the following: New moon quadrant equals 0 to 15 % Full moon quadrant equals 85 to 100 % first and last quarter quadrant equals 16 to 86 % When we sort the 35 phase data into their quadrants we get the following: Quakes during New moon = 15 Quakes during Full moon = 7 Quakes during First & Last quarter = 13 When we combine the New and Full quarters to compare with First and Last quarters we get: Quakes during New & Full moon = 22 Conclusion: The New moon quadrant favors the Full moon quadrant by a little more than double! The combined New and Full quadrants favor the First and Last quadrants by not quite double! Interesting!!!!! I was led to believe that there was no statistical correlation between quakes and Moon phases??? Perhaps if we added the mag. 6 and 7 quakes we would find different conclusions,,,, that is for someone else to do!!! List of mag. 8 quakes or greater,, With percent of Moon Phase listed 0% = New Moon, 100% = Full Moon, 50% = either First or Last Quarter Please forgive any TYPOs # Moon Year Mo. Day UTC Place Approx. Phase Time Mag. 1 ??% 1556 Jan. 23 ?? China 8 2 ??% 1668 Aug. 17 ?? Turkey 8 3 ??% 1700 Jan. 26 ?? Vancouver 9 ************************************************ 4 10% 1755 Nov. 1 10:16 Portugal 8.7 5 0% 1811 Dec. 16 08:00 Missouri 8.1 6 33% 1812 Feb. 7 09:45 Missouri 8 7 43% 1855 Jan. 24 10:11 New Zealand 8 8 20% 1891 Oct. 27 21:38 Japan 8 9 21% 1896 Jun. 15 19:32 Japan 8.5 10 91% 1897 Jun. 12 11:06 India 8.3 11 29% 1899 Sep. 10 21:41 Alaska 8 12 8% 1905 Jul. 5 09:40 Mongolia 8.4 13 41% 1906 Jan. 31 15:36 Colombia 8.8 14 9% 1906 Aug. 17 00:40 Chile 8.2 15 29% 1920 Dec. 16 12:05 China 8.6 16 34% 1933 Mar. 2 17:31 Japan 8.4 17 0% 1934 Jan. 15 08:43 India 8.1 18 88% 1938 Nov. 10 20:18 Alaska 8.2 19 54% 1944 Dec. 7 04:35 Japan 8.1 20 48% 1946 Aug. 4 17:51 Dom. Repub. 8.0 21 6% 1946 Dec. 20 19:19 Japan 8.1 22 5% 1949 Aug. 22 04:01 Q. Charlo. Is. 8.1 23 4% 1950 Aug. 15 14:09 Tibet 8.6 24 91% 1952 Nov. 4 16:58 Russia 9 25 51% 1957 Mar. 9 14:22 Alaska 9.1 26 90% 1957 Dec. 4 03:37 Mongolia 8.1 27 6% 1960 May 22 19:11 Chile 9.5 28 99% 1964 Mar. 28 03:36 Alaska 9.2 29 5% 1965 Feb. 4 05:01 Alaska 8.7 30 2% 1970 Jul. 31 17.08 Colombia 8 31 28% 1985 Sep. 19 13:17 Mexico 8 32 0% 1986 May 7 22:47 Alaska 8 33 0% 1994 Jun. 9 00:33 Bolivia 8.2 34 76% 2000 Nov. 16 04:54 New Ireland 8 35 7% 2001 Jun. 23 20:33 Peru 8.4 36 0% 2003 Sep. 25 19:50 Japan 8.3 37 91% 2004 Dec. 23 14:59 Macquarie 8.1 38 99% 2004 Dec. 26 00:59 Sumatra 9.0 tchannel wrote: > Hi Folks, Just curious about the subject of Earthquake Predictions. > We all can predict earthquakes, if we keep the "when" and "where" > nonspecific. But on a serious note, are there any scientific tools > used? Do the phases of the moon and the tides play a part? I have > asked this question to several people and received just as many opinions. > > Thanks, Ted FYI,,  Following this little introduction, is a simple study I did a few years ago!!   Since then I have tried to correlate the events to Solid Earth Tide,,,   so far I have found no correlation!!    My conclusion at this point is that I think there may be a moon and or sun tide connection, but like trying to predict the position in the bending cycle where a wire will finally break, that you bend with your fingers, there appears to be a similar problem with trying to tie a tidal phase point to quakes????  It simply breaks when it is ready, no matter where in the tidal cycle of bending it happens to be????   The complexity of water tides may also contribute to the problem for events that happen in the vicinity of ocean tides?????   The reason I feel that there may be a phase connection, becomes clear from the following study where we see that the time of the new moon, where we have the greatest tidal motion, also favors the greatest number of quakes??????    I am open to correction, other studies, other data, and or other conclusions!!!!
  Stephen
  PSN Station #55


Subject:
Large quakes (mag. 8 and above) and their relationship to Moon phases, using data found over the web at the following links:

http://en.wikipedia.org/wiki/List_of_earthquakes

http://www.fourmilab.ch/cgi-bin/uncgi/Earth/action?opt=-m&img=Moon.evif

Using the top link to find quake times and mag., then using the bottom link to compare them to moon phases, I found 38 quakes of mag. 8 or greater since 1556, of which I used 35 because the first three did not have times listed.  Where local times were listed I converted them to UTC time for compatibility with the Moon phase link.

After finding the data, the next problem is determining how to illustrate it with statistics!  Statistics can be used in many ways to manipulate data!   Do we use only one or two days around the new and full moon and compare that to the total, or should we divide it into approx. 4 equal quadrants?   For my simple analysis I will use 4 quadrants.   The moon link above uses approx. 29.4 days for a complete cycle, so I will use approx. 7.35 days per quadrant, which when related to the phases works out to about the following:
New moon quadrant equals                  0 to 15 %
Full moon quadrant equals                 85 to 100 %
first and last quarter quadrant equals    16 to 86 %
When we sort the 35 phase data into their quadrants we get the following:
Quakes during New moon               =   15
Quakes during Full moon              =    7
Quakes during First & Last quarter   =   13
When we combine the New and Full quarters to compare with First and Last quarters we get:
Quakes during New & Full moon        =   22
Conclusion:
The New moon quadrant favors the Full moon quadrant by a little more than double!
The combined New and Full quadrants favor the First and Last quadrants by not quite double!
Interesting!!!!!    I was led to believe that there was no statistical correlation between quakes and Moon phases???     Perhaps if we added the mag. 6 and 7 quakes we would find different conclusions,,,,   that is for someone else to do!!!

List of mag. 8 quakes or greater,,   With percent of Moon Phase listed
0% = New Moon,  100% = Full Moon,    50% = either First or Last Quarter
                        Please forgive any TYPOs

 #   Moon  Year    Mo.  Day    UTC      Place        Approx.
     Phase                     Time                    Mag.
 1    ??%   1556  Jan.   23     ??      China           8
 2    ??%   1668  Aug.   17     ??      Turkey          8
 3    ??%   1700  Jan.   26     ??      Vancouver       9
************************************************
 4    10%   1755   Nov.   1    10:16    Portugal        8.7
 5     0%   1811   Dec.  16    08:00    Missouri        8.1
 6    33%   1812   Feb.   7    09:45    Missouri        8
 7    43%   1855   Jan.  24    10:11    New Zealand     8
 8    20%   1891   Oct.  27    21:38    Japan           8
 9    21%   1896   Jun.  15    19:32    Japan           8.5
10    91%   1897   Jun.  12    11:06    India           8.3
11    29%   1899   Sep.  10    21:41    Alaska          8
12     8%   1905   Jul.   5    09:40    Mongolia        8.4
13    41%   1906   Jan.  31    15:36    Colombia        8.8
14     9%   1906   Aug.  17    00:40    Chile           8.2
15    29%   1920   Dec.  16    12:05    China           8.6
16    34%   1933   Mar.   2    17:31    Japan           8.4
17     0%   1934   Jan.  15    08:43    India           8.1
18    88%   1938   Nov.  10    20:18    Alaska          8.2
19    54%   1944   Dec.   7    04:35    Japan           8.1
20    48%   1946   Aug.   4    17:51    Dom. Repub.     8.0
21     6%   1946   Dec.  20    19:19    Japan           8.1
22     5%   1949   Aug.  22    04:01    Q. Charlo. Is.  8.1
23     4%   1950   Aug.  15    14:09    Tibet           8.6
24    91%   1952   Nov.   4    16:58    Russia          9
25    51%   1957   Mar.   9    14:22    Alaska          9.1
26    90%   1957   Dec.   4    03:37    Mongolia        8.1
27     6%   1960   May   22    19:11    Chile           9.5
28    99%   1964   Mar.  28    03:36    Alaska          9.2
29     5%   1965   Feb.   4    05:01    Alaska          8.7
30     2%   1970   Jul.  31    17.08    Colombia        8
31    28%   1985   Sep.  19    13:17    Mexico          8
32     0%   1986   May    7    22:47    Alaska          8
33     0%   1994   Jun.   9    00:33    Bolivia         8.2
34    76%   2000   Nov.  16    04:54    New Ireland     8
35     7%   2001   Jun.  23    20:33    Peru            8.4
36     0%   2003   Sep.  25    19:50    Japan           8.3
37    91%   2004   Dec.  23    14:59    Macquarie       8.1
38    99%   2004   Dec.  26    00:59    Sumatra         9.0


tchannel wrote:
Hi Folks,  Just curious about the subject of Earthquake Predictions.   We all can predict earthquakes, if we keep the "when" and "where" nonspecific.   But on a serious note, are there any scientific tools used?   Do the phases of the moon and the tides play a part?   I have asked this question to several people and received just as many opinions.
 
Thanks, Ted
Subject: Re: Predictions From: shammon1@............. Date: Sat, 21 Apr 2007 02:14:27 -0400 (EDT)

Chris makes a lot of good points about predictions and I ag= ree with him. The main point in my mind is made with the understanding that= if you live in a zone with natural disasters, you need to understand the r= isks with your choice of locations and prepare for the possibilities that a= re associated with it.

On a personal note, I experienced another side effect assoc= iated with predictions following the Loma P event in 1989. I lived in South= San Jose and a young nine year old came to my front door because a guy nam= e Jack (I don=E2=80=99t remember his last name) had been on the local news = claiming he could predict earthquakes and in fact had predicted a big one i= n a few week. She was scared out of her wits and knowing I had seismographs= running at a local elementary school wanted to know if Jack=E2=80=99s pred= ictions were true.

What are the issues at hand?  1) Jack knows what he was talking about and we should all = prepare for the great event. 2) We should continue to prepare for the event= uality of a great event. 3) We should ignore the fact that a great event co= uld occur at any time. I=E2= =80=99ll leave the answer up to you. I spent a few hours talking to th= is child and from the experence gained a better understanding of the impact= it can have on people.

 

Regards, Steve Hammond

PSN San Jose, Aptos, CA


-----Original Message-----
From: ChrisAtUpw@.......
= Sent: Apr 20, 2007 8:23 PM
To: psn-l@..............
Subject: Re: Pr= edictions

In a message dated 2007/04/20, tchannel@.............. w= rites:

Just curious about the subj= ect of Earthquake Predictions. But on a serious note, are there any scienti= fic tools used? Do the phases of the moon and the tides play a part? I have= asked this question to several people and received just as many opinions.<= /FONT>

Hi Ted,

       Type E= arthquake Prediction into Google?
       S= ee http://www.nature.com/nature/debates/earthquake/equake_frameset.html
=
       Short answer is that we don't know= .. Strong quakes may be associated with parts of the tide cycle. The questio= n is which cycle? The local background noise may decrease before a large qu= ake. There may be physical movement before shallower quakes, but you are un= likely to get much observable effect at the surface if the rupture is 100 k= m down. About 1/3 of quakes show precursor quakes. There may be a few cycle= s of very long period precursor. There may be changes in the water table, c= hanges in Radon emission, electric / RF field noise, animals seem to be abl= e to sense 'something'.....
       One th= ing is certain. If you say we will never be able to predict quakes and no f= unds to experiment are allocated, we WON'T develop the / any ability!! Even= if we could only get timely warning for a few quake locations / depths, th= e benefits could be very significant. A lot of the severe quakes are associ= ated with subduction zones, like those off the west coast of the Americas, = but the interval may be hundreds of years.

    &= nbsp;  Regards,

       Chris Chap= man
Subject: Re: Predictions From: ChrisAtUpw@....... Date: Sat, 21 Apr 2007 08:22:32 EDT In a message dated 2007/04/20, tchannel@.............. writes: > Just curious about the subject of Earthquake Predictions. But on a serious > note, are there any scientific tools used? Hi Ted, One application may be practical. Assuming you have had a severe quake and are trying to recover the injured from damaged buildings etc, if you instrument the region with radio linked sensors, you can pick up the fast P waves of aftershocks, analyse them and get a few seconds warning before the rest of the waves arrive. On the 'be prepared' front, during WWII many people in the UK had a steel table in the living room to provide protection from falling masonry. You could sleep under it at night or dive for cover. It does take a building a few seconds to collapse, so similar provisions in earthquake areas where the existing buildings have poor quake resistance, could save lives. It would also do the flagging steel industries no harm at all.....! Regards, Chris Chapman In a me= ssage dated 2007/04/20, tchannel@.............. writes:

Just curious about the subject=20= of Earthquake Predictions. But on a serious note, are there any scientific t= ools used?


Hi Ted,

       One application may be practical. Assum= ing you have had a severe quake and are trying to recover the injured from d= amaged buildings etc, if you instrument the region with radio linked sensors= , you can pick up the fast P waves of aftershocks, analyse them and get a fe= w seconds warning before the rest of the waves arrive.

       On the 'be prepared' front, during WWII= many people in the UK had a steel table in the living room to provide prote= ction from falling masonry. You could sleep under it at night or dive for co= ver. It does take a building a few seconds to collapse, so similar provision= s in earthquake areas where the existing buildings have poor quake resistanc= e, could save lives. It would also do the flagging steel industries no harm=20= at all.....!

       Regards,

       Chris Chapman Subject: Time of Quake?? From: "Paul Cianciolo" Paulc@........ Date: Sat, 21 Apr 2007 09:23:17 -0400 Hello Folks, In the past many of you on the list have been extremely helpful. For the past month I have been working on a horizontal pendulum sensor and I am going through my maiden voyage with it. The clock is accurate to within 10 seconds, I am using the Amaseis program, and a 12 bit ADC. I would like to try and compare events elsewhere in the world/ country to my sensor. At this site I can see various locations. The question. If I know in when in UTC an event occurred, and where.. how do I convert that to a UTC time when the event would arrive at my location, if ever. In other words how ho long does it take to get here?? I am on the Northwest corner of Connecticut. Realize this is a very broad question, and I am new to this . Thank you Paul Cianciolo W1VLF
Hello=20 Folks,
 
In the=20 past many of you on the list have been extremely helpful. =
For=20 the past month I have been working on a horizontal pendulum sensor and I = am=20 going through my maiden voyage with it.
 
The=20 clock is accurate to within 10 seconds, I am using the Amaseis program, = and a 12=20 bit ADC.
 
I=20 would like to try and compare events elsewhere in the world/ country to = my=20 sensor.
At=20 this site I can see various locations.
 
The=20 question.
 
If I know in  when in UTC an event = occurred, and=20 where.. how do I convert that to a UTC time when the event would = arrive at my location, if=20 ever.
&nbs= p;
In other = words how ho=20 long does it take to get = here??
&nbs= p;
I am on = the Northwest=20 corner of Connecticut.  =
&nbs= p;
Realize = this is a very=20 broad question, and I am new to this=20 ..
&nbs= p;
Thank = you=20
&nbs= p;
Paul=20 Cianciolo
W1VLF
&nbs= p;
&nbs= p;
Subject: Re: Time of Quake?? From: "Thomas Dick" dickthomas01@............. Date: Sat, 21 Apr 2007 08:29:21 -0500 You can calculate arrival time using = http://neic.usgs.gov/neis/travel_times/=20
 
 
You = can calculate=20 arrival time using http://neic.usgs.gov/nei= s/travel_times/ 
=
&nbs= p;
Subject: RE: Time of Quake?? From: "Paul Cianciolo" Paulc@........ Date: Sat, 21 Apr 2007 09:50:53 -0400 Tom, Thank you, How could I have missed that??? I need to run some calculations now PauLC -----Original Message----- From: psn-l-request@.............. [mailto:psn-l-request@................. Behalf Of Thomas Dick Sent: Saturday, April 21, 2007 9:29 AM To: psn-l@.............. Subject: Re: Time of Quake?? You can calculate arrival time using http://neic.usgs.gov/neis/travel_times/
Tom,
 
Thank=20 you, 
How=20 could I have missed that???
 
I need=20 to run some calculations now
 
PauLC
 
-----Original Message-----
From: = psn-l-request@................. [mailto:psn-l-request@...............On Behalf Of Thomas=20 Dick
Sent: Saturday, April 21, 2007 9:29 AM
To:=20 psn-l@..............
Subject: Re: Time of=20 Quake??

 
 
You = can calculate=20 arrival time using http://neic.usgs.gov/nei= s/travel_times/ 
=
&nbs= p;
Subject: RE: Time of Quake?? From: "Paul Cianciolo" Paulc@........ Date: Sat, 21 Apr 2007 09:57:39 -0400 I am at Lat N41.78 Long W73.00 So to check me... would this event DATE-(UTC)-TIME LAT LON DEPTH MAG Q COMMENTS 2007/04/21 07:12:47 3.55S 151.31E 401.5 6.3 US: NEW IRELAND REGION, P.N. delta azimuth (degrees clockwise from north) (deg) eq-to-station station-to-eq 125.10 39.7 301.5 travel arrival time # code time(s) dy hr mn sec 1 Pdiff 891.60 0 7 27 38 2 PKPdf 1093.09 0 7 31 0 3 PKiKP 1093.63 0 7 31 0 4 LQ 3175.16 0 8 5 42 5 LR 3523.98 0 8 11 30 Arrive at roughly 14:40 UTC?? Which has not occurred yet??? PauLC -----Original Message----- From: psn-l-request@.............. [mailto:psn-l-request@................. Behalf Of Thomas Dick Sent: Saturday, April 21, 2007 9:29 AM To: psn-l@.............. Subject: Re: Time of Quake?? You can calculate arrival time using http://neic.usgs.gov/neis/travel_times/
I am=20 at  Lat N41.78    Long  = W73.00
 
So to=20 check me... would this event 
 
 DATE-(UTC)-TIME   =20 LAT    LON     DEPTH MAG  =20 Q   COMMENTS
  2007/04/21 07:12:47   3.55S = 151.31E=20 401.5 6.3      US: NEW IRELAND REGION, = P.N.
 =20
delta   azimuth (degrees clockwise from north)
=20 (deg)      = eq-to-station    =20 station-to-eq
125.10        &n= bsp; =20 39.7           &nb= sp;=20 301.5

          =       =20 travel   arrival time
    # =20 code      time(s)  dy hr mn=20 sec
    1  Pdiff     =20 891.60   0  7 27 38
    2 =20 PKPdf     1093.09   0  7 31 =20 0
    3  PKiKP    =20 1093.63   0  7 31  0
    4 =20 LQ        3175.16   0  = 8 =20 5 42
    5  = LR       =20 3523.98   0  8 11 30
 
 
Arrive=20 at  roughly 14:40 UTC??
 
Which=20 has not occurred yet???
 
PauLC
 
 
 
-----Original Message-----
From: = psn-l-request@................. [mailto:psn-l-request@...............On Behalf Of Thomas=20 Dick
Sent: Saturday, April 21, 2007 9:29 AM
To:=20 psn-l@..............
Subject: Re: Time of=20 Quake??

 
 
You = can calculate=20 arrival time using http://neic.usgs.gov/nei= s/travel_times/ 
=
&nbs= p;
Subject: Re: Time of Quake?? From: Stephen & Kathy skmort@............ Date: Sat, 21 Apr 2007 08:03:48 -0700 Your travel times are given in UTC, so, your answer is 07:27:38 UTC (I think you tried to add the arrival time to the start time??) it took about 891.60 seconds for the P wave to arrive at your location!! 07:12:47 UTC plus 891.60s = approx. 07:27:38 UTC ,,,, 891.6/60 = 14.86 minutes,,, for rough distance, 69*125.1 = approx. 8632 miles,, or 111.12 * 125.1 = approx. 13901.112 km!! Stephen PSN Station #55 Paul Cianciolo wrote: > I am at Lat N41.78 Long W73.00 > > So to check me... would this event > > DATE-(UTC)-TIME LAT LON DEPTH MAG Q COMMENTS > 2007/04/21 07:12:47 3.55S 151.31E 401.5 6.3 US: NEW IRELAND > REGION, P.N. > > delta azimuth (degrees clockwise from north) > (deg) eq-to-station station-to-eq > 125.10 39.7 301.5 > > travel arrival time > # code time(s) dy hr mn sec > 1 Pdiff 891.60 0 7 27 38 > 2 PKPdf 1093.09 0 7 31 0 > 3 PKiKP 1093.63 0 7 31 0 > 4 LQ 3175.16 0 8 5 42 > 5 LR 3523.98 0 8 11 30 > > > Arrive at roughly 14:40 UTC?? > > Which has not occurred yet??? > > PauLC > > > > > -----Original Message----- > *From:* psn-l-request@.............. > [mailto:psn-l-request@.................. Behalf Of *Thomas Dick > *Sent:* Saturday, April 21, 2007 9:29 AM > *To:* psn-l@.............. > *Subject:* Re: Time of Quake?? > > > > > You can calculate arrival time using > http://neic.usgs.gov/neis/travel_times/ > > Your travel times are given in UTC, so, your answer is 07:27:38 UTC  (I think you tried to add the arrival time to the start time??)    it took about 891.60 seconds for the P wave to arrive at your location!!  07:12:47 UTC plus 891.60s = approx. 07:27:38 UTC ,,,,   891.6/60 = 14.86 minutes,,,  for rough distance, 69*125.1 = approx. 8632 miles,,  or 111.12 * 125.1 = approx. 13901.112 km!!
  Stephen
  PSN Station #55

Paul Cianciolo wrote:
I am at  Lat N41.78    Long  W73.00
 
So to check me... would this event 
 
 DATE-(UTC)-TIME    LAT    LON     DEPTH MAG   Q   COMMENTS
  2007/04/21 07:12:47   3.55S 151.31E 401.5 6.3      US: NEW IRELAND REGION, P.N.
 
delta   azimuth (degrees clockwise from north)
(deg)      eq-to-station     station-to-eq
125.10           39.7             301.5

                 travel   arrival time
    #  code      time(s)  dy hr mn sec
    1  Pdiff      891.60   0  7 27 38
    2  PKPdf     1093.09   0  7 31  0
    3  PKiKP     1093.63   0  7 31  0
    4  LQ        3175.16   0  8  5 42
    5  LR        3523.98   0  8 11 30
 
 
Arrive at  roughly 14:40 UTC??
 
Which has not occurred yet???
 
PauLC
 
 
 
-----Original Message-----
From: psn-l-request@.............. [mailto:psn-l-request@..............]On Behalf Of Thomas Dick
Sent: Saturday, April 21, 2007 9:29 AM
To: psn-l@..............
Subject: Re: Time of Quake??

 
 
You can calculate arrival time using http://neic.usgs.gov/neis/travel_times/ 
 
Subject: Re: Predictions From: "tchannel" tchannel@.............. Date: Sat, 21 Apr 2007 09:19:10 -0600 Stephen and Everyone, This is just great input....Stephen, Yes I sure = would like to see your study expanded to include M6 and M7's. I = printed you message. I wish I know something about Statistics. Thanks, Ted ----- Original Message -----=20 From: Stephen & Kathy=20 To: psn-l@................. Sent: Saturday, April 21, 2007 12:12 AM Subject: Re: Predictions FYI,, Following this little introduction, is a simple study I did a = few years ago!! Since then I have tried to correlate the events to = Solid Earth Tide,,, so far I have found no correlation!! My = conclusion at this point is that I think there may be a moon and or sun = tide connection, but like trying to predict the position in the bending = cycle where a wire will finally break, that you bend with your fingers, = there appears to be a similar problem with trying to tie a tidal phase = point to quakes???? It simply breaks when it is ready, no matter where = in the tidal cycle of bending it happens to be???? The complexity of = water tides may also contribute to the problem for events that happen in = the vicinity of ocean tides????? The reason I feel that there may be a = phase connection, becomes clear from the following study where we see = that the time of the new moon, where we have the greatest tidal motion, = also favors the greatest number of quakes?????? I am open to = correction, other studies, other data, and or other conclusions!!!! Stephen PSN Station #55 Subject: Large quakes (mag. 8 and above) and their relationship to Moon phases, = using data found over the web at the following links: http://en.wikipedia.org/wiki/List_of_earthquakes = http://www.fourmilab.ch/cgi-bin/uncgi/Earth/action?opt=3D-m&img=3DMoon.ev= if Using the top link to find quake times and mag., then using the bottom = link to compare them to moon phases, I found 38 quakes of mag. 8 or = greater since 1556, of which I used 35 because the first three did not = have times listed. Where local times were listed I converted them to = UTC time for compatibility with the Moon phase link. After finding the data, the next problem is determining how to = illustrate it with statistics! Statistics can be used in many ways to = manipulate data! Do we use only one or two days around the new and = full moon and compare that to the total, or should we divide it into = approx. 4 equal quadrants? For my simple analysis I will use 4 = quadrants. The moon link above uses approx. 29.4 days for a complete = cycle, so I will use approx. 7.35 days per quadrant, which when related = to the phases works out to about the following: New moon quadrant equals 0 to 15 % Full moon quadrant equals 85 to 100 % first and last quarter quadrant equals 16 to 86 % When we sort the 35 phase data into their quadrants we get the = following: Quakes during New moon =3D 15 Quakes during Full moon =3D 7 Quakes during First & Last quarter =3D 13 When we combine the New and Full quarters to compare with First and = Last quarters we get: Quakes during New & Full moon =3D 22 Conclusion: The New moon quadrant favors the Full moon quadrant by a little more = than double! The combined New and Full quadrants favor the First and Last quadrants = by not quite double! Interesting!!!!! I was led to believe that there was no statistical = correlation between quakes and Moon phases??? Perhaps if we added = the mag. 6 and 7 quakes we would find different conclusions,,,, that = is for someone else to do!!! List of mag. 8 quakes or greater,, With percent of Moon Phase listed 0% =3D New Moon, 100% =3D Full Moon, 50% =3D either First or Last = Quarter Please forgive any TYPOs=20 # Moon Year Mo. Day UTC Place Approx. Phase Time Mag. 1 ??% 1556 Jan. 23 ?? China 8 2 ??% 1668 Aug. 17 ?? Turkey 8 3 ??% 1700 Jan. 26 ?? Vancouver 9 ************************************************ 4 10% 1755 Nov. 1 10:16 Portugal 8.7 5 0% 1811 Dec. 16 08:00 Missouri 8.1 6 33% 1812 Feb. 7 09:45 Missouri 8 7 43% 1855 Jan. 24 10:11 New Zealand 8 8 20% 1891 Oct. 27 21:38 Japan 8 9 21% 1896 Jun. 15 19:32 Japan 8.5 10 91% 1897 Jun. 12 11:06 India 8.3 11 29% 1899 Sep. 10 21:41 Alaska 8 12 8% 1905 Jul. 5 09:40 Mongolia 8.4 13 41% 1906 Jan. 31 15:36 Colombia 8.8 14 9% 1906 Aug. 17 00:40 Chile 8.2 15 29% 1920 Dec. 16 12:05 China 8.6 16 34% 1933 Mar. 2 17:31 Japan 8.4 17 0% 1934 Jan. 15 08:43 India 8.1 18 88% 1938 Nov. 10 20:18 Alaska 8.2 19 54% 1944 Dec. 7 04:35 Japan 8.1 20 48% 1946 Aug. 4 17:51 Dom. Repub. 8.0 21 6% 1946 Dec. 20 19:19 Japan 8.1 22 5% 1949 Aug. 22 04:01 Q. Charlo. Is. 8.1 23 4% 1950 Aug. 15 14:09 Tibet 8.6 24 91% 1952 Nov. 4 16:58 Russia 9 25 51% 1957 Mar. 9 14:22 Alaska 9.1 26 90% 1957 Dec. 4 03:37 Mongolia 8.1 27 6% 1960 May 22 19:11 Chile 9.5 28 99% 1964 Mar. 28 03:36 Alaska 9.2 29 5% 1965 Feb. 4 05:01 Alaska 8.7 30 2% 1970 Jul. 31 17.08 Colombia 8 31 28% 1985 Sep. 19 13:17 Mexico 8 32 0% 1986 May 7 22:47 Alaska 8 33 0% 1994 Jun. 9 00:33 Bolivia 8.2 34 76% 2000 Nov. 16 04:54 New Ireland 8 35 7% 2001 Jun. 23 20:33 Peru 8.4 36 0% 2003 Sep. 25 19:50 Japan 8.3 37 91% 2004 Dec. 23 14:59 Macquarie 8.1 38 99% 2004 Dec. 26 00:59 Sumatra 9.0 tchannel wrote:=20 Hi Folks, Just curious about the subject of Earthquake Predictions. = We all can predict earthquakes, if we keep the "when" and "where" = nonspecific. But on a serious note, are there any scientific tools = used? Do the phases of the moon and the tides play a part? I have = asked this question to several people and received just as many = opinions. Thanks, Ted
Stephen and Everyone,  This is = just great=20 input....Stephen, Yes I sure would like to see your study expanded to = include M6=20 and M7's.   I printed you message.   I wish I know = something=20 about Statistics.
Thanks, Ted
----- Original Message -----
From:=20 Stephen &=20 Kathy
Sent: Saturday, April 21, 2007 = 12:12=20 AM
Subject: Re: Predictions

FYI,,  Following this = little=20 introduction, is a simple study I did a few years ago!!   = Since then=20 I have tried to correlate the events to Solid Earth = Tide,,,   so far=20 I have found no correlation!!    My conclusion at this point = is that=20 I think there may be a moon and or sun tide connection, but like = trying to=20 predict the position in the bending cycle where a wire will finally = break,=20 that you bend with your fingers, there appears to be a similar problem = with=20 trying to tie a tidal phase point to quakes????  It simply breaks = when it=20 is ready, no matter where in the tidal cycle of bending it happens to = be????=20   The complexity of water tides may also contribute to the = problem for=20 events that happen in the vicinity of ocean tides?????   The = reason=20 I feel that there may be a phase connection, becomes clear from the = following=20 study where we see that the time of the new moon, where we have the = greatest=20 tidal motion, also favors the greatest number of=20 quakes??????    I am open to correction, other studies, = other=20 data, and or other conclusions!!!!
  Stephen
  PSN = Station=20 #55


Subject:
Large quakes (mag. 8 and = above) and=20 their relationship to Moon phases, using data found over the web at = the=20 following links:

http://en.wikip= edia.org/wiki/List_of_earthquakes

http://www.fourmilab.ch/cgi-bin/uncgi/Earth/action?opt=3D= -m&img=3DMoon.evif

Using=20 the top link to find quake times and mag., then using the bottom link = to=20 compare them to moon phases, I found 38 quakes of mag. 8 or greater = since=20 1556, of which I used 35 because the first three did not have times=20 listed.  Where local times were listed I converted them to UTC = time for=20 compatibility with the Moon phase link.

After finding the data, = the=20 next problem is determining how to illustrate it with = statistics! =20 Statistics can be used in many ways to manipulate data!   Do = we use=20 only one or two days around the new and full moon and compare that to = the=20 total, or should we divide it into approx. 4 equal = quadrants?   For=20 my simple analysis I will use 4 quadrants.   The moon link = above=20 uses approx. 29.4 days for a complete cycle, so I will use approx. = 7.35 days=20 per quadrant, which when related to the phases works out to about the=20 following:
New moon quadrant=20 = equals           &= nbsp;     =20 0 to 15 %
Full moon quadrant=20 = equals           &= nbsp;    =20 85 to 100 %
first and last quarter quadrant = equals    16 to=20 86 %
When we sort the 35 phase data into their quadrants we get the = following:
Quakes during New=20 = moon           &nb= sp;  =20 =3D   15
Quakes during Full=20 = moon           &nb= sp; =20 =3D    7
Quakes during First & Last = quarter  =20 =3D   13
When we combine the New and Full quarters to = compare with=20 First and Last quarters we get:
Quakes during New & Full=20 moon        =3D  =20 22
Conclusion:
The New moon quadrant favors the Full moon = quadrant by a=20 little more than double!
The combined New and Full quadrants favor = the=20 First and Last quadrants by not quite=20 double!
Interesting!!!!!    I was led to believe = that there=20 was no statistical correlation between quakes and Moon=20 phases???     Perhaps if we added the mag. 6 and 7 = quakes=20 we would find different conclusions,,,,   that is for = someone else=20 to do!!!

List of mag. 8 quakes or greater,,   With = percent of=20 Moon Phase listed
0% =3D New Moon,  100% =3D Full = Moon,   =20 50% =3D either First or Last=20 = Quarter
          &n= bsp;           &nb= sp;=20 Please forgive any TYPOs

 #   Moon =20 Year    Mo.  Day   =20 UTC     =20 Place       =20 Approx.
    =20 = Phase           &n= bsp;        =20 = Time           &nb= sp;       =20 Mag.
 1    ??%   1556  = Jan.  =20 23     ??     =20 China          =20 8
 2    ??%   1668  = Aug.  =20 17     ??     =20 Turkey         =20 8
 3    ??%   1700  = Jan.  =20 26     ??     =20 Vancouver      =20 = 9
************************************************
 4 &nb= sp; =20 10%   1755   Nov.   1   =20 10:16    = Portugal       =20 8.7
 5     0%   1811   = Dec.  16    08:00   =20 Missouri       =20 8.1
 6    33%   1812  =20 Feb.   7    09:45   =20 Missouri       =20 8
 7    43%   1855   = Jan. =20 24    10:11    New=20 Zealand     8
 8    = 20%  =20 1891   Oct.  27    = 21:38   =20 Japan          =20 8
 9    21%   1896   = Jun. =20 15    19:32   =20 Japan          =20 8.5
10    91%   1897   = Jun. =20 12    11:06   =20 India          =20 8.3
11    29%   1899   = Sep. =20 10    21:41   =20 Alaska         =20 8
12     8%   1905  =20 Jul.   5    09:40   =20 Mongolia        = 8.4
13   =20 41%   1906   Jan.  31   =20 15:36    = Colombia       =20 8.8
14     9%   1906   = Aug. =20 17    00:40   =20 Chile          =20 8.2
15    29%   1920   = Dec. =20 16    12:05    China=20          =20 8.6
16    34%   1933   = Mar.  =20 2    17:31   =20 Japan          =20 8.4
17     0%   1934   = Jan. =20 15    08:43   =20 India          =20 8.1
18    88%   1938   = Nov. =20 10    20:18   =20 Alaska         =20 8.2
19    54%   1944   = Dec.  =20 7    04:35   =20 Japan          =20 8.1
20    48%   1946   = Aug.  =20 4    17:51    Dom.=20 Repub.     8.0
21    =20 6%   1946   Dec.  20   =20 19:19   =20 Japan          =20 8.1
22     5%   1949   = Aug. =20 22    04:01    Q. Charlo. Is. =20 8.1
23     4%   1950   = Aug. =20 15    14:09   =20 Tibet          =20 8.6
24    91%   1952   = Nov.  =20 4    16:58   =20 Russia         =20 9
25    51%   1957   = Mar.  =20 9    14:22   =20 Alaska         =20 9.1
26    90%   1957   = Dec.  =20 4    03:37   =20 Mongolia       =20 8.1
27     6%   1960  =20 May   22    19:11   =20 Chile          =20 9.5
28    99%   1964   = Mar. =20 28    03:36   =20 Alaska         =20 9.2
29     5%   1965  =20 Feb.   4    05:01   =20 Alaska         =20 8.7
30     2%   1970   = Jul. =20 31    17.08   =20 Colombia        = 8
31   =20 28%   1985   Sep.  19   =20 13:17   =20 Mexico         =20 8
32     0%   1986  =20 May    7    22:47   =20 Alaska         =20 8
33     0%   1994  =20 Jun.   9    00:33   =20 Bolivia        =20 8.2
34    76%   2000   = Nov. =20 16    04:54    New=20 Ireland     8
35     = 7%  =20 2001   Jun.  23    = 20:33   =20 Peru            = 8.4
36     0%   2003   = Sep. =20 25    19:50   =20 Japan          =20 8.3
37    91%   2004   = Dec. =20 23    14:59   =20 Macquarie       = 8.1
38   =20 99%   2004   Dec.  26   =20 00:59   =20 Sumatra        =20 9.0


tchannel wrote:=20
Hi Folks,  Just curious about = the subject=20 of Earthquake Predictions.   We all can predict = earthquakes, if we=20 keep the "when" and "where" nonspecific.   But on a = serious=20 note, are there any scientific tools used?   Do the = phases of=20 the moon and the tides play a part?   I have asked this = question=20 to several people and received just as many opinions.
 
Thanks,=20 Ted
Subject: Re: Predictions From: Angel sismos@.............. Date: Sat, 21 Apr 2007 15:24:59 +0000

Hello Ted,


Just about the entire issue of "Seismological Reaserch Letters" Vol 78, Number 1 Jan/Feb 2007 is dedicated to "Regional Earthquake likelihood Models"  They don't use the word "predict" and almost don't use the words "forecast" but just the same "likelihood" is one of the bricks in the road to "predict". 

 

I have a articles on "predicting" earthquakes using well levels in Greece, they have predicted a few.  It is VERY localized but works for that local. The reference is:

"Pre-seismic responses of underground water levels and temperature concerning a 4.8 mag earthquake in Greece"  Tectonophysis, 170 (1989) 165-169


I attended a lecture by the author who is not a seismologist but a civil engineer working building codes and warning systems for small villages in Greece. 


In my opinion early warning is the holy grail of seismology.  Volcanologist are pretty good at this, they came close with St; Hellens, nailed it at Pinatubo and several other places.  



Angel 




Friday, April 20, 2007, 10:24:41 PM, you wrote:


>

Hi Folks,  Just curious about the subject of Earthquake Predictions.   We all can predict earthquakes, if we keep the "when" and "where" nonspecific.   But on a serious note, are there any scientific tools used?   Do the phases of the moon and the tides play a part?   I have asked this question to several people and received just as many opinions.

 

Thanks, Ted





-- 

Best regards,

 Angel

Subject: Re: Time of Quake?? From: ChrisAtUpw@....... Date: Sat, 21 Apr 2007 11:34:35 EDT In a message dated 2007/04/21, Paulc@........ writes: > For the past month I have been working on a horizontal pendulum sensor > and I am going through my maiden voyage with it. > The clock is accurate to within 10 seconds, I am using the Amaseis > program, and a 12 bit ADC. Hi Paul, The P waves may travel at 8.2 km / sec. You need your clock accurate to about 1 sec for practical purposes. I suggest that you keep a note of the errors for a day or two. They are often very large. You can buy a radio corrected crystal clock for less than $20. They are very useful and are accurate to 20 mS. They update every hour. You can also visit http://nist.time.gov/ and cross check on-line, but do watch out for transient data delays. > I would like to try and compare events elsewhere in the world / country > to my sensor. At this site I can see various locations. > > The question. > > If I know in when in UTC an event occurred, and where.. how do I > convert that to a UTC time when the event would arrive at my location, if ever. > In other words how ho long does it take to get here?? Y> ou can calculate arrival time using > http://neic.usgs.gov/neis/travel_times/ > and also download tables and charts to measure the distance from the P to S delay time. Regards, Chris Chapman In a me= ssage dated 2007/04/21, Paulc@........ writes:

   
For the=20= past month I have been working on a horizontal pendulum sensor and I am goin= g through my maiden voyage with it.
    The clock is accurate to within 10 seconds, I am using t= he Amaseis program, and a 12 bit ADC.


Hi Paul,

       The P waves may travel at 8.2 km / sec.= You need your clock accurate to about 1 sec for practical purposes. I sugge= st that you keep a note of the errors for a day or two. They are often very=20= large.
       You can buy a radio corrected crystal c= lock for less than $20. They are very useful and are accurate to 20 mS. They= update every hour.
       You can also visit http://nist.time.gov= / and cross check on-line, but do watch out for transient data delays.

    I would lik= e to try and compare events elsewhere in the world / country to my sensor. A= t this site I can see various locations.

The question.

    If I know in  when in UTC an event occurred, and wh= ere.. how do I convert that to a UTC time when the event would arrive at my=20= location, if ever.
In other words how ho long does it take to get here??


   Y
ou can calculat= e arrival time using htt= p://neic.usgs.gov/neis/travel_times/

       and also download tables and charts= to measure the distance from the P to S delay time.

       Regards,

       Chris Chapman

 Subject: Re: Predictions From: George Bush ke6pxp@....... Date: Sat, 21 Apr 2007 09:40:51 -0700 At 04:24 PM 4/20/2007 -0600, you wrote: >>>> Hi Folks, Just curious about the subject of Earthquake Predictions. We all can predict earthquakes, if we keep the "when" and "where" nonspecific. But on a serious note, are there any scientific tools used? Do the phases of the moon and the tides play a part? I have asked this question to several people and received just as many opinions. Thanks, Ted <<<<<<<< Ted- I live along the coast and along the San Andreas Fault, and am a member of the California Magnetometer Net. We have sensing stations spread around the state to detect Ultra Low Frequency (ULF) electromotive waves that could be caused by earth strain. My station consists of a PC monitoring 3-axis ferromagnetic antennas and while I haven't detected any quake precursors, it did detect a magnetic storm from the Sun. The CalMagNet is sponsored by Quakefinder (http://www.quakefinder.com/), who's vision is "QuakeFinder is dedicated to earthquake forecasting research to ultimately develop, within the next decade, a global warning system of imminent destructive earthquakes" If you are curious, you can go to the website and learn more about the group. You can also see the data from my station by clicking on the map on the website and selecting the Sea Ranch station. George Bush Sea Ranch, CA, USA 38.73775N, 123.48882W Subject: RE: Time of Quake?? From: "Bob Hancock" carpediem1@......... Date: Sat, 21 Apr 2007 10:26:11 -0700 Another timing option if you cannot get a good WWV signal or if your GPS signal is blocked by surrounding terrain, buildings, vegetation, etc, is Tardis 2000. This is best used with a continuous internet connection or at least you could set it up so it checks the timing while you are recording data. It connects at pre-determined time intervals to various timing locations around the globe of your choosing and updates your computer timing. It sells for $20 (US), and here is the link to their web site: http://www.kaska.demon.co.uk/ I used this for 3 years before we moved to a location where I could use GPS. I found it to be highly reliable and did not have any problems with it. Bob Hancock Three Points, AZ _____ From: psn-l-request@.............. [mailto:psn-l-request@............... On Behalf Of ChrisAtUpw@....... Sent: Saturday, April 21, 2007 08:35 To: psn-l@.............. Subject: Re: Time of Quake?? In a message dated 2007/04/21, Paulc@........ writes: For the past month I have been working on a horizontal pendulum sensor and I am going through my maiden voyage with it. The clock is accurate to within 10 seconds, I am using the Amaseis program, and a 12 bit ADC. Hi Paul, The P waves may travel at 8.2 km / sec. You need your clock accurate to about 1 sec for practical purposes. I suggest that you keep a note of the errors for a day or two. They are often very large. You can buy a radio corrected crystal clock for less than $20. They are very useful and are accurate to 20 mS. They update every hour. You can also visit http://nist.time.gov/ and cross check on-line, but do watch out for transient data delays. I would like to try and compare events elsewhere in the world / country to my sensor. At this site I can see various locations. The question. If I know in when in UTC an event occurred, and where.. how do I convert that to a UTC time when the event would arrive at my location, if ever. In other words how ho long does it take to get here?? Y ou can calculate arrival time using http://neic.usgs.gov/neis/travel_times/ and also download tables and charts to measure the distance from the P to S delay time. Regards, Chris Chapman

Another timing option if you cannot = get a good WWV signal or if your GPS signal is blocked by surrounding terrain, buildings, vegetation, etc, is Tardis 2000.  This is best used with = a continuous internet connection or at least you could set it up so it = checks the timing while you are recording data.  It connects at pre-determined = time intervals to various timing locations around the globe of your choosing = and updates your computer timing.  It sells for $20 (US), and here is the link = to their web site:    http://www.kaska.demon.co.uk/<= o:p>

 

I used this for 3 years before we = moved to a location where I could use GPS.  I found it to be highly reliable = and did not have any problems with it.

 

Bob = Hancock

Three Points, = AZ

 

From: psn-l-request@.............. [mailto:psn-l-request@............... = On Behalf Of = ChrisAtUpw@.......
Sent: Saturday, April 21, = 2007 08:35
To: = psn-l@..............
Subject: Re: Time of = Quake??

 

In a message dated 2007/04/21, Paulc@........ = writes:

   

For the past month = I have been working on a horizontal pendulum sensor and I am going through my = maiden voyage with it.
    The clock is accurate to within 10 seconds, I am using the Amaseis program, and a 12 bit = ADC.



Hi Paul,

       The P waves may travel at 8.2 km / = sec. You need your clock accurate to about 1 sec for practical purposes. I = suggest that you keep a note of the errors for a day or two. They are often very = large.
       You can buy a radio corrected = crystal clock for less than $20. They are very useful and are accurate to 20 mS. = They update every hour.
       You can also visit = http://nist.time.gov/ and cross check on-line, but do watch out for transient data = delays.


   = = I would like to try and compare events elsewhere in the world / country to my = sensor. At this site I can see various locations.

The question.

    If I know in  when in UTC an = event occurred, and where.. how do I convert that to a UTC time when the event = would arrive at my location, if ever.
In other words how ho long does it take to get = here??



   Y<= /font>

ou can calculate = arrival time using http://neic.usgs.gov/nei= s/travel_times/


       and also download = tables and charts to measure the distance from the P to S delay time.

       Regards,

       Chris Chapman

Subject: Re: Time of Quake?? From: dave dalex@............ Date: Sat, 21 Apr 2007 10:45:16 -0700 gentlemen. there is a program at http://home.att.net/~Tom.Horsley/ntptime.html that keeps your computer within tenths of a second and is free. if you have an always on connection it can update time as often as you like. once in awhile the program appears to not work and what i found is that the server it is using to get the time has failed. if you select another server things will be ok. short of using a gps disciplined clock this is probably the easy and is accurate enough for us. dave k7da ChrisAtUpw@....... wrote: > In a message dated 2007/04/21, Paulc@........ writes: > > > >> For the past month I have been working on a horizontal pendulum sensor >> and I am going through my maiden voyage with it. >> The clock is accurate to within 10 seconds, I am using the Amaseis >> program, and a 12 bit ADC. > > > > Hi Paul, > > The P waves may travel at 8.2 km / sec. You need your clock > accurate to about 1 sec for practical purposes. I suggest that you keep > a note of the errors for a day or two. They are often very large. > You can buy a radio corrected crystal clock for less than $20. > They are very useful and are accurate to 20 mS. They update every hour. > You can also visit http://nist.time.gov/ and cross check on-line, > but do watch out for transient data delays. > >> I would like to try and compare events elsewhere in the world / >> country to my sensor. At this site I can see various locations. >> >> The question. >> >> If I know in when in UTC an event occurred, and where.. how do I >> convert that to a UTC time when the event would arrive at my location, >> if ever. >> In other words how ho long does it take to get here?? > > > > You can calculate arrival time using >> http://neic.usgs.gov/neis/travel_times/ > > > and also download tables and charts to measure the distance from > the P to S delay time. > > Regards, > > Chris Chapman > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Time of Quake?? From: "tchannel" tchannel@.............. Date: Sat, 21 Apr 2007 11:53:51 -0600 Hi Chris, A question about P travel time? I read somewhere it varies, = from __km to __km per second. Does it vary depending on the material, type of earth, that it is moving = through? I have calculated, from recordings, a range of 10,000 to 30,000 miles = per hour. That's a big range. I would like to have a better understanding of it. Thanks, Ted ----- Original Message -----=20 From: ChrisAtUpw@.......... To: psn-l@................. Sent: Saturday, April 21, 2007 9:34 AM Subject: Re: Time of Quake?? In a message dated 2007/04/21, Paulc@........ writes: =20 For the past month I have been working on a horizontal pendulum = sensor and I am going through my maiden voyage with it. The clock is accurate to within 10 seconds, I am using the = Amaseis program, and a 12 bit ADC. Hi Paul, The P waves may travel at 8.2 km / sec. You need your clock = accurate to about 1 sec for practical purposes. I suggest that you keep = a note of the errors for a day or two. They are often very large. You can buy a radio corrected crystal clock for less than $20. = They are very useful and are accurate to 20 mS. They update every hour.=20 You can also visit http://nist.time.gov/ and cross check = on-line, but do watch out for transient data delays. I would like to try and compare events elsewhere in the world / = country to my sensor. At this site I can see various locations. The question. If I know in when in UTC an event occurred, and where.. how do = I convert that to a UTC time when the event would arrive at my location, = if ever. In other words how ho long does it take to get here?? Y ou can calculate arrival time using = http://neic.usgs.gov/neis/travel_times/=20 and also download tables and charts to measure the distance = from the P to S delay time. Regards, Chris Chapman
Hi Chris, A question about P travel = time?  I=20 read somewhere it varies, from __km to __km per second.
Does it vary depending on the material, = type of=20 earth, that it is moving through?
I have calculated, from recordings, a = range of=20 10,000 to 30,000 miles per hour. That's a big range.
 
I would like to have a better = understanding of=20 it.   Thanks, Ted
----- Original Message -----
From:=20 ChrisAtUpw@.......
Sent: Saturday, April 21, 2007 = 9:34=20 AM
Subject: Re: Time of = Quake??

In a=20 message dated 2007/04/21, Paulc@........=20 writes:

    For the past month I have been working on a horizontal = pendulum=20 sensor and I am going through my maiden voyage with it.
    The clock=20 is accurate to within 10 seconds, I am using the Amaseis program, = and a 12=20 bit ADC.


Hi=20 Paul,

       The P waves may = travel at=20 8.2 km / sec. You need your clock accurate to about 1 sec for = practical=20 purposes. I suggest that you keep a note of the errors for a day or = two. They=20 are often very large.
       You can = buy a=20 radio corrected crystal clock for less than $20. They are very useful = and are=20 accurate to 20 mS. They update every hour.=20
       You can also visit=20 http://nist.time.gov/ and cross check on-line, but do watch out for = transient=20 data delays.

    I would like to = try and=20 compare events elsewhere in the world / country to my sensor. At = this site I=20 can see various locations.

The = question.

    If I know=20 in  when in UTC an event occurred, and where.. how do I convert = that to=20 a UTC time when the event would arrive at my location, if = ever.
In other words = how ho long=20 does it take to get here??

   Y ou can calculate arrival time using http://neic.usgs.gov/nei= s/travel_times/=20

      =20 and also = download tables=20 and charts to measure the distance from the P to S delay=20 time.

      =20 Regards,

       Chris = Chapman

 Subject: RE: Time of Quake?? From: "Paul Cianciolo" Paulc@........ Date: Sat, 21 Apr 2007 14:54:40 -0400 Hey Guys, Thanks for all the input on the time question. First I did make a mistake, as Steven pointed out. Thanks Steve... Yup I was adding the time.. Sorry for the dumb mistake. I am going to check out the links that you folks pointed out. I also have a 10 MHz GPS discipline standard... a Z3801 and will look into interfacing that to my computer. But will somebody please tell me why the clock accuracy is so important?? It appears that events last multiples of minutes and longer. Why is clock accuracy in milliseconds so important. Unless one is trying to "triangulate" or compare phase of signals.. I must be missing something. PauLC W1VLF -----Original Message----- From: psn-l-request@.............. [mailto:psn-l-request@................. Behalf Of dave Sent: Saturday, April 21, 2007 1:45 PM To: psn-l@.............. Subject: Re: Time of Quake?? gentlemen. there is a program at http://home.att.net/~Tom.Horsley/ntptime.html that keeps your computer within tenths of a second and is free. if you have an always on connection it can update time as often as you like. once in awhile the program appears to not work and what i found is that the server it is using to get the time has failed. if you select another server things will be ok. short of using a gps disciplined clock this is probably the easy and is accurate enough for us. dave k7da ChrisAtUpw@....... wrote: > In a message dated 2007/04/21, Paulc@........ writes: > > > >> For the past month I have been working on a horizontal pendulum sensor >> and I am going through my maiden voyage with it. >> The clock is accurate to within 10 seconds, I am using the Amaseis >> program, and a 12 bit ADC. > > > > Hi Paul, > > The P waves may travel at 8.2 km / sec. You need your clock > accurate to about 1 sec for practical purposes. I suggest that you keep > a note of the errors for a day or two. They are often very large. > You can buy a radio corrected crystal clock for less than $20. > They are very useful and are accurate to 20 mS. They update every hour. > You can also visit http://nist.time.gov/ and cross check on-line, > but do watch out for transient data delays. > >> I would like to try and compare events elsewhere in the world / >> country to my sensor. At this site I can see various locations. >> >> The question. >> >> If I know in when in UTC an event occurred, and where.. how do I >> convert that to a UTC time when the event would arrive at my location, >> if ever. >> In other words how ho long does it take to get here?? > > > > You can calculate arrival time using >> http://neic.usgs.gov/neis/travel_times/ > > > and also download tables and charts to measure the distance from > the P to S delay time. > > Regards, > > Chris Chapman > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: RE: Time of Quake?? From: "Paul Cianciolo" Paulc@........ Date: Sat, 21 Apr 2007 15:38:31 -0400 Ted, Is it you that is using a DATAQ device... ? a 154 or a 158 PauLC -----Original Message----- From: psn-l-request@.............. [mailto:psn-l-request@................. Behalf Of tchannel Sent: Saturday, April 21, 2007 1:54 PM To: psn-l@.............. Subject: Re: Time of Quake?? Hi Chris, A question about P travel time? I read somewhere it varies, from __km to __km per second. Does it vary depending on the material, type of earth, that it is moving through? I have calculated, from recordings, a range of 10,000 to 30,000 miles per hour. That's a big range. I would like to have a better understanding of it. Thanks, Ted ----- Original Message ----- From: ChrisAtUpw@....... To: psn-l@.............. Sent: Saturday, April 21, 2007 9:34 AM Subject: Re: Time of Quake?? In a message dated 2007/04/21, Paulc@........ writes: For the past month I have been working on a horizontal pendulum sensor and I am going through my maiden voyage with it. The clock is accurate to within 10 seconds, I am using the Amaseis program, and a 12 bit ADC. Hi Paul, The P waves may travel at 8.2 km / sec. You need your clock accurate to about 1 sec for practical purposes. I suggest that you keep a note of the errors for a day or two. They are often very large. You can buy a radio corrected crystal clock for less than $20. They are very useful and are accurate to 20 mS. They update every hour. You can also visit http://nist.time.gov/ and cross check on-line, but do watch out for transient data delays. I would like to try and compare events elsewhere in the world / country to my sensor. At this site I can see various locations. The question. If I know in when in UTC an event occurred, and where.. how do I convert that to a UTC time when the event would arrive at my location, if ever. In other words how ho long does it take to get here?? Y ou can calculate arrival time using http://neic.usgs.gov/neis/travel_times/ and also download tables and charts to measure the distance from the P to S delay time. Regards, Chris Chapman
Ted,
 
Is it=20 you that is using a DATAQ device...  ?
 
a 154=20 or a 158
PauLC
-----Original Message-----
From: = psn-l-request@................. [mailto:psn-l-request@...............On Behalf Of=20 tchannel
Sent: Saturday, April 21, 2007 1:54 = PM
To:=20 psn-l@..............
Subject: Re: Time of=20 Quake??

Hi Chris, A question about P travel = time?  I=20 read somewhere it varies, from __km to __km per second.
Does it vary depending on the = material, type of=20 earth, that it is moving through?
I have calculated, from recordings, a = range of=20 10,000 to 30,000 miles per hour. That's a big range.
 
I would like to have a better = understanding of=20 it.   Thanks, Ted
----- Original Message -----
From:=20 ChrisAtUpw@.......
Sent: Saturday, April 21, = 2007 9:34=20 AM
Subject: Re: Time of = Quake??

In a=20 message dated 2007/04/21, Paulc@........=20 writes:

    For the past month I have been working on a horizontal = pendulum sensor and I am going through my maiden voyage with=20 it.
    The clock=20 is accurate to within 10 seconds, I am using the Amaseis program, = and a 12=20 bit ADC.


Hi=20 Paul,

       The P waves may = travel at=20 8.2 km / sec. You need your clock accurate to about 1 sec for = practical=20 purposes. I suggest that you keep a note of the errors for a day or = two.=20 They are often very large.
       = You can=20 buy a radio corrected crystal clock for less than $20. They are very = useful=20 and are accurate to 20 mS. They update every hour.=20
       You can also visit=20 http://nist.time.gov/ and cross check on-line, but do watch out for=20 transient data delays.

    I would like = to try and=20 compare events elsewhere in the world / country to my sensor. At = this site=20 I can see various locations.

The = question.

    If I know=20 in  when in UTC an event occurred, and where.. how do I = convert that=20 to a UTC time when the event would arrive at my location, if=20 ever.
In other words = how ho long=20 does it take to get here??

   = Y=20 ou can calculate arrival time using http://neic.usgs.gov/nei= s/travel_times/=20

      = ;=20 and also=20 download tables and charts to measure the distance from the P to S = delay=20 time.

      =20 Regards,

       Chris=20 Chapman

<= /HTML> Subject: Re: Time of Quake?? From: "tchannel" tchannel@.............. Date: Sat, 21 Apr 2007 14:02:45 -0600 Hi Paul, Yes I am using the very inexpensive $30? DataQ 194 I am = very happy with it, I actually use two of them for two different = stations. You can see my .gif's on the Psn new events page. Ted ----- Original Message -----=20 From: Paul Cianciolo=20 To: psn-l@................. Sent: Saturday, April 21, 2007 1:38 PM Subject: RE: Time of Quake?? Ted, Is it you that is using a DATAQ device... ? a 154 or a 158=20 PauLC -----Original Message----- From: psn-l-request@.............. = [mailto:psn-l-request@................. Behalf Of tchannel Sent: Saturday, April 21, 2007 1:54 PM To: psn-l@.............. Subject: Re: Time of Quake?? Hi Chris, A question about P travel time? I read somewhere it = varies, from __km to __km per second. Does it vary depending on the material, type of earth, that it is = moving through? I have calculated, from recordings, a range of 10,000 to 30,000 = miles per hour. That's a big range. I would like to have a better understanding of it. Thanks, Ted ----- Original Message -----=20 From: ChrisAtUpw@.......... To: psn-l@................. Sent: Saturday, April 21, 2007 9:34 AM Subject: Re: Time of Quake?? In a message dated 2007/04/21, Paulc@........ writes: =20 For the past month I have been working on a horizontal pendulum = sensor and I am going through my maiden voyage with it. The clock is accurate to within 10 seconds, I am using the = Amaseis program, and a 12 bit ADC. Hi Paul, The P waves may travel at 8.2 km / sec. You need your clock = accurate to about 1 sec for practical purposes. I suggest that you keep = a note of the errors for a day or two. They are often very large. You can buy a radio corrected crystal clock for less than = $20. They are very useful and are accurate to 20 mS. They update every = hour.=20 You can also visit http://nist.time.gov/ and cross check = on-line, but do watch out for transient data delays. I would like to try and compare events elsewhere in the = world / country to my sensor. At this site I can see various locations. The question. If I know in when in UTC an event occurred, and where.. how = do I convert that to a UTC time when the event would arrive at my = location, if ever. In other words how ho long does it take to get here?? Y=20 ou can calculate arrival time using = http://neic.usgs.gov/neis/travel_times/=20 and also download tables and charts to measure the distance = from the P to S delay time. Regards, Chris Chapman
Hi Paul, Yes I am using the very  = inexpensive=20 $30?  DataQ 194   I am very happy with it, I actually use = two of=20 them for two different stations.  You can see my .gif's on the Psn = new=20 events page.  Ted
----- Original Message -----
From:=20 Paul = Cianciolo
Sent: Saturday, April 21, 2007 = 1:38=20 PM
Subject: RE: Time of = Quake??

Ted,
 
Is=20 it you that is using a DATAQ device...  ?
 
a=20 154 or a 158
PauLC
-----Original Message-----
From: psn-l-request@............... =20 [mailto:psn-l-request@...............On Behalf Of=20 tchannel
Sent: Saturday, April 21, 2007 1:54 = PM
To:=20 psn-l@..............
Subje= ct:=20 Re: Time of Quake??

Hi Chris, A question about P travel = time? =20 I read somewhere it varies, from __km to __km per = second.
Does it vary depending on the = material, type of=20 earth, that it is moving through?
I have calculated, from recordings, = a range of=20 10,000 to 30,000 miles per hour. That's a big = range.
 
I would like to have a better = understanding of=20 it.   Thanks, Ted
----- Original Message ----- =
From:=20 ChrisAtUpw@.......
Sent: Saturday, April 21, = 2007 9:34=20 AM
Subject: Re: Time of = Quake??

In a=20 message dated 2007/04/21, Paulc@........=20 writes:

    For the past month I have been working on a = horizontal=20 pendulum sensor and I am going through my maiden voyage with=20 it.
    The clock is accurate to = within 10=20 seconds, I am using the Amaseis program, and a 12 bit = ADC.


Hi=20 Paul,

       The P waves may = travel=20 at 8.2 km / sec. You need your clock accurate to about 1 sec for = practical=20 purposes. I suggest that you keep a note of the errors for a day = or two.=20 They are often very large.
       = You can=20 buy a radio corrected crystal clock for less than $20. They are = very=20 useful and are accurate to 20 mS. They update every hour.=20
       You can also visit=20 http://nist.time.gov/ and cross check on-line, but do watch out = for=20 transient data delays.

    I would like = to try and=20 compare events elsewhere in the world / country to my sensor. At = this=20 site I can see various locations.

The = question.

    If I=20 know in  when in UTC an event occurred, and where.. how do = I=20 convert that to a UTC time when the event would arrive at my = location,=20 if ever.
In other words how ho long does it take to get=20 here??


   = Y=20 ou can calculate arrival time using http://neic.usgs.gov/nei= s/travel_times/=20

      =20 and=20 also download tables and charts to measure the distance from the P = to S=20 delay time.

      =20 Regards,

       Chris=20 Chapman

 Subject: Re: Time of Quake?? From: Stephen & Kathy skmort@............ Date: Sat, 21 Apr 2007 13:24:12 -0700 FYI,, you are correct,, exact timing is only important to the pros and those who are trying to use their own traces in conjunction with others to find exact start time of the event, exact location and magnitude! If you plan to send your files to PSN for others to use and analyze, then you need to get serious about better timing, otherwise just enjoy,,, your relative P and S times will still give you the distance from your station and you can still determine a magnitude based on your station parameters, but trying to correlate your trace with others becomes a bit of a pain! If you know your timing error, some of the viewing software, (like winquake), allows some shifting of the time after the fact! I use the old Radio Shack version of dataq, the 12 bit DI-150RS, in conjunction with Amaseis software,,, my system gains about 13 seconds per day and I use Atomic time, (over a phone line), to reset once per day and then it is set to compensate each hour,,, but it only compensates after it is out by at least one second, which means it only compensates about every two hours! Once in a while, atomic time will hang and I won't notice it for several days,,,, it is just a hobby for me so timing isn't critical, or serious!!!! I do have a fixed GPS and for a while, when I was running the dataq software, I let it record time hacks on the second channel and could easily determine my error! Stephen PSN Station #55 where dumb mistakes are a regular part of my adventure in life, ha!! Paul Cianciolo wrote: > Hey Guys, > > Thanks for all the input on the time question. > > First I did make a mistake, as Steven pointed out. Thanks Steve... Yup I > was adding the time.. Sorry for the dumb mistake. > > I am going to check out the links that you folks pointed out. > > I also have a 10 MHz GPS discipline standard... a Z3801 and will look into > interfacing that to my computer. > > But will somebody please tell me why the clock accuracy is so important?? > It appears that events last multiples of minutes and longer. Why is clock > accuracy in milliseconds so important. > Unless one is trying to "triangulate" or compare phase of signals.. I must > be missing something. > > PauLC > W1VLF > > > FYI,,  you are correct,,  exact timing is only important to the pros and those who are trying to use their own traces in conjunction with others to find exact start time of the event, exact location and magnitude!   If you plan to send your files to PSN for others to use and analyze, then you need to get serious about better timing, otherwise just enjoy,,,   your relative P and S times will still give you the distance from your station and you can still determine a magnitude based on your station parameters, but trying to correlate your trace with others becomes a bit of a pain!   If you know your timing error, some of the viewing software, (like winquake), allows some shifting of the time after the fact!   I use the old Radio Shack version of dataq, the 12 bit DI-150RS, in conjunction with Amaseis software,,,   my system gains about 13 seconds per day and I use Atomic time, (over a phone line), to reset once per day and then it is set to compensate each hour,,,  but it only compensates after it is out by at least one second, which means it only compensates about every two hours!   Once in a while, atomic time will hang and I won't notice it for several days,,,,   it is just a hobby for me so timing isn't critical, or serious!!!!   I do have a fixed GPS and for a while, when I was running the dataq software, I let it record time hacks on the second channel and could easily determine my error!  
  Stephen
  PSN Station #55
  where dumb mistakes are a regular part of my adventure in life, ha!!

Paul Cianciolo wrote: 
Hey Guys,

Thanks for all the input on the time question.

First I did make a mistake, as Steven pointed out.  Thanks Steve...  Yup I
was adding the time..  Sorry for the dumb mistake.

I am going to check out the links that you folks pointed out.

I also have a 10 MHz GPS discipline standard... a Z3801  and will look into
interfacing that to my computer.

But will somebody please tell me why the clock accuracy is so important??
It appears that events last multiples of minutes and longer.  Why is clock
accuracy in milliseconds so important.
Unless one is trying to "triangulate" or compare phase of signals.. I must
be missing something.

PauLC
W1VLF
Subject: Re: Time of Quake?? From: ChrisAtUpw@....... Date: Sat, 21 Apr 2007 16:43:43 EDT In a message dated 2007/04/21, Paulc@........ writes: > But will somebody please tell me why the clock accuracy is so important? > It appears that events last multiples of minutes and longer. Why is clock > accuracy in milliseconds so important. > Unless one is trying to "triangulate" or compare phase of signals.. I must > be missing something. Hi Paul, You use the accurate quake time to determine the epicentre, using the P wave records of several stations. You don't generally need millisecond accuracy unless you are monitoring a local volcano or a similar feature, when the time delays are less than a second. The timing problem is due to cumulative clock errors. 1 ppm = 1 sec every 11.57 days. It is relatively difficult to hold even a quartz clock to this accuracy over the ambient temperature range. If you have a 10 ppm drift, this translates into about a second a day. Most computers use the cheap 32 kHz watch crystals. These can have quite large temperature drifts. The reason that I suggested using abouttime, is that your computer reads the time signal and it then sends a 'ping' signal which is immediatly reflected by abouttime. This enables you to measure and correct for transmission delays. Before digital circuits were used on phone networks, the delays were small. Now the digital information packet can be delayed by other traffic. I have seen delays of NIST of over 3 seconds in Europe. Regards, Chris Chapman In a me= ssage dated 2007/04/21, Paulc@........ writes:

But will somebody please tell m= e why the clock accuracy is so important?
It appears that events last multiples of minutes and longer.  Why is cl= ock
accuracy in milliseconds so important.
Unless one is trying to "triangulate" or compare phase of signals.. I must be missing something.


Hi Paul,

       You use the accurate quake time to dete= rmine the epicentre, using the P wave records of several stations.
       You don't generally need millisecond a= ccuracy unless you are monitoring a local volcano or a similar feature, when= the time delays are less than a second.
       The timing problem is due to cumulative= clock errors. 1 ppm =3D 1 sec every 11.57 days. It is relatively difficult=20= to hold even a quartz clock to this accuracy over the ambient temperature ra= nge. If you have a 10 ppm drift, this translates into about a second a day.=20= Most computers use the cheap 32 kHz watch crystals. These can have quite lar= ge temperature drifts.
       The reason that I suggested using about= time, is that your computer reads the time signal and it then sends a 'ping'= signal which is immediatly reflected by abouttime. This enables you to meas= ure and correct for transmission delays. Before digital circuits were used o= n phone networks, the delays were small. Now the digital information packet=20= can be delayed by other traffic. I have seen delays of NIST of over 3 second= s in Europe.

       Regards,

       Chris Chapman Subject: Re: Time of Quake?? From: ChrisAtUpw@....... Date: Sat, 21 Apr 2007 17:21:29 EDT In a message dated 2007/04/21, tchannel@.............. writes: > Hi Chris, A question about P travel time? I read somewhere it varies, from > __km to __km per second. > Does it vary depending on the material, type of earth, that it is moving > through? > I have calculated, from recordings, a range of 10,000 to 30,000 miles per > hour. That's a big range. Hi Ted, I suggest that you download and print out a copy of the Seismograph Training manual from http://psn.quake.net/info/analysis.pdf and also a travel time graph from http://neic.usgs.gov/neis/travel_times/ The velocity of P waves in the mantle increase with depth from 8.2 to 13.5 km / sec. P and S wave velocities depend on the depth and on the rock type. There are large variations in the surface rocks, but the incidence angle is often quite steep, so uncertainties may be relatively small. The tables / graphs of velocities with angular distance are averaged velocities. You may notice variations if say you are west of the Rockies and the quake is to the east, or vice versa. You also have the problem that a plane wave often follows an upwardly curving path through the earth - NOT a straight line! This is due to the variation of the velocity with depth and to the curve of the earth. Regards, Chris Chapman In a me= ssage dated 2007/04/21, tchannel@.............. writes:

Hi Chris, A question about P tr= avel time?  I read somewhere it varies, from __km to __km per second.<= BR> Does it vary depending on the material, type of earth, that it is moving th= rough?
I have calculated, from recordings, a range of 10,000 to 30,000 miles per h= our. That's a big range.


Hi Ted,

       I suggest that you download and print o= ut a copy of the Seismograph Training manual from http://psn.quake.net/info/= analysis.pdf and also a travel time graph from
http://neic.usgs.gov/ne= is/travel_times/
       The velocity of P waves in the mant= le increase with depth from 8.2 to 13.5 km / sec.

       P and S wave velocities depend on the d= epth and on the rock type. There are large variations in the surface rocks,=20= but the incidence angle is often quite steep, so uncertainties may be relati= vely small. The tables / graphs of velocities with angular distance are aver= aged velocities. You may notice variations if say you are west of the Rockie= s and the quake is to the east, or vice versa. You also have the problem tha= t a plane wave often follows an upwardly curving path through the earth - NO= T a straight line! This is due to the variation of the velocity with depth a= nd to the curve of the earth.

       Regards,

       Chris Chapman Subject: RE: Predictions From: "Kareem Lanier, Heyjoojoo.Com" system98765@............. Date: Sat, 21 Apr 2007 20:10:49 -0700 I so believe that we are getting closer.. _____ From: psn-l-request@.............. [mailto:psn-l-request@............... On Behalf Of ChrisAtUpw@....... Sent: Friday, April 20, 2007 8:23 PM To: psn-l@.............. Subject: Re: Predictions In a message dated 2007/04/20, tchannel@.............. writes: Just curious about the subject of Earthquake Predictions. But on a serious note, are there any scientific tools used? Do the phases of the moon and the tides play a part? I have asked this question to several people and received just as many opinions. Hi Ted, Type Earthquake Prediction into Google? See http://www.nature.com/nature/debates/earthquake/equake_frameset.html Short answer is that we don't know. Strong quakes may be associated with parts of the tide cycle. The question is which cycle? The local background noise may decrease before a large quake. There may be physical movement before shallower quakes, but you are unlikely to get much observable effect at the surface if the rupture is 100 km down. About 1/3 of quakes show precursor quakes. There may be a few cycles of very long period precursor. There may be changes in the water table, changes in Radon emission, electric / RF field noise, animals seem to be able to sense 'something'..... One thing is certain. If you say we will never be able to predict quakes and no funds to experiment are allocated, we WON'T develop the / any ability!! Even if we could only get timely warning for a few quake locations / depths, the benefits could be very significant. A lot of the severe quakes are associated with subduction zones, like those off the west coast of the Americas, but the interval may be hundreds of years. Regards, Chris Chapman
I so believe that we are getting=20 closer..

From: psn-l-request@................. [mailto:psn-l-request@............... On Behalf Of=20 ChrisAtUpw@.......
Sent: Friday, April 20, 2007 8:23=20 PM
To: psn-l@..............
Subject: Re:=20 Predictions

In = a message=20 dated 2007/04/20, tchannel@.............. writes:

Just curious about the subject of Earthquake Predictions. = But on a=20 serious note, are there any scientific tools used? Do the phases of = the moon=20 and the tides play a part? I have asked this question to several = people and=20 received just as many opinions.

Hi=20 Ted,

       Type Earthquake = Prediction into=20 Google?
       See=20 http://www.nature.com/nature/debates/earthquake/equake_frameset.html
<= BR>      =20 Short answer is that we don't know. Strong quakes may be associated with = parts=20 of the tide cycle. The question is which cycle? The local background = noise may=20 decrease before a large quake. There may be physical movement before = shallower=20 quakes, but you are unlikely to get much observable effect at the = surface if the=20 rupture is 100 km down. About 1/3 of quakes show precursor quakes. There = may be=20 a few cycles of very long period precursor. There may be changes in the = water=20 table, changes in Radon emission, electric / RF field noise, animals = seem to be=20 able to sense 'something'.....
       = One=20 thing is certain. If you say we will never be able to predict quakes and = no=20 funds to experiment are allocated, we WON'T develop the / any ability!! = Even if=20 we could only get timely warning for a few quake locations / depths, the = benefits could be very significant. A lot of the severe quakes are = associated=20 with subduction zones, like those off the west coast of the Americas, = but the=20 interval may be hundreds of = years.

      =20 Regards,

       Chris = Chapman=20 Subject: Re: Time of Quake?? From: John or Jan Lahr JohnJan@........ Date: Sat, 21 Apr 2007 21:26:09 -0700 To better visualize the way that seismic waves travel within the earth, I highly recommend downloading and running the free program SeismicWaves, which was written by Alan Jones. (He's also the author of AmaSeis and SeismicEruption). These programs are available from his web site: http://www.geol.binghamton.edu/faculty/jones/ You can also add your own trace to SeismicWaves; it's particularly easy if you're running AmaSeis, but any file in SAC format can be displayed. Cheers, John __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: RE: Predictions From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@......... Date: Sun, 22 Apr 2007 09:59:46 +0000 Hi all The best way, proven so far (that I know of) in predicting earthquakes is to monitor buildup of small earthquakes or monitor areas that lack earthquakes over a long periods of time but are active in earthquakes. In Iceland, both rules applies. Some areas make small earthquakes over a long period of time while other areas don't. I try to monitor for both signs. But this mixed sucsess. Regards. --=20 J=F3n Fr=EDmann http://www.jonfr.com http://www.simnet.is/jonfr500/earthquake/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Prediction From: Tangazazen@....... Date: Sun, 22 Apr 2007 08:52:04 EDT Hi all, As a new member of the group it's been interesting reading the numerous e-mail's. I hear a lot about millisecond timing of events, etc. which I am not in a position to do yet. I do wonder how important it is, last evening here in England I picked up the South Chile earth quake ( 17:53:47 Mag 6.2 ). Since this is situated in the shadow zone I only receive the surface waves. We are talking of a travel time of 45 minutes +/- 5 minutes. I suppose if the earthquake is on your back door then a few millisecond is important before it clobbers you. Martin Page
Hi all,
 
 As a new member of the group it's been interesting reading the=20 numerous e-mail's.
I hear a lot about millisecond timing of events, etc. which I am not in= =20 a position to do yet.
I do wonder how important it is, last evening here in England I picked=20= up=20 the South Chile earth quake ( 17:53:47 Mag 6.2 ). Since this is situated in=20= the=20 shadow zone I only receive the surface waves. We are talking of a travel tim= e of=20 45 minutes +/- 5 minutes. I suppose if the earthquake is on your back door t= hen=20 a few millisecond is important before it clobbers you.
 
 Martin Page 
 Subject: Re: Predictions From: Stephen & Kathy skmort@............ Date: Sun, 22 Apr 2007 15:34:38 -0700 FYI,, here is a 7 mag and moon phase study,, it is easy to mess up,, so, corrections are welcome! Stephen PSN Station #55 Comparing Moon Phase and 7.0 to 7.9 magnitude quakes. From the first of the following two web sites, I located 61 quakes in the magnitude range of 7.0 to 7.9 from the years 1812 to 2003. From the second link I found the Moon Phase at the time of the quake. I divided the phase into 4 approximately equal time quadrants. The phase and time quadrants work out to about the following. 0 to 15% = New Moon quadrant 85 to 100% = Full Moon quadrant 16 to 84% = first or last quarter quadrant For the data below, an F = First quarter, L = Last quarter quadrant http://en.wikipedia.org/wiki/List_of_earthquakes http://www.fourmilab.ch/cgi-bin/uncgi/Earth/action?opt=-m&img=Moon.evif It sorts out to the following: 0 to 15% = 17 85 to 100% = 12 16 to 84% at F = 15 16 to 84% at L = 17 Conclusion: Compared to the sorting of the 8 and 9 mag. quakes, the 7 mag. events seem to start averaging out! While the New Moon favors the Full Moon, the quarter moon quadrants have a slight edge over the new and full moon quadrants in this study! # Moon Year Mo. Day UTC Place Approx. Phase Mag. 1 76%F 1812 Jan 23 15:00 Missouri 7.8 2 47%L 1823 Jun 2 8:00 Hawaii 7.0 3 99% 1857 Jan 9 16:24 California 7.9 4 78%F 1868 Apr 3 2:25 Hawaii 7.9 5 97% 1872 Mar 26 10:30 California 7.6 6 99% 1872 Dec 15 5:40 Washington 7.3 7 10% 1873 Nov 23 5:00 Ca-Or coast 7.3 8 3% 1886 Aug 31 2:51 So Carolina 7.3 9 1% 1899 Sep 4 0:22 Alaska 7.9 10 98% 1900 Oct 9 12:28 Alaska 7.7 11 96% 1904 Aug 27 21:56 Alaska 7.3 12 23%L 1906 Apr 18 13:12 California 7.8 13 27%F 1908 Dec 28 4:20 Italy 7.2 14 32%L 1915 Oct 3 6:52 Nevada 7.1 15 33%F 1918 Oct 11 14:14 Puerto Rico 7.5 16 7% 1918 Dec 6 8:41 Canada 7.0 17 10% 1922 Jan 31 13:17 California 7.3 18 25%F 1923 Jan 22 9:04 California 7.2 19 72%L 1923 Sep 1 2:58 Japan 7.9 20 18%F 1927 Mar 7 9:27 Japan 7.6 21 64%L 1927 May 22 22:32 China 7.9 22 70%F 1927 Nov 4 13:51 California 7.1 23 95% 1929 Nov 18 20:32 Canada 7.3 24 45%L 1932 Dec 21 6:10 Nevada 7.2 25 15% 1933 Nov 20 23:21 Canada 7.4 26 99% 1937 Jul 22 17:09 Alaska 7.3 27 99% 1939 Dec 26 23:57 Turkey 7.8 28 92% 1940 May 19 4:36 California 7.1 29 0% 1946 Apr 1 12:28 Alaska 7.3 30 3% 1947 Oct 16 2:09 Alaska 7.2 31 99% 1949 Apr 13 19:55 Washington 7.1 32 0% 1952 Jul 21 11:52 California 7.3 33 33%L 1954 Mar 29 6:17 Spain 7.9 34 56%L 1954 Dec 16 11:07 Nevada 7.1 35 83%L 1958 Apr 7 15:30 Alaska 7.3 36 38%L 1958 Jul 10 6:15 Alaska 7.7 37 99% 1959 Aug 18 6:37 Montana 7.3 38 41%F 1964 Jun 16 4:01 Japan 7.5 39 11% 1970 May 31 20:23 Peru 7.9 40 37%L 1975 Feb 4 11:36 China 7.0 41 15% 1975 Nov 29 14:47 Hawaii 7.2 42 15% 1976 Feb 4 9:01 Guatemala 7.5 43 0% 1976 Jul 27 19:42 Tangshan 7.6 44 0% 1980 Nov 8 10:27 California 7.2 45 56%L 1983 Oct 28 14:06 Idaho 7.0 46 78%F 1987 Nov 30 19:23 Alaska 7.9 47 90% 1988 Mar 6 22:35 Alaska 7.8 48 56%F 1991 Aug 17 22:17 California 7.1 49 41%L 1992 Apr 25 18:06 California 7.2 50 5% 1992 Jun 28 11:57 California 7.3 51 30%F 1992 Sep 2 0:16 Nicaragua 7.7 52 19%L 1994 Sep 1 15:15 California 7.1 53 41%L 1998 Jul 17 8:49 New Guinea 7.0 54 30%F 1999 Aug 17 0:01 Turkey 7.6 55 76%F 1999 Sep 20 17:47 Taiwan 7.7 56 38%F 1999 Oct 16 9:46 California 7.2 57 17%F 1999 Nov 12 16:57 Turkey 7.2 58 79%L 2001 Jan 13 17:33 El Salvador 7.7 59 2% 2001 Jan 26 3:16 India 7.7 60 1% 2002 Nov 3 22:12 Alaska 7.9 61 48%L 2003 Nov 17 6:43 Alaska 7.8 tchannel wrote: > Stephen and Everyone, This is just great input....Stephen, Yes I sure > would like to see your study expanded to include M6 and M7's. I > printed you message. I wish I know something about Statistics. > Thanks, Ted FYI,,  here is a 7 mag and moon phase study,,  it is easy
to mess up,,  so, corrections are welcome!
  Stephen
  PSN Station #55

    Comparing Moon Phase and 7.0 to 7.9 magnitude quakes.
From the first of the following two web sites, I located 61 quakes
in the magnitude range of 7.0 to 7.9   from the years  1812 to 2003.
From the second link I found the Moon Phase at the time of the quake.
I divided the phase into 4 approximately equal time quadrants.
The phase and time quadrants work out to about the following.
         0 to  15% = New Moon quadrant
        85 to 100% = Full Moon quadrant
        16 to 84%  = first or last quarter quadrant
    For the data below, an F = First quarter, L = Last quarter quadrant
http://en.wikipedia.org/wiki/List_of_earthquakes
http://www.fourmilab.ch/cgi-bin/uncgi/Earth/action?opt=-m&img=Moon.evif
    It sorts out to the following:
         0 to 15%       = 17
        85 to 100%      = 12
        16 to 84% at F  = 15
        16 to 84% at L  = 17
Conclusion:
    Compared to the sorting of the 8 and 9 mag. quakes, the 7 mag.
    events seem to start averaging out!  While the New Moon favors
    the Full Moon, the quarter moon quadrants have a slight edge
    over the new and full moon quadrants in this study!  

 #  Moon  Year  Mo. Day   UTC    Place     Approx.
    Phase                                   Mag.
 1  76%F  1812  Jan  23  15:00  Missouri    7.8
 2  47%L  1823  Jun   2   8:00  Hawaii      7.0
 3  99%   1857  Jan   9  16:24  California  7.9
 4  78%F  1868  Apr   3   2:25  Hawaii      7.9
 5  97%   1872  Mar  26  10:30  California  7.6
 6  99%   1872  Dec  15   5:40  Washington  7.3
 7  10%   1873  Nov  23   5:00  Ca-Or coast 7.3
 8   3%   1886  Aug  31   2:51  So Carolina 7.3
 9   1%   1899  Sep   4   0:22  Alaska      7.9
10  98%   1900  Oct   9  12:28  Alaska      7.7
11  96%   1904  Aug  27  21:56  Alaska      7.3
12  23%L  1906  Apr  18  13:12  California  7.8
13  27%F  1908  Dec  28   4:20  Italy       7.2
14  32%L  1915  Oct   3   6:52  Nevada      7.1
15  33%F  1918  Oct  11  14:14  Puerto Rico 7.5
16   7%   1918  Dec   6   8:41  Canada      7.0
17  10%   1922  Jan  31  13:17  California  7.3
18  25%F  1923  Jan  22   9:04  California  7.2
19  72%L  1923  Sep   1   2:58  Japan       7.9
20  18%F  1927  Mar   7   9:27  Japan       7.6
21  64%L  1927  May  22  22:32  China       7.9
22  70%F  1927  Nov   4  13:51  California  7.1
23  95%   1929  Nov  18  20:32  Canada      7.3
24  45%L  1932  Dec  21   6:10  Nevada      7.2
25  15%   1933  Nov  20  23:21  Canada      7.4
26  99%   1937  Jul  22  17:09  Alaska      7.3
27  99%   1939  Dec  26  23:57  Turkey      7.8
28  92%   1940  May  19   4:36  California  7.1
29   0%   1946  Apr   1  12:28  Alaska      7.3
30   3%   1947  Oct  16   2:09  Alaska      7.2
31  99%   1949  Apr  13  19:55  Washington  7.1
32   0%   1952  Jul  21  11:52  California  7.3
33  33%L  1954  Mar  29   6:17  Spain       7.9
34  56%L  1954  Dec  16  11:07  Nevada      7.1
35  83%L  1958  Apr   7  15:30  Alaska      7.3
36  38%L  1958  Jul  10   6:15  Alaska      7.7
37  99%   1959  Aug  18   6:37  Montana     7.3
38  41%F  1964  Jun  16   4:01  Japan       7.5
39  11%   1970  May  31  20:23  Peru        7.9
40  37%L  1975  Feb   4  11:36  China       7.0
41  15%   1975  Nov  29  14:47  Hawaii      7.2
42  15%   1976  Feb   4   9:01  Guatemala   7.5
43   0%   1976  Jul  27  19:42  Tangshan    7.6
44   0%   1980  Nov   8  10:27  California  7.2
45  56%L  1983  Oct  28  14:06  Idaho       7.0
46  78%F  1987  Nov  30  19:23  Alaska      7.9
47  90%   1988  Mar   6  22:35  Alaska      7.8
48  56%F  1991  Aug  17  22:17  California  7.1
49  41%L  1992  Apr  25  18:06  California  7.2
50   5%   1992  Jun  28  11:57  California  7.3
51  30%F  1992  Sep   2   0:16  Nicaragua   7.7
52  19%L  1994  Sep   1  15:15  California  7.1
53  41%L  1998  Jul  17   8:49  New Guinea  7.0     
54  30%F  1999  Aug  17   0:01  Turkey      7.6
55  76%F  1999  Sep  20  17:47  Taiwan      7.7     
56  38%F  1999  Oct  16   9:46  California  7.2
57  17%F  1999  Nov  12  16:57  Turkey      7.2
58  79%L  2001  Jan  13  17:33  El Salvador 7.7
59   2%   2001  Jan  26   3:16  India       7.7
60   1%   2002  Nov   3  22:12  Alaska      7.9
61  48%L  2003  Nov  17   6:43  Alaska      7.8
 
tchannel wrote:
Stephen and Everyone,  This is just great input....Stephen, Yes I sure would like to see your study expanded to include M6 and M7's.   I printed you message.   I wish I know something about Statistics.
Thanks, Ted
Subject: Inverse filter for seismic sensors. From: Bobhelenmcclure@....... Date: Mon, 23 Apr 2007 22:19:04 EDT I am an amateur seismographer, located in Locust Valley, NY. My station consists of home built sensors of rather short natural period. Out of necessity, I have developed a digital inverse filter, which allows extension of the natural period of the sensors to five or more times their natural period. It took a lot of grunting and straining to perfect this filter, and I want to share it with anybody who could benefit. It ended up being simple to code and use. All you need to set it up is the natural period and damping of the sensor, and the desired filter period. It can be used in real time or on completed files. In case you have any need to enhance the performance of geophones or any other open loop sensor you operate, please refer to web page _http://www.jclahr.com/science/psn/mcclure/filter.html_ (http://www.jclahr.com/science/psn/mcclure/filter.html) This page describes the analog prototype of the filter and the pseudocode for its digital version. A mathematical analysis demonstrates that the filter's frequency response is correct. This filter is implemented in my programs "WQFilter.exe" and "Heliplot.exe", which can be downloaded from _http://www.jclahr.com/science/psn/mcclure/wdq_utilities/index.html_ (http://www.jclahr.com/science/psn/mcclure/wdq_utilities/index.html) "WQFilter.exe" is a utility program for filtering WinQuake PSN Type 4 event files. "Heliplot.exe" is a program for filtering and displaying Dataq WQD format files. It would be easy for me to code these applications for other file formats, including Little Endian SAC binary files. Dr. Alan Jones has also incorporated this filter into "AmaSeis.exe" for filtering SAC binary format event files. However, the version he has coded is no longer up-to-date, and the response is not quite so accurate as the latest version. All my applications are written using Visual Basic 6.0 for Windows. Alan is currently re-coding Amaseis using Java, so that it can be compiled for other operating systems. Please note that "WQFilter.exe" also includes Butterworth filters for lowpass and highpass filtering. Forward, backward, and forward-backward filtering can be selected. If you apply both my period extending filter and a second order highpass backward filter to the event data, you can end up with a broader bandwidth file which has no phase distortion and no time delay in the passband. Robert (Bob) McClure ************************************** See what's free at http://www.aol.com.
  I am an amateur seismographer, located in Locust Valley, NY. My=20 station consists of home built sensors of rather short natural period. Out o= f=20 necessity, I have developed a digital inverse filter, which allows extension= of=20 the natural period of the sensors to five or more times their natural period= .. It=20 took a lot of grunting and straining to perfect this filter, and I want to s= hare=20 it with anybody who could benefit. It ended up being simple to code and use.= All=20 you need to set it up is the natural period and damping of the sensor, and t= he=20 desired filter period. It can be used in real time or on completed files.
 
  In case you have any need to enhance the performance of geophone= s or=20 any other open loop sensor you operate, please refer to web page
 
  http://www.jc= lahr.com/science/psn/mcclure/filter.html
 
  This page describes the analog prototype of the filter and the=20 pseudocode for its digital version. A mathematical analysis demonstrates tha= t=20 the filter's frequency response is correct.
 
  This filter is implemented in my programs "WQFilter.exe" and=20 "Heliplot.exe", which can be downloaded from
 
  = http://www.jclahr.com/science/psn/mcclure/wdq_utilities/index.html
 
  "WQFilter.exe" is a utility program for filtering WinQuake PSN T= ype=20 4 event files. "Heliplot.exe" is a program for filtering and displaying Data= q=20 WQD format files. It would be easy for me to code these applications for oth= er=20 file formats, including Little Endian SAC binary files.
 
  Dr. Alan Jones has also incorporated this filter into "AmaSeis.e= xe"=20 for filtering SAC binary format event files. However, the version he has cod= ed=20 is no longer up-to-date, and the response is not quite so accurate as the la= test=20 version.
 
  All my applications are written using Visual Basic 6.0 for Windo= ws.=20 Alan is currently re-coding Amaseis using Java, so that it can be compiled f= or=20 other operating systems.
 
  Please note that "WQFilter.exe" also includes Butterworth filter= s=20 for lowpass and highpass filtering. Forward, backward, and forward-backward=20 filtering can be selected. If you apply both my period extending filter and=20= a=20 second order highpass backward filter to the event data, you can end up with= a=20 broader bandwidth file which has no phase distortion and no time delay = in=20 the passband.
 
Robert (Bob) McClure



=
See what's free at AOL.com.
Subject: Unknown earthquake From: "tchannel" tchannel@.............. Date: Tue, 24 Apr 2007 09:07:49 -0600 Hi folks, At 04:33:13 UTC on 2007/04/24 I receive a moderate/light = earthquake trace. I went to the USGS and see nothing posted for that time, except 3.7M at = 04:24:09 In Alaska. I guess that must be it, but I was surprise that a = 3.7m was recorded from that distance, and that clear. At first glance, = I thought it was Local, somewhere near Idaho. I looked a Hailey Id. = station, and they saw it bigtime. Other stations, few reliable, in = this area, showed smaller recording. Has anyone seen this one, and is it the 3.7m from Alaska? I will = process it and see where the P and S fall. Thanks, Ted
Hi folks,  At 04:33:13 UTC on = 2007/04/24 I=20 receive a moderate/light earthquake trace.
I went to the USGS and see nothing = posted for that=20 time, except 3.7M at 04:24:09 In Alaska.  I guess that must be it, = but I=20 was surprise that a 3.7m was recorded from that distance, and that = clear. =20  At first glance, I thought it was Local, somewhere near = Idaho.  I=20 looked a Hailey Id. station, and they saw it bigtime.   Other=20 stations, few reliable, in this area, showed smaller=20 recording.
 
Has anyone seen this one, and is it the = 3.7m from=20 Alaska?   I will process it and see where the P and S=20 fall.
Thanks, Ted
Subject: Re: Unknown earthquake From: John or Jan Lahr JohnJan@........ Date: Tue, 24 Apr 2007 09:14:44 -0700 At 08:07 AM 4/24/2007, you wrote: >Hi folks, At 04:33:13 UTC on 2007/04/24 I receive a moderate/light >earthquake trace. >I went to the USGS and see nothing posted for that time, except 3.7M >at 04:24:09 In Alaska. I guess that must be it, but I was surprise >that a 3.7m was recorded from that distance, and that clear. At >first glance, I thought it was Local, somewhere near Idaho. I >looked a Hailey Id. station, and they saw it bigtime. Other >stations, few reliable, in this area, showed smaller recording. > >Has anyone seen this one, and is it the 3.7m from Alaska? I will >process it and see where the P and S fall. >Thanks, Ted There appears to be a swarm of events on the mid-Atlantic ridge See: http://aslwww.cr.usgs.gov/Seismic_Data/telemetry_data/BBSR_24hr.html I don't see an event at 04:33 on 4/24 however. John __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Unknow earthquake From: "tchannel" tchannel@.............. Date: Tue, 24 Apr 2007 10:17:40 -0600 I processed this 04:24:09 Alaska Earthquake M3.7 My event was recorded 54 seconds later. I check my clock and it was accurate. This is new to me in, that, = first my trace looked too large for a M3.7 from Alaska. My trace arrived 54 seconds too late for Alaska. I have been looking and have found nothing, that matches. Any help = would be appreciated. Thanks, Ted
I processed this 04:24:09 Alaska = Earthquake=20 M3.7
My event was recorded 54 seconds=20 later.
I check my clock and it was = accurate.  =20 This is new to me in, that, first my trace looked too large for a M3.7 = from=20 Alaska.
My trace arrived 54 seconds too late = for=20 Alaska.
I have been looking and have found = nothing, that=20 matches.  Any help would be appreciated.
Thanks, Ted
 
Subject: Re: Unknown earthquake From: "Geoffrey" gmvoeth@........... Date: Tue, 24 Apr 2007 10:01:19 -0700 I am at 33.42138N -111.57477W and as of 17:00 UTC have had nothing record with an MDL (Minimum Discernable Level) of 4.0 (Richter) at 6 degrees away. You can translate that sensitivity if you know how to other distances. My station is SPZ only. If you want to see a satellite image try out free GOOGLE EARTH they have a nice satellite image of my place there. ----- Original Message ----- From: "tchannel" To: Sent: Tuesday, April 24, 2007 08:07 Subject: Unknown earthquake Hi folks, At 04:33:13 UTC on 2007/04/24 I receive a moderate/light earthquake trace. I went to the USGS and see nothing posted for that time, except 3.7M at 04:24:09 In Alaska. I guess that must be it, but I was surprise that a 3.7m was recorded from that distance, and that clear. At first glance, I thought it was Local, somewhere near Idaho. I looked a Hailey Id. station, and they saw it bigtime. Other stations, few reliable, in this area, showed smaller recording. Has anyone seen this one, and is it the 3.7m from Alaska? I will process it and see where the P and S fall. Thanks, Ted __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Heliplot and filtering From: "Randy" rpratt@............. Date: Tue, 24 Apr 2007 13:09:48 -0500 Hi All, I have been using Bob's programs with the Dataq 154 for about 6 months. = The period extending filter is very useful with a short period = instrument such as the 1.35 sec vertical I finished this winter. I have = also found advantages that Bob has not mentioned using the logger and = heliplot programs. With heliplot I can view 2 or more filters on the = same channel simultaniously either while recording or from history. = Also, I can view 1 to 4 channels real time from one AD and com port. = Finally, I can export directly from Heliplot to create a single channel = filtered file and bypass having to split the Windaq format into single = channels if I wish to convert to PSN format. I have really appreciated = the ability to get full use of the Dataq device.
Hi All,
 
I have been using Bob's programs with = the Dataq 154=20 for about 6 months.  The period extending filter is very useful = with a=20 short period instrument such as the 1.35 sec vertical I finished this=20 winter.  I have also found advantages that Bob has not mentioned = using the=20 logger and heliplot programs.  With heliplot I can view 2 or more = filters=20 on the same channel simultaniously either while recording or from = history. =20 Also, I can view 1 to 4 channels real time from one AD and com = port. =20 Finally, I can export directly from Heliplot to create a single channel = filtered=20 file and bypass having to split the Windaq format into single channels = if I wish=20 to convert to PSN format.  I have really appreciated the ability to = get=20 full use of the Dataq device. 
Subject: Re: Unknow earthquake From: "Dave Wolny" dwolny@............. Date: Tue, 24 Apr 2007 15:44:17 -0600 Ted, Looks like this event is much closer to you then Alaska. Check out the = following helicorder at University of Utah (Hansel Valley). =20 http://www.seis.utah.edu/helicorder/heli/utah/Uuss.HVU_SHZ_UU.2007042300.gi= f =20 The event should have an OT of around 04:33+ Dave >>> "tchannel" 04/24/07 10:17 AM >>> I processed this 04:24:09 Alaska Earthquake M3.7 My event was recorded 54 seconds later. I check my clock and it was accurate. This is new to me in, that, first = my trace looked too large for a M3.7 from Alaska. My trace arrived 54 seconds too late for Alaska. I have been looking and have found nothing, that matches. Any help would = be appreciated. Thanks, Ted __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Inverse filter for seismic sensors. From: "Jim ODonnell" geophysics@.......... Date: Tue, 24 Apr 2007 22:27:29 GMT Hi Bob- Well your timing is good. = I am getting ready to deploy 3 BH seismometers down hole and am using th= e Mark Products L15B (4.5Hz) elements. Two deployments will be at the S= kyWalk Bridge, AZ and 1 at the new NV State College in Henderson. The L15B goes for ~$100/component where the better L4 (1Hz) is ~$1K/comp= onent and is a much larger size than the geophone. You essentially have turned my L15 geophones into a L4...T~0.2s to 1s. = I will let you know how your filter works and THANKS......Jim Jim O'Donnell = Geological/Geophysical Consultant GEOTECHNICAL APPLICATIONS 702.293.5664 geophysics@.......... 702.281.9081 cell jimo17@........ -- Bobhelenmcclure@....... wrote: I am an amateur seismographer, located in Locust Valley, NY. My statio= n consists of home built sensors of rather short natural period. Out of = necessity, I have developed a digital inverse filter, which allows exten= sion of the natural period of the sensors to five or more times their na= tural period. It took a lot of grunting and straining to perfect this fi= lter, and I want to share it with anybody who could benefit. It ended up= being simple to code and use. All you need to set it up is the natural = period and damping of the sensor, and the desired filter period. It can = be used in real time or on completed files. In case you have any need = to enhance the performance of geophones or any other open loop sensor yo= u operate, please refer to web page http://www.jclahr.com/science/psn= /mcclure/filter.html This page describes the analog prototype of the f= ilter and the pseudocode for its digital version. A mathematical analysi= s demonstrates that the filter's frequency response is correct. This f= ilter is implemented in my programs "WQFilter.exe" and "Heliplot.exe", w= hich can be downloaded from http://www.jclahr.com/science/psn/mcclure/= wdq_utilities/index.html "WQFilter.exe" is a utility program for filte= ring WinQuake PSN Type 4 event files. "Heliplot.exe" is a program for fi= ltering and displaying Dataq WQD format files. It would be easy for me t= o code these applications for other file formats, including Little Endia= n SAC binary files. Dr. Alan Jones has also incorporated this filter i= nto "AmaSeis.exe" for filtering SAC binary format event files. However, = the version he has coded is no longer up-to-date, and the response is no= t quite so accurate as the latest version. All my applications are wri= tten using Visual Basic 6.0 for Windows. Alan is currently re-coding Ama= seis using Java, so that it can be compiled for other operating systems.= Please note that "WQFilter.exe" also includes Butterworth filters for= lowpass and highpass filtering. Forward, backward, and forward-backward= filtering can be selected. If you apply both my period extending filter= and a second order highpass backward filter to the event data, you can = end up with a broader bandwidth file which has no phase distortion and n= o time delay in the passband. Robert (Bob) McClure See what's free at AOL.com.

Hi Bob- Well your timing is good.  
I am getting r= eady to deploy 3 BH seismometers down hole and am using the Mark Product= s L15B (4.5Hz) elements.  Two deployments will be at the SkyWalk Br= idge, AZ and 1 at the new NV State College in Henderson.

The L15B goes for ~$100/component where the better L4 (1Hz) is ~$1K/c= omponent and is a much larger size than the geophone.
You essentially= have turned my L15 geophones into a L4...T~0.2s to 1s. 
I will = let you know how your filter works and THANKS......Jim




         &nb= sp;         Jim O'Donn= ell     
      = ;   Geological/Geophysical Consultant
  = ;          GEOTECHNICA= L APPLICATIONS
702.293.5664     geophysics@m= ysite.com
702.281.9081 cell   jimo17@........
=
-- Bobhelenmcclure@....... wrote:

  I am an amateur seismographer, located in Locust Valley, NY.= My station consists of home built sensors of rather short natural perio= d. Out of necessity, I have developed a digital inverse filter, which al= lows extension of the natural period of the sensors to five or more time= s their natural period. It took a lot of grunting and straining to perfe= ct this filter, and I want to share it with anybody who could benefit. I= t ended up being simple to code and use. All you need to set it up is th= e natural period and damping of the sensor, and the desired filter perio= d. It can be used in real time or on completed files.
 
  In case you have any need to enhance the performance of geop= hones or any other open loop sensor you operate, please refer to web pag= e
 
 
  This page describes the analog prototype of the filter and t= he pseudocode for its digital version. A mathematical analysis demonstra= tes that the filter's frequency response is correct.
 
  This filter is implemented in my programs "WQFilter.exe" and= "Heliplot.exe", which can be downloaded from
 
 
  "WQFilter.exe" is a utility program for filtering WinQuake P= SN Type 4 event files. "Heliplot.exe" is a program for filtering and dis= playing Dataq WQD format files. It would be easy for me to code these ap= plications for other file formats, including Little Endian SAC binary fi= les.
 
  Dr. Alan Jones has also incorporated this filter into "AmaSe= is.exe" for filtering SAC binary format event files. However, the versio= n he has coded is no longer up-to-date, and the response is not quite so= accurate as the latest version.
 
  All my applications are written using Visual Basic 6.0 for W= indows. Alan is currently re-coding Amaseis using Java, so that it can b= e compiled for other operating systems.
 
  Please note that "WQFilter.exe" also includes Butterworth fi= lters for lowpass and highpass filtering. Forward, backward, and forward= -backward filtering can be selected. If you apply both my period extendi= ng filter and a second order highpass backward filter to the event data,= you can end up with a broader bandwidth file which has no phase distort= ion and no time delay in the passband.
 
Robert (Bob) McClure



See what's free at AOL.com.
Subject: My error From: "tchannel" tchannel@.............. Date: Tue, 24 Apr 2007 17:30:22 -0600 Hi Folk, I think I have found my mystery earthquake. It was the M3.7 = 04/24/2007 04:24:09 utc from Alaska This is what happen, "someone might learn from my mistake" I adjust my = clock manually, often it is off by many seconds, I advance the clock to = the next minute, and when the times match I push "okay" to reset my = computer clock, to the correct time. Works fine unless I put in an = extra minute. So instead of an adjustment of + 4 second I adjusted +64 = seconds. I went to the second station, we are operating, at the Museum. That = station recorded the same event and the P and S were placed correctly. = I was sure my problem had to do with my equipment, and this event was = surely the Alaska M3.7 I made an clock adjustment of +64 seconds to my station and the P and S = were right on. The thing that fooled me was I could not believe a M 3.7 from Alaska = 4816km or 2992 miles from Boise was so pronounced. Thanks, for you advise. Ted
Hi Folk,  I think I have = found  my=20 mystery earthquake.  It was the  M3.7 04/24/2007 04:24:09 utc = from=20 Alaska
 
This is what happen, "someone might = learn from my=20 mistake"  I adjust my clock manually, often it is off by many = seconds, I=20 advance the clock to the next minute, and when the times match I push = "okay" to=20 reset my computer clock, to the correct time.  Works fine unless I = put in=20 an extra minute.  So instead of an adjustment of + 4 second I = adjusted +64=20 seconds.
 
I went to the second station, we are = operating, at=20 the Museum.  That station recorded the same event and the P and S = were=20 placed correctly.  I was sure my problem had to do with my = equipment, and=20 this event was surely the Alaska  M3.7
 
I made an clock adjustment of +64 = seconds to my=20 station and the P and S were right on.
 
The thing that fooled me was I could = not believe a=20 M 3.7 from Alaska 4816km or 2992 miles from Boise was so=20 pronounced.
 
 
Thanks, for you advise.  =20 Ted
Subject: Re: My error From: Angel sismos@.............. Date: Wed, 25 Apr 2007 00:10:23 +0000

Hello Ted,


Is your "seismo computer" on the internet even for a few minutes a day?? You could then use any of many time servers to set the clock on that computer.  There is even software that learns the drift of your clock and tries to keep it in closer time than a few seconds.


Angel


Tuesday, April 24, 2007, 11:30:22 PM, you wrote:


>

Hi Folk,  I think I have found  my mystery earthquake.  It was the  M3.7 04/24/2007 04:24:09 utc from Alaska

 

This is what happen, "someone might learn from my mistake"  I adjust my clock manually, often it is off by many seconds, I advance the clock to the next minute, and when the times match I push "okay" to reset my computer clock, to the correct time.  Works fine unless I put in an extra minute.  So instead of an adjustment of + 4 second I adjusted +64 seconds.

 

I went to the second station, we are operating, at the Museum.  That station recorded the same event and the P and S were placed correctly.  I was sure my problem had to do with my equipment, and this event was surely the Alaska  M3.7

 

I made an clock adjustment of +64 seconds to my station and the P and S were right on.

 

The thing that fooled me was I could not believe a M 3.7 from Alaska 4816km or 2992 miles from Boise was so pronounced.

 

 

Thanks, for you advise.   Ted





-- 

Best regards,

 Angel

Subject: Re: My error From: ChrisAtUpw@....... Date: Wed, 25 Apr 2007 10:34:32 EDT In a message dated 2007/04/25, tchannel@.............. writes: > I adjust my clock manually, often it is off by many seconds, I advance the > clock to the next minute, and when the times match I push "okay" to reset my > computer clock, to the correct time. Works fine unless I put in an extra > minute. So instead of an adjustment of + 4 second I adjusted +64 seconds. Hi Ted, You can get details of time servers from http://tf.nist.gov/timefreq/index.html A good free server is AboutTime See http://www.arachnoid.com/abouttime/ It sends you the correct time, your computer then 'pings' AboutTime, which returns the signal immediatly, allowing your computer to measure and correct for time delays on the line. It is possible to buy a WWVB time receiver which automatically corrects your computer or network. Another alternative is to buy one of the Radio Corrected WWVB wall clocks with a sweep second hand. You can fit a LED and a photocell on the dial and sense the second hand for the minute marks. Bob does this Bobhelenmc clure@....... - you need a large second hand to do this, or an Al foil extension. I am not sure what software he uses. I seem to remember that you can also buy the radio PCB and a computer board to decode WWVB signals from Galleon at http://www.ntp-time-server.com/ These are produced in Germany for all radio time systems. I use a similar system on DCF77 in Europe. Regards, Chris Chapman In a me= ssage dated 2007/04/25, tchannel@.............. writes:

I adjust my clock manually, oft= en it is off by many seconds, I advance the clock to the next minute, and wh= en the times match I push "okay" to reset my computer clock, to the correct=20= time.  Works fine unless I put in an extra minute.  So instead of=20= an adjustment of + 4 second I adjusted +64 seconds.


Hi Ted,

       You can get details of time servers fro= m http://tf.nist.gov/timefreq/index.html

       A good free server is AboutTime See http://www.arachnoid.com/aboutt= ime/
       It sends you the correct time, your com= puter then 'pings' AboutTime, which returns the signal immediatly, allowing=20= your computer to measure and correct for time delays on the line.

    It is possible to buy a WWVB time receiver which automati= cally  corrects your computer or network.

       Another alternative is to buy one of th= e Radio Corrected WWVB wall clocks with a sweep second hand. You can fit a L= ED and a photocell on the dial and sense the second hand for the minute mark= s. Bob does this Bobhelenmcclure@....... - you need a large second hand to d= o this, or an Al foil extension. I am not sure what software he uses.
  
       I seem to remember that you can also bu= y the radio PCB and a computer board to decode WWVB signals from Galleon at=20= http://www.ntp-time-server.com/ These are produced in Germany for all radio=20= time systems. I use a similar system on DCF77 in Europe.

       Regards,

       Chris Chapman
 Subject: Re: My error From: "Kris Paige" bluegrey@............. Date: Wed, 25 Apr 2007 11:35:59 -0800 who are you guys trying to communicate w/ I don't know you!! ----- Original Message -----=20 From: ChrisAtUpw@.......... To: psn-l@................. Sent: Wednesday, April 25, 2007 6:34 AM Subject: Re: My error In a message dated 2007/04/25, tchannel@.............. writes: I adjust my clock manually, often it is off by many seconds, I = advance the clock to the next minute, and when the times match I push = "okay" to reset my computer clock, to the correct time. Works fine = unless I put in an extra minute. So instead of an adjustment of + 4 = second I adjusted +64 seconds. Hi Ted, You can get details of time servers from = http://tf.nist.gov/timefreq/index.html A good free server is AboutTime See = http://www.arachnoid.com/abouttime/=20 It sends you the correct time, your computer then 'pings' = AboutTime, which returns the signal immediatly, allowing your computer = to measure and correct for time delays on the line. It is possible to buy a WWVB time receiver which automatically = corrects your computer or network.=20 Another alternative is to buy one of the Radio Corrected WWVB = wall clocks with a sweep second hand. You can fit a LED and a photocell = on the dial and sense the second hand for the minute marks. Bob does = this Bobhelenmcclure@....... - you need a large second hand to do this, = or an Al foil extension. I am not sure what software he uses. =20 I seem to remember that you can also buy the radio PCB and a = computer board to decode WWVB signals from Galleon at = http://www.ntp-time-server.com/ These are produced in Germany for all = radio time systems. I use a similar system on DCF77 in Europe. Regards, Chris Chapman
who are you guys trying to communicate = w/ I don't=20 know you!!
----- Original Message -----
From:=20 ChrisAtUpw@.......
Sent: Wednesday, April 25, 2007 = 6:34=20 AM
Subject: Re: My error

In a=20 message dated 2007/04/25, tchannel@..............=20 writes:

I adjust my clock manually, often it is off by many = seconds, I=20 advance the clock to the next minute, and when the times match I = push "okay"=20 to reset my computer clock, to the correct time.  Works fine = unless I=20 put in an extra minute.  So instead of an adjustment of + 4 = second I=20 adjusted +64 seconds.

Hi=20 Ted,

       You can get details = of time=20 servers from=20 = http://tf.nist.gov/timefreq/index.html

    &nb= sp; =20 A good free server is AboutTime See http://www.arachnoid.com/abo= uttime/=20
       It sends you the correct = time, your=20 computer then 'pings' AboutTime, which returns the signal immediatly, = allowing=20 your computer to measure and correct for time delays on the=20 line.

    It is possible to buy a WWVB time = receiver=20 which automatically  corrects your computer or network.=20

       Another alternative is to = buy one=20 of the Radio Corrected WWVB wall clocks with a sweep second hand. You = can fit=20 a LED and a photocell on the dial and sense the second hand for the = minute=20 marks. Bob does this Bobhelenmcclure@....... - you need a large second = hand to=20 do this, or an Al foil extension. I am not sure what software he=20 uses.
  
       I seem = to=20 remember that you can also buy the radio PCB and a computer board to = decode=20 WWVB signals from Galleon at http://www.ntp-time-server.com/ These are = produced in Germany for all radio time systems. I use a similar system = on=20 DCF77 in Europe.

      =20 Regards,

       Chris=20 Chapman
 Subject: Seismology Books Suggestions From: "Rex Klopfenstein" rklopfen@......... Date: Thu, 26 Apr 2007 20:39:57 -0400 All I have a copy of "Modern Global Seismology" by Lay & Wallace. I am looking for suggestions of book titles on seismology. Any suggestions would be greatly appreciated. Thanks Rex Klopfenstein Bowling Green, OH 43402

All

I have a copy of “Modern Global = Seismology” by Lay & Wallace.  I am looking for suggestions of book titles on = seismology.  Any suggestions would be greatly = appreciated.

Thanks

 

Rex Klopfenstein

Bowling = Green, OH  43402

 

Subject: Re: Seismology Books Suggestions From: Angel sismos@.............. Date: Fri, 27 Apr 2007 01:04:31 +0000

Hello Rex,


I have lots of books on Seismology, lots, but the one that really got me going and fascinates me every time I read it is


Ota Kulhanek's book "anatomy of seismograms"  it is still in print and still being sold for a ridiculously high price. 


It is basic, simple, clear and full of examples.  If only everyone would be so clear.  178 pages and sells for a little under a dollar a page.  Mine was a gift or I might never have bought it.


Angel


Friday, April 27, 2007, 12:39:57 AM, you wrote:


>

All

I have a copy of “Modern Global Seismology” by Lay & Wallace.  I am looking for suggestions of book titles on seismology.  Any suggestions would be greatly appreciated.

Thanks

 

Rex Klopfenstein

Bowling Green, OH  43402

 





-- 

Best regards,

 Angel

Subject: Re: Seismology Books Suggestions From: Angel sismos@.............. Date: Fri, 27 Apr 2007 01:24:45 +0000

Hello Rex and everyone,


I guess that is must not be in print because I just serached for it and found these two items:


http://product.half.ebay.com/Anatomy-of-Seismograms_W0QQtgZinfoQQprZ652217


http://www.amazon.com/gp/offer-listing/0444883754/ref=dp_olp_1/103-1726741-7299048



If this is the case maybe I will scan mine and make it available to the list, I have to think a bit about this.


angel




Friday, April 27, 2007, 12:39:57 AM, you wrote:


>

All

I have a copy of “Modern Global Seismology” by Lay & Wallace.  I am looking for suggestions of book titles on seismology.  Any suggestions would be greatly appreciated.

Thanks

 

Rex Klopfenstein

Bowling Green, OH  43402

 





-- 

Best regards,

 Angel

Subject: Re: Seismology Books Suggestions From: "Jim ODonnell" geophysics@.......... Date: Fri, 27 Apr 2007 02:24:03 GMT Look at any of Bruce Bolt's books on Amazon: http://www.amazon.com/exec/obidos/search-handle-url/002-3142573-1306440?= %5Fencoding=3DUTF8&search-type=3Dss&index=3Dbooks&field-author=3DBruce%2= 0Bolt Jim O'Donnell = Geological/Geophysical Consultant GEOTECHNICAL APPLICATIONS 702.293.5664 geophysics@.......... 702.281.9081 cell jimo17@........ -- "Rex Klopfenstein" wrote: All I have a copy of =93Modern Global Seismology=94 by Lay & Wallace. I am = looking for suggestions of book titles on seismology. Any suggestions w= ould be greatly appreciated. Thanks = Rex Klopfenstein Bowling Green, OH 43402 =

Look at any of Bruce Bolt's books on Amazon:

http://www.amazon.com/exec/obidos/searc= h-handle-url/002-3142573-1306440?%5Fencoding=3DUTF8&search-type=3Dss= &index=3Dbooks&field-author=3DBruce%20Bolt




         &nb= sp;         Jim O'Donn= ell     
      = ;   Geological/Geophysical Consultant
  = ;          GEOTECHNICA= L APPLICATIONS
702.293.5664     geophysics@m= ysite.com
702.281.9081 cell   jimo17@........
=
-- "Rex Klopfenstein" <rklopfen@.........> = ;wrote:

All

I have a copy of =93Modern Global Seismolog= y=94 by Lay & Wallace.  I am looking for suggestions of book ti= tles on seismology.  Any suggestions would be greatly appreciated.<= o:p>

Thanks

 

Rex Klopfenstein

Bowling Green, OH  43402

 

Subject: RE: Seismology Books Suggestions From: "Bob Hancock" carpediem1@......... Date: Thu, 26 Apr 2007 20:33:42 -0700 Everyone - I had been searching for a copy of ANATOMY OF SEISMOGRAMS for several years. I would search on both Google and various book searches, and recently found it in a bookstore in the UK. It was a new copy with only shelf wear. The price was about $250, and my wife has demanded equal time. Keep looking, as this book appears to come up from time to time, and is truly one of the best, if not the best for seismogram interpretation. Another source for this book may be a university library. I found it in the University of Arizona (UA) library - however some schools have expensive library cards. When they raised the annual fee for a library card (non-student) from $60.00 to $100.00, I dropped the card. However, you should be able to enter their libraries for free and make copies of the areas you want for pennies per page. I have done that from time to time at the UA. Some other books to consider: WHOLE EARTH GEOPHYSICS - by Robert J. Lillie - It gives a good intro, and is light on math. This is used in introductory Geophysics courses. THE SEISMIC WAVEFIELD - by B.L.N. Kennett - This comes in two volumes - Volume 1 - Introduction and Theoretical Development (heavy on math), and Volume 2 Interpretation of Seismograms on Regional and Global Scales - I found this to be a good reference and the math is much reduced from Volume 1. AN INTRODUCTION TO SEISMOLOGY, EARTHQUAKES, and EARTH STRUCTURE - by Seth Stein and Michael Wysession - This is an introductory seismology text book used in several schools. The math in it is moderate, but there are many sections that are light on math. Another good reference book. THE MECHANICS OF EARTHQUAKES AND FAULTING - by Christopher H. Scholz - Another good reference book - Overall very light on math. INTRODUCTION TO SEISMOLOGY - by Peter M. Shearer - Another good reference book, but above average in math - I would class it as between moderate and heavy. PLATE TECTONICS - An Insider's History of the Modern Theory of the Earth - by Naomi Oreskes - An EXCELLENT book for the background on plate tectonics. Gives a good foundation in this subject. A BOOK TO AVOID - Unless you have a degree in mathematics: SEISMIC WAVES and SOURCES - by Ari Ben-Menahem and Sarva Jit Singh - VERY HEAVY IN MATH . I hope this helps. Bob Hancock Three Points, AZ _____ From: psn-l-request@.............. [mailto:psn-l-request@............... On Behalf Of Rex Klopfenstein Sent: Thursday, April 26, 2007 17:40 To: psn-l@.............. Subject: Seismology Books Suggestions All I have a copy of "Modern Global Seismology" by Lay & Wallace. I am looking for suggestions of book titles on seismology. Any suggestions would be greatly appreciated. Thanks Rex Klopfenstein Bowling Green, OH 43402

Everyone = –

 

I had been searching for a copy of = ANATOMY OF SEISMOGRAMS for several years.  I would search on both Google = and various book searches, and recently found it in a bookstore in the = UK.  It was a new copy with only shelf wear.  The price was about $250, and = my wife has demanded equal time.  Keep looking, as this book appears = to come up from time to time, and is truly one of the best, if not the best for seismogram interpretation. 

 

Another source for this book may be = a university library.  I found it in the University of Arizona (UA) library = – however some schools have expensive library cards.  When they raised the = annual fee for a library card (non-student) from $60.00 to $100.00, I dropped = the card.  However, you should be able to enter their libraries for = free and make copies of the areas you want for pennies per page.  I have = done that from time to time at the UA.

 

Some other books to = consider:

 

WHOLE EARTH GEOPHYSICS – by = Robert J. Lillie - It gives a good intro, and is light on math.  This is = used in introductory Geophysics courses. 

 

THE SEISMIC WAVEFIELD – by = B.L.N. Kennett – This comes in two volumes – Volume 1 – Introduction = and Theoretical Development (heavy on math), and Volume 2 Interpretation of Seismograms on Regional and Global Scales – I found this to be a = good reference and the math is much reduced from Volume = 1.

 

AN INTRODUCTION TO SEISMOLOGY, = EARTHQUAKES, and EARTH STRUCTURE – by Seth Stein and Michael Wysession – = This is an introductory seismology text book used in several schools.  The = math in it is moderate, but there are many sections that are light on = math.  Another good reference book.

 

THE MECHANICS OF EARTHQUAKES AND = FAULTING – by Christopher H. Scholz – Another good reference book – = Overall very light on math.

 

INTRODUCTION TO SEISMOLOGY – = by Peter M. Shearer – Another good reference book, but above average in = math – I would class it as between moderate and = heavy.

 

PLATE TECTONICS – An = Insider’s History of the Modern Theory of the Earth – by Naomi Oreskes = – An EXCELLENT book for the background on plate tectonics.  Gives a good = foundation in this subject.

 

A BOOK TO AVOID – Unless you = have a degree in mathematics:

 

SEISMIC WAVES and SOURCES – = by Ari Ben-Menahem and Sarva Jit Singh – VERY HEAVY IN MATH = ..

 

I hope this = helps.

 

Bob = Hancock

Three Points, = AZ

 

From: = psn-l-request@.............. [mailto:psn-l-request@............... On Behalf Of Rex Klopfenstein
Sent: Thursday, April 26, = 2007 17:40
To: = psn-l@..............
Subject: Seismology Books Suggestions

 

All

I have a copy of “Modern Global = Seismology” by Lay & Wallace.  I am looking for suggestions of book titles on seismology.  Any suggestions would be greatly = appreciated.

Thanks

 

Rex Klopfenstein

Bowling = Green, OH  43402

 

Subject: Loudspeader Seismograph From: "Arie Verveer" greensky@.............. Date: Fri, 27 Apr 2007 11:45:12 +0800 Hi, The "May 2007" issue of "elektor electronics" magazine, contains an article using a loudspeaker as a vibration sensor (seismograph). Plus an article on ELF reception and a magnetometer. www.elektor-electronics.co.uk May be of interest ? Cheers Arie __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Fwd: Loudspeader Seismograph From: John or Jan Lahr JohnJan@........ Date: Thu, 26 Apr 2007 22:43:35 -0700 Hi Lars, What can you tell me about the seismic system that's being sold via Elektor? Do you have any seismograms of recorded earthquakes? Have you considered joining the Public Seismic Network to share your experience and plans? What software is required for compilation? Some of the zip files require a password. Why is that? Thanks, John Lahr >X-Original-To: jclahr >Delivered-To: jclahr@.................. >Date: Fri, 27 Apr 2007 11:45:12 +0800 >To: PSN >Subject: Loudspeader Seismograph >From: "Arie Verveer" >Organization: Space Ship Earth >User-Agent: Opera Mail/9.20 (Win32) >Reply-To: psn-l@.............. >Sender: psn-l-request@.............. >X-RCPT-TO: >X-SA-Poll-Id: 1177645713840..428254594..1..1177645512000 >X-SA-USERIDNR: 3394894 >X-SA-MPREASON: enabled mailing list (psn-l@............... > >Hi, The "May 2007" issue of "elektor electronics" >magazine, contains an article using a loudspeaker >as a vibration sensor (seismograph). Plus an article >on ELF reception and a magnetometer. > >www.elektor-electronics.co.uk > > >May be of interest ? > > >Cheers Arie > > > > >__________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email PSN-L-REQUEST@.............. with the body >of the message (first line only): unsubscribe >See http://www.seismicnet.com/maillist.html for more information. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Fwd: Loudspeader Seismograph re: the Elektor magnetometer article From: "Charles R. Patton" charles.r.patton@........ Date: Fri, 27 Apr 2007 12:07:37 -0700 Don't waste your money on this article. It is done using a coil salvaged from a transformer fed to an amplifier with lots of gain. Strictly AC, no DC response possible. I consider the definition of "magnetometer" requires DC response. Misleading advertising. As additional criticism, using a small coil salvaged from a transformer has very little window area (limiting the "effective antenna height" acting as another limit) if you intend to receive ELF. Bah, humbug, $2 wasted. Charles Patton >> Hi, The "May 2007" issue of "elektor electronics" >> magazine, contains an article using a loudspeaker >> as a vibration sensor (seismograph). Plus an article >> on ELF reception and a magnetometer. >> >> www.elektor-electronics.co.uk >> >> >> May be of interest ? >> >> >> Cheers Arie >> >> >> >> >> __________________________________________________________ >> >> Public Seismic Network Mailing List (PSN-L) >> >> To leave this list email PSN-L-REQUEST@.............. with the body >> of the message (first line only): unsubscribe >> See http://www.seismicnet.com/maillist.html for more information. > > > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with the body of > the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Fwd: Loudspeader Seismograph re: the Elektor magnetometer article From: "Geoffrey" gmvoeth@........... Date: Sat, 28 Apr 2007 00:03:50 -0700 Why Doesnt anyone ever talk Hall-Effect or Strain Guage or Variable Resistance or magnetic levitation like you take up most the strain with a spring but levitate grain or so with an electro magnet to counter gravity and set the period ?? You can use some kind of PID (Proportional Integral Derivative) Like the cruise control of an automobile to set the operational point ?? If I had cash I would try some of these but you need to have a PHD in Physics to get a Government Grant. ----- Original Message ----- From: "Charles R. Patton" To: Sent: Friday, April 27, 2007 12:07 Subject: Re: Fwd: Loudspeader Seismograph re: the Elektor magnetometer article > Don't waste your money on this article. It is done using a coil salvaged from a transformer fed to an amplifier with lots of > gain. Strictly AC, no DC response possible. I consider the definition of "magnetometer" requires DC response. Misleading > advertising. As additional criticism, using a small coil salvaged from a transformer has very little window area (limiting the > "effective antenna height" acting as another limit) if you intend to receive ELF. Bah, humbug, $2 wasted. > Charles Patton >>> Hi, The "May 2007" issue of "elektor electronics" >>> magazine, contains an article using a loudspeaker >>> as a vibration sensor (seismograph). Plus an article >>> on ELF reception and a magnetometer. >>> >>> www.elektor-electronics.co.uk >>> >>> >>> May be of interest ? >>> >>> >>> Cheers Arie >>> >>> >>> >>> >>> __________________________________________________________ >>> >>> Public Seismic Network Mailing List (PSN-L) >>> >>> To leave this list email PSN-L-REQUEST@.............. with the body of the message (first line only): unsubscribe >>> See http://www.seismicnet.com/maillist.html for more information. >> >> >> __________________________________________________________ >> >> Public Seismic Network Mailing List (PSN-L) >> >> To leave this list email PSN-L-REQUEST@.............. with the body of the message (first line only): unsubscribe >> See http://www.seismicnet.com/maillist.html for more information. >> > > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Mag 5 Earthquake in UK From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@......... Date: Sat, 28 Apr 2007 08:22:27 +0000 Hi all This dosen't happen often. But this morning at 07:18 there was a mag 5 earthquake in the UK. See more here, http://www.emsc-csem.org/index.php?page=3Dcurrent&sub=3Ddetail&id=3D42748 http://news.bbc.co.uk/1/hi/uk/6602677.stm Regards. --=20 J=F3n Fr=EDmann http://www.jonfr.com http://www.simnet.is/jonfr500/earthquake/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Mag 5 Earthquake in UK From: Tangazazen@....... Date: Sat, 28 Apr 2007 06:06:28 EDT Hi. Being based in Ashford Kent I certainly did pick it up. As my broadband seismometer was recording from 0.1 to 0.02 Hz the trace is not large but very distict. A very rare event indeed, about 10km below Romany Marsh and should have woken up a few sheep. Martin Page
Hi.
   Being based in Ashford Kent I certainly did pick it up. As= my=20 broadband seismometer was recording from 0.1 to 0.02 Hz the trace is not lar= ge=20 but very distict. A very rare event indeed, about 10km below Romany Mar= sh=20 and should have woken up a few sheep.
 
 
Martin Page  
 Subject: Re: Mag 4.9 Earthquake in UK From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@......... Date: Sat, 28 Apr 2007 10:57:58 +0000 Hi Too bad that you don't have a short period device. I did notice that the earthquake apppeared well in the Netherlands on a station that is there. I am surpriced by the reported damage, but according to BBC News 24 ( http://news.bbc.co.uk/1/hi/uk/6602677.stm) and Sky News there appears to be a lot of damage in towns closest to the epicenter. I do expect aftershocks there, but far as history goes. It might not happen at all. But the earthquake is happening on a old faultline that lies there. EMSC has downgraded the earthquake to 4.9ML. Regards. --=20 J=F3n Fr=EDmann http://www.jonfr.com http://www.simnet.is/jonfr500/earthquake/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Mag 4.9 Earthquake in UK From: Tangazazen@....... Date: Sat, 28 Apr 2007 07:15:09 EDT Hi, I have only one a channel recorder but have now switched to the 5 -1 Hz band, so may be I'll pick up possible after shocks. Martin Page
Hi,
     I have only one a channel recorder but have no= w=20 switched to the 5 -1 Hz band, so may be I'll pick up possible after=20 shocks.
 
 
Martin Page 
 Subject: How to bolt a geophone to the floor ? From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@......... Date: Sat, 28 Apr 2007 15:30:14 +0000 Hi all How can I bolt (stuck) a geophone down to a floor plate so it doesn't move in a case of a large earthquake ? I am preparing to setup a second earthquake station in a friends place. He is a lot closer to major earthquake zones then I am and large earthquakes can make thing shake in his area and move objects around. Regards. --=20 J=F3n Fr=EDmann http://www.jonfr.com http://www.simnet.is/jonfr500/earthquake/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: How to bolt a geophone to the floor ? From: Angel sismos@.............. Date: Sat, 28 Apr 2007 17:49:26 +0000 Hello Jón, I have used silicone the kind that is used for sealing windows, but it doesn't work well with linux. It makes it so it will not move during a earthquake but you can get it up without too much trouble. angel Saturday, April 28, 2007, 3:30:14 PM, you wrote: > Hi all > How can I bolt (stuck) a geophone down to a floor plate so it doesn't > move in a case of a large earthquake ? > I am preparing to setup a second earthquake station in a friends place. > He is a lot closer to major earthquake zones then I am and large > earthquakes can make thing shake in his area and move objects around. > Regards. -- Best regards, Angel __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Loudspeader Seismograph re: the Elektor magnetometer article From: ChrisAtUpw@....... Date: Sat, 28 Apr 2007 14:32:22 EDT In a message dated 2007/04/28, gmvoeth@........... writes: > Why Doesnt anyone ever talk Hall-Effect or Strain Guage or Variable > Resistance or magnetic levitation like you take up most the strain with a spring but > levitate grain or so with an electro magnet to counter gravity and set the > period ? Hi Geoff, You would probably have to put the coil on the arm and the magnets on the baseplate. One of the problems is the relatively high drift of the magnet strength with temperature. Maintaining the field would take an appreciable amount of current from a highly regulated source. Putting magnetic components on a seismometer arm makes it liable to pick up a lot of interference signals. You would need to completely and effectively screen the sensor and this is not easy to do, or cheap. You can make Hall-Effect sensors, but to get good seismic sensitivity, you have to use strong magnets and the movement range is then less then +/-1 mm. Not a problem for a simple pendulum or a spring accelerometer. Strain gauges will not give you the signal to noise ratio necessary. Simple optical systems using a miniature tungsten filamant bulb, a moving slot shutter screen and two Si large area photocells connected differentially can give a better performance. Eg VTD34, BPW34 or larger. For a Lehman, you might choose 10mm or longer photo cells - see Silonex. I run the bulbs at about 0.8 of their rated voltage to give a very long and stable light output and use a voltage regulator + bypass transistor to do it. You need the large area photocells to get the S/N ratio up. The tiny 1mm square Si cells do NOT work well enough, particularly those in LED form cases with an end lens. Regards, Chris Chapman In a me= ssage dated 2007/04/28, gmvoeth@........... writes:

Why Doesnt anyone ever talk Hal= l-Effect or Strain Guage or Variable Resistance or magnetic levitation like=20= you take up most the strain with a spring but levitate grain or so with an e= lectro magnet to counter gravity and set the period ?


Hi Geoff,

       You would probably have to put the coil= on the arm and the magnets on the baseplate. One of the problems is the rel= atively high drift of the magnet strength with temperature. Maintaining the=20= field would take an appreciable amount of current from a highly regulated so= urce.
       Putting magnetic components on a seismo= meter arm makes it liable to pick up  a lot of interference signals. Yo= u would need to completely and effectively screen the sensor and this is not= easy to do, or cheap.
       You can make Hall-Effect sensors, but t= o get good seismic sensitivity, you have to use strong magnets and the movem= ent range is then less then +/-1 mm. Not a problem for a simple pendulum or=20= a spring accelerometer.
       Strain gauges will not give you the sig= nal to noise ratio necessary.
       Simple optical systems using a miniatur= e tungsten filamant bulb, a moving slot shutter screen and two Si large area= photocells connected differentially can give a better performance. Eg VTD34= , BPW34 or larger. For a Lehman, you might choose 10mm or longer photo cells= - see Silonex. I run the bulbs at about 0.8 of their rated voltage to give=20= a very long and stable light output and use a voltage regulator + bypass tra= nsistor to do it. You need the large area photocells to get the S/N ratio up= .. The tiny 1mm square Si cells do NOT work well enough, particularly those i= n LED form cases with an end lens. 

       Regards,

       Chris Chapman Subject: Re: How to bolt a geophone to the floor ? From: ChrisAtUpw@....... Date: Sat, 28 Apr 2007 14:38:41 EDT In a message dated 2007/04/28, jonfr@......... writes: > How can I bolt (stuck) a geophone down to a floor plate so it doesn't > move in a case of a large earthquake ? Hi Jon, I would use a mastic adhesive called BluTack or WhiteTack. It is a putty like adhesive material which never sets hard. I buy it from stationery and hardware suppliers. An alternative method would be to drill holes on the floor and fit rawlbolts and a metal strap over the top of the seismometer case. Regards, Chris Chapman In a me= ssage dated 2007/04/28, jonfr@......... writes:

How can I bolt (stuck) a geopho= ne down to a floor plate so it doesn't
move in a case of a large earthquake ?


Hi Jon,
      
       I would use a mastic adhesive called Bl= uTack or WhiteTack. It is a putty like adhesive material which never sets ha= rd. I buy it from stationery and hardware suppliers.
       An alternative method would be to drill= holes on the floor and fit rawlbolts and a metal strap over the top of the=20= seismometer case.

       Regards,

       Chris Chapman Subject: Re: Mag 4.9 Earthquake in UK From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@......... Date: Sat, 28 Apr 2007 19:09:07 +0000 Hi all Emsc has put up a webpage about this earthquake. According to that webpage this earthquake was also felt in France. Here is the webpage. http://www.emsc-csem.org/index.php?page=3Dcurrent&sub=3Drecent&evt=3D200704= 28_UK I do not know if there are going to be more earthquakes there, it is possible. But I lack data to setup a theory to predict it. Regards. --=20 J=F3n Fr=EDmann http://www.jonfr.com http://www.simnet.is/jonfr500/earthquake/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: RE: How to bolt a geophone to the floor ? From: "Stephen Hammond" shammon1@............. Date: Sat, 28 Apr 2007 14:48:59 -0700 The guy's that worked at the USGS back in the late 80's mixed up a couple of cups of light plaster and glopped it on the cement floor and sat the geophone in it.=20 Steve Hammond PSN San Jose, Aptos, CA -----Original Message----- From: psn-l-request@.............. [mailto:psn-l-request@............... On Behalf Of J=F3n Fr=EDmann Sent: Saturday, April 28, 2007 8:30 AM To: PSN-Postlist Subject: How to bolt a geophone to the floor ? Hi all How can I bolt (stuck) a geophone down to a floor plate so it doesn't move in a case of a large earthquake ? I am preparing to setup a second earthquake station in a friends place. He is a lot closer to major earthquake zones then I am and large earthquakes can make thing shake in his area and move objects around. Regards. --=20 J=F3n Fr=EDmann http://www.jonfr.com http://www.simnet.is/jonfr500/earthquake/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: RE: Seismology Books Suggestions From: "Rex Klopfenstein" rklopfen@......... Date: Sat, 28 Apr 2007 18:07:52 -0400 I found a price for Anatomy of Seismographs at the publisher (www.elsevier.com ) for $140US _____ From: psn-l-request@.............. [mailto:psn-l-request@............... On Behalf Of Bob Hancock Sent: Thursday, April 26, 2007 11:34 PM To: psn-l@.............. Subject: RE: Seismology Books Suggestions Everyone - I had been searching for a copy of ANATOMY OF SEISMOGRAMS for several years. I would search on both Google and various book searches, and recently found it in a bookstore in the UK. It was a new copy with only shelf wear. The price was about $250, and my wife has demanded equal time. Keep looking, as this book appears to come up from time to time, and is truly one of the best, if not the best for seismogram interpretation. Another source for this book may be a university library. I found it in the University of Arizona (UA) library - however some schools have expensive library cards. When they raised the annual fee for a library card (non-student) from $60.00 to $100.00, I dropped the card. However, you should be able to enter their libraries for free and make copies of the areas you want for pennies per page. I have done that from time to time at the UA. Some other books to consider: WHOLE EARTH GEOPHYSICS - by Robert J. Lillie - It gives a good intro, and is light on math. This is used in introductory Geophysics courses. THE SEISMIC WAVEFIELD - by B.L.N. Kennett - This comes in two volumes - Volume 1 - Introduction and Theoretical Development (heavy on math), and Volume 2 Interpretation of Seismograms on Regional and Global Scales - I found this to be a good reference and the math is much reduced from Volume 1. AN INTRODUCTION TO SEISMOLOGY, EARTHQUAKES, and EARTH STRUCTURE - by Seth Stein and Michael Wysession - This is an introductory seismology text book used in several schools. The math in it is moderate, but there are many sections that are light on math. Another good reference book. THE MECHANICS OF EARTHQUAKES AND FAULTING - by Christopher H. Scholz - Another good reference book - Overall very light on math. INTRODUCTION TO SEISMOLOGY - by Peter M. Shearer - Another good reference book, but above average in math - I would class it as between moderate and heavy. PLATE TECTONICS - An Insider's History of the Modern Theory of the Earth - by Naomi Oreskes - An EXCELLENT book for the background on plate tectonics. Gives a good foundation in this subject. A BOOK TO AVOID - Unless you have a degree in mathematics: SEISMIC WAVES and SOURCES - by Ari Ben-Menahem and Sarva Jit Singh - VERY HEAVY IN MATH . I hope this helps. Bob Hancock Three Points, AZ _____ From: psn-l-request@.............. [mailto:psn-l-request@............... On Behalf Of Rex Klopfenstein Sent: Thursday, April 26, 2007 17:40 To: psn-l@.............. Subject: Seismology Books Suggestions All I have a copy of "Modern Global Seismology" by Lay & Wallace. I am looking for suggestions of book titles on seismology. Any suggestions would be greatly appreciated. Thanks Rex Klopfenstein Bowling Green, OH 43402

I found a price for Anatomy of Seismographs at the publisher (www.elsevier.com) for $140US

 

From: psn-l-request@.............. [mailto:psn-l-request@............... = On Behalf Of Bob Hancock
Sent: Thursday, April 26, = 2007 11:34 PM
To: psn-l@..............
Subject: RE: Seismology = Books Suggestions

 

Everyone = –

 

I had been searching for a copy of = ANATOMY OF SEISMOGRAMS for several years.  I would search on both Google = and various book searches, and recently found it in a bookstore in the = UK.  It was a new copy with only shelf wear.  The price was about $250, = and my wife has demanded equal time.  Keep looking, as this book appears = to come up from time to time, and is truly one of the best, if not the best for seismogram interpretation. 

 

Another source for this book may be = a university library.  I found it in the University of Arizona (UA) = library – however some schools have expensive library cards.  When = they raised the annual fee for a library card (non-student) from $60.00 to = $100.00, I dropped the card.  However, you should be able to enter their = libraries for free and make copies of the areas you want for pennies per = page.  I have done that from time to time at the UA.

 

Some other books to = consider:

 

WHOLE EARTH GEOPHYSICS – by = Robert J. Lillie - It gives a good intro, and is light on math.  This is = used in introductory Geophysics courses. 

 

THE SEISMIC WAVEFIELD – by = B.L.N. Kennett – This comes in two volumes – Volume 1 – = Introduction and Theoretical Development (heavy on math), and Volume 2 Interpretation = of Seismograms on Regional and Global Scales – I found this to be a = good reference and the math is much reduced from Volume = 1.

 

AN INTRODUCTION TO SEISMOLOGY, EARTHQUAKES, and EARTH STRUCTURE – by Seth Stein and Michael = Wysession – This is an introductory seismology text book used in several schools.  The math in it is moderate, but there are many sections = that are light on math.  Another good reference = book.

 

THE MECHANICS OF EARTHQUAKES AND = FAULTING – by Christopher H. Scholz – Another good reference book = – Overall very light on math.

 

INTRODUCTION TO SEISMOLOGY – = by Peter M. Shearer – Another good reference book, but above average = in math – I would class it as between moderate and = heavy.

 

PLATE TECTONICS – An = Insider’s History of the Modern Theory of the Earth – by Naomi Oreskes = – An EXCELLENT book for the background on plate tectonics.  Gives a good foundation in this subject.

 

A BOOK TO AVOID – Unless you = have a degree in mathematics:

 

SEISMIC WAVES and SOURCES – = by Ari Ben-Menahem and Sarva Jit Singh – VERY HEAVY IN MATH = ..

 

I hope this = helps.

 

Bob = Hancock

Three Points, = AZ

 

From: psn-l-request@.............. [mailto:psn-l-request@............... = On Behalf Of Rex Klopfenstein
Sent: Thursday, April 26, = 2007 17:40
To: psn-l@..............
Subject: Seismology Books Suggestions

 

All

I have a copy of “Modern Global = Seismology” by Lay & Wallace.  I am looking for suggestions of book titles on seismology.  Any suggestions would be greatly = appreciated.

Thanks

 

Rex Klopfenstein

Bowling = Green, OH  43402

 

Subject: Re[2]: Seismology Books Suggestions From: Angel sismos@.............. Date: Sat, 28 Apr 2007 22:28:03 +0000

Hello Rex,


Saturday, April 28, 2007, 10:07:52 PM, you wrote:


>

I found a price for Anatomy of Seismographs at the publisher (www.elsevier.com) for $140US


If is available from the publisher it would be nice to know. I don't see how it could be and have the secondary market be so high. 


Angel


Subject: Channels name change on my station. From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@......... Date: Sun, 29 Apr 2007 14:37:42 +0000 Hi all This is for those who link agenst my plots. The channels have had a name change. All channels now have the name hvtz and so on. This update has already taken place and the older name has stopped updateing. Regards. --=20 J=F3n Fr=EDmann http://www.jonfr.com http://www.simnet.is/jonfr500/earthquake/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Size of a lehman type sensor ? From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@......... Date: Sun, 29 Apr 2007 16:23:32 +0000 Hi all Next month I finally can start building a lehman type sensor. But I need to know what size / hight I need to use for the sensor. I have made my own version of the lehman sensor (on the drawing board). How it is going to work is going to be intresting to see. Regards. --=20 J=F3n Fr=EDmann http://www.jonfr.com http://www.simnet.is/jonfr500/earthquake/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Size of a lehman type sensor ? From: "tchannel" tchannel@.............. Date: Sun, 29 Apr 2007 10:38:37 -0600 Jon, Happy to help, with dimensions and pictures from my Lehman, it is very much like Chris's, that is what I use as a target. Ted. ----- Original Message ----- From: "Jón Frímann" To: "PSN-Postlist" Sent: Sunday, April 29, 2007 10:23 AM Subject: Size of a lehman type sensor ? Hi all Next month I finally can start building a lehman type sensor. But I need to know what size / hight I need to use for the sensor. I have made my own version of the lehman sensor (on the drawing board). How it is going to work is going to be intresting to see. Regards. -- Jón Frímann http://www.jonfr.com http://www.simnet.is/jonfr500/earthquake/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Size of a lehman type sensor ? From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@......... Date: Sun, 29 Apr 2007 17:08:13 +0000 Hi Ted Pictures of a lehman type seismometer are welcomed. That helps me to do a final configureation of the seismometer on the drawing board. Regards. --=20 J=F3n Fr=EDmann http://www.jonfr.com http://www.simnet.is/jonfr500/earthquake/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Size of a lehman type sensor ? From: ChrisAtUpw@....... Date: Sun, 29 Apr 2007 15:38:49 EDT In a message dated 2007/04/29, jonfr@......... writes: > Next month I finally can start building a lehman type sensor. But I need > to know what size / height I need to use for the sensor. Hi Jon, Take a look at http://jclahr.com/science/psn/chapman/lehman/index.html and http://jclahr.com/science/psn/chapman/school/MKII/index.html This is a modern type with NdFeB magnetic damping and sensing. There is quite a lot of helpful information on pendulums at http://jclahr.com/science/psn/epics/links.html I know that you are short of space, but the absolute minimum length for the arm is about 35 cm from the bearing on the upright to the CENTRE of the mass. It is preferable to use about 60 cm, but lengths of 1 m are OK. Larger than this and you tend to get problems with the enclosure and thermal stability. The whole arm and base need to be a bit longer. It is usual to use about a 30, 60, 90 triangle for the suspension, with the 30 deg at the mass end, but you can use 45 deg OK. Make the seismometer as a single unit on a base frame. Use NdFeB magnetic damping. It is clean, effective and dead easy to adjust. The arm needs to be light but rigid - preferably tube, not solid rod. I use 15 mm SS water pipe. It is cheap, rigid and you can get compresssion fittings to fit it. The mass may be ~1 kg. Keep any magnets or ferromagnetic material OFF the arm. Put the sensor and damping magnets on the baseplate. Design the vertical position of the damping plate and the centre of the sensor coil to lie ~on the line from the centre of mass to the lower bearing - offset the mass below the arm if necessary. What sort of suspensions were you considering? Use a V wire from the mass to the top of the upright. Do NOT use either a point in a cup or a knife edge suspension. They are both unsatisfactory. A SS ball bearing in a Tungsten carbide triangle, or a hardened Martensitic SS plate works fine. Crossed Tungsten carbide or Martensitic SS cylinders work fime. You can buy TC needle bearings, TC drills and also 415 grade SS shoulder bolts. See http://pages.prodigy.net/fxc/JC.html I use 3" x 1" U channel Aluminum for the frame with either large joint plates or cross bracing to make it really rigid / strong. The upright must not bend / flex / oscillate as the arm swings. I have made suggestions for magnetic dampers and sensors at http://jclahr.com/science/psn/chapman/lehman/index.html The sensors give a higher output than the large coils and U Alnico magnets pictured elsewhere. You will need an airtight insulating cover to house the seismometer. See http://pages.prodigy.net/fxc/ Al covered Cellotex is usually used. Hope that this helps. Chris Chapman In a me= ssage dated 2007/04/29, jonfr@......... writes:

Next month I finally can start=20= building a lehman type sensor. But I need
to know what size / height I need to use for the sensor.


Hi Jon,

       Take a look at http://jclahr.com/scienc= e/psn/chapman/lehman/index.html
and http://jclahr.com/science/psn/chapman/school/MKII/index.html
       This is a modern type with NdFeB magnet= ic damping and sensing.
       There is quite a lot of helpful informa= tion on pendulums at http://jclahr.com/science/psn/epics/links.html

       I know that you are short of space, but= the absolute minimum length for the arm is about 35 cm from the bearing on=20= the upright to the CENTRE of the mass. It is preferable to use about 60 cm,=20= but lengths of 1 m are OK. Larger than this and you tend to get problems wit= h the enclosure and thermal stability. The whole arm and base need to be a b= it longer.
       It is usual to use about a 30, 60, 90 t= riangle for the suspension, with the 30 deg at the mass end, but you can use= 45 deg OK.
       Make the seismometer as a single uni= t on a base frame.
       Use NdFeB  magnetic damping. It is= clean, effective and dead easy to adjust.
       The arm needs to be light but rigid - p= referably tube, not solid rod. I use 15 mm SS water pipe. It is cheap, rigid= and you can get compresssion fittings to fit it. The mass may be ~1 kg. Kee= p any magnets or ferromagnetic material OFF the arm. Put the sensor and damp= ing magnets on the baseplate.
       Design the vertical position of the dam= ping plate and the centre of the sensor coil to lie ~on the line from the ce= ntre of mass to the lower bearing - offset the mass below the arm if necessa= ry.
       What sort of suspensions were you consi= dering? Use a V wire from the mass to the top of the upright.
             = Do NOT use either a point in a cup or a knife edge suspension. They are both= unsatisfactory.
       A SS ball bearing in a Tungsten car= bide triangle, or a hardened Martensitic SS plate works fine. Crossed Tungst= en carbide or Martensitic SS cylinders work fime. You can buy TC needle bear= ings, TC drills and also 415 grade SS shoulder bolts.
See http://pages.prodigy.net/fxc/JC.html
       I use 3" x 1" U channel Aluminum for th= e frame with either large joint plates or cross bracing to make it really ri= gid / strong. The upright must not bend / flex / oscillate as the arm swings= ..
       I have made suggestions for magnetic da= mpers and sensors at http://jclahr.com/science/psn/chapman/lehman/index.html= The sensors give a higher output than the large coils and U Alnico magnets=20= pictured elsewhere.
       You will need an airtight insulating co= ver to house the seismometer. See http://pages.prodigy.net/fxc/
        Al covered Cellotex is usually us= ed.

       Hope that this helps.
      
       Chris Chapman

 Subject: geophone too close ? From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@......... Date: Sun, 29 Apr 2007 22:41:56 +0000 hi all In a attemt to get rid of noise from varius sources, at least reduse it a bit. I am testing to have my geophone in my computer room. But I did notice on my Borgarnes test setup that the noise level was not much diffrent in the corner then I was having on my main system (Hvammstangi) at it's location in my apartment. But this means that the geophone is less then three meters away from me. I do see footsteps and such noise, but I do not get the door noise and the window noise that I get when I open and close the window. I've like to get opinion on this if possible. Regards. --=20 J=F3n Fr=EDmann http://www.jonfr.com http://www.simnet.is/jonfr500/earthquake/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: RE: Re[2]: Seismology Books Suggestions From: "Rex Klopfenstein" rklopfen@......... Date: Sun, 29 Apr 2007 23:11:06 -0400 I think if you look at Amazon the price comes up over $1000!! _____ From: psn-l-request@.............. [mailto:psn-l-request@............... On Behalf Of Angel Sent: Saturday, April 28, 2007 6:28 PM To: Rex Klopfenstein Subject: Re[2]: Seismology Books Suggestions Hello Rex, Saturday, April 28, 2007, 10:07:52 PM, you wrote: > I found a price for Anatomy of Seismographs at the publisher ( www.elsevier.com) for $140US If is available from the publisher it would be nice to know. I don't see how it could be and have the secondary market be so high. Angel

I think if you look at Amazon the = price comes up over $1000!!

 

From: psn-l-request@.............. [mailto:psn-l-request@............... = On Behalf Of Angel
Sent: Saturday, April 28, = 2007 6:28 PM
To: Rex Klopfenstein
Subject: Re[2]: = Seismology Books Suggestions

 

Hello = Rex,

 

Saturday, April 28, 2007, = 10:07:52 PM, you wrote:

 

> 

I found a price for Anatomy of Seismographs = at the publisher (www.elsevier.com) = for $140US

 

If is available from the = publisher it would be nice to know. I don't see how it could be and have the = secondary market be so high. 

 

Angel

 

Subject: Re: geophone too close ? From: ian ian@........... Date: Mon, 30 Apr 2007 07:53:15 +0100 Hi, could it be like the school experiment where you scatter salt on a metal sheet and then vibrate the sheet with a few KHz of sound. The salt grains move to areas of the metal sheet where the vibrations are least. Perhaps your floor is like that, with parts of it vibrating less than others? But does that meain that seismic vibration will be less there too? Ian Jón Frímann wrote: >hi all > >In a attemt to get rid of noise from varius sources, at least reduse it >a bit. I am testing to have my geophone in my computer room. But I did >notice on my Borgarnes test setup that the noise level was not much >diffrent in the corner then I was having on my main system (Hvammstangi) >at it's location in my apartment. But this means that the geophone is >less then three meters away from me. I do see footsteps and such noise, >but I do not get the door noise and the window noise that I get when I >open and close the window. > >I've like to get opinion on this if possible. > >Regards. > > Ian www.festivalpreviews.com -- Hi,

could it be like the school experiment where you scatter salt on a metal sheet and then vibrate the sheet with a few KHz of sound.  The salt grains move to areas of the metal sheet where the vibrations are least.  Perhaps your floor is like that, with parts of it vibrating less than others?  But does that meain that seismic vibration will be less there too?

Ian

Jón Frímann wrote: 
hi all

In a attemt to get rid of noise from varius sources, at least reduse it
a bit. I am testing to have my geophone in my computer room. But I did
notice on my Borgarnes test setup that the noise level was not much
diffrent in the corner then I was having on my main system (Hvammstangi)
at it's location in my apartment. But this means that the geophone is
less then three meters away from me. I do see footsteps and such noise,
but I do not get the door noise and the window noise that I get when I
open and close the window.

I've like to get opinion on this if possible.

Regards.

Ian
www.festivalpreviews.com
--

Subject: Re: geophone too close ? From: ian ian@........... Date: Mon, 30 Apr 2007 07:53:15 +0100 Hi, could it be like the school experiment where you scatter salt on a metal sheet and then vibrate the sheet with a few KHz of sound. The salt grains move to areas of the metal sheet where the vibrations are least. Perhaps your floor is like that, with parts of it vibrating less than others? But does that meain that seismic vibration will be less there too? Ian Jón Frímann wrote: >hi all > >In a attemt to get rid of noise from varius sources, at least reduse it >a bit. I am testing to have my geophone in my computer room. But I did >notice on my Borgarnes test setup that the noise level was not much >diffrent in the corner then I was having on my main system (Hvammstangi) >at it's location in my apartment. But this means that the geophone is >less then three meters away from me. I do see footsteps and such noise, >but I do not get the door noise and the window noise that I get when I >open and close the window. > >I've like to get opinion on this if possible. > >Regards. > > Ian www.festivalpreviews.com -- Hi,

could it be like the school experiment where you scatter salt on a metal sheet and then vibrate the sheet with a few KHz of sound.  The salt grains move to areas of the metal sheet where the vibrations are least.  Perhaps your floor is like that, with parts of it vibrating less than others?  But does that meain that seismic vibration will be less there too?

Ian

Jón Frímann wrote: 
hi all

In a attemt to get rid of noise from varius sources, at least reduse it
a bit. I am testing to have my geophone in my computer room. But I did
notice on my Borgarnes test setup that the noise level was not much
diffrent in the corner then I was having on my main system (Hvammstangi)
at it's location in my apartment. But this means that the geophone is
less then three meters away from me. I do see footsteps and such noise,
but I do not get the door noise and the window noise that I get when I
open and close the window.

I've like to get opinion on this if possible.

Regards.

Ian
www.festivalpreviews.com
--

Subject: Re: geophone too close ? From: "Geoffrey" gmvoeth@........... Date: Mon, 30 Apr 2007 01:41:43 -0700 I have seen microcircuitry rooms that are vibration isolated you need to cut a slot around the slab where the geophone will be located then fill the slot with a material that will let the two slabs move independently. They build these rooms in a russian doll fashion because the traces are so small on the microchips that the slightest vobration will ruin the whole lot they are making. ----- Original Message ----- From: "ian" To: Cc: "PSN-Postlist" Sent: Sunday, April 29, 2007 23:53 Subject: Re: geophone too close ? > Hi, > > could it be like the school experiment where you scatter salt on a metal > sheet and then vibrate the sheet with a few KHz of sound. The salt > grains move to areas of the metal sheet where the vibrations are least. > Perhaps your floor is like that, with parts of it vibrating less than > others? But does that meain that seismic vibration will be less there too? > > Ian > > Jón Frímann wrote: > >>hi all >> >>In a attemt to get rid of noise from varius sources, at least reduse it >>a bit. I am testing to have my geophone in my computer room. But I did >>notice on my Borgarnes test setup that the noise level was not much >>diffrent in the corner then I was having on my main system (Hvammstangi) >>at it's location in my apartment. But this means that the geophone is >>less then three meters away from me. I do see footsteps and such noise, >>but I do not get the door noise and the window noise that I get when I >>open and close the window. >> >>I've like to get opinion on this if possible. >> >>Regards. >> >> > > Ian > www.festivalpreviews.com > -- > > > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: geophone too close ? From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@......... Date: Mon, 30 Apr 2007 11:19:05 +0000 Hi After a few hours of testing. I found out that the geophone was too close. So I put it at more distance this time from the window and the door. In a part of my apartment where there is little traffic. It is also the place where I plan to setup the Lehman type sensor I plan to build next month. Regards. --=20 J=F3n Fr=EDmann http://www.jonfr.com http://www.simnet.is/jonfr500/earthquake/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: RE: geophone too close ? From: "Bob Hancock" carpediem1@......... Date: Mon, 30 Apr 2007 09:00:31 -0700 Jon - One important question you need to answer is what the source of your = noise is. Setting the instrument inside a residence means that your = instrument will be affected by residence itself. As pointed out in a previous = email, one way would be to separate the base that the geophone resides on from = the base of the residence. This may not prove to be practical, and winds or people walking about a residence will affect an instrument. Another consideration is shielding the instrument itself. Ambient wind currents and temperature changes can affect an instrument and bring = about significant variations. If you could cover the instrument with a bucket lined in fiberglass or something similar to shield it from these = changes, it could reduce your ambient noise. =20 Avoid using foams or Styrofoam as they have minute air pockets in them = and as pressure changes, they will expand or contract and these changes will = be transmitted to the instrument. Bob Hancock Three Points, AZ -----Original Message----- From: psn-l-request@.............. [mailto:psn-l-request@............... = On Behalf Of J=F3n Fr=EDmann Sent: Monday, April 30, 2007 04:19 To: psn-l@.............. Subject: Re: geophone too close ? Hi After a few hours of testing. I found out that the geophone was too close. So I put it at more distance this time from the window and the door. In a part of my apartment where there is little traffic. It is also the place where I plan to setup the Lehman type sensor I plan to build next month. Regards. --=20 J=F3n Fr=EDmann http://www.jonfr.com http://www.simnet.is/jonfr500/earthquake/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Size of a lehman type sensor ? From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@......... Date: Mon, 30 Apr 2007 16:15:11 +0000 Hi all, Chris Is it possible to get the dimater in a easy form ? But I am going to get a help from a local car shop here to help me build the seismoter. But they want to get the size in exact numbers so they don't have to spend a lot of time thinking on the details. Thanks and regards. --=20 J=F3n Fr=EDmann http://www.jonfr.com http://www.simnet.is/jonfr500/earthquake/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: RE: geophone too close ? From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@......... Date: Mon, 30 Apr 2007 17:29:58 +0000 Hi The sources of noise near my sensors are my own traffic in the apartment, mostly. But also car traffic, wind, ocean (sometimes) and so on. I hope that in the not so distant future that I will move to a house that is more fitted for earthquake recording. Also at the moment, the hvt sensor is the only one how is going to be mostly affected by this type noise. Due to its location. Regards. --=20 J=F3n Fr=EDmann http://www.jonfr.com http://www.simnet.is/jonfr500/earthquake/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: geophone too close ? From: ChrisAtUpw@....... Date: Mon, 30 Apr 2007 14:43:11 EDT In a message dated 2007/04/30, carpediem1@......... writes: > Avoid using foams or Styrofoam as they have minute air pockets in them and > as pressure changes, they will expand or contract and these changes will be > transmitted to the instrument. Hi Bob, Have any problems of this sort been actually documented? We have been using Cellotex cases for years apparently without problem. This is a sealed cell styrofoam with two layers of glass scrim glued to the surfaces. I would not rest my seismometer on such, but I would not expect any problems with a Cellotex case which is supported on the floor. The total mass is low. How would this be transmitted to the instrument? Regards, Chris Chapman In a me= ssage dated 2007/04/30, carpediem1@......... writes:

Avoid using foams or Styrofoam=20= as they have minute air pockets in them and
as pressure changes, they will expand or contract and these changes will be<= BR> transmitted to the instrument.


Hi Bob,

       Have any problems of this sort been=20= actually documented? We have been using Cellotex cases for years apparen= tly without problem. This is a sealed cell styrofoam with two layers of glas= s scrim glued to the surfaces. I would not rest my seismometer on such, but=20= I would not expect any problems with a Cellotex case which is supported o= n the floor. The total mass is low.
       How would this be transmitted to the in= strument?

       Regards,

       Chris Chapman Subject: RE: geophone too close ? From: "Bob Hancock" carpediem1@......... Date: Mon, 30 Apr 2007 12:29:16 -0700 Hi Chris - OOPS - I dropped part of a sentence....My fault...According to the installation engineers at the Albuquerque Seismological Laboratory, they have experienced problems when the Styrofoam was in DIRECT contact with the instrument. Under these conditions, changes in air pressure have caused increases in ambient noise on their instruments. I am unaware of any problems when Styrofoam is used as a thermal shield and not in direct contact with the instrument. Bob Hancock _____ From: psn-l-request@.............. [mailto:psn-l-request@............... On Behalf Of ChrisAtUpw@....... Sent: Monday, April 30, 2007 11:43 To: psn-l@.............. Subject: Re: geophone too close ? In a message dated 2007/04/30, carpediem1@......... writes: Avoid using foams or Styrofoam as they have minute air pockets in them and as pressure changes, they will expand or contract and these changes will be transmitted to the instrument. Hi Bob, Have any problems of this sort been actually documented? We have been using Cellotex cases for years apparently without problem. This is a sealed cell styrofoam with two layers of glass scrim glued to the surfaces. I would not rest my seismometer on such, but I would not expect any problems with a Cellotex case which is supported on the floor. The total mass is low. How would this be transmitted to the instrument? Regards, Chris Chapman

Hi Chris = –

 

OOPS – I dropped part of a = sentence……….My fault………According to the installation engineers at the Albuquerque Seismological Laboratory, they have experienced =  problems when the Styrofoam was in DIRECT contact with the instrument. Under these conditions, changes in air pressure have caused increases in ambient = noise on their instruments.  I am unaware of any problems when Styrofoam is used = as a thermal shield and not in direct contact with the instrument.  =   

 

Bob = Hancock

 

 

 

From: psn-l-request@.............. [mailto:psn-l-request@............... = On Behalf Of = ChrisAtUpw@.......
Sent: Monday, April 30, = 2007 11:43
To: psn-l@..............
Subject: Re: geophone too = close ?

 

In a message dated 2007/04/30, carpediem1@......... = writes:


Avoid using foams or Styrofoam as they have minute = air pockets in them and
as pressure changes, they will expand or contract and these changes will = be
transmitted to the instrument.



Hi Bob,

       Have any problems of this sort = been actually documented? We have been using Cellotex cases for years = apparently without problem. This is a sealed cell styrofoam with two layers of = glass scrim glued to the surfaces. I would not rest my seismometer on such, but I = would not expect any problems with a Cellotex case which is supported on the = floor. The total mass is low.
       How would this be transmitted to = the instrument?

       Regards,

       Chris Chapman =

Subject: Re: Size of a lehman type sensor? From: Bobhelenmcclure@....... Date: Mon, 30 Apr 2007 18:59:58 EDT In a message dated 2007/04/29, jonfr@......... writes: > Next month I finally can start building a lehman type sensor. But I need > to know what size / height I need to use for the sensor. Hi Jon, You do not have to build a big clunker Lehman to have a useful sensor. I use compact horizontal sensors set to 6 to 13 seconds period. I extend the long period response using my utility program WQFilter.exe. If you use either a long period Lehman or a period-extended medium period Lehman, your site will have a lot to do with your results. The sensor must rest on firm ground, and you must not walk anywhere near it. (Long period horizontal sensors are very sensitive to tilt.) Ground tilt induced by wind gusts is a big problem for me. My sensors are on the basement floor of my home. They were placed where walking around on the floor above produces the least response. Information about my sensors and software can be found at _http://www.jclahr.com/science/psn/mcclure/index.html_ (http://www.jclahr.com/science/psn/mcclure/index.html) I use WQFilter exclusively for WinQuake event file filtering. It is contained in seismic_dataq.zip, which can be downloaded from _http://www.jclahr.com/science/psn/mcclure/wdq_utilities/index.html_ (http://www.jclahr.com/science/psn/mcclure/wdq_utilities/index.html) WQFilter has a selection of lowpass and highpass filters, and my special period extending filter. This filter can make the period either shorter or longer than the physical period of the pendulum. It can also correct for under-or-overdamping. For examples of the benefits of using WQFilter, see _http://www.jclahr.com/science/psn/mcclure/filter_examples/index.html_ (http://www.jclahr.com/science/psn/mcclure/filter_examples/index.html) By the way, if anyone is presently using WQFilter.exe older than version 2.0.15, please download the update. It is now rigorously accurate, as proven in _http://www.jclahr.com/science/psn/mcclure/filter/index.html_ (http://www.jclahr.com/science/psn/mcclure/filter/index.html) Bob McClure PSN Station REM ************************************** See what's free at http://www.aol.com.
In a message dated 2007/04/29, jonfr@......... writes:
 
> Next month I finally can start building a lehman type sensor. But=20= I=20 need
> to know what size / height I need to use for the sensor.
 
Hi Jon,
 
  You do not have to build a big clunker Lehman to have a useful=20 sensor. I use compact horizontal sensors set to 6 to 13 seconds period. I ex= tend=20 the long period response using my utility program WQFilter.exe. If you use=20 either a long period Lehman or a period-extended medium period Lehman, your=20= site=20 will have a lot to do with your results. The sensor must rest on firm=20 ground, and you must not walk anywhere near it. (Long period horizontal sens= ors=20 are very sensitive to tilt.) Ground tilt induced by wind gusts is a big prob= lem=20 for me. My sensors are on the basement floor of my home. They were placed wh= ere=20 walking around on the floor above produces the least response.
 
  Information about my sensors and software can be found at
 
  http://www.jcl= ahr.com/science/psn/mcclure/index.html
 
  I use WQFilter exclusively for WinQuake event file filtering. It= is=20 contained in seismic_dataq.zip, which can be downloaded from
 
  = http://www.jclahr.com/science/psn/mcclure/wdq_utilities/index.html
 
  WQFilter has a selection of lowpass and highpass filters, and my= =20 special period extending filter. This filter can make the period either shor= ter=20 or longer than the physical period of the pendulum. It can also correct for=20 under-or-overdamping. For examples of the benefits of using WQFilter, see
 
   http://www.jclahr.com/science/psn/mcclure/filter_examples/index.html
 
  By the way, if anyone is presently using WQFilter.exe older than= =20 version 2.0.15, please download the update. It is now rigorously accurate, a= s=20 proven in
 
  http://= www.jclahr.com/science/psn/mcclure/filter/index.html =20
 
 
Bob McClure
PSN Station=20 REM



See what's free at AOL.com.
Subject: Re: Mag 4.9 Earthquake in UK From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@......... Date: Wed, 02 May 2007 01:45:08 +0000 Hi all Have there been any aftershocks of the mag 4.9 earthquake few days ago. Regards. --=20 J=F3n Fr=EDmann http://www.jonfr.com http://www.simnet.is/jonfr500/earthquake/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Mag 4.9 Earthquake in UK From: ChrisAtUpw@....... Date: Tue, 1 May 2007 22:58:09 EDT In a message dated 2007/05/02, jonfr@......... writes: > Have there been any aftershocks of the mag 4.9 earthquake few days ago Hi Jon, It was M 4.2. There don't seem to have been any significant aftershocks. See http://www.earthquakes.bgs.ac.uk/helicorder/heli.html select Swindon and the period range. Regards, Chris Chapman In a me= ssage dated 2007/05/02, jonfr@......... writes:

Have there been any aftershocks= of the mag 4.9 earthquake few days ago


Hi Jon,

       It was M 4.2. There don't seem to have=20= been any significant aftershocks.

       See http://www.earthquakes.bgs.ac.uk/he= licorder/heli.html select Swindon and the period range.

       Regards,

       Chris Chapman Subject: Hey Guys whats shakin?? Nothing here. From: "Paul Cianciolo" Paulc@........ Date: Fri, 4 May 2007 14:38:10 -0400 Hey Folks, I think I have a problem with my sensor. Here is where I am Latitude Longitude At this site http://quake.bc.edu:8000/cgi-bin/NESN/24hr_heli?jday=124&kstn=NCB&chan=BHE&b and=Long%20Period one can see the ascension island quake clearly on most of the machines. I have looked at a number of these sensors that surround my location, and I see the AI event, but it is not on seen by my machine. First thanks to Ted Channel who got me squared away on a number of difficulties already. I have a coupel of questions. 1) What is the width of your horizontal sensors. I mean the distance between the leveling legs? Mine is 21" and the boom length is 40" 2) This sensor seems very susecptible to tilt and but has yet to record a quake... SO is it possible for the "stance" of the machine to be too wide, making it world well as a tilt machine and poorly as a lateral mothin machine. I can send this info to anyone who might want to look. 1) The ascension Island SAC file 2) an random 1 hour SAC file so you guys can see the noise floor. 3) A SAC file of the sensor with the coil locked down so you can once again see the noise flor 4) A SAC file of me standing 3 feet away from the sensor, perpendicular to the boom, for 5 secs so you can see the tilt response. Any takers?? PauLC W1VLF Quakeless in Connecticut
Hey=20 Folks,
 
I=20 think I have a problem with my sensor.
 
Here=20 is where I am
 
Latitude
Longitude
 
 
At=20 this site http://quake.bc.edu:800= 0/cgi-bin/NESN/24hr_heli?jday=3D124&kstn=3DNCB&chan=3DBHE&ban= d=3DLong%20Period
one=20 can see the ascension island quake clearly on most of the=20 machines.
 
I have=20 looked at a number of these sensors that surround my location, = and I=20 see the AI event,  but it is not on seen by my = machine.
First=20 thanks to Ted Channel who got me squared away on a number of = difficulties=20 already.
 
I have=20 a coupel of questions.
 
1)=20 What is the width of your horizontal sensors.  I mean the distance = between=20 the leveling legs?
 
Mine=20 is 21"  and the boom length is 40"
 
2)=20 This sensor seems very susecptible to tilt and but has yet to record a=20 quake...
SO is=20 it possible for the "stance" of the machine to be too wide, making it = world well=20 as a tilt machine and poorly as a lateral mothin = machine.
 
I can=20 send this info to anyone who might want to look.
 
1) The=20 ascension Island SAC file
 
2) an=20 random 1 hour SAC file so you guys can see the noise = floor.
 
3) A=20 SAC file of the sensor with the coil locked down so you can once again = see the=20 noise flor
4) A=20 SAC file of  me standing 3 feet away from the sensor, perpendicular = to the=20 boom, for 5 secs  so you can see the tilt = response.
 
Any=20 takers??
 
PauLC
W1VLF
Quakeless in Connecticut
 
 
 
 
 
Subject: Re: Hey Guys whats shakin?? Nothing here. From: ChrisAtUpw@....... Date: Fri, 4 May 2007 15:28:03 EDT In a message dated 2007/05/04, Paulc@........ writes: > I have a couple of questions. > 1) What is the width of your horizontal sensors. I mean the distance > between the leveling legs? Hi Paul, About half the length of the arm. If you make it less, you may find it hard to level. > Mine is 21" and the boom length is 40" Sounds about right. > 2) This sensor seems very susecptible to tilt and but has yet to record a > quake... > SO is it possible for the "stance" of the machine to be too wide, making it > world well as a tilt machine and poorly as a lateral mothin machine. No. All Lehmans are sensitive to tilt. What is it resting on? Check your period. What is it? Check for free swing movement. OK? Check the damping is ~ critical and not seriously overdamped. What sort of damping are you using? Check the orientation with respect to the source? Lehmans may be better on transverse Love waves. They DON'T respond equally in all directions! > I can send this info to anyone who might want to look. > 2) an random 1 hour SAC file so you guys can see the noise floor. Check that you are picking up the six second microseisms OK. If not, you may need more amplification, or have a wiring problem? What sensor are you using? > 3) A SAC file of the sensor with the coil locked down so you can once > again see the noise floor > 4) A SAC file of me standing 3 feet away from the sensor, perpendicular to > the boom, for 5 secs so you can see the tilt response. If you are getting an OK tilt response when you move in both directions, it sounds more like an orientation or sensitivity problem. Do you have a photo of the seismometer? Regards, Chris Chapman In a me= ssage dated 2007/05/04, Paulc@........ writes:

I have a couple of questions.<= /FONT>=
1) What is the width of your horizontal sensors.  I mean the distance=20= between the leveling legs?


Hi Paul,

       About half the length of the arm. If yo= u make it less, you may find it hard to level.

Mine is 21"  and the boom= length is 40"


       Sounds about right.

2) This sensor seems very sus= ecptible to tilt and but has yet to record a quake...
SO is it possible for the "stance" of the machine to be too wide, making it= world well as a tilt machine and poorly as a lateral mothin machine.=

       No. All Lehmans are sensitive to tilt.= What is it resting on?
       Check your period. What is it?
       Check for free swing movement. OK?
       Check the damping is ~ critical and not= seriously overdamped. What sort of damping are you using?
       Check the orientation with respect to t= he source? Lehmans may be better on transverse Love waves. They DON'T res= pond equally in all directions!

I can send this info to anyon= e who might want to look.
2) an random 1 hour SAC file so you guys can see the noise floor.

       Check that you are picking up the six=20= second microseisms OK. If not, you may need more amplification, or have a wi= ring problem? What sensor are you using?

3) A SAC file of the sensor w= ith the coil locked down so you can once again see the noise floor
4) A SAC file of  me standing 3 feet away from the sensor, perpendicul= ar to the boom, for 5 secs  so you can see the tilt response.

       If you are getting an OK tilt response=20= when you move in both directions, it sounds more like an orientation or sens= itivity problem.

       Do you have a photo of the seismometer?=

       Regards,

       Chris Chapman Subject: New station From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@......... Date: Fri, 04 May 2007 22:59:19 +0000 Hi all I have started a new station. It is located in a town called Borgarnes and is a lot closer to all the major seismic zones in Iceland. Regards. --=20 J=F3n Fr=EDmann http://www.jonfr.com http://www.simnet.is/jonfr500/earthquake/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Hey Guys whats shakin?? Nothing here. From: Bobhelenmcclure@....... Date: Fri, 4 May 2007 23:01:29 EDT Hi Paul, I operate PSN station REM on Long Island, New York. The Ascension Island event you refer to came in here weakly, especially on the N-S channel. If you are sensing N-S, I am not surprised if you didn't see much of anything. My file is posted at _http://www.seismicnet.com/cgi-dos/event.exe_ (http://www.seismicnet.com/cgi-dos/event.exe) as 070504.121500.rem.psn. I am near the Palisades, NY station PAL. You can see their heliplots at _http://www.ldeo.columbia.edu/cgi-bin/LCSN/WebSeis/24hr_heli.pl?id_ (http://www.ldeo.columbia.edu/cgi-bin/LCSN/WebSeis/24hr_heli.pl?id) = Bob ************************************** See what's free at http://www.aol.com.
Hi Paul,
 
  I operate PSN station REM on Long Island, New York. The Ascensio= n=20 Island event you refer to came in here weakly, especially on the N-S channel= .. If=20 you are sensing N-S, I am not surprised if you didn't see much of=20 anything.
 
  My file is posted at http://www.seismicnet.c= om/cgi-dos/event.exe=20 as 070504.121500.rem.psn.
 
  I am near the Palisades, NY station PAL. You can see their=20 heliplots at
 
  h= ttp://www.ldeo.columbia.edu/cgi-bin/LCSN/WebSeis/24hr_heli.pl?id=3D
 
Bob



See what's= free at AOL.co= m.
Subject: Re: Hey Guys whats shakin?? Nothing here. From: ChrisAtUpw@....... Date: Sat, 5 May 2007 14:03:42 EDT In a message dated 2007/05/05, Bobhelenmcclure@....... writes: > Hi Paul, > I operate PSN station REM on Long Island, New York. The Ascension Island > event you refer to came in here weakly, especially on the N-S channel. If you > are sensing N-S, I am not surprised if you didn't see much of anything. > > I am near the Palisades, NY station PAL. You can see their heliplots at > http://www.ldeo.columbia.edu/cgi-bin/LCSN/WebSeis/24hr_heli.pl?id= > > Bob Hi Bob, I appreciate what you say about your record, but PAL shows the LP N trace quite clearly, as does NESN. The signal should have been way above the noise at that time. Regards, Chris In a me= ssage dated 2007/05/05, Bobhelenmcclure@....... writes:

Hi Paul,
  I operate PSN station REM on Long Island, New York. The Ascension Isl= and event you refer to came in here weakly, especially on the N-S channel. I= f you are sensing N-S, I am not surprised if you didn't see much of anything= ..

   I am near the Palisades, NY station PAL. You can see their heli= plots at
   http://www.ldeo.columbia.edu/cgi-bin/LCSN/WebSeis/24hr_heli.p= l?id=3D

Bob


Hi Bob,

       I appreciate what you say about your re= cord, but PAL shows the LP N trace quite clearly, as does NESN. The signal s= hould have been way above the noise at that time.

       Regards,

       Chris Subject: Quiet times From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@......... Date: Thu, 10 May 2007 17:21:46 +0000 Hi all It is rather quiet in earthquakes this past days. But it appears to be a global quiet time. There is also quiet in earthquakes in Iceland at the moment. Regards. --=20 J=F3n Fr=EDmann http://www.jonfr.com http://www.simnet.is/jonfr500/earthquake/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Hammer of Eden.. the book From: "Paul Cianciolo" Paulc@........ Date: Thu, 10 May 2007 20:22:16 -0400 Hello Folks, A book I read sometime ago, By Ken Follet. Hammer of Eden. Its an interesting book, which has the topic of seismolgy in it. Not knowing all that much about seismology, I cannot say wether the author may or may not have taken any liberties. For what its worth I enjoyed it... Lets face it... its not everyday this topic is covered in a book. An excerpt from the authors web. http://www.ken-follett.com/bibliography/hammereden.html The Hammer of Eden The one thing Californians fear most is a full-scale earthquake. The thing Priest fears most is the destruction of his commune in the Sierra Nevada foothills - the one place he can hide from his mobster past. He has to make the Governor of California listen to him. And now he has a way. He knows how to create an earthquake. And if his demands aren't met, the next quake is just 48 hours away... The Hammer of Eden is a story where the bad guys figure out how to cause an earthquake. They use a machine called a seismic vibrator which is an enormous hammer mounted on the back of a truck. It is usually used to find oil. The hammer sends shockwaves through the earth's crust and the reflections of the vibrations are then mapped to show the sub-surface of the earth. PauLC __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Earthquakes with low frequancy From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@......... Date: Sat, 12 May 2007 15:16:30 +0000 Hi all My new station at Borgarnes is close enugh to record earthquakes from the Myrdalsjokull Volcano (http://www.volcano.si.edu/world/volcano.cfm?vnum=3D1702-03=3D). I have already recored few earthquakes from that volcano. But most of them are small, from mag 1.5 to 2.2 on the ricther scale. But most of those earthquakes have strange carticstics that I have known about for years, but never been able to understand or see before. Most of thease earthquakes have frequancy that goes down to 1Hz and lower. Based on the poor recordings I currently got, there appears to be small tremor noise (magma moving?) following the earthquakes. But because how the poor current recordings are, that is unconfirmed at the moment. Any suggestions on what I am looking at are welcomed. Since I am unsure what is going on in the Myrdalsjokull (Katla) Volcano. But it is known that the Myrdalsjokull Volcano has been warming up for a long time now and is ready to blow at any time. Regards. --=20 J=F3n Fr=EDmann http://www.jonfr.com http://www.simnet.is/jonfr500/earthquake/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Weather Cam From: 1goss@........... Date: Thu, 17 May 2007 23:39:45 +0000 I Thought some of you might be interested In our latest PTZ Camera and live weather station. It is on a weather sight at Pickwick Lake TN. The camera overlooks the lake and the Pickwick Dam I know its not seismology related but their is a seismograph at this location as well,PWLA EHZ NM : Pickwick Lake, AL Tell me what you think of the site. www.pickwickweather.com Bryan S Goss Corinth MS __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Weather Cam From: "Arie Verveer" greensky@.............. Date: Fri, 18 May 2007 10:08:35 +0800 Hi, A very slick site. I still find it odd looking at web cam image from the other side of the planet. Cheers Arie On Fri, 18 May 2007 07:39:45 +0800, <1goss@...........> wrote: > I Thought some of you might be interested In our latest PTZ Camera and > live weather station. It is on a weather sight at Pickwick Lake TN. The > camera overlooks the lake and the Pickwick Dam I know its not seismology > related but their is a seismograph > at this location as well,PWLA EHZ NM : Pickwick Lake, AL > > Tell me what you think of the site. > www.pickwickweather.com > > Bryan S Goss > Corinth MS > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: gain for lehman type sensor ? From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@......... Date: Sun, 20 May 2007 12:01:03 +0000 Hi all What is the best gain for Lehman type sensor ? I am going to use coils and magnet from Larry. The gain on the board is set on 1000. Regards. --=20 J=F3n Fr=EDmann http://www.jonfr.com http://www.simnet.is/jonfr500/earthquake/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: gain for lehman type sensor ? From: ChrisAtUpw@....... Date: Sun, 20 May 2007 08:55:36 EDT In a message dated 2007/05/20, jonfr@......... writes: > Hi all > What is the best gain for Lehman type sensor? I am going to use coils > and magnet from Larry. The gain on the board is set on 1000. > J=F3n Fr=EDmann Hi Jon, The 'best' gain is determined by the instrument period, the strength=20 of the magnet and the coil shape, area and turns. In practice you set the=20 Lehman to give a period of maybe 25 seconds and select the gain to give coun= ts of=20 say 200. The signal will be mostly background microseisms, which you have to= =20 filter out, leaving the quake signals. Can you not get any NdFeB square magnets? I use four off 1" square x=20 1/8" thick ones on two 6mm mild steel backing plates and wind my own=20 rectangular coils to suit, made from old glass circuit board. See 'Sensor Co= il / Magnet=20 System' at the bottom of=20 http://jclahr.com/science/psn/chapman/lehman/index.html This allows about +/-12 mm tilt drift to still give the same output=20 sensitivity. You should be able to buy 0.125 mm dia insulated copper wire re= f.=20 YN92A from your Maplins agent in Iceland. It will give a much higher output= =20 than the Alnico U magnets. Regards, Chris Chapman =20 In a me= ssage dated 2007/05/20, jonfr@......... writes:

Hi all
What is the best gain for Lehman type sensor? I am going to use coils
and magnet from Larry. The gain on the board is set on 1000.
J=F3n Fr=EDmann


Hi Jon,

       The 'best' gain is determined by the in= strument period, the strength of the magnet and the coil shape, area and tur= ns. In practice you set the Lehman to give a period of maybe 25 seconds and=20= select the gain to give counts of say 200. The signal will be mostly backgro= und microseisms, which you have to filter out, leaving the quake signals.        Can you not get any NdFeB square magnet= s? I use four off 1" square x 1/8" thick ones on two 6mm mild steel backing=20= plates and wind my own rectangular coils to suit, made from old glass circui= t board. See 'Sensor Coil / Magnet System' at the bottom of http://jclahr.co= m/science/psn/chapman/lehman/index.html
       This allows about +/-12 mm tilt drift t= o still give the same output sensitivity. You should be able to buy 0.125 mm= dia insulated copper wire ref. YN92A from your  Maplins agent in Icela= nd. It will give a much higher output than the Alnico U magnets.

       Regards,

       Chris Chapman Subject: Torsion spring From: "tchannel" tchannel@.............. Date: Sun, 20 May 2007 09:38:21 -0600 Hi All, First thing, is it just me or is it quiet, "too quiet"? Today = is the 11th day on my calendar since I recorded an earthquake. My = average, here, is about 2 per week. I am overdue, so I will be watching = closely today and tomorrow. On a different issue: I have been restoring old mantle clock. Recently = a 400 day Anniversary clock. It uses a "torsion spring".........I know = very little about clocks, but this is an interesting concept. A long = thin, flat spring wire, is twisted slightly, and uses little energy. = The result is a very long running clock train. Has anyone tried to use this concept for a seismometer? Just thinking, = the period might be long. On the clock I think the spring rotates about = once every 4 secs in each direction. Could a long spring, something = like a band-saw blade, but without teeth, be un wrapped and configured = to move a horizontal arm, left and right, with a long period of approx. = 20 seconds. Just wondering if this has been tried. "Watch your helicorders" Ted
Hi All, First thing, is it just me or = is it quiet,=20 "too quiet"?  Today is the 11th day on my calendar since I recorded = an=20 earthquake.  My average, here, is about 2 per week.  I am = overdue, so=20 I will be watching closely today and tomorrow.
 
On a different issue:  I have been = restoring=20 old mantle clock.  Recently a 400 day Anniversary clock.  It = uses a=20 "torsion spring".........I know very little about clocks, but this is an = interesting concept.  A long thin, flat spring wire, is twisted = slightly,=20 and uses little energy.  The result is a very long running clock=20 train.
Has anyone tried to use this concept = for a=20 seismometer?   Just thinking, the period might be long.  = On the=20 clock I think the spring rotates about once every 4 secs in each=20 direction.   Could a long spring, something like a band-saw = blade, but=20 without teeth, be un wrapped and configured to move a horizontal = arm, left=20 and right, with a long period of approx. 20 seconds.
Just wondering if this has been = tried.
 
 
"Watch your helicorders"
Ted
Subject: Nice quake From: Pete Rowe ptrowe@......... Date: Sun, 20 May 2007 16:34:24 -0700 (PDT) We just had a nice 3.4 pretty much right under me in the east hills of San Jose. I heard it coming and then the S wave hit with a boom. Cool. I always like a nice earthquake. Pete ____________________________________________________________________________________Shape Yahoo! in your own image. Join our Network Research Panel today! http://surveylink.yahoo.com/gmrs/yahoo_panel_invite.asp?a=7 __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Kinemetrics VS-3 Triaxial Seismic Trigger on e-bay From: "Louis Taber" ltaber@......... Date: Sun, 20 May 2007 17:04:12 -0700 Hi, taat-ricardo (Not me. I am not interested in buying it.) has a .01G Kinemetrics VS-3 three axis trigger listed on e-bay. Item # 160117388801. It could be used for an earthquake alarm so you don't miss any local earthquakes! I am not the seller and I am not interested in buying it. But, it does look interesting. - Louis Hi,

taat-ricardo (Not me. I am not interested in buying it.) has a .01G Kinemetrics VS-3 three axis trigger listed on e-bay.  Item # 160117388801.  It could be used for an earthquake alarm so you don't miss any local earthquakes!   I am not the seller and I am not interested in buying it.  But, it does look interesting.

  - Louis
 Subject: Re: Torsion spring From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@......... Date: Mon, 21 May 2007 01:36:03 +0000 Hi all, Ted I don't know about springs, but I do know about earthquakes. I agree with you on that it is too quiet at the moment. It has also been awfully quiet in earthquakes around Iceland for the past three weeks now. If it wheren't for the tempuary station I have connection to and the remote station that I have in, I would not have recored any earthquakes for at least two weeks. On a global scale, it has been pretty quiet, besides the one mag 6.3 earthquake in Laos the other day. I don't think that the slowness is going to last more then 15 days, 25 days tops. Something must be on time for a mag 7 to 8 earthquake. Regards. --=20 J=F3n Fr=EDmann http://www.jonfr.com http://www.simnet.is/jonfr500/earthquake/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: RE: Nice quake From: "Kareem of Heyjoojoo" system98765@............. Date: Sun, 20 May 2007 21:12:53 -0700 Hey Pete, Felt that up here in El Sobrante but wasn't sure at the time. Slight, almost imperceptible quivvering motion. I looked up to my model airplanes to see if they were moving. They weren't but I figured it was a very small event somewhere in the bay area. Yeah, that was your classic san jose quake - it's been a while. BTW, I thought the "boom" would be the P wave arriving (especially if you heard it coming) at your location rather than the S waves. No? Kareem -----Original Message----- From: psn-l-request@.............. [mailto:psn-l-request@............... On Behalf Of Pete Rowe Sent: Sunday, May 20, 2007 4:34 PM To: psn-l@.............. Subject: Nice quake We just had a nice 3.4 pretty much right under me in the east hills of San Jose. I heard it coming and then the S wave hit with a boom. Cool. I always like a nice earthquake. Pete ____________________________________________________________________________ ________Shape Yahoo! in your own image. Join our Network Research Panel today! http://surveylink.yahoo.com/gmrs/yahoo_panel_invite.asp?a=7 __________________________________________________________ Public Seismic Network Mailing List (PSN-L) __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Torsion springs... From: "Daryl P. Dacko" mycrump@........ Date: Mon, 21 May 2007 01:20:56 -0400 I know that there was a type of unit that used a torsion suspension, I saw it in an old Scientific American magazine. A small post held a wire vertically between two clamps, the top clamp being adjustable to set the zero. It used a small copper 'flag' that mounted to the wire, and had a mirror mounted on the flag. There was a magnet mounted to damp the flag, which was the pendulum. The readout was via a light beam onto a photopaper covered drum. There were two little rods with slots that held oil drops to help damp the wire. It's in that CD that has the collection of all of of SA's Amiature Scientist columns. I'm not sure why this type went out of style, but I remember some discussion on this list a long while back about it's shortcomings. Hope this helps, Daryl __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Torsion spring From: "Geoffrey" gmvoeth@........... Date: Mon, 21 May 2007 00:27:02 -0700 The one major problem that I would think of is temperature changes. I have been thinking that possibly a 5# mass with a specific gravity of between 1.05 and 1.1 to be suspended by vertical extemsion springs extended 10 to 12 inches might also make a sensor that would also be damped but the idea of temp changes really bother me about any new ideas. It takes the experience of a mechanical engineer to really understand how these things might behave before spending money on these ideas. You might hold temp constant with one of these new fangled PN junction heat transfer jobbies with a pid loop diode temp sensor. I think experimentation takes too much money Id rather eat than try things I am certain others have already tried but are keeping things secret. Good luck if you try this spring idea out and please keep us all posted on your results. Whatever you try use a balanced system so the temp effects will somewhat null out. ----- Original Message ----- From: "tchannel" To: Sent: Sunday, May 20, 2007 08:38 Subject: Torsion spring Hi All, First thing, is it just me or is it quiet, "too quiet"? Today is the 11th day on my calendar since I recorded an earthquake. My average, here, is about 2 per week. I am overdue, so I will be watching closely today and tomorrow. On a different issue: I have been restoring old mantle clock. Recently a 400 day Anniversary clock. It uses a "torsion spring".........I know very little about clocks, but this is an interesting concept. A long thin, flat spring wire, is twisted slightly, and uses little energy. The result is a very long running clock train. Has anyone tried to use this concept for a seismometer? Just thinking, the period might be long. On the clock I think the spring rotates about once every 4 secs in each direction. Could a long spring, something like a band-saw blade, but without teeth, be un wrapped and configured to move a horizontal arm, left and right, with a long period of approx. 20 seconds. Just wondering if this has been tried. "Watch your helicorders" Ted __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Lowdown in earthquakes From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@......... Date: Tue, 22 May 2007 07:17:12 +0000 Hi all The lowdown in earthquakes continues. I wonder why that is. Regards. --=20 J=F3n Fr=EDmann http://www.jonfr.com http://www.simnet.is/jonfr500/earthquake/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Mini Lehman From: "Connie and Jim Lehman" lehmancj@........... Date: Mon, 22 Jan 1990 08:54:50 -0500 PSN Friends--A friend brought to my attention a web site of a novel = modification of a Lehman sensor. If you've never seen the = Mini-Seismometer by Charlie Thompson--the design is good for a few = chuckles. http://charliethompson.50megs.com/minileh.html Have a good day, Jim Lehman=20
PSN Friends--A friend brought to my = attention a web=20 site of a novel modification of a Lehman sensor.  If you've never = seen=20 the Mini-Seismometer by Charlie Thompson--the design is = good for a=20 few chuckles.
    http://charlietho= mpson.50megs.com/minileh.html
 
Have a good day,   Jim=20 Lehman 
Subject: Re: Lowdown in earthquakes From: "tchannel" tchannel@.............. Date: Tue, 22 May 2007 07:15:05 -0600 Hi All, If you are like me, you're watching the computer screen every few hours. Tomorrow is day 14, with no recorded events for my station. It will be 52 days since a M7+ I don't have much experience on this subject, but I started a calendar where I log the events. Each system is different, but this give me a simple way to follow what has happened. The more weeks and months I keep track of the better to see patterns or at least past frequencies. From my station I am getting a average of 3 earthquakes recorded per week, 4's 5's and 6's. The last 14 days, none. We all know it's just a matter of time. I also have noticed after a period of little or no activity, I get events in rapid secession, sometimes 3 per days and from different locations. I have read that one event can trigger another, but surprised regarding the great distances between them. Is there a world wide system for posting "Likelihood's"? These events cause little damage where I live, but in high risk zones, these facts might be of greater consequence than, just conversations. In some areas of the world, I would be sleeping outdoors for the next few nights. Ted ----- Original Message ----- From: "Jón Frímann" To: "PSN-Postlist" Sent: Tuesday, May 22, 2007 1:17 AM Subject: Lowdown in earthquakes Hi all The lowdown in earthquakes continues. I wonder why that is. Regards. -- Jón Frímann http://www.jonfr.com http://www.simnet.is/jonfr500/earthquake/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Lowdown in earthquakes From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@......... Date: Tue, 22 May 2007 13:31:45 +0000 Hi All I am having bit problem trying to guess good problal locations of next strong earthquake, that is mag 7 and stronger. I have my own scale, it works like this. Local earthquakes, mag 0.0 to 8.0, but mag 8.0 being the max mag I can get in Iceland. Regional earthquakes, mag 3.5 to 8.0. Same. Teleseismic earthquakes. Mag 5.0 to 9.6. The earthquakes that are at more distace then 1400 km away from me. Due to my current setup I don't record anything less then mag 7.0 word wide, depending on location. But I can tell you that the earthquake lowdown is also ongoing in Iceland, in almost three weeks nothing special has been happening. I've recorded few earthquakes that where less then mag 2.5, but nothing more. If it wheren't for my second station, I would problay not have recored anything at all. Regards.=20 --=20 J=F3n Fr=EDmann http://www.jonfr.com http://www.simnet.is/jonfr500/earthquake/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Lowdown in earthquakes From: ChrisAtUpw@....... Date: Tue, 22 May 2007 10:16:27 EDT In a message dated 2007/05/22, tchannel@.............. writes: > If you are like me, you're watching the computer screen every few > hours. Tomorrow is day 14, with no recorded events for my station. Hi Ted, You should have seen 16-MAY-2007 08:56:18 20.47 100.70 6.1 38.1 SOUTHEAST ASIA It showed up world wide and I received it. Regards, Chris Chapman In a me= ssage dated 2007/05/22, tchannel@.............. writes:

If you are like me, you're watc= hing the computer screen every few
hours.  Tomorrow is day 14, with no recorded events for my station.

Hi Ted,

       You should have seen
       16-MAY-2007 08:56:1= 8 20.47 100.70 6.1 38.1 SOUTHEAST ASIA
                    It showed up world wide and I received=20= it.

       Regards,

       Chris Chapman
 Subject: Re: Lowdown in earthquakes From: "tchannel" tchannel@.............. Date: Tue, 22 May 2007 08:51:02 -0600 Hi Chris, Yes I should have, but I did not. I double checked, and the = background was quiet at that time. I also checked with some other stations in Idaho, and I don't see it on = their helicorders either. Thanks, Ted ----- Original Message -----=20 From: ChrisAtUpw@.......... To: psn-l@................. Sent: Tuesday, May 22, 2007 8:16 AM Subject: Re: Lowdown in earthquakes In a message dated 2007/05/22, tchannel@.............. writes: If you are like me, you're watching the computer screen every few=20 hours. Tomorrow is day 14, with no recorded events for my station.=20 Hi Ted, You should have seen=20 16-MAY-2007 08:56:18 20.47 100.70 6.1 38.1 SOUTHEAST ASIA=20 =20 It showed up world wide and I received it. Regards, Chris Chapman
Hi Chris,  Yes I should have, but = I did=20 not.  I double checked, and the background was quiet at that=20 time.
I also checked with some other stations = in Idaho,=20 and I don't see it on their helicorders either.
 
Thanks, Ted
 
----- Original Message -----
From:=20 ChrisAtUpw@.......
Sent: Tuesday, May 22, 2007 = 8:16 AM
Subject: Re: Lowdown in = earthquakes

In a=20 message dated 2007/05/22, tchannel@..............=20 writes:

If you are like me, you're watching the computer screen = every=20 few
hours.  Tomorrow is day 14, with no recorded events for = my=20 station.


Hi=20 Ted,

       You should have seen=20
       16-MAY-2007=20 08:56:18 20.47 100.70 6.1 38.1 SOUTHEAST ASIA=20 =
           &nb= sp;=20
       It showed up world wide and I = received it.

      =20 Regards,

       Chris=20 Chapman
Subject: Re: Lowdown in earthquakes From: ChrisAtUpw@....... Date: Tue, 22 May 2007 11:11:19 EDT In a message dated 2007/05/22, tchannel@.............. writes: > Hi Chris, Yes I should have, but I did not. I double checked, and the > background was quiet at that time. > I also checked with some other stations in Idaho, and I don't see it on > their helicorders either. Hi Ted, What was the direction wrt your seismometer orientation? > You should have seen > 16-MAY-2007 08:56:18 20.47 100.70 6.1 38.1 SOUTHEAST ASIA Regards, Chris Chapman In a me= ssage dated 2007/05/22, tchannel@.............. writes:


Hi Chris,  Yes I should ha= ve, but I did not.  I double checked, and the background was quiet at t= hat time.
I also checked with some other stations in Idaho, and I don't see it on the= ir helicorders either.


Hi Ted,

       What was the direction wrt your seismom= eter orientation?

  You should have seen        16-MAY-2007 08:56:1= 8 20.47 100.70 6.1 38.1 SOUTHEAST ASIA


       Regards,

       Chris Chapman Subject: Re: Lowdown in earthquakes From: "tchannel" tchannel@.............. Date: Tue, 22 May 2007 09:24:08 -0600 Hi Chris, North/South.........Funny that others in Idaho did not see it? = Ted ----- Original Message -----=20 From: ChrisAtUpw@.......... To: psn-l@................. Sent: Tuesday, May 22, 2007 9:11 AM Subject: Re: Lowdown in earthquakes In a message dated 2007/05/22, tchannel@.............. writes: Hi Chris, Yes I should have, but I did not. I double checked, and = the background was quiet at that time. I also checked with some other stations in Idaho, and I don't see it = on their helicorders either. Hi Ted, What was the direction wrt your seismometer orientation? You should have seen=20 16-MAY-2007 08:56:18 20.47 100.70 6.1 38.1 SOUTHEAST ASIA=20 Regards, Chris Chapman
Hi Chris, North/South.........Funny = that others in=20 Idaho did not see it?   Ted
----- Original Message -----
From:=20 ChrisAtUpw@.......
Sent: Tuesday, May 22, 2007 = 9:11 AM
Subject: Re: Lowdown in = earthquakes

In a=20 message dated 2007/05/22, tchannel@..............=20 writes:


Hi Chris,  Yes I should have, but I did not.  = I double=20 checked, and the background was quiet at that time.
I also checked = with some other=20 stations in Idaho, and I don't see it on their helicorders=20 either.

Hi=20 Ted,

       What was the = direction wrt=20 your seismometer orientation?

  You should have seen=20
       16-MAY-2007=20 08:56:18 20.47 100.70 6.1 38.1 SOUTHEAST = ASIA=20

      =20 Regards,

       Chris = Chapman=20 Subject: RE: Lowdown in earthquakes From: "Kareem of Heyjoojoo" system98765@............. Date: Tue, 22 May 2007 08:37:20 -0700 Yes, would love to hear how a conversation like this fits in to the = activity in the San Francisco bay area region. It sounds like we're discussing "seismic quiescence" or "seismic drought" which eventually leads us to a series of events or one significant one.=20 Continuing to listen... =20 -----Original Message----- From: psn-l-request@.............. [mailto:psn-l-request@............... = On Behalf Of tchannel Sent: Tuesday, May 22, 2007 6:15 AM To: psn-l@.............. Subject: Re: Lowdown in earthquakes Hi All, If you are like me, you're watching the computer screen every = few=20 hours. Tomorrow is day 14, with no recorded events for my station. It = will be 52 days since a M7+ I don't have much experience on this subject, = but I started a calendar where I log the events. Each system is different, = but this give me a simple way to follow what has happened. The more weeks = and months I keep track of the better to see patterns or at least past frequencies. From my station I am getting a average of 3 earthquakes recorded per = week,=20 4's 5's and 6's. The last 14 days, none. We all know it's just a matter of time. I also have noticed after a = period of little or no activity, I get events in rapid secession, sometimes 3 = per days and from different locations. I have read that one event can = trigger another, but surprised regarding the great distances between them. Is there a world wide system for posting "Likelihood's"? These events=20 cause little damage where I live, but in high risk zones, these facts = might be of greater consequence than, just conversations. In some areas of = the world, I would be sleeping outdoors for the next few nights. Ted ----- Original Message ----- From: "J=F3n Fr=EDmann" To: "PSN-Postlist" Sent: Tuesday, May 22, 2007 1:17 AM Subject: Lowdown in earthquakes Hi all The lowdown in earthquakes continues. I wonder why that is. Regards. --=20 J=F3n Fr=EDmann http://www.jonfr.com http://www.simnet.is/jonfr500/earthquake/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) __________________________________________________________ Public Seismic Network Mailing List (PSN-L) __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Lowdown in earthquakes From: "Thomas Dick" dickthomas01@............. Date: Tue, 22 May 2007 13:04:31 -0500 I too in southern Indiana got very little on that quake -- only the E-W = Lehman showed every a little indication
I too in southern Indiana got very = little on that=20 quake -- only the E-W Lehman showed every a little = indication
 
Subject: Re: Lowdown in earthquakes From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@......... Date: Wed, 23 May 2007 10:36:53 +0000 Hi all The lowdown in earthquakes continues. But I did get the mb5.5 earthquake on the mid atlantic ridge. But counting in number of earthquakes, it is still pretty quiet at the moment. Regards --=20 J=F3n Fr=EDmann http://www.jonfr.com http://www.simnet.is/jonfr500/earthquake/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Lowdown in earthquakes From: "Michael Kimzey" mckimzey@........... Date: Wed, 23 May 2007 08:14:11 -0400 >The lowdown in earthquakes continues. But I did get the mb5.5 earthquake >on the mid atlantic ridge. But counting in number of earthquakes, it is >still pretty quiet at the moment. I picked up that one also this morning, and it came through pretty well (around 4 am local, so very little background noise). Regards, Mike __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Lowdown in earthquakes From: "tchannel" tchannel@.............. Date: Wed, 23 May 2007 08:42:56 -0600 Hi Folks, I got this one also, here in Boise Idaho around 4:51 utc.........I too had very little background noise. Here is hoping that Paul C. got it in Connecticut. Ted ----- Original Message ----- From: "Michael Kimzey" To: Sent: Wednesday, May 23, 2007 6:14 AM Subject: Re: Lowdown in earthquakes > >>The lowdown in earthquakes continues. But I did get the mb5.5 earthquake >>on the mid atlantic ridge. But counting in number of earthquakes, it is >>still pretty quiet at the moment. > > I picked up that one also this morning, and it came through pretty well > (around 4 am local, so very little background noise). > > Regards, > > Mike > > > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with the body of the > message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Wrong channel configuration ? From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@......... Date: Sun, 27 May 2007 00:52:16 +0000 Hi all Is there a way for me to tell if I have incorrectly configured the channels on my remote sensor ? Here are the latest traces from that station. http://seismicnet.com/cgi-dos/makegif.exe?/quakes/0705/070527.000300.brgz.p= sn http://seismicnet.com/cgi-dos/makegif.exe?/quakes/0705/070527.000300.brgn.p= sn http://seismicnet.com/cgi-dos/makegif.exe?/quakes/0705/070527.000300.brge.p= sn Here are comparison traces that I know are correct. http://seismicnet.com/cgi-dos/makegif.exe?/quakes/0705/070527.000300.hvtz.p= sn http://seismicnet.com/cgi-dos/makegif.exe?/quakes/0705/070527.000300.hvtn.p= sn http://seismicnet.com/cgi-dos/makegif.exe?/quakes/0705/070527.000300.hvte.p= sn What did make me question the setup is the fact that Z channel on Hvammstangi station is more like N-S on Borgarnes station. But because of little activie in past three weeks it has been hard to me know if this setup is bugged or not. There might be other reasons for this, like the fracture of the earthquake and location etc. But it is important to have the channels correct. Thanks for the help in advance. Regards. --=20 J=F3n Fr=EDmann http://www.jonfr.com http://www.simnet.is/jonfr500/earthquake/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Geophone questions From: "tchannel" tchannel@.............. Date: Sun, 27 May 2007 06:43:11 -0600 I have a few questions about magnets and coils: 1 I have seen a cross section of a Geophone, magnet, spring and mass = etc. When used in a Seismic Sensor, how is it dampened, or is it do = electronically? 2 I am making a new vertical sensor, and this question has to do with = the coil and magnet. The coil is a spool with a 1" dia. hole in the = center. The thickness of the coil is 3/4" The value of the coil is = 500ohms. The magnet will be suspended from a rod and centered in this = 1" hole. Left to Right and Top to Bottom. I can choose from three magnets. One magnet 1/4" thick x 3/4" dia. = centered leaving 1/4" of coil above and below the magnet......... OR Two = magnets 1/4" thick, together to equal 1/2" x 3/4", leaving 1/8" of coil = above and below the two magnets when centered........... Lastly I could = use One magnet 1/2" thick x 3/4" dia. leaving 1/8" above and below. This is a basic question about the magnet's surface and the N/S poles, = I do not know the science, but just curious about just these three = scenarios, which arrangement is the best?.....I could try all three and = measure the result, but in theory is it better one way or the other? Thanks, Ted
I have a few questions about magnets = and=20 coils:
 
1  I have seen a cross section of = a Geophone,=20 magnet, spring and mass etc.  When used in a Seismic Sensor, how is = it=20 dampened, or is it do electronically?
 
2 I am making a new vertical sensor, = and this=20 question has to do with the coil and magnet.  The coil is a spool = with a 1"=20 dia. hole in the center.  The thickness of the coil is = 3/4"   The=20 value of the coil is 500ohms.   The magnet will be suspended = from a=20 rod and centered in this 1" hole. Left to Right and Top to = Bottom.
 
I can choose from three = magnets.  One magnet 1/4" thick x 3/4" dia. centered = leaving 1/4"=20 of coil above and below the magnet......... OR Two magnets 1/4" = thick,=20 together to equal 1/2" x 3/4", leaving 1/8" of coil above and below the = two=20 magnets when centered........... Lastly I could use One magnet 1/2" = thick x 3/4"=20 dia. leaving 1/8" above and below.
 
This is a basic question about the = magnet's surface=20 and the N/S poles,  I do not know the science, but just curious = about just=20 these three scenarios, which arrangement is the best?.....I could try = all three=20 and measure the result, but in theory is it better one way or the=20 other?
 
Thanks, Ted
Subject: Re: Geophone questions From: ChrisAtUpw@....... Date: Sun, 27 May 2007 21:58:27 EDT In a message dated 2007/05/27, tchannel@.............. writes: > I have a few questions about magnets and coils: > > 1 I have seen a cross section of a Geophone, magnet, spring and mass etc. > When used in a Seismic Sensor, how is it dampened, or is it do > electronically? Hi Ted, Geophone coils are usually wound on a copper former, but this usually gives only maybe 40% of the critical induced damping required. It is usual to solder a carefully chosen resistor across the output terminals, which adds the rest of the damping. PSN seismic amplifiers have a 10 K input resistor fitted already and this needs to be taken into account when calculating the value of the required resistor. > 2 I am making a new vertical sensor, and this question has to do with the > coil and magnet. The coil is a spool with a 1" dia. hole in the center. The > thickness of the coil is 3/4" The value of the coil is 500ohms. The > magnet will be suspended from a rod and centered in this 1" hole. Left to Right > and Top to Bottom. > > I can choose from three magnets. One magnet 1/4" thick x 3/4" dia. centered > leaving 1/4" of coil above and below the magnet......... OR Two magnets 1/4" > thick, together to equal 1/2" x 3/4", leaving 1/8" of coil above and below > the two magnets when centered........... Lastly I could use One magnet 1/2" > thick x 3/4" dia. leaving 1/8" above and below. > > This is a basic question about the magnet's surface and the N/S poles, I do > not know the science, but just curious about just these three scenarios, > which arrangement is the best?.....I could try all three and measure the result, > but in theory is it better one way or the other? Putting a magnet on a seismometer arm will enable you to pick up transients from the building Utility Power Wiring, passing trucks and cars, changes in the Earth's magnetic field.... If you really want too monitor any of these, OK, otherwise put the coil on the arm and the magnet on the frame ! ! None of them will be satisfactory. The centralised magnet position will give you an output minimum. Consider how a loudspeaker is made. You have an external cylindrical magnet with poles at either end. One end A has a flat iron plate with a large hole in it. The other end B is fitted with another flat plate with a central solid iron rod which projects a xially to the top of the hole in the plate A. The coil moves in the radial annular field between plate A and the central iron rod. Can you get a mild steel tube which will surround the coil, a flat 1/4" mild steel plate and a stub of 3/4" mild steel rod with flat machined ends? Lap the end of the tube flat with emery paper on the plate. Sit the magnets on top of the rod and the rod on the centre of the plate. Put the iron tube centrally around the magnets and lower in the coil so that the top face of the magnets is about half way down it. Alternatively, get three strips of 1/16" mild steel, bend them in a U shape and mount the mild steel column in the centre, with the strips at 120 degrees. Cut the strips to length so that when stacked they end level with the top of the magnets. You could also use a taller stack of magnets, but 2 off 1/4" ones won't reach the centre of the coil and allow for any free motion. You will probably need to stick the strips together with acrylic glue to form a rigid cup structure. Then give it a coat of anti rust paint. Regards, Chris Chapman In a me= ssage dated 2007/05/27, tchannel@.............. writes:

I have a few questions about ma= gnets and coils:

1  I have seen a cross section of a Geophone, magnet, spring and mass=20= etc.  When used in a Seismic Sensor, how is it dampened, or is it do el= ectronically?


Hi Ted,

       Geophone coils are usually wound on a c= opper former, but this usually gives only maybe 40% of the critical induced=20= damping required. It is usual to solder a carefully chosen resistor across t= he output terminals, which adds the rest of the damping. PSN seismic amplifi= ers have a 10 K input resistor fitted already and this needs to be taken int= o account when calculating the value of the required resistor.

2 I am making a new vertical=20= sensor, and this question has to do with the coil and magnet.  The coil= is a spool with a 1" dia. hole in the center.  The thickness of the co= il is 3/4"   The value of the coil is 500ohms.   The mag= net will be suspended from a rod and centered in this 1" hole. Left to Right= and Top to Bottom.

I can choose from three magnets.  One magnet 1/4" thick x 3/4" dia. ce= ntered leaving 1/4" of coil above and below the magnet......... OR Two magne= ts 1/4" thick, together to equal 1/2" x 3/4", leaving 1/8" of coil above and= below the two magnets when centered........... Lastly I could use One magne= t 1/2" thick x 3/4" dia. leaving 1/8" above and below.

This is a basic question about the magnet's surface and the N/S poles, = ; I do not know the science, but just curious about just these three scenari= os, which arrangement is the best?.....I could try all three and measure the= result, but in theory is it better one way or the other?


       Putting a magnet on a seismometer arm w= ill enable you to pick up transients from the building Utility Power Wiring,= passing trucks and cars, changes in the Earth's magnetic field.... If you r= eally want too monitor any of these, OK, otherwise put the coil on the arm a= nd the magnet on the frame ! !

      None of them will be satisfactory. The centra= lised magnet position will give you an output minimum.

       Consider how a loudspeaker is made. You= have an external cylindrical magnet with poles at either end. One end A has= a flat iron plate with a large hole in it. The other end B is fitted with a= nother flat plate with a central solid iron rod which projects a xially to t= he top of the hole in the plate A. The coil moves in the radial annular fiel= d between plate A and the central iron rod.

       Can you get a mild steel tube which wil= l surround the coil, a flat 1/4" mild steel plate and a stub of 3/4" mild st= eel rod with flat machined ends? Lap the end of the tube flat with emery pap= er on the plate. Sit the magnets on top of the rod and the rod on the centre= of the plate. Put the iron tube centrally around the magnets and lower in t= he coil so that the top face of the magnets is about half way down it. =    
       Alternatively, get three strips of 1/16= " mild steel, bend them in a U shape and mount the mild steel column in the=20= centre, with the strips at 120 degrees. Cut the strips to length so that whe= n stacked they end level with the top of the magnets. You could also use a t= aller stack of magnets, but 2 off 1/4" ones won't reach the centre of the co= il and allow for any free motion. You will probably need to stick the strips= together with acrylic glue to form a rigid cup structure. Then give it a co= at of anti rust paint.

       Regards,

       Chris Chapman Subject: Re: Geophone questions From: "tchannel" tchannel@.............. Date: Sun, 27 May 2007 21:31:57 -0600 Hi Chris, Thanks for your reply: Your notes: = My Questions: 1 "Can you get a mild steel tube which will surround the = coil,"................ Is this to shield? 2 "a flat 1/4" mild steel plate and a stub of 3/4" mild steel rod with = flat machined ends?"......................Say a 1/4" thick plate, 1"x 2" = as the top of the inverted T...........Centered on this the 3/4" rod?=20 3 "Sit the magnets on top of the rod and the rod on the center of the = plate."........................ Now I place the magnet on top of the = rod, so I have an inverted T , made of PLATE, ROD, MAGNET? 4 "Put the iron tube centrally around the magnets and lower in the coil = so that the top face of the magnets is about half way down it." = ............................. Now I place the steel tube over the = inverted T? Now I lower the coil, so that the CENTER OF THE COIL, is = lined up with the top surface of the magnet? This would result with the top half of the COIL, 3/8", above the top = surface of the MAGNET, and bottom half of the COIL below the top surface = of the MAGNET? With no space below this point as the 3/4" rod continues = down. In other words, the magnet is moving OVER A FINGER, RESTING AT THE TOP = OF THE FINGER? If this is the idea, I see the One Pole, say North Pole of the magnet = positioned in the center of the coil, the South Pole of the magnet well = below the coil, as the 3/4" rod has extended the pole to the rod and the = plate. Is the objective to only move One Pole in and out of the coil? Thank you for you help, Ted ----- Original Message -----=20 From: ChrisAtUpw@.......... To: psn-l@................. Sent: Sunday, May 27, 2007 7:58 PM Subject: Re: Geophone questions In a message dated 2007/05/27, tchannel@.............. writes: I have a few questions about magnets and coils: 1 I have seen a cross section of a Geophone, magnet, spring and = mass etc. When used in a Seismic Sensor, how is it dampened, or is it = do electronically? Hi Ted, Geophone coils are usually wound on a copper former, but this = usually gives only maybe 40% of the critical induced damping required. = It is usual to solder a carefully chosen resistor across the output = terminals, which adds the rest of the damping. PSN seismic amplifiers = have a 10 K input resistor fitted already and this needs to be taken = into account when calculating the value of the required resistor. 2 I am making a new vertical sensor, and this question has to do = with the coil and magnet. The coil is a spool with a 1" dia. hole in = the center. The thickness of the coil is 3/4" The value of the coil = is 500ohms. The magnet will be suspended from a rod and centered in = this 1" hole. Left to Right and Top to Bottom. I can choose from three magnets. One magnet 1/4" thick x 3/4" dia. = centered leaving 1/4" of coil above and below the magnet......... OR Two = magnets 1/4" thick, together to equal 1/2" x 3/4", leaving 1/8" of coil = above and below the two magnets when centered........... Lastly I could = use One magnet 1/2" thick x 3/4" dia. leaving 1/8" above and below. This is a basic question about the magnet's surface and the N/S = poles, I do not know the science, but just curious about just these = three scenarios, which arrangement is the best?.....I could try all = three and measure the result, but in theory is it better one way or the = other? Putting a magnet on a seismometer arm will enable you to pick = up transients from the building Utility Power Wiring, passing trucks and = cars, changes in the Earth's magnetic field.... If you really want too = monitor any of these, OK, otherwise put the coil on the arm and the = magnet on the frame ! ! None of them will be satisfactory. The centralised magnet = position will give you an output minimum.=20 Consider how a loudspeaker is made. You have an external = cylindrical magnet with poles at either end. One end A has a flat iron = plate with a large hole in it. The other end B is fitted with another = flat plate with a central solid iron rod which projects a xially to the = top of the hole in the plate A. The coil moves in the radial annular = field between plate A and the central iron rod.=20 Can you get a mild steel tube which will surround the coil, a = flat 1/4" mild steel plate and a stub of 3/4" mild steel rod with flat = machined ends? Lap the end of the tube flat with emery paper on the = plate. Sit the magnets on top of the rod and the rod on the centre of = the plate. Put the iron tube centrally around the magnets and lower in = the coil so that the top face of the magnets is about half way down it. = =20 Alternatively, get three strips of 1/16" mild steel, bend them = in a U shape and mount the mild steel column in the centre, with the = strips at 120 degrees. Cut the strips to length so that when stacked = they end level with the top of the magnets. You could also use a taller = stack of magnets, but 2 off 1/4" ones won't reach the centre of the coil = and allow for any free motion. You will probably need to stick the = strips together with acrylic glue to form a rigid cup structure. Then = give it a coat of anti rust paint. Regards, Chris Chapman
Hi Chris,   Thanks for your=20 reply:
 
 
Your=20 notes:           &= nbsp;           &n= bsp;           &nb= sp;           &nbs= p;            = ;            =             &= nbsp;      =20 My Questions:
1  "Can you get a mild steel tube = which will=20 surround the coil,"................  Is this to = shield?
 
2  "a flat 1/4" mild steel plate = and a stub of=20 3/4" mild steel rod with flat machined = ends?"......................Say a 1/4" thick plate, 1"x 2" as the top of the = inverted=20 T...........Centered on this the 3/4" rod? 
 
3  "Sit the magnets on top of the = rod and the=20 rod on the center of the = plate."........................    Now I=20 place the magnet on top of the rod, so I have an inverted T , made = of=20 PLATE, ROD, MAGNET?
 
4  "Put the iron tube centrally = around the=20 magnets and lower in the coil so that the top face of the magnets is = about half=20 way down it." ............................     Now I = place=20 the steel tube over the inverted T?   Now I lower the coil, so = that=20 the CENTER OF THE COIL, is lined up with the top surface of the=20 magnet?
 
 
This would result with the = top half of the=20 COIL, 3/8", above the top surface of the MAGNET, and bottom half of = the COIL below the top surface of the MAGNET?  With no space = below=20 this point as the 3/4" rod continues down.
In other words, the magnet is moving = OVER A FINGER,=20 RESTING AT THE TOP OF THE FINGER?
 
If this is the idea,  I see the = One Pole, say=20 North Pole of the magnet positioned in the center of the coil, the South = Pole of=20 the magnet well below the coil, as the 3/4" rod has extended the pole to = the rod=20 and the plate.
Is the objective to only move One Pole = in and out=20 of the coil?
 
Thank you for you help,
Ted
 
 
----- Original Message -----
From:=20 ChrisAtUpw@.......
Sent: Sunday, May 27, 2007 7:58 = PM
Subject: Re: Geophone = questions

In a=20 message dated 2007/05/27, tchannel@..............=20 writes:

I have a few questions about magnets and = coils:

1  I have = seen a cross=20 section of a Geophone, magnet, spring and mass etc.  When used = in a=20 Seismic Sensor, how is it dampened, or is it do = electronically?

Hi=20 Ted,

       Geophone coils are = usually=20 wound on a copper former, but this usually gives only maybe 40% of the = critical induced damping required. It is usual to solder a carefully = chosen=20 resistor across the output terminals, which adds the rest of the = damping. PSN=20 seismic amplifiers have a 10 K input resistor fitted already and this = needs to=20 be taken into account when calculating the value of the required=20 resistor.

2 I am=20 making a new vertical sensor, and this question has to do with the = coil and=20 magnet.  The coil is a spool with a 1" dia. hole in the = center. =20 The thickness of the coil is 3/4"   The value of the coil = is=20 500ohms.   The magnet will be suspended from a rod and = centered in=20 this 1" hole. Left to Right and Top to Bottom.

I can choose = from three=20 magnets.  One magnet 1/4" thick x 3/4" dia. centered leaving = 1/4" of=20 coil above and below the magnet......... OR Two magnets 1/4" thick, = together=20 to equal 1/2" x 3/4", leaving 1/8" of coil above and below the two = magnets=20 when centered........... Lastly I could use One magnet 1/2" thick x = 3/4"=20 dia. leaving 1/8" above and below.

This is a basic = question about=20 the magnet's surface and the N/S poles,  I do not know the = science, but=20 just curious about just these three scenarios, which arrangement is = the=20 best?.....I could try all three and measure the result, but in = theory is it=20 better one way or the=20 other?

       = Putting a=20 magnet on a seismometer arm will enable you to pick up transients from = the=20 building Utility Power Wiring, passing trucks and cars, changes in the = Earth's=20 magnetic field.... If you really want too monitor any of these, OK, = otherwise=20 put the coil on the arm and the magnet on the frame !=20 !

      None of them will be = satisfactory. The=20 centralised magnet position will give you an output minimum.=20

       Consider how a = loudspeaker is=20 made. You have an external cylindrical magnet with poles at either = end. One=20 end A has a flat iron plate with a large hole in it. The other end B = is fitted=20 with another flat plate with a central solid iron rod which projects a = xially=20 to the top of the hole in the plate A. The coil moves in the radial = annular=20 field between plate A and the central iron rod.=20

       Can you get a mild steel = tube=20 which will surround the coil, a flat 1/4" mild steel plate and a stub = of 3/4"=20 mild steel rod with flat machined ends? Lap the end of the tube flat = with=20 emery paper on the plate. Sit the magnets on top of the rod and the = rod on the=20 centre of the plate. Put the iron tube centrally around the magnets = and lower=20 in the coil so that the top face of the magnets is about half way down = it.    
      =20 Alternatively, get three strips of 1/16" mild steel, bend them in a U = shape=20 and mount the mild steel column in the centre, with the strips at 120 = degrees.=20 Cut the strips to length so that when stacked they end level with the = top of=20 the magnets. You could also use a taller stack of magnets, but 2 off = 1/4" ones=20 won't reach the centre of the coil and allow for any free motion. You = will=20 probably need to stick the strips together with acrylic glue to form a = rigid=20 cup structure. Then give it a coat of anti rust=20 paint.

      =20 Regards,

       Chris = Chapman=20 Subject: Re: Geophone questions From: ChrisAtUpw@....... Date: Mon, 28 May 2007 00:33:35 EDT In a message dated 2007/05/28, tchannel@.............. writes: > Questions: > 1 "Can you get a mild steel tube which will surround the > coil,"................ Is this to shield? Hi Ted, No, this forms the return path of the magnetic field. Consider the loudspeaker construction. > 2 "a flat 1/4" mild steel plate and a stub of 3/4" mild steel rod with > flat machined ends?"......................Say a 1/4" thick plate, 1"x 2" as the > top of the inverted T...........Centered on this the 3/4" rod? Lets start again. You put the 3/4" magnet on one end of a short 3/4" dia circular iron rod. You put the other end of the rod on the centre of a 1/4" thick iron baseplate. You put the outer iron tube centrally over the rod so that it rests on the baseplate. So you have a cylindrical steel cup with the magnet on a stalk in the centre. You lower the coil over the magnet so that it is 3/8" down - half in and half out of the field. If the top of the magnet is N, the S pole will be in contact with the iron stub. The field from the S pole will go through the stub, spread out through the baseplate, up the outer cylinder and appear across the annular cylinder / magnet gap. Similar to the loudspeaker construction > 3 "Sit the magnets on top of the rod and the rod on the center of the > plate."........................ Now I place the magnet on top of the rod, so > I have an inverted T , made of PLATE, ROD, MAGNET? > > 4 "Put the iron tube centrally around the magnets and lower in the coil so > that the top face of the magnets is about half way down it." > ............................ Now I place the steel tube over the inverted T? Now I > lower the coil, so that the CENTER OF THE COIL, is lined up with the top surface > of the magnet? Correct. > This would result with the top half of the COIL, 3/8", above the top > surface of the MAGNET, and bottom half of the COIL below the top surface of the > MAGNET? Correct. With no space below this point as the 3/4" rod continues down.> > In other words, the magnet is moving OVER A FINGER, RESTING AT THE TOP OF > THE FINGER? The magnet does not move at all. It is the coil which moves in the radial field between the top of the magnet and the outer iron tube. > If this is the idea, I see the One Pole, say North Pole of the magnet > positioned in the center of the coil, the South Pole of the magnet well below > the coil, as the 3/4" rod has extended the pole to the rod and the plate. > Is the objective to only move One Pole in and out of the coil? The top of the magnet is say the N pole. The outer steel tube is the S pole and the radial magnetic field is in the annular gap between the two. The coil moves further into and out of the tube. Exactly like a loudspeaker, but with a much thicker coil. Regards, Chris Chapman In a me= ssage dated 2007/05/28, tchannel@.............. writes:

Questions:
1  "Can you get a mild steel tube which will surround the coil,"......= ...........  Is this to shield?


Hi Ted,

       No, this forms the return path of the m= agnetic field. Consider the loudspeaker construction.

2  "a flat 1/4" mild stee= l plate and a stub of 3/4" mild steel rod with flat machined ends?".........= ..............Say a 1/4" thick plate, 1"x 2" as the top of the inverted T....= ........Centered on this the 3/4" rod?


       Lets start again.
       You put the 3/4" magnet on one end of a= short 3/4" dia circular iron rod.
    You put the other end of the rod on the centre of a 1= /4" thick iron baseplate.
    You put the outer iron tube centrally over the rod so= that it rests on the baseplate.
    So you have a cylindrical steel cup with the magnet on a=20= stalk in the centre.
    You lower the coil over the magnet so that it is 3/8" dow= n - half in and half out of the field.
     If the top of the magnet is N, the S pole will be i= n contact with the iron stub. The field from the S pole will go through the=20= stub, spread out through the baseplate, up the outer cylinder and appear acr= oss the annular cylinder / magnet gap. Similar to the loudspeaker constructi= on

3  "Sit the magnets on t= op of the rod and the rod on the center of the plate."......................= ...    Now I place the magnet on top of the rod, so I have an=20= inverted T , made of PLATE, ROD, MAGNET?

4  "Put the iron tube centrally around the magnets and lower in the co= il so that the top face of the magnets is about half way down it." .........= ....................     Now I place the steel tube over=20= the inverted T?   Now I lower the coil, so that the CENTER OF THE=20= COIL, is lined up with the top surface of the magnet?


       Correct.

This would result with the top= half of the COIL, 3/8", above the top surface of the MAGNET, and bottom hal= f of the COIL below the top surface of the MAGNET?


       Correct.

  With no space below this point as the 3/4" rod continues down.=
In other words, the magnet is moving OVER A FINGER, RESTING AT THE TOP OF T= HE FINGER?

       The magnet does not move at all. It is= the coil which moves in the radial field between the top of the magnet and=20= the outer iron tube.

If this is the idea,  I=20= see the One Pole, say North Pole of the magnet positioned in the center of t= he coil, the South Pole of the magnet well below the coil, as the 3/4" rod h= as extended the pole to the rod and the plate.
Is the objective to only move One Pole in and out of the coil?
=

       The top of the magnet is say the N pole= .. The outer steel tube is the S pole and the radial magnetic field is in the= annular gap between the two. The coil moves further into and out of the tub= e. Exactly like a loudspeaker, but with a much thicker coil.

       Regards,

       Chris Chapman Subject: Re: Geophone questions From: "Geoffrey" gmvoeth@........... Date: Mon, 28 May 2007 03:22:57 -0700 Ideally you want a uniform magnetic field through which the wire moves puhsing the electrons all in the same direction. Take that idea and you will see that the B fields seems to need to be n-s at one side and s-n at the other of any kind of coil but I would imagine that a rectangular loop is better than a circular one so that the coil moves at right angle to the fiels on both sides. The strength of the B field is ectremely important, the stronger the better. I once saw an impressive demonstration of magnetic field strength at Arizona State University where an aluminum bar was dropped from vertical (hinged at one end) and was stopped cold by the magnetic field alone. but the magnet was absolutely huge. it was tapered to concentrate the magnetic lines of force. You want a uniform field through which the wire moves. The current is dependent upon the B field strength and the voltage the number of loops.of wire I would think the same amount of energy is present no matter what the coil so if you could make an ideal current sensor that looks only at hole flow is really what you may want instead of lots of turns og 40ga wire. I can only imagine what the researchers are using today with technology being what it is and everything I suspect they have sensors we have never imagined before. Coils and magnets are ancient history but that about all po-folk can play with. ----- Original Message ----- From: "tchannel" To: Sent: Sunday, May 27, 2007 05:43 Subject: Geophone questions I have a few questions about magnets and coils: 1 I have seen a cross section of a Geophone, magnet, spring and mass etc. When used in a Seismic Sensor, how is it dampened, or is it do electronically? 2 I am making a new vertical sensor, and this question has to do with the coil and magnet. The coil is a spool with a 1" dia. hole in the center. The thickness of the coil is 3/4" The value of the coil is 500ohms. The magnet will be suspended from a rod and centered in this 1" hole. Left to Right and Top to Bottom. I can choose from three magnets. One magnet 1/4" thick x 3/4" dia. centered leaving 1/4" of coil above and below the magnet......... OR Two magnets 1/4" thick, together to equal 1/2" x 3/4", leaving 1/8" of coil above and below the two magnets when centered........... Lastly I could use One magnet 1/2" thick x 3/4" dia. leaving 1/8" above and below. This is a basic question about the magnet's surface and the N/S poles, I do not know the science, but just curious about just these three scenarios, which arrangement is the best?.....I could try all three and measure the result, but in theory is it better one way or the other? Thanks, Ted __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Lowdown in earthquakes From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@......... Date: Mon, 28 May 2007 11:48:54 +0000 Hi all The lowdown in earthquakes continues. This is now week 4 by my account, but my monitoring is based around Iceland. But I have also been monitoring large earthquakes around the world and this is week 3 (?) in lowdown there, but I am meaning in earthquakes above mag 7.0. Regards. --=20 J=F3n Fr=EDmann http://www.jonfr.com http://www.simnet.is/jonfr500/earthquake/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Geophone questions From: ChrisAtUpw@....... Date: Mon, 28 May 2007 08:58:39 EDT In a message dated 2007/05/28, tchannel@.............. writes: > Hi Chris, Thanks for your reply: > Hi Ted, See: http://jclahr.com/science/psn/chapman/coil/index.html Regards, Chris In a me= ssage dated 2007/05/28, tchannel@.............. writes:

Hi Chris,   Thanks fo= r your reply:

Hi Ted,

    See:  http://jclahr.com/science/psn/chapman/coil/ind= ex.html

    Regards,

    Chris

 Subject: Re: Lowdown in earthquakes From: "tchannel" tchannel@.............. Date: Mon, 28 May 2007 07:48:39 -0600 Hi All, As a newcomer to this earth science, I find this time interestingly quiet. I would say there are three possibilities: 1 Things will just continue quiet. 2 When the quiet breaks, it will be a big one. 3 When the quiet breaks, it will return to normal activity, followed by a big one. I would not say when one of the three possibly occurs it creates a pattern for the end of the next quiet time, but it will offer one historical perspective. At any rate it makes each morning, when I turn on the monitor, very interesting. Ted ----- Original Message ----- From: "Jón Frímann" To: Sent: Monday, May 28, 2007 5:48 AM Subject: Re: Lowdown in earthquakes Hi all The lowdown in earthquakes continues. This is now week 4 by my account, but my monitoring is based around Iceland. But I have also been monitoring large earthquakes around the world and this is week 3 (?) in lowdown there, but I am meaning in earthquakes above mag 7.0. Regards. -- Jón Frímann http://www.jonfr.com http://www.simnet.is/jonfr500/earthquake/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Geophone questions From: "tchannel" tchannel@.............. Date: Mon, 28 May 2007 08:02:27 -0600 Hi Chris, The wed site was very helpful, and your additional = explanation. It is now clear Thanks, Ted ----- Original Message -----=20 From: ChrisAtUpw@.......... To: psn-l@................. Sent: Monday, May 28, 2007 6:58 AM Subject: Re: Geophone questions In a message dated 2007/05/28, tchannel@.............. writes: Hi Chris, Thanks for your reply: Hi Ted, See: http://jclahr.com/science/psn/chapman/coil/index.html Regards, Chris
Hi Chris,  The=20 wed site was very helpful,  and your additional explanation.  = It is=20 now clear
 
Thanks, Ted
----- Original Message -----
From:=20 ChrisAtUpw@.......
Sent: Monday, May 28, 2007 6:58 = AM
Subject: Re: Geophone = questions

In a=20 message dated 2007/05/28, tchannel@..............=20 writes:

Hi Chris,   Thanks for your reply:

Hi = Ted,

    See: =20 http://jcl= ahr.com/science/psn/chapman/coil/index.html

   = =20 Regards,

    Chris

 Subject: Re: Geophone questions From: "tchannel" tchannel@.............. Date: Mon, 28 May 2007 08:21:10 -0600 Hi Geoffrey, This is a follow up question. Which would create the most useful current, under these conditions: The coil, being a donut, 1" hole, 3/4" thick. The magnet inserted into the 1" hole, is a ring, 1/4" thick, 3/4" OD, with a 1/4" hole in the center. 1 The N pole enters and exit the top 1/4" of the coil, in and out. This results in only the N pole entering the coil. or 2 The magnet, at rest, is now midway inserted into the coil. This results in both the N and S poles actively engaging the coil. My thinking is that you would be getting a push/pull affect, as it moves in either direction. Thanks, Ted ----- Original Message ----- From: "Geoffrey" To: Sent: Monday, May 28, 2007 4:22 AM Subject: Re: Geophone questions > Ideally you want a uniform magnetic field through which the wire moves > puhsing the electrons all in the same direction. > Take that idea and you will see that the B fields seems to need > to be n-s at one side and s-n at the other of any kind of coil > but I would imagine that a rectangular loop is better than a circular one > so that the coil moves at right angle to the fiels on both sides. > The strength of the B field is ectremely important, the stronger the > better. > I once saw an impressive demonstration of magnetic field strength at > Arizona State University where an aluminum bar was dropped from vertical > (hinged at one end) and was stopped cold by the magnetic field alone. but > the magnet was absolutely huge. it was tapered to concentrate the magnetic > lines of force. > You want a uniform field through which the wire moves. The current is > dependent upon the B field strength and the voltage the number of loops.of > wire I would think the same amount of energy is present no matter what the > coil so if you could make an ideal current sensor that looks only at hole > flow is really what you may want instead of lots of turns og 40ga wire. I > can only imagine what the researchers are using today with technology > being what it is and everything I suspect they have sensors we have never > imagined before. > Coils and magnets are ancient history but that about all po-folk can play > with. > > > ----- Original Message ----- > From: "tchannel" > To: > Sent: Sunday, May 27, 2007 05:43 > Subject: Geophone questions > > > I have a few questions about magnets and coils: > > 1 I have seen a cross section of a Geophone, magnet, spring and mass etc. > When used in a Seismic Sensor, how is it dampened, or is it do > electronically? > > 2 I am making a new vertical sensor, and this question has to do with the > coil and magnet. The coil is a spool with a 1" dia. hole in the center. > The thickness of the coil is 3/4" The value of the coil is 500ohms. > The magnet will be suspended from a rod and centered in this 1" hole. Left > to Right and Top to Bottom. > > I can choose from three magnets. One magnet 1/4" thick x 3/4" dia. > centered leaving 1/4" of coil above and below the magnet......... OR Two > magnets 1/4" thick, together to equal 1/2" x 3/4", leaving 1/8" of coil > above and below the two magnets when centered........... Lastly I could > use One magnet 1/2" thick x 3/4" dia. leaving 1/8" above and below. > > This is a basic question about the magnet's surface and the N/S poles, I > do not know the science, but just curious about just these three > scenarios, which arrangement is the best?.....I could try all three and > measure the result, but in theory is it better one way or the other? > > Thanks, Ted > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with the body of the > message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Geophone questions From: ChrisAtUpw@....... Date: Mon, 28 May 2007 11:11:57 EDT In a message dated 2007/05/28, tchannel@.............. writes: > Hi Geoffrey, This is a follow up question. > Which would create the most useful current, under these conditions: > The coil, being a donut, 1" hole, 3/4" thick. > The magnet inserted into the 1" hole, is a ring, 1/4" thick, 3/4" OD, with a > > 1/4" hole in the center. > > 1 The N pole enters and exit the top 1/4" of the coil, in and out. This > results in only the N pole entering the coil. > or > 2 The magnet, at rest, is now midway inserted into the coil. This results > in both the N and S poles actively engaging the coil. My thinking is that > you would be getting a push/pull affect, as it moves in either direction. Hi Geoff, Ted, 1 gives the max output In 2 you DO get a push pull effect, but since the movement direction and the winding direction are all constant, the induced voltages tend to CANCEL ! If you want to use a single magnet like this, you need to wind two coils on the same former, end to end but connected serially in the opposite sense. The overall coil length might be 3x the magnet length, or a bit more. Regards, Chris Chapman In a me= ssage dated 2007/05/28, tchannel@.............. writes:

Hi Geoffrey,   This i= s a follow up question.
Which would create the most useful current, under these conditions:
The coil, being a donut, 1" hole, 3/4" thick.
The magnet inserted into the 1" hole, is a ring, 1/4" thick, 3/4" OD, with a=
1/4" hole in the center.

1  The N pole enters and exit the top 1/4" of the coil, in and out.&nbs= p; This
results in only the N pole entering the coil.
or
2  The magnet, at rest, is now midway inserted into the coil.  Thi= s results
in both the N and S poles actively engaging the coil. My thinking is that you would be getting a push/pull affect, as it moves in either direction.

Hi Geoff, Ted,

       1 gives the max output
      
       In 2 you DO get a push pull effect, but= since the movement direction and the winding direction are all constant, th= e induced voltages tend to CANCEL !

       If you want to use a single magnet like= this, you need to wind two coils on the same former, end to end but connect= ed serially in the opposite sense. The overall coil length might be 3x the m= agnet length, or a bit more. 

       Regards,

       Chris Chapman Subject: Re: Geophone questions From: "tchannel" tchannel@.............. Date: Mon, 28 May 2007 10:26:54 -0600 Hi Chris, I understand. I think I see this arrangement in a cut-away of = a Geophone. One magnet, and two coils, one top and one bottom, perhaps = wound as you describe. Thanks, Ted ----- Original Message -----=20 From: ChrisAtUpw@.......... To: psn-l@................. Sent: Monday, May 28, 2007 9:11 AM Subject: Re: Geophone questions In a message dated 2007/05/28, tchannel@.............. writes: Hi Geoffrey, This is a follow up question. Which would create the most useful current, under these conditions: The coil, being a donut, 1" hole, 3/4" thick. The magnet inserted into the 1" hole, is a ring, 1/4" thick, 3/4" = OD, with a=20 1/4" hole in the center. 1 The N pole enters and exit the top 1/4" of the coil, in and out. = This=20 results in only the N pole entering the coil. or 2 The magnet, at rest, is now midway inserted into the coil. This = results=20 in both the N and S poles actively engaging the coil. My thinking is = that=20 you would be getting a push/pull affect, as it moves in either = direction. Hi Geoff, Ted, 1 gives the max output=20 =20 In 2 you DO get a push pull effect, but since the movement = direction and the winding direction are all constant, the induced = voltages tend to CANCEL ! If you want to use a single magnet like this, you need to wind = two coils on the same former, end to end but connected serially in the = opposite sense. The overall coil length might be 3x the magnet length, = or a bit more. =20 Regards, Chris Chapman
Hi Chris, I understand.  I think I = see this=20 arrangement in a cut-away of a Geophone. One magnet, and two coils, one = top and=20 one bottom, perhaps wound as you describe.
Thanks, Ted
----- Original Message -----
From:=20 ChrisAtUpw@.......
Sent: Monday, May 28, 2007 9:11 = AM
Subject: Re: Geophone = questions

In a=20 message dated 2007/05/28, tchannel@..............=20 writes:

Hi Geoffrey,   This is a follow up = question.
Which=20 would create the most useful current, under these conditions:
The = coil,=20 being a donut, 1" hole, 3/4" thick.
The magnet inserted into the = 1" hole,=20 is a ring, 1/4" thick, 3/4" OD, with a
1/4" hole in the=20 center.

1  The N pole enters and exit the top 1/4" of = the coil,=20 in and out.  This
results in only the N pole entering the=20 coil.
or
2  The magnet, at rest, is now midway inserted = into the=20 coil.  This results
in both the N and S poles actively = engaging the=20 coil. My thinking is that
you would be getting a push/pull = affect, as it=20 moves in either direction.


Hi Geoff,=20 Ted,

       1 gives the max = output=20
      =20
       In 2 you DO get a push pull = effect,=20 but since the movement direction and the winding direction are all = constant,=20 the induced voltages tend to CANCEL=20 !

       If you want to use a = single=20 magnet like this, you need to wind two coils on the same former, end = to end=20 but connected serially in the opposite sense. The overall coil length = might be=20 3x the magnet length, or a bit more. =20

      =20 Regards,

       Chris = Chapman=20 Subject: Surface Waves From: "Randy" rpratt@............. Date: Tue, 29 May 2007 20:34:40 -0500 Hi All, I have been having trouble recording any surface waves lately. I used = the instrument several years ago and had no problem but now I do not = seem to get low frequency. I am using the PSN schematic for the = preamp, filter and final stages. There is both an unfiltered quake and = an FFT posted at http://mit.midco.net/rpratt/ I noted the high = frequency side of 2 peaks seems to have hard cutoff on this quake but = have not noticed this before. Where should I look to trouble shoot? My = suspicion is the electrolytic cap coupling to the final. Randy
Hi All,
 
I have been having trouble recording = any surface=20 waves lately.  I used the instrument several years ago and had = no=20 problem but now I do not seem to get low frequency.   I am = using the=20 PSN schematic for the preamp, filter and final stages.  There is = both an=20 unfiltered quake and an FFT posted at http://mit.midco.net/rpratt/&nb= sp; I=20 noted the high frequency side of 2 peaks seems to have hard cutoff on = this quake=20 but have not noticed this before.  Where should I look to trouble=20 shoot?  My suspicion is the electrolytic cap coupling to the=20 final.
 
Randy
Subject: Magnets From: "Randy" rpratt@............. Date: Tue, 29 May 2007 20:49:16 -0500 Ted, I have found the combination of teenage boys and subwoofers has created = an abundant source of strong magnets for your type applicatiion. We = just had a junk day in town and speakers were plentiful. If no junk day = or neighbor boys then stop by an automotive sound shop and ask for some = blown speakers. The ring magnets are generally much larger ID than the = visible gap so the gap can easily be cut out on a lathe or with a dremel = tool and the post turned to fit your coil if need be. =20 Randy
Ted,
 
I have found the combination of teenage = boys and=20 subwoofers has created an abundant source of strong magnets for your = type=20 applicatiion.  We just had a junk day in town and speakers were=20 plentiful.  If no junk day or neighbor boys then stop by an = automotive=20 sound shop and ask for some blown speakers.  The ring magnets are = generally=20 much larger ID than the visible gap so the gap can easily be cut out on = a lathe=20 or with a dremel tool and the post turned to fit your coil if need = be. =20
 
Randy 
Subject: Re: Magnets From: ChrisAtUpw@....... Date: Tue, 29 May 2007 22:49:56 EDT In a message dated 2007/05/30, rpratt@............. writes: > I have found the combination of teenage boys and subwoofers has created an > abundant source of strong magnets for your type applicatiion. We just had a > junk day in town and speakers were plentiful. If no junk day or neighbor > boys then stop by an automotive sound shop and ask for some blown speakers. The > ring magnets are generally much larger ID than the visible gap so the gap > can easily be cut out on a lathe or with a dremel tool and the post turned to > fit your coil if need be. Hi Randy, The problem that I have found with this approach is that most speakers these days seem to use ferrite magnets and they are glued with epoxy to both pole pieces. If you can get old speakers with cylindrical Alnico magnets, fine. Ferrite is rated for use up to about 250c and it looses it's magnetism at 450 C. You need cook them to 150-180C, which is the temperature at which epoxies loose strength and you can lever them apart. If you have a lathe you may be able to turn out the flat top elect rode, but cleaning out the turnings out can be a problem, if you try to do it with the mangets in place > I have been having trouble recording any surface waves lately. I used the > instrument several years ago and had no problem but now I do not seem to get > low frequency. I suggest that you measure the capacity of any old electrolytic coupliing capacitors and maybe replace them. PSN amplifiers use polyester coupling, which should be reliable. Non polar electrolytic types are not expensive. At what period is your sensor set? If you have a Lehman, but it is only set up for say 12 secs, it won't bring in 20 second waves very well. They resetting to 25 secs? Regards, Chris Chapman In a me= ssage dated 2007/05/30, rpratt@............. writes:

I have found the combination of= teenage boys and subwoofers has created an abundant source of strong magnet= s for your type applicatiion.  We just had a junk day in town and speak= ers were plentiful.  If no junk day or neighbor boys then stop by an au= tomotive sound shop and ask for some blown speakers.  The ring magnets=20= are generally much larger ID than the visible gap so the gap can easily be c= ut out on a lathe or with a dremel tool and the post turned to fit your coil= if need be. 


Hi Randy,
      
       The problem that I have found with this= approach is that most speakers these days seem to use ferrite magnets and t= hey are glued with epoxy to both pole pieces. If you can get old speakers wi= th cylindrical Alnico magnets, fine. Ferrite is rated for use up to about 25= 0c and it looses it's magnetism at 450 C. You need cook them to 150-180C, wh= ich is the temperature at which epoxies loose strength and you can lever the= m apart.
       If you have a lathe you may be able to=20= turn out the flat top electrode, but cleaning out the turnings out can be a=20= problem, if you try to do it with the mangets in place


I have been having trouble reco= rding any surface waves lately.  I used the instrument several years ag= o and had no problem but now I do not seem to get low frequency. 

       I suggest that you measure the capacity= of any old electrolytic coupliing capacitors and maybe replace them. PSN am= plifiers use polyester coupling, which should be reliable. Non polar electro= lytic types are not expensive.

       At what period is your sensor set? If y= ou have a Lehman, but it is only set up for say 12 secs, it won't bring in 2= 0 second waves very well. They resetting to 25 secs?

       Regards,

       Chris Chapman Subject: Re: Digest from 05/29/2007 00:00:24 From: "Randy" rpratt@............. Date: Wed, 30 May 2007 17:26:37 -0500 Chris, You are absolutely correct about getting turnings out. It is difficult and they tend to stand up and stick fingers very easily. Otherwise it is quite easy to turn the gap out without dissassembling and the wider gap gets easier to clean. I have also had some speakers with bolts or rivits from front to back and these will sometimes break free after drilling out the rivit and tapping a chisel between the magnet and pole piece. My period is set at about 22 seconds so I think it must be electrical problem involved. What confuses me is the background noise and walk up test don't seem much different than before when I could receive surface waves easily. I would expect the lower freqencies of these to look like a high pass filtered FFT also. Randy > .------ ------ ------ ------ ------ ------ ------ ------ ------ ------. > | Message 3 | > '------ ------ ------ ------ ------ ------ ------ ------ ------ ------' > Subject: Re: Magnets > From: ChrisAtUpw@....... > Date: Tue, 29 May 2007 22:49:56 EDT > > > --part1_cf6.1135803d.338e4054_boundary > Content-Type: text/plain; charset="US-ASCII" > Content-Transfer-Encoding: 7bit > > In a message dated 2007/05/30, rpratt@............. writes: > > > I have found the combination of teenage boys and subwoofers has created an > > abundant source of strong magnets for your type applicatiion. We just had a > > junk day in town and speakers were plentiful. If no junk day or neighbor > > boys then stop by an automotive sound shop and ask for some blown speakers. The > > ring magnets are generally much larger ID than the visible gap so the gap > > can easily be cut out on a lathe or with a dremel tool and the post turned to > > fit your coil if need be. > > Hi Randy, > > The problem that I have found with this approach is that most speakers > these days seem to use ferrite magnets and they are glued with epoxy to both > pole pieces. If you can get old speakers with cylindrical Alnico magnets, > fine. Ferrite is rated for use up to about 250c and it looses it's magnetism at > 450 C. You need cook them to 150-180C, which is the temperature at which epoxies > loose strength and you can lever them apart. > If you have a lathe you may be able to turn out the flat top elect > rode, but cleaning out the turnings out can be a problem, if you try to do it with > the mangets in place > > > > I have been having trouble recording any surface waves lately. I used the > > instrument several years ago and had no problem but now I do not seem to get > > low frequency. > > I suggest that you measure the capacity of any old electrolytic > coupliing capacitors and maybe replace them. PSN amplifiers use polyester coupling, > which should be reliable. Non polar electrolytic types are not expensive. > > At what period is your sensor set? If you have a Lehman, but it is > only set up for say 12 secs, it won't bring in 20 second waves very well. They > resetting to 25 secs? > > Regards, > > Chris Chapman __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Digest from 05/29/2007 00:00:24 From: ChrisAtUpw@....... Date: Wed, 30 May 2007 19:08:53 EDT In a message dated 2007/05/30, rpratt@............. writes: I> t is quite easy to turn the gap out without dissassembling and the wider > gap gets > easier to clean. Hi Randy, After you have done this, give the iron a coat of anti rust paint. This prevents problems. > My period is set at about 22 seconds so I think it must be electrical > problem involved. What confuses me is the background noise and walk up test > don't seem much different than before when I could receive surface waves > easily. I would expect the lower freqencies of these to look like a high > pass filtered FFT also. Wait till the next quake and see what the FFT looks like. Is it flat across the top from long periods, humpy, or what? What did old' FFTs look like? We have been having an earthquake 'low' so the characterisitcs may have changed in reality. Shallow quakes give more high frequencies. Check that there is no fluff / debris anywhere and that there is full and free movement. I 'clean' magnets by sticking Gaffer tape on them and then peeling it off. Do you have an instrument or DVM which can measure capacitance? What value is it supposed to be? I would be very inclined to unsolder the coupling capacitor and measure it. Electrolytics do degrade with time. Do you have a 'spare' first opamp? Their characteristics can also change / get damaged. Is the offset of the first opamp OK? Regards, Chris Chapman In a me= ssage dated 2007/05/30, rpratt@............. writes:

I
t is quite easy to turn the ga= p out without dissassembling and the wider gap gets
easier to clean. 


Hi Randy,

       After you have done this, give the iron= a coat of anti rust paint. This prevents problems.

My period is set at about 22 se= conds so I think it must be electrical
problem involved.  What confuses me is the background noise and walk up= test
don't seem much different than before when I could receive surface waves
easily.  I would expect the lower freqencies of these to look like a hi= gh
pass filtered FFT also.


       Wait till the next quake and see what t= he FFT looks like. Is it flat across the top from long periods, humpy, or wh= at? What did old' FFTs look like? We have been having an earthquake 'low' so= the characterisitcs may have changed in reality. Shallow quakes give more h= igh frequencies.

       Check that there is no fluff  / de= bris anywhere and that there is full and free movement. I 'clean' magnets by= sticking Gaffer tape on them and then peeling it off.

       Do you have an instrument or DVM which=20= can measure capacitance? What value is it supposed to be? I would be very in= clined to unsolder the coupling capacitor and measure it. Electrolytics do d= egrade with time. Do you have a 'spare' first opamp? Their characteristics c= an also change / get damaged. Is the offset of the first opamp OK?

       Regards,
      
       Chris Chapman
 Subject: Re: Quiet in earthquakes From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@......... Date: Thu, 31 May 2007 01:19:43 +0000 Hi all The quietness in the earthquakes continues, this is getting really strange. Besides the mag 6.4 earthquake today, nothing specal has been going on. Based on data from EMSC webpage today had it smallest number of earthquakes since this did start. I think that we might be in for a mag 8.3+ earthquake soon. I don't know where it might happen. Maybe the Kamatacha earthquake today was pre-quake to such a event. I did update the title, due to a english correction that I got. Regards. --=20 J=F3n Fr=EDmann http://www.jonfr.com http://www.simnet.is/jonfr500/earthquake/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Surface Waves From: Roger Sparks rsparks@.......... Date: Wed, 30 May 2007 20:39:59 -0700 Hi Randy, I think the sharp cutoff on the high frequency side of the FFT, is because of your sample rate. Winquake limits the FFT on the high side to about 1/2 of the sample rate for reasons of "aliasing", which relates to the Nyquist frequency and the ability of digital sampling to accurately reconstruct a sine wave. Here is a link for further study. > http://en.wikipedia.org/wiki/Nyquist%E2%80%93Shannon_sampling_theorem Roger psn-l-digest-request@.............. wrote: > .------ ------ ------ ------ ------ ------ ------ ------ ------ ------. > | Message 1 | > '------ ------ ------ ------ ------ ------ ------ ------ ------ ------' > Subject: Surface Waves > From: "Randy" > Date: Tue, 29 May 2007 20:34:40 -0500 > > This is a multi-part message in MIME format. > > ------=_NextPart_000_0171_01C7A230.C8539800 > Content-Type: text/plain; > charset="iso-8859-1" > Content-Transfer-Encoding: quoted-printable > > Hi All, > > I have been having trouble recording any surface waves lately. I used = > the instrument several years ago and had no problem but now I do not = > seem to get low frequency. I am using the PSN schematic for the = > preamp, filter and final stages. There is both an unfiltered quake and = > an FFT posted at http://mit.midco.net/rpratt/ I noted the high = > frequency side of 2 peaks seems to have hard cutoff on this quake but = > have not noticed this before. Where should I look to trouble shoot? My = > suspicion is the electrolytic cap coupling to the final. > > Randy > > > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Surface Waves From: ChrisAtUpw@....... Date: Thu, 31 May 2007 11:16:35 EDT In a message dated 2007/05/30, rpratt@............. writes: > My suspicion is the electrolytic cap coupling to the final. Hi Randy. Where is this capacitor and what value does it have? The PSN circuit on John Lahr's website has ieither a 1 or a 2 mu F POLYESTER coupling capacitor into 10 Meg Ohms, giving RC of either 10 or 20 sec, coupling to 60 or 120 sec periods?? Regards, Chris Chapman In a me= ssage dated 2007/05/30, rpratt@............. writes:

My suspicion is the electrolyt= ic cap coupling to the final.


Hi Randy.

       Where is this capacitor and what value=20= does it have? The PSN circuit on John Lahr's website has ieither a 1 or a 2=20= mu F POLYESTER coupling capacitor into 10 Meg Ohms, giving RC of either 10 o= r 20 sec, coupling to 60 or 120 sec periods??

       Regards,

       Chris Chapman Subject: Re: Quiet in earthquakes From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@......... Date: Fri, 01 Jun 2007 18:05:42 +0000 Hi all The quietness in earthquakes continues and if anything the rate of mag 5.0 earthquakes appears also to be dropping at strange rate. Last two days have been the most quiet onces in a long time. I am wondering the reason for it. It is quiet possible that some plate is in a lock state at the moment and not moving. or everything is moving smooth at the moment. Either way, it is quiet in earthquakes. Regards. --=20 J=F3n Fr=EDmann http://www.jonfr.com http://www.simnet.is/jonfr500/earthquake/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Earthquake in a strange location From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@......... Date: Sat, 02 Jun 2007 06:48:02 +0000 Hi all Tonight there was a mag 3.3 earthquake in a strange location. Due to the location I didn't record it, but IMO did. The location of the earthquake was on the ocean plate, near the Icelandic "plate" and the ocean floor, not far from the Iceland - Forey ridge. The location can be seen here, http://www.emsc-csem.org/index.php?page=3Dcurrent&sub=3Ddetail&id=3D46207 Along with time and depth. This is the first time I see a earthquake in that location, but mag 5.0 earthquakes have happend more east of Iceland, close to a older ridge system that is located east of Iceland. I do not know if other earthquakes will follow this mag 3.3 earthquake. That will be seen in the next 24 hours or so. Regards. --=20 J=F3n Fr=EDmann http://www.jonfr.com http://www.simnet.is/jonfr500/earthquake/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Surface Waves From: Bobhelenmcclure@....... Date: Sun, 3 Jun 2007 14:45:12 EDT On Thu, 31 May 2007 11:16:35 EDT, ChrisAtUpw wrote: Where is this capacitor and what value does it have? The PSN circuit on John Lahr's website has either a 1 or a 2 uF POLYESTER coupling capacitor into 10 Meg Ohms, giving RC of either 10 or 20 sec, coupling to 60 or 120 sec periods?< Hi Randy, I use an old version of the Cochrane amplifier on my Z channel. It has a 1 uF polyester coupling capacitor, giving a time constant of 10 seconds. This was entirely too short for my needs. I ended up shorting out the capacitor, which yielded a DC amplifier with a lot of output bias. I was just able to null out the bias by readjusting the bias pot to its full limit. The resulting performance is quite satisfactory. There is a little bit of bias response to ambient temperature rises and falls. I had to add a 1 uf shunt capacitor across the input terminals to suppress a parasitic oscillation in the amplifier, invisible at the output, but causing the output bias to be unstable whenever the sensor was connected to the amplifier. If you want to assess the performance of your amplifier, I suggest a step function test. Make up a voltage divider consisting of, say, 1 megohm in series with 1K. Connect the amplifier to the 1K. Apply a 1.5v battery across the series combination of 1 meg and 1K while recording. You should see a sharp jump in ADC output, following by an exponential decay. The time constant of this decay will give you the RC cutoff period. Removing the battery should yield another transient of opposite sign. The high frequency gain of the amplifier can be calculated from the peak height of the transient, the voltage divider ratio, the amplifier input resistance, and the applied voltage. Bob ************************************** See what's free at http://www.aol.com.
On Thu, 31 May 2007 11:16:35 EDT, ChrisAtUpw wrote: Where is this capac= itor=20 and what value does it have? The PSN circuit on John Lahr's website has eith= er a=20 1 or a 2 uF POLYESTER coupling capacitor into 10 Meg Ohms, giving RC of eith= er=20 10 or 20 sec, coupling to 60 or 120 sec periods?<
 
Hi Randy,
 
  I use an old version of the Cochrane amplifier on my Z channel.=20= It=20 has a 1 uF polyester coupling capacitor, giving a time constant of 10 second= s.=20 This was entirely too short for my needs. I ended up shorting out the capaci= tor,=20 which yielded a DC amplifier with a lot of output bias. I was just able to n= ull=20 out the bias by readjusting the bias pot to its full limit. The resulting=20 performance is quite satisfactory. There is a little bit of bias response to= =20 ambient temperature rises and falls. I had to add a 1 uf shunt capacitor acr= oss=20 the input terminals to suppress a parasitic oscillation in the amplifier,=20 invisible at the output, but causing the output bias to be unstable whenever= the=20 sensor was connected to the amplifier.
 
  If you want to assess the performance of your amplifier, I sugge= st a=20 step function test. Make up a voltage divider consisting of, say, 1 megohm i= n=20 series with 1K. Connect the amplifier to the 1K. Apply a 1.5v battery across= the=20 series combination of 1 meg and 1K while recording. You should see a sharp j= ump=20 in ADC output, following by an exponential decay. The time constant of this=20 decay will give you the RC cutoff period. Removing the battery should yield=20 another transient of opposite sign. The high frequency gain of the amplifier= can=20 be calculated from the peak height of the transient, the voltage divider rat= io,=20 the amplifier input resistance, and the applied voltage.
 
Bob



See wh= at's free at AOL.c= om.
Subject: Surface waves From: "Randy" rpratt@............. Date: Mon, 4 Jun 2007 12:46:25 -0500 Bob, Thanks for the reply on using the resistors to test RC filter of system. = I didn't try it yet but it sounds very similar to the calibration = method shown in the manual of seismological practice put to a different = use. I have tried that in the past and seen the decay curves you = mention. I would assume for the purpose of testing the filter response = the boom would be locked or the coil disconnected completely to = eliminate any mechanical response. =20 For gain computation do I just consider the input resistance as parallel = to the 1K and figure drop across the pair as compared to the AD voltage? Randy ---------------- If you want to assess the performance of your amplifier, I suggest a = step=20 function test. Make up a voltage divider consisting of, say, 1 megohm in = =20 series with 1K. Connect the amplifier to the 1K. Apply a 1.5v battery = across the =20 series combination of 1 meg and 1K while recording. You should see a = sharp=20 jump in ADC output, following by an exponential decay. The time = constant of this=20 decay will give you the RC cutoff period. Removing the battery should = yield =20 another transient of opposite sign. The high frequency gain of the = amplifier=20 can be calculated from the peak height of the transient, the voltage = divider=20 ratio, the amplifier input resistance, and the applied voltage.
Bob,
 
Thanks for the reply on using the = resistors to test=20 RC filter of system.  I didn't try it yet but it sounds very = similar to the=20 calibration method shown in the manual of seismological practice put to = a=20 different use.  I have tried that in the past and seen the decay = curves you=20 mention.  I would assume for the purpose of testing the filter = response the=20 boom would be locked or the coil disconnected completely to eliminate = any=20 mechanical response. 
 
For gain computation do I just consider = the input=20 resistance as parallel to the 1K and figure drop across the pair as = compared to=20 the AD voltage?
 
Randy
 
 
----------------
 If you=20 want to assess the performance of your amplifier, I suggest a  step =
function test. Make up a voltage divider consisting of, say, 1 = megohm=20 in 
series with 1K. Connect the amplifier to the 1K. Apply a = 1.5v=20 battery across the 
series combination of 1 meg and 1K while = recording.=20 You should see a sharp
jump  in ADC output, following by an = exponential=20 decay. The time constant of this
 decay will give you the RC = cutoff=20 period. Removing the battery should yield 
another transient of = opposite sign. The high frequency gain of the amplifier
can  be = calculated from the peak height of the transient, the voltage divider=20
ratio,  the amplifier input resistance, and the applied=20 voltage.
Subject: Springs for Verticals From: "tchannel" tchannel@.............. Date: Mon, 4 Jun 2007 14:21:05 -0600 Hi Everyone, I wanted to ask some questions about choosing a spring for = a vertical spring sensor. Pictures three situations, three different springs being pulled = straight down by a mass. No triangular modifications, just straight = down. 1 One is a strong spring like a screen door spring, pulled down by a = large mass. 2 One is a weak spring being pulled down by very little mass. 3 One is a rubber band being pulled down by a small mass. Just for comparisons, say they all had the same period of 1.5 seconds. = Is one of the three better for recording earthquakes? Two questions = here: Is there an advantage in using a weak spring, or strong spring, = if the resulting period is the same. And Secondly is a rubber band = spring every used? What prompted the question is seeing how small the spring in a geophones = is. Is the idea to have the smallest spring which would move under = the smaller stimulus. Thanks, Ted
Hi Everyone,  I wanted to ask some = questions=20 about choosing a spring for a vertical spring sensor.
 
   Pictures three situations, = three=20 different springs being pulled straight down by a mass. = No triangular=20 modifications, just straight down.
 
1 One is a strong spring like a screen = door spring,=20 pulled down by a large mass.
 
2  One is a weak spring  = being pulled=20 down by very little mass.
 
3  One is a rubber band being = pulled down by a=20 small mass.
 
Just for comparisons, say they all had = the same=20 period of 1.5 seconds.   Is one of the three better for = recording=20 earthquakes?   Two questions here:  Is there an advantage = in=20 using a weak spring, or strong spring, if the resulting period is the=20 same.  And Secondly is a rubber band spring every = used?
 
What prompted the question is seeing = how small the=20 spring in a geophones is.    Is the idea to have the = smallest spring which would move under the smaller = stimulus.
 
Thanks, Ted
 
Subject: Re: Springs for Verticals From: Ben Bradley benbradley@............... Date: Mon, 04 Jun 2007 17:39:01 -0500 tchannel wrote: > Hi Everyone, I wanted to ask some questions about choosing a spring for a vertical spring sensor. > > Pictures three situations, three different springs being pulled straight down by a mass. No triangular modifications, just straight down. > > 1 One is a strong spring like a screen door spring, pulled down by a large mass. > > 2 One is a weak spring being pulled down by very little mass. > > 3 One is a rubber band being pulled down by a small mass. > > Just for comparisons, say they all had the same period of 1.5 seconds. Is one of the three better for recording earthquakes? Two questions here: Is there an advantage in using a weak spring, or strong spring, if the resulting period is the same. And Secondly is a rubber band spring every used? > I understand that rubber bands are quite temperature sensitive (their force changes substantially with a change in temperature, many times more than a steel spring does), and for that reason alone I cannot imagine a rubber band would work well in a geophone or seismometer. The effect is so great that it can be put to good use in other devices, as in The Amateur Scientist column in the April 1971 Scientific American magazine, titled "Some Delightful Engines Driven By the Heating of Rubber Bands." You can get a CD of all the Amateur Scientist columns, which also includes several seismograph designs, at the bottom of this page: http://www.brightscience.com/ As far as 1 vs. 2, I can't say which one would be better, except to note that the larger mass/stronger spring combination of 1 would be less sensitive to air movements (there should be no such air movements in such a device, but I would still pick the more resistant combination just in case). Without any other observations or conclusions about which would be better, I would pick 1 for that reason. > What prompted the question is seeing how small the spring in a geophones is. Is the idea to have the smallest spring which would move under the smaller stimulus. > For a "portable" device such as a geophone, I would think the idea is to have the smallest device that does the job. If a larger, more massive design does the job better in a fixed-location amateur (non-commercial) device, I would go with the larger design. > Thanks, Ted > > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Springs for Verticals From: ChrisAtUpw@....... Date: Mon, 4 Jun 2007 20:25:02 EDT In a message dated 2007/06/04, tchannel@.............. writes: > Hi Everyone, I wanted to ask some questions about choosing a spring for a > vertical spring sensor. > > Pictures three situations, three different springs being pulled straight > down by a mass. No triangular modifications, just straight down. > > 1 One is a strong spring like a screen door spring, pulled down by a large > mass. > > 2 One is a weak spring being pulled down by very little mass. > > 3 One is a rubber band being pulled down by a small mass. > > Just for comparisons, say they all had the same period of 1.5 seconds. Is > one of the three better for recording earthquakes? Two questions here: Is > there an advantage in using a weak spring, or strong spring, if the resulting > period is the same. You will only get this sort of period with quite large extensions. You need a certain mass for the motion not to be swamped by thermal or environmental agitation. It is the product M x T x Q, which is important for noise considerations, not just the mass. For a simple spring, the extension E = g x T^2 / (2 x Pi)^2, where T is the period. Thus to get a period of say 10 sec, you need an extension of ~25 metres.... And Secondly is a rubber band spring every used? No. Rubber is highly temperature sensitive and it also has a lot of loss (hysteresis) associated with the extension. > What prompted the question is seeing how small the spring in a geophones > is. Is the idea to have the smallest spring which would move under the smaller > stimulus. The coil springs used for seismometers have very specific characteristics. They are designed to have a zero or negative length when extended. The wire is twisted as it is wound and this makes the coils clamp tightly together. If you plot the length versus the load, the length stays constant up to a certain load and you then get an extension proportional to the load. A plot of the load / length graph can be extended back to zero load and the 'zero load extension' can be negative. You need a net zero length to get an 'infinite period' on a vertical seismometer. The changes in metal properties with temperature give a practical limit of about 5 seconds for ordinary steel springs and you may only have ~a 5 C Deg temperature range before re-balancing becomes necessary. The 'easy' way around this is to extend the period electronically, but the noise performance then becomes critical. A maximum period extension of about x10 max is practicable. It is not very difficult to extend a 2.5 second period sensor to 25 seconds. The use of Sm-Co or NdFeB magnets has enabled the output to be considerably increased over Alnico magnet systems, reducing problems with noise. Regards, Chris Chapman In a me= ssage dated 2007/06/04, tchannel@.............. writes:

Hi Everyone, I wanted to ask so= me questions about choosing a spring for a vertical spring sensor.

   Pictures three situations, three different springs being pulle= d straight down by a mass. No triangular modifications, just straight down.<= /FONT>=

1 One is a strong spring like a screen door spring, pulled down by a large=20= mass.

2 One is a weak spring being pulled down by very little mass.

3 One is a rubber band being pulled down by a small mass.

Just for comparisons, say they all had the same period of 1.5 seconds. = ; Is one of the three better for recording earthquakes?  Two questions=20= here: Is there an advantage in using a weak spring, or strong spring, if the= resulting period is the same. 


    You will only get this sort of period with quite large ex= tensions. You need a certain mass for the motion not to be swamped by therma= l or environmental agitation.

    It is the product M x T x Q, which is important for noise= considerations, not just the mass.

    For a simple spring, the extension E =3D g x T^2 / (2 x P= i)^2, where T is the period. Thus to get a period of say 10 sec, you need an= extension of ~25 metres....

And Secondly is a rubber band spring every used?

       No. Rubber is highly temperature sensit= ive and it also has a lot of loss (hysteresis) associated with the extension= ..

What prompted the question is=20= seeing how small the spring in a geophones is. Is the idea to have the small= est spring which would move under the smaller stimulus.


       The coil springs used for seismometers=20= have very specific characteristics. They are designed to have a zero or nega= tive length when extended. The wire is twisted as it is wound and this makes= the coils clamp tightly together. If you plot the length versus the load, t= he length stays constant up to a certain load and you then get an extension=20= proportional to the load. A plot of the load / length graph can be extended=20= back to zero load and the 'zero load extension' can be negative. You need a=20= net zero length to get an 'infinite period' on a vertical seismometer.

       The changes in metal properties with te= mperature give a practical limit of about 5 seconds for ordinary steel sprin= gs and you may only have ~a 5 C Deg temperature range before re-balancing be= comes necessary. The 'easy' way around this is to extend the period electron= ically, but the noise performance then becomes critical. A maximum period ex= tension of about x10 max is practicable. It is not very difficult to extend=20= a 2.5 second period sensor to 25 seconds. The use of Sm-Co or NdFeB magnets=20= has enabled the output to be considerably increased over Alnico magnet syste= ms, reducing problems with noise.

       Regards,

       Chris Chapman
       Subject: Re: Springs for Verticals From: "tchannel" tchannel@.............. Date: Mon, 4 Jun 2007 18:34:27 -0600 Ben and Chris, This is great information, Thanks, for your response. ----- Original Message -----=20 From: ChrisAtUpw@.......... To: psn-l@................. Sent: Monday, June 04, 2007 6:25 PM Subject: Re: Springs for Verticals In a message dated 2007/06/04, tchannel@.............. writes: Hi Everyone, I wanted to ask some questions about choosing a spring = for a vertical spring sensor. Pictures three situations, three different springs being pulled = straight down by a mass. No triangular modifications, just straight = down. 1 One is a strong spring like a screen door spring, pulled down by a = large mass. 2 One is a weak spring being pulled down by very little mass. 3 One is a rubber band being pulled down by a small mass. Just for comparisons, say they all had the same period of 1.5 = seconds. Is one of the three better for recording earthquakes? Two = questions here: Is there an advantage in using a weak spring, or strong = spring, if the resulting period is the same. =20 You will only get this sort of period with quite large extensions. = You need a certain mass for the motion not to be swamped by thermal or = environmental agitation.=20 It is the product M x T x Q, which is important for noise = considerations, not just the mass.=20 For a simple spring, the extension E =3D g x T^2 / (2 x Pi)^2, = where T is the period. Thus to get a period of say 10 sec, you need an = extension of ~25 metres.... And Secondly is a rubber band spring every used? No. Rubber is highly temperature sensitive and it also has a = lot of loss (hysteresis) associated with the extension. What prompted the question is seeing how small the spring in a = geophones is. Is the idea to have the smallest spring which would move = under the smaller stimulus. The coil springs used for seismometers have very specific = characteristics. They are designed to have a zero or negative length = when extended. The wire is twisted as it is wound and this makes the = coils clamp tightly together. If you plot the length versus the load, = the length stays constant up to a certain load and you then get an = extension proportional to the load. A plot of the load / length graph = can be extended back to zero load and the 'zero load extension' can be = negative. You need a net zero length to get an 'infinite period' on a = vertical seismometer. The changes in metal properties with temperature give a = practical limit of about 5 seconds for ordinary steel springs and you = may only have ~a 5 C Deg temperature range before re-balancing becomes = necessary. The 'easy' way around this is to extend the period = electronically, but the noise performance then becomes critical. A = maximum period extension of about x10 max is practicable. It is not very = difficult to extend a 2.5 second period sensor to 25 seconds. The use of = Sm-Co or NdFeB magnets has enabled the output to be considerably = increased over Alnico magnet systems, reducing problems with noise. Regards, Chris Chapman
 Ben and Chris,   This = is great=20 information,  Thanks, for your response.
----- Original Message -----
From:=20 ChrisAtUpw@.......
Sent: Monday, June 04, 2007 = 6:25 PM
Subject: Re: Springs for = Verticals

In a=20 message dated 2007/06/04, tchannel@..............=20 writes:

Hi Everyone, I wanted to ask some questions about = choosing a=20 spring for a vertical spring sensor.

   = Pictures three=20 situations, three different springs being pulled straight down by a = mass. No=20 triangular modifications, just straight down.

1 One is a = strong spring like=20 a screen door spring, pulled down by a large mass.

2 One is a weak = spring being=20 pulled down by very little mass.

3 One is a = rubber band being=20 pulled down by a small mass.

Just for = comparisons, say they=20 all had the same period of 1.5 seconds.  Is one of the three = better for=20 recording earthquakes?  Two questions here: Is there an = advantage in=20 using a weak spring, or strong spring, if the resulting period is = the=20 same. 


    You will only = get this=20 sort of period with quite large extensions. You need a certain mass = for the=20 motion not to be swamped by thermal or environmental agitation.=20

    It is the product M x T x Q, which is = important for=20 noise considerations, not just the mass.

    = For a=20 simple spring, the extension E =3D g x T^2 / (2 x Pi)^2, where T is = the period.=20 Thus to get a period of say 10 sec, you need an extension of ~25=20 metres....

And=20 Secondly is a rubber band spring every=20 used?

       No. Rubber is highly = temperature sensitive and it also has a lot of loss (hysteresis) = associated=20 with the extension.

 What prompted the question is seeing how small the = spring in a=20 geophones is. Is the idea to have the smallest spring which would = move under=20 the smaller stimulus.

       The=20 coil springs used for seismometers have very specific characteristics. = They=20 are designed to have a zero or negative length when extended. The wire = is=20 twisted as it is wound and this makes the coils clamp tightly = together. If you=20 plot the length versus the load, the length stays constant up to a = certain=20 load and you then get an extension proportional to the load. A plot of = the=20 load / length graph can be extended back to zero load and the 'zero = load=20 extension' can be negative. You need a net zero length to get an = 'infinite=20 period' on a vertical = seismometer.

      =20 The changes in metal properties with temperature give a practical = limit of=20 about 5 seconds for ordinary steel springs and you may only have ~a 5 = C Deg=20 temperature range before re-balancing becomes necessary. The 'easy' = way around=20 this is to extend the period electronically, but the noise performance = then=20 becomes critical. A maximum period extension of about x10 max is = practicable.=20 It is not very difficult to extend a 2.5 second period sensor to 25 = seconds.=20 The use of Sm-Co or NdFeB magnets has enabled the output to be = considerably=20 increased over Alnico magnet systems, reducing problems with=20 noise.

      =20 Regards,

       Chris=20 Chapman
      =20 Subject: Re: Springs for Verticals From: "Geoffrey" gmvoeth@........... Date: Tue, 5 Jun 2007 00:20:48 -0700 To me, from personal experience, I say a very large mass is your best bet for the best signal to noise ratio. Just about any extension spring will give you a one second period if the spring will extent ten to twelve inches undere the weights mass. That is of course if the spring has no inherent tension when fully relaxed. It might be best to have a spring in the shape of a flattened helix then use a plain old wire spring. I think you can give such a spring a pre-tension that means it will only hang extended a small bit instead of a full 10 to 12 inches with mass attached. Such a spring should be built by an industry or research lab insted of a common man because the lowest of temperature coefficients are necessary for a good spring otherwise you will need to control temps within tight specs. like having the mechanisim located in a deep cave. Sensitivity as well as signal to noise ratio are the two things that make a good sensor. Good Luck, geoff ----- Original Message ----- From: "Ben Bradley" To: Sent: Monday, June 04, 2007 15:39 Subject: Re: Springs for Verticals > tchannel wrote: >> Hi Everyone, I wanted to ask some questions about choosing a spring for a vertical spring sensor. >> >> Pictures three situations, three different springs being pulled straight down by a mass. No triangular modifications, just >> straight down. >> >> 1 One is a strong spring like a screen door spring, pulled down by a large mass. >> >> 2 One is a weak spring being pulled down by very little mass. >> >> 3 One is a rubber band being pulled down by a small mass. >> >> Just for comparisons, say they all had the same period of 1.5 seconds. Is one of the three better for recording earthquakes? >> Two questions here: Is there an advantage in using a weak spring, or strong spring, if the resulting period is the same. And >> Secondly is a rubber band spring every used? >> > > I understand that rubber bands are quite temperature sensitive (their force changes substantially with a change in temperature, > many times more than a steel spring does), and for that reason alone I cannot imagine a rubber band would work well in a geophone > or seismometer. The effect is so great that it can be put to good use in other devices, as in The Amateur Scientist column in the > April 1971 Scientific American magazine, titled "Some Delightful Engines Driven By the Heating of Rubber Bands." You can get a CD > of all the Amateur Scientist columns, which also includes several seismograph designs, at the bottom of this page: > http://www.brightscience.com/ > > As far as 1 vs. 2, I can't say which one would be better, except to note that the larger mass/stronger spring combination of 1 > would be less sensitive to air movements (there should be no such air movements in such a device, but I would still pick the more > resistant combination just in case). Without any other observations or conclusions about which would be better, I would pick 1 for > that reason. > >> What prompted the question is seeing how small the spring in a geophones is. Is the idea to have the smallest spring which >> would move under the smaller stimulus. >> > > For a "portable" device such as a geophone, I would think the idea is to have the smallest device that does the job. If a > larger, more massive design does the job better in a fixed-location amateur (non-commercial) device, I would go with the larger > design. > >> Thanks, Ted >> >> > > > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Springs for Verticals From: ChrisAtUpw@....... Date: Tue, 5 Jun 2007 16:29:23 EDT In a message dated 2007/06/05, tchannel@.............. writes: > Ben and Chris, This is great information, Thanks, for your response. > Hi Ted and anyone trying to make a simple vertical spring system, Suppressing sideways and rotational movements of the mass can be 'a pain'. It is easier to do this if you use an extension rod to join the mass to the spring and place everything in a vertical Al tube. Try modifying the simple design shown at http://mariottim.interfree.it/doc02v_e.htm in this way. It is also possible to use two circular iron disks separated by say 4 square / rectangtular NdFeB magnets, connected all with the same polarity, or a large disk magnet with a central hole. For the sensor coil, wind two side by side coils with a similar number of turns, about 2 to 4 x the length of the magnet separation and connect them in opposition - not so that the fields add. It is not difficult to make 'a sensor' this way, but to make a 'good' one is more difficult. It is easier to make a frame and use a LaCoste type arm and suspension. Geophones are designed with spiral leaf springs to keep the moving copper cylinder mass and the coils aligned axially. This principle can be extended to a simple vertical by using very thin horizontal parallel brass shim leaf 'springs' at the top and the bottom of the mass to keep it aligned axially and to prevent any pendulum sideways movement, with the main axial load still taken by a vertical coil spring. It is no longer a simple spring / weight system, but it may be the simplest system which works satisfactorily. Regards, Chris Chapman In a me= ssage dated 2007/06/05, tchannel@.............. writes:

Ben and Chris,   Thi= s is great information,  Thanks, for your response.

Hi Ted and anyone trying to make a simple vertical spring system,

       Suppressing sideways and rotational mov= ements of the mass can be 'a pain'. It is easier to do this if you use an ex= tension rod to join the mass to the spring and place everything in a vertica= l Al tube. Try modifying the simple design shown at http://mariottim.interfr= ee.it/doc02v_e.htm in this way. It is also possible to use two circular iron= disks separated by say 4 square / rectangtular NdFeB magnets, connected all= with the same polarity, or a large disk magnet with a central hole.
       For the sensor coil, wind two side by s= ide coils with a similar number of turns, about 2 to 4 x the length of the m= agnet separation and connect them in opposition - not so that the fields add= .. It is not difficult to make 'a sensor' this way, but to make a 'good' one=20= is more difficult. It is easier to make a frame and use a LaCoste type arm a= nd suspension.
       Geophones are designed with spiral leaf= springs to keep the moving copper cylinder mass and the coils aligned axial= ly. This principle can be extended to a simple vertical by using very thin h= orizontal parallel brass shim leaf 'springs' at the top and the bottom of th= e mass to keep it aligned axially and to prevent any pendulum sideways movem= ent, with the main axial load still taken by a vertical coil spring.
       It is no longer a simple spring / weigh= t system, but it may be the simplest system which works satisfactorily.

       Regards,

       Chris Chapman Subject: Re: Quiet in earthquakes From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@......... Date: Tue, 05 Jun 2007 22:31:57 +0000 Hi all Dosen't anyone else then me find it strange how few earthquakes we have been seeing in past weeks. I do think that this really strange on a global scale. Since this is week three for the world to have no earthquake stronger then mag 7.0. Also in that time, there have only been two or three earthquakes larger then mag 6.0 I am unsure what is going on, but I find it strange. Regards. --=20 J=F3n Fr=EDmann http://www.jonfr.com http://www.simnet.is/jonfr500/earthquake/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Set of plans From: "tchannel" tchannel@.............. Date: Wed, 6 Jun 2007 10:20:54 -0600 Hi All, I would like to create a set of seismic sensor plans for school = age kids, or adults. I have built six sensors of different = configurations. I have found the best results, to be the horz. = pendulum, using Chris's design as inspiration, but my version was and = expensive project. I have two simple, inexpensive verticals which work very well for me. = Both would lend themselves to someone with limited resources. Is there anyone in the group who has a computer design program, like = CAD? and would like to produce a nice set of isometric drawings, from = these designs. I have no program like that, and recorded my work in = photos, sketches, and dimensions. I think the finished plan, would be = small enough to email or post and free for others who would like to = build their first sensor. It takes time and talent to produce a nice set of drawings, and I have = seen some outstanding work using today's drawing tools. The two = vertical designs I have are not perfect, but produce very good results. = If they could be shared with others it will only inspire them to build = and use them, and eventually to make improvements. Please email me if you would like to team up on such a project. Thanks, Ted
Hi All,  I would like to create a = set of=20 seismic sensor plans for school age kids, or adults.  I have = built six=20 sensors of different configurations.  I have found the best = results, to be=20 the horz. pendulum, using Chris's design as inspiration, but my version = was and=20 expensive project.
I have two simple, inexpensive = verticals which work=20 very well for me.  Both would lend themselves to someone with = limited=20 resources.
 
Is there anyone in the group who has a = computer=20 design program, like CAD? and would like to produce a nice set of = isometric=20 drawings, from these designs.   I have no program like that, = and=20 recorded my work in photos, sketches, and dimensions.  I think the = finished=20 plan, would be small enough to email or post and free for others who = would like=20 to build their first sensor.
 
It takes time and talent to produce a = nice set of=20 drawings, and I have seen some outstanding  work using today's = drawing=20 tools.   The two vertical designs I have are not perfect, but = produce=20 very good results.  If they could be shared with others it will = only=20 inspire them to build and use them, and eventually to make=20 improvements.
 
Please email me if you would like to = team up on=20 such a project.
Thanks, Ted
 
 
Subject: How many volts ? From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@......... Date: Mon, 11 Jun 2007 12:25:13 +0000 Hi all I got a coil and magnet from Larry today and I was wondering what the voltage level of the coil is. But the coil is 9000 ohms. Regards. --=20 J=F3n Fr=EDmann http://www.jonfr.com http://www.simnet.is/jonfr500/earthquake/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: How many volts ? From: ChrisAtUpw@....... Date: Mon, 11 Jun 2007 08:39:29 EDT In a message dated 11/06/2007, jonfr@......... writes: Hi all I got a coil and magnet from Larry today and I was wondering what the voltage level of the coil is. But the coil is 9000 ohms. Hi Jon, You need to place the centre of the coil at about the 1/2 peak field position of the U magnet. Without measuring your magnet, I am not sure how far from the plane of the polepiece this is. If you can set up your arm to oscillate over ~a mm, you might move the two nearer together until you get the maximum recorded signal? There should be a 'known distance', but I don't know what this is. Which magnet are you using? Regards, Chris Chapman
In a message dated 11/06/2007, jonfr@......... writes:
<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size= =3D2>Hi=20 all
I got a coil and magnet from Larry today and I was wondering what=20 the
voltage level of the coil is. But the coil is 9000=20 ohms.
Hi Jon,
 
    You need to place the centre of the coil at abo= ut=20 the 1/2 peak field position of the U magnet. Without measuring your magnet,=20= I am=20 not sure how far from the plane of the polepiece this is. If you can set up=20= your=20 arm to oscillate over ~a mm, you might move the two nearer together until yo= u=20 get the maximum recorded signal? There should be a 'known distance', but I d= on't=20 know what this is. Which magnet are you using?
 
    Regards,
 
    Chris Chapman
 Subject: Re: How many volts ? From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@......... Date: Mon, 11 Jun 2007 13:07:55 +0000 Hi Chris I am using a magnet from Larry, the details are on this webpage. http://seismicnet.com/coilmag.html Also, since I don't have the real long period seismometer ready, I did create a simple seismomter out of few materials that I had lying around in my apartment. This simple seismometer actually works, you can see a picture here. I don't expect to record anything of intrest on it, but it does work as you see it on this picture to my surprice. http://www.jonfr.com/myndir/v/geology/seismometer/p6110001.jpg.html Regards. --=20 J=F3n Fr=EDmann http://www.jonfr.com http://www.simnet.is/jonfr500/earthquake/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: I have no saved files!!! From: "Paul Cianciolo" Paulc@........ Date: Mon, 11 Jun 2007 11:26:01 -0400 Today for the first time. I tried to go back about 5 days and look at a event. I save 4 says to the screen. SO opening the correct folders, which there is one for each day Amaseis has been running. But there are no files. No SAC's no PePPS no PSN's!! Very suspicious! SAC-Less in Connecticut PC W1VLF __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: I have no saved files!!! From: "tchannel" tchannel@.............. Date: Mon, 11 Jun 2007 10:52:53 -0600 Hi Paul, I have experienced this also...........I hope they are really there for you........ You may know all or part of this.......... 1 AmaSeis helicorder will allow you to go back, SETTING/ GO TO DATE AND TIME..........I think you can go back as far as....where you have the helicorder set for. SETTING/ HELICORDER/ DAYS TO RETAIN RECORDS............Then press NOW to return to current time. 2 This is the hard part to explain. AmaSeis logs all the data in a folder, in this case the name is "2007" in this folder is the month folder "06", inside that is a day folder "11" inside that is the hour FILES, "15.z" for the 15 hour. 3. This part is also hard to explain. My path for this is C:Program files\2007\06\11 However there is also a path C:Program files\AmaSeis\2007........my files are not in this folder? 4 This part is also hard to explain. At one time I download an HOUR FILE ending with a (.z) It was of a hurricane. When I downloaded it, it would not show.......My hour files ended with an(.n) at that time. So I change the downloaded file's name from "xxxxx.z" to "xxxxx.n" and AmaSeis then opened it. If this is confusing Just call me and I might be able to walk you thru it. Do let me know. Ted ----- Original Message ----- From: "Paul Cianciolo" To: Sent: Monday, June 11, 2007 9:26 AM Subject: I have no saved files!!! > Today for the first time. I tried to go back about 5 days and look at a > event. > > I save 4 says to the screen. > SO opening the correct folders, which there is one for each day Amaseis > has > been running. > But there are no files. > > No SAC's no PePPS no PSN's!! > > Very suspicious! > > > SAC-Less in Connecticut > > PC > W1VLF > > > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Period of a seismometer (seconds) From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@......... Date: Tue, 12 Jun 2007 00:11:25 +0000 Hi all How do I terminate the period of a seismometer in seconds and hz ? Regards. --=20 J=F3n Fr=EDmann http://www.jonfr.com http://www.simnet.is/jonfr500/earthquake/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Drum Recorders From: Jan Froom JDarwin@............. Date: Mon, 11 Jun 2007 18:56:59 -0700 Does anyone know where one might find the newer type drum recorders. I have a whole shed full of the old ones which move laterally as the drum turns, but I've been asked to set up a seismic display in a public area and I'm just not happy using the old drum recorders. And I think the giant pen motors I have... must be 80 years old... if not older. Jan in Gilroy.... Does anyone know where one might find the newer type drum recorders.

I have a whole shed full of the old ones which move laterally as the drum turns,
but I've been asked to set up a seismic display in a public area and I'm just
not happy using the old drum recorders. 
And I think the giant pen motors I have... must be 80 years old... if not older.

Jan in Gilroy....
Subject: Re: Drum Recorders From: ChrisAtUpw@....... Date: Mon, 11 Jun 2007 23:34:01 EDT In a message dated 12/06/2007 02:57:29 GMT Daylight Time, JDarwin@............. writes: I have a whole shed full of the old ones which move laterally as the drum turns, but I've been asked to set up a seismic display in a public area and I'm just not happy using the old drum recorders. Hi Jan, The old equipment works and works well. Take an Aspirin and make progress! If you want to be modern, why not use computers? Regards, Chris Chapman
In a message dated 12/06/2007 02:57:29 GMT Daylight Time,=20 JDarwin@............. writes:
<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3D"Comic Sans MS" color=3D#00= 0000=20 size=3D3>I have a whole shed full of the old ones which move laterally as=20= the=20 drum turns,
but I've been asked to set up a seismic display in a publi= c=20 area and I'm just
not happy using the old drum recorders. =20
Hi Jan,
 
    The old equipment works and works well. Take an= =20 Aspirin and make progress!
 
    If you want to be modern, why not use=20 computers?
 
    Regards,
 
    Chris Chapman
 Subject: Re: How many volts ? From: "Geoffrey" gmvoeth@........... Date: Tue, 12 Jun 2007 03:18:36 -0700 There are formulas for figuring out voltages and turns and magnetic fields such as design formulas for transformers since most power today is AC. But it has been so terribly long ago that I ever did such things I can no longer tell the technical detales. Plain Old Physics should have an ideal kind of law that will answer your questions without being exact but give you an excellent idea of what to expect. The internet is the best place to start looking but out there is some mathematician/physicist that would love to share his knowledge with you. Possibly an old Electronics book that deals with such things as designed for understanding by a layman/noobe. Mathematicians must account for all units etc. but i think for a laymen experimentation and curve tracing can give you good results so long as the goes ins and outs are close enough for government work. Simply matching a math curve to the data points found so you put in the known to get the unknown without knowing what goes on in the middle. Magic Numbers and stuff. (I just wish i knew a few myself) ----- Original Message ----- From: "Jón Frímann" To: "PSN-Postlist" Sent: Monday, June 11, 2007 05:25 Subject: How many volts ? Hi all I got a coil and magnet from Larry today and I was wondering what the voltage level of the coil is. But the coil is 9000 ohms. Regards. -- Jón Frímann http://www.jonfr.com http://www.simnet.is/jonfr500/earthquake/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Period of a seismometer (seconds) From: "Geoffrey" gmvoeth@........... Date: Tue, 12 Jun 2007 03:26:41 -0700 P == Period measured in seconds per cycle F == Frquency in Hertz Cycles Per Second Inversions of each other P=1/f F=1/P just like Q and Damping are the inverses Q=1/Damp Damp=1/Q Dont know the symbol for Damping tho. Generally the free period of an undamped system which never really exists due to ENTROPY if nothing else. ----- Original Message ----- From: "Jón Frímann" To: "PSN-Postlist" Sent: Monday, June 11, 2007 17:11 Subject: Period of a seismometer (seconds) Hi all How do I terminate the period of a seismometer in seconds and hz ? Regards. -- Jón Frímann http://www.jonfr.com http://www.simnet.is/jonfr500/earthquake/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: I have no saved files!!! From: "Geoffrey" gmvoeth@........... Date: Tue, 12 Jun 2007 03:32:05 -0700 I dont know how your particular program works but most require you set up the configuration of where to save things etc before you run the program for the first time. If you can find that file it should tell you the default location if any at all. Most programs are not user friendly and require learning no matter how much you dont want to. I sure hope things get better in the future but technology seems to be abused because of the money oriented society in which we live. ----- Original Message ----- From: "Paul Cianciolo" To: Sent: Monday, June 11, 2007 08:26 Subject: I have no saved files!!! > Today for the first time. I tried to go back about 5 days and look at a > event. > > I save 4 says to the screen. > SO opening the correct folders, which there is one for each day Amaseis has > been running. > But there are no files. > > No SAC's no PePPS no PSN's!! > > Very suspicious! > > > SAC-Less in Connecticut > > PC > W1VLF > > > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Digest from 06/11/2007 00:01:28 From: Roger Sparks rsparks@.......... Date: Tue, 12 Jun 2007 07:07:18 -0700 Hi Paul, Amaseis runs from a file with the name AS1.exe. It places the data files in the same directory in which you find AS1.exe. The data files are located in a series of nested year/month/day/hour files. You should be able to find the path of the data files by searching for "*.z", without the quotes of course. You make the sac, pepp, or psn files by extracting an event and then saving in which ever format you choose. They will save in the directory you choose, including the WinQuake/Events directory if you so choose. Best wishes, Roger > > > .------ ------ ------ ------ ------ ------ ------ ------ ------ ------. > | Message 4 | > '------ ------ ------ ------ ------ ------ ------ ------ ------ ------' > Subject: I have no saved files!!! > From: "Paul Cianciolo" > Date: Mon, 11 Jun 2007 11:26:01 -0400 > > Today for the first time. I tried to go back about 5 days and look at a > event. > > I save 4 says to the screen. > SO opening the correct folders, which there is one for each day Amaseis has > been running. > But there are no files. > > No SAC's no PePPS no PSN's!! > > Very suspicious! > > > SAC-Less in Connecticut > > PC > W1VLF > > > > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: I have no saved files!!! From: Roger Sparks rsparks@.......... Date: Tue, 12 Jun 2007 08:15:50 -0700 Hi Ted, Good advice. I might add that Amaseis should go back to what ever date you insert, but the helicorder screen will only fill if data is found for the requested date. The number of days the helicorder has stored does not affect the "GO TO DATE AND TIME" menu, nor does it affect the permanent storage of data Roger | Message 5 | '------ ------ ------ ------ ------ ------ ------ ------ ------ ------' Subject: Re: I have no saved files!!! From: "tchannel" Date: Mon, 11 Jun 2007 10:52:53 -0600 Hi Paul, I have experienced this also...........I hope they are really there for you........ You may know all or part of this.......... 1 AmaSeis helicorder will allow you to go back, SETTING/ GO TO DATE AND TIME..........I think you can go back as far as....where you have the helicorder set for. SETTING/ HELICORDER/ DAYS TO RETAIN RECORDS............Then press NOW to return to current time. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: I have no saved files!!! From: ChrisAtUpw@....... Date: Tue, 12 Jun 2007 11:23:40 EDT In a message dated 11/06/2007 16:31:29 GMT Daylight Time, Paulc@........ writes: Today for the first time. I tried to go back about 5 days and look at a event. Hi Paul, I presume that Amaseis is displaying a drumplot of data? Have you updated your station name or anything? Regards, Chris Chapman
In a message dated 11/06/2007 16:31:29 GMT Daylight Time, Paulc@........ t=20 writes:
<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size= =3D2>Today=20 for the first time. I tried to go back about 5 days and look at=20 a
event.
Hi Paul,
 
    I presume that Amaseis is displaying a drumplot= of=20 data?
 
    Have you updated your station name or=20 anything?
 
    Regards,
 
    Chris Chapman
 Subject: Re: I have no saved files!!! From: John Lahr johnjan@........ Date: Tue, 12 Jun 2007 08:29:59 -0700 Paul, I've posted quite a bit of information on the AS-1 seismic system and much of it relates to AmaSeis. http://jclahr.com/science/psn/as1 The FAQ section: http://jclahr.com/science/psn/as1/faq/ describes how the data are stored. Also, this manual goes into a lot of detail on the use of AmaSeis. http://www.scieds.com/spinet/pdf/AS1AmaSeis.pdf Cheers, John At 07:07 AM 6/12/2007, Roger Sparks wrote: >Hi Paul, > >Amaseis runs from a file with the name AS1.exe. It places the data >files in the same directory in which you find AS1.exe. The data >files are located in a series of nested year/month/day/hour files. >You should be able to find the path of the data files by searching >for "*.z", without the quotes of course. > >You make the sac, pepp, or psn files by extracting an event and then >saving in which ever format you choose. They will save in the >directory you choose, including the WinQuake/Events directory if you so choose. > >Best wishes, > >Roger > > >> >> >>.------ ------ ------ ------ ------ ------ ------ ------ ------ ------. >>| Message 4 | >>'------ ------ ------ ------ ------ ------ ------ ------ ------ ------' >>Subject: I have no saved files!!! >>From: "Paul Cianciolo" >>Date: Mon, 11 Jun 2007 11:26:01 -0400 >> >>Today for the first time. I tried to go back about 5 days and look at a >>event. >> >>I save 4 says to the screen. >>SO opening the correct folders, which there is one for each day Amaseis has >>been running. >>But there are no files. >> >>No SAC's no PePPS no PSN's!! >> >>Very suspicious! >> >> >>SAC-Less in Connecticut >> >>PC >>W1VLF >> >> >> >> >__________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email PSN-L-REQUEST@.............. with the body >of the message (first line only): unsubscribe >See http://www.seismicnet.com/maillist.html for more information. > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: RE: I have no saved files!!! From: "Paul Cianciolo" Paulc@........ Date: Tue, 12 Jun 2007 12:33:41 -0400 Hello Ted, Your email prompted me to do some more checking. There ARE files under all the folders, but not SAC. PSN. They all have a .N extension. They are also all 42 K in size. The reason I could not see them is AMASEIS was looking for a known extension type and does not display a .N?? What eve a .N is?? PC -----Original Message----- From: psn-l-request@.............. [mailto:psn-l-request@................. Behalf Of tchannel Sent: Monday, June 11, 2007 12:53 PM To: psn-l@.............. Subject: Re: I have no saved files!!! Hi Paul, I have experienced this also...........I hope they are really there for you........ You may know all or part of this.......... 1 AmaSeis helicorder will allow you to go back, SETTING/ GO TO DATE AND TIME..........I think you can go back as far as....where you have the helicorder set for. SETTING/ HELICORDER/ DAYS TO RETAIN RECORDS............Then press NOW to return to current time. 2 This is the hard part to explain. AmaSeis logs all the data in a folder, in this case the name is "2007" in this folder is the month folder "06", inside that is a day folder "11" inside that is the hour FILES, "15.z" for the 15 hour. 3. This part is also hard to explain. My path for this is C:Program files\2007\06\11 However there is also a path C:Program files\AmaSeis\2007........my files are not in this folder? 4 This part is also hard to explain. At one time I download an HOUR FILE ending with a (.z) It was of a hurricane. When I downloaded it, it would not show.......My hour files ended with an(.n) at that time. So I change the downloaded file's name from "xxxxx.z" to "xxxxx.n" and AmaSeis then opened it. If this is confusing Just call me and I might be able to walk you thru it. Do let me know. Ted ----- Original Message ----- From: "Paul Cianciolo" To: Sent: Monday, June 11, 2007 9:26 AM Subject: I have no saved files!!! > Today for the first time. I tried to go back about 5 days and look at a > event. > > I save 4 says to the screen. > SO opening the correct folders, which there is one for each day Amaseis > has > been running. > But there are no files. > > No SAC's no PePPS no PSN's!! > > Very suspicious! > > > SAC-Less in Connecticut > > PC > W1VLF > > > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Opinion on seismometer From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@......... Date: Tue, 12 Jun 2007 18:31:59 +0000 Hi all I have finised the basic lehman type seismemter build. A picture of it can be seen here, http://www.jonfr.com/myndir/v/geology/seismometer/p6120001.jpg.html What currently is missing is decent magnetic damping and a decent mass. But I also would like a opinion on this design that I am using. The plot from this seismoeter can be seen on my webpage. Regards. --=20 J=F3n Fr=EDmann http://www.jonfr.com http://www.simnet.is/jonfr500/earthquake/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Opinion on seismometer From: ChrisAtUpw@....... Date: Tue, 12 Jun 2007 17:56:49 EDT In a message dated 12/06/2007, jonfr@......... writes: I have finished the basic lehman type seismometer build. A picture of it can be seen here, http://www.jonfr.com/myndir/v/geology/seismometer/p6120001.jpg.html What currently is missing is decent magnetic damping and a decent mass. But I also would like an opinion on this design that I am using. The plot from this seismometer can be seen on my webpage. Hi Jon, I can't see from your photo what sort of top and bottom bearings you are using. Ball on a plane or crossed cylinder systems are both easy to make and give excellent performance. You can also use flexing piano wire. You are unlikely to get long periods easily / reliably if you use knife edge or point in a cup joints. It is much better if you put a crossbar immediately behind the mass and use a V suspension from the ends up to the top bearing. This stops the arm trying to rotate about it's long axis. Go to a shop which sells fishing tackle and buy some nylon coated 7 strand SS trace wire, preferably rated at 30 lbs or over. This can be attached by loops and crimp tubes, usually sold with the reel of wire. You can buy it rated up to 200 lbs, but this is excessive for a Lehman. A magnetic damping system for a Lehman can be seen at _http://jclahr.com/science/psn/chapman/lehman/index.html_ (http://jclahr.com/science/psn/chapman/lehman/index.html) You do need rectangular damping magnets NOT round ones. You can also use a couple of Alnico magnets firmly attached to the baseplate with a vertical copper or aluminum sheet in between, as on the first Lehman design. However, the rectangular NdFeB quad magnet design is much cheaper, more powerful and easier to adjust. If you use a horizontal damping tongue, you simply slide the magnet housing over it until you get adequate damping. I suggest that you do not even consider oil damping. It is temperature sensitive, relatively difficult to adjust and potentially quite messy. I suggest that you use a mass of about 1 kg, preferably non magnetic. I use round brass rod or square / rectangular brass bar. It is better if you can extend the base, say with L angle steel or Al to the far end of the mass and put the vertical period adjust screw there. In the photo shown, the mass is on the end of the arm, then comes the coil + sensor magnet, then the suspension fitting, then the horizontal damping blade and the sliding damping magnet. It is made as a single unit. How long an arm are you using? Regards, Chris Chapman
In a message dated 12/06/2007, jonfr@......... writes:
<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size= =3D2>I have=20 finished the basic lehman type seismometer build. A picture of it
can b= e=20 seen=20 here,
http://www.jonfr.com/myndir/v/geology/seismometer/p6120001.jpg.ht= ml

What=20 currently is missing is decent magnetic damping and a decent mass.
But=20= I=20 also would like an opinion on this design that I am using.

The plot= =20 from this seismometer can be seen on my webpage.
Hi Jon,
 
    I can't see from your photo what sort of top an= d=20 bottom bearings you are using. Ball on a plane or crossed cylinder systems a= re=20 both easy to make and give excellent performance. You can also use flexing p= iano=20 wire.
    You are unlikely=20 to get long periods easily / reliably if you use knife edge or point in a cu= p=20 joints.
    
    It is much better if you put a crossbar immedia= tely=20 behind the mass and use a V suspension from the ends up to the top bearing.=20= This=20 stops the arm trying to rotate about it's long axis. Go to a shop which sell= s=20 fishing tackle and buy some nylon coated 7 strand SS trace wire, preferably=20 rated at 30 lbs or over. This can be attached by loops and crimp tubes, usua= lly=20 sold with the reel of wire. You can buy it rated up to 200 lbs, but this is=20 excessive for a Lehman.
 
    A magnetic damping system for a Lehman can be s= een=20 at http://jcla= hr.com/science/psn/chapman/lehman/index.html You=20 do need rectangular damping magnets NOT round ones.
 
    You can also use a couple of Alnico magnets fir= mly=20 attached to the baseplate with a vertical copper or aluminum sheet in betwee= n,=20 as on the first Lehman design. However, the rectangular NdFeB quad magnet de= sign=20 is much cheaper, more powerful and easier to adjust. If you use a=20 horizontal damping tongue, you simply slide the magnet housing over it=20 until you get adequate damping. I suggest that you do not even=20 consider oil damping. It is temperature sensitive, relatively difficult= to=20 adjust and potentially quite messy.
 
    I suggest that you use a mass of about 1 kg,=20 preferably non magnetic. I use round brass rod or square / rectang= ular=20 brass bar. It is better if you can extend the base, say with L ang= le=20 steel or Al to the far end of the mass and put the vertical period adjust sc= rew=20 there. In the photo shown, the mass is on the end of the arm, then comes the= =20 coil + sensor magnet, then the suspension fitting, then the horizontal dampi= ng=20 blade and the sliding damping magnet. It is made as a single unit.
 
    How long an arm are you using?
 
    Regards,
 
    Chris Chapman
 Subject: Re: Opinion on seismometer From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@......... Date: Tue, 12 Jun 2007 22:19:43 +0000 Hi Chris. The sensor is 95% done, I hopefully am going to finish it in about two weeks time or around that. The arm is 60 cm long. I am using a simple wire on the arm, from the top to bottom.=20 I plan to use the magnet damping system as it is on that webpage you pointed to. I just can't set it up at the moment, I am going to get help in two weeks time to fix that issue and setup the sensor in a decent way. I am also going to fix few bugs that I currently have. But the arm goes straigt trugh the holder, it was a mistake that I did when it was setup up for me, my mistake. It is going to get that corrected, along with few other things. Regards. --=20 J=F3n Fr=EDmann http://www.jonfr.com http://www.simnet.is/jonfr500/earthquake/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Opinion on seismometer From: ChrisAtUpw@....... Date: Tue, 12 Jun 2007 19:24:20 EDT In a message dated 12/06/2007, jonfr@......... writes: Hi Chris. The sensor is 95% done Hi Jon, OK. Let me know if you want advice or help? The top suspension is as important as the bottom one. Regards, Chris Chapman
In a message dated 12/06/2007, jonfr@......... writes:
<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size= =3D2>Hi=20 Chris.
The sensor is 95% done
Hi Jon,
 
    OK. Let me know if you want advice or help? The= top=20 suspension is as important as the bottom one.
 
    Regards,
 
    Chris Chapman 
 Subject: Re: I have no saved files!!! From: "Dale Hardy" photon1@........... Date: Wed, 13 Jun 2007 12:44:46 +1000 Paul, I have the same 'N' files which Amaseis opens, make sure in the 'Settings'>'Helicorder'> "number of days to scroll back" is set at the appropriate value regards Dale ----- Original Message ----- From: "Paul Cianciolo" To: Sent: Wednesday, June 13, 2007 2:33 AM Subject: RE: I have no saved files!!! > Hello Ted, > > Your email prompted me to do some more checking. > > There ARE files under all the folders, but not SAC. PSN. > They all have a .N extension. > > They are also all 42 K in size. > > The reason I could not see them is AMASEIS was looking for a known > extension > type and does not display a .N?? > > What eve a .N is?? > > PC > > > > -----Original Message----- > From: psn-l-request@.............. > [mailto:psn-l-request@................. Behalf Of tchannel > Sent: Monday, June 11, 2007 12:53 PM > To: psn-l@.............. > Subject: Re: I have no saved files!!! > > > Hi Paul, I have experienced this also...........I hope they are really > there for you........ > You may know all or part of this.......... > 1 AmaSeis helicorder will allow you to go back, SETTING/ GO TO DATE AND > TIME..........I think you can go back as far as....where you have the > helicorder set for. SETTING/ HELICORDER/ DAYS TO RETAIN > RECORDS............Then press NOW to return to current time. > > 2 This is the hard part to explain. AmaSeis logs all the data in a > folder, > in this case the name is "2007" in this folder is the month folder "06", > inside that is a day folder "11" inside that is the hour FILES, "15.z" for > the 15 hour. > > 3. This part is also hard to explain. My path for this is C:Program > files\2007\06\11 > However there is also a path C:Program files\AmaSeis\2007........my files > are not in this folder? > > 4 This part is also hard to explain. At one time I download an HOUR FILE > ending with a (.z) > It was of a hurricane. When I downloaded it, it would not show.......My > hour files ended with an(.n) at that time. > So I change the downloaded file's name from "xxxxx.z" to "xxxxx.n" and > AmaSeis then opened it. > > If this is confusing Just call me and I might be able to walk you thru it. > Do let me know. > > Ted > > > ----- Original Message ----- > From: "Paul Cianciolo" > To: > Sent: Monday, June 11, 2007 9:26 AM > Subject: I have no saved files!!! > > >> Today for the first time. I tried to go back about 5 days and look at a >> event. >> >> I save 4 says to the screen. >> SO opening the correct folders, which there is one for each day Amaseis >> has >> been running. >> But there are no files. >> >> No SAC's no PePPS no PSN's!! >> >> Very suspicious! >> >> >> SAC-Less in Connecticut >> >> PC >> W1VLF >> >> >> __________________________________________________________ >> >> Public Seismic Network Mailing List (PSN-L) >> >> To leave this list email PSN-L-REQUEST@.............. with >> the body of the message (first line only): unsubscribe >> See http://www.seismicnet.com/maillist.html for more information. >> > > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. > > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. > > > -- > No virus found in this incoming message. > Checked by AVG Free Edition. > Version: 7.5.472 / Virus Database: 269.8.13/844 - Release Date: 11/06/2007 > 5:10 PM > > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: I have no saved files!!! From: John Lahr johnjan@........ Date: Tue, 12 Jun 2007 21:41:46 -0700 The files will be .N, .E, or .Z depending on the orientation of the seismometer. These file can only be read by AmaSeis when they are within the year, month, day directory structure beneath as1.exe. John At 07:44 PM 6/12/2007, you wrote: >Paul, I have the same 'N' files which Amaseis opens, make sure in the >'Settings'>'Helicorder'> "number of days to scroll back" is set at >the appropriate value >regards >Dale > > >----- Original Message ----- From: "Paul Cianciolo" >To: >Sent: Wednesday, June 13, 2007 2:33 AM >Subject: RE: I have no saved files!!! > > >>Hello Ted, >> >>Your email prompted me to do some more checking. >> >>There ARE files under all the folders, but not SAC. PSN. >>They all have a .N extension. >> >>They are also all 42 K in size. >> >>The reason I could not see them is AMASEIS was looking for a known extension >>type and does not display a .N?? >> >>What eve a .N is?? >> >>PC >> >> >> >>-----Original Message----- >>From: psn-l-request@.............. >>[mailto:psn-l-request@................. Behalf Of tchannel >>Sent: Monday, June 11, 2007 12:53 PM >>To: psn-l@.............. >>Subject: Re: I have no saved files!!! >> >> >>Hi Paul, I have experienced this also...........I hope they are really >>there for you........ >>You may know all or part of this.......... >>1 AmaSeis helicorder will allow you to go back, SETTING/ GO TO DATE AND >>TIME..........I think you can go back as far as....where you have the >>helicorder set for. SETTING/ HELICORDER/ DAYS TO RETAIN >>RECORDS............Then press NOW to return to current time. >> >>2 This is the hard part to explain. AmaSeis logs all the data in a folder, >>in this case the name is "2007" in this folder is the month folder "06", >>inside that is a day folder "11" inside that is the hour FILES, "15.z" for >>the 15 hour. >> >>3. This part is also hard to explain. My path for this is C:Program >>files\2007\06\11 >>However there is also a path C:Program files\AmaSeis\2007........my files >>are not in this folder? >> >>4 This part is also hard to explain. At one time I download an HOUR FILE >>ending with a (.z) >>It was of a hurricane. When I downloaded it, it would not show.......My >>hour files ended with an(.n) at that time. >>So I change the downloaded file's name from "xxxxx.z" to "xxxxx.n" and >>AmaSeis then opened it. >> >>If this is confusing Just call me and I might be able to walk you thru it. >>Do let me know. >> >>Ted >> >> >>----- Original Message ----- >>From: "Paul Cianciolo" >>To: >>Sent: Monday, June 11, 2007 9:26 AM >>Subject: I have no saved files!!! >> >> >>>Today for the first time. I tried to go back about 5 days and look at a >>>event. >>> >>>I save 4 says to the screen. >>>SO opening the correct folders, which there is one for each day Amaseis >>>has >>>been running. >>>But there are no files. >>> >>>No SAC's no PePPS no PSN's!! >>> >>>Very suspicious! >>> >>> >>>SAC-Less in Connecticut >>> >>>PC >>>W1VLF >>> >>> >>>__________________________________________________________ >>> >>>Public Seismic Network Mailing List (PSN-L) >>> >>>To leave this list email PSN-L-REQUEST@.............. with >>>the body of the message (first line only): unsubscribe >>>See http://www.seismicnet.com/maillist.html for more information. >> >>__________________________________________________________ >> >>Public Seismic Network Mailing List (PSN-L) >> >>To leave this list email PSN-L-REQUEST@.............. with >>the body of the message (first line only): unsubscribe >>See http://www.seismicnet.com/maillist.html for more information. >> >>__________________________________________________________ >> >>Public Seismic Network Mailing List (PSN-L) >> >>To leave this list email PSN-L-REQUEST@.............. with >>the body of the message (first line only): unsubscribe >>See http://www.seismicnet.com/maillist.html for more information. >> >> >>-- >>No virus found in this incoming message. >>Checked by AVG Free Edition. >>Version: 7.5.472 / Virus Database: 269.8.13/844 - Release Date: >>11/06/2007 5:10 PM >> > >__________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email PSN-L-REQUEST@.............. with the body >of the message (first line only): unsubscribe >See http://www.seismicnet.com/maillist.html for more information. > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: How many volts ? From: Brad Douglas rez@.................. Date: Tue, 12 Jun 2007 21:53:07 -0700 E = I x R E = volts I = current (Amps) R = resistance (Ohms) There may be a reactance phase shift from the coil/magnet that may or may not need to be taken into account. Hope that helps. On Tue, 2007-06-12 at 03:18 -0700, Geoffrey wrote: > There are formulas for figuring out voltages and turns > and magnetic fields such as design formulas for > transformers since most power today is AC. > But it has been so terribly long ago that I ever > did such things I can no longer tell the technical detales. > Plain Old Physics should have an ideal kind of law > that will answer your questions without being exact > but give you an excellent idea of what to expect. > The internet is the best place to start looking > but out there is some mathematician/physicist that would love > to share his knowledge with you. > Possibly an old Electronics book that deals with such things > as designed for understanding by a layman/noobe. > Mathematicians must account for all units etc. but i think > for a laymen experimentation and curve tracing can > give you good results so long as the goes ins and outs > are close enough for government work. > Simply matching a math curve to the data points found > so you put in the known to get the unknown without > knowing what goes on in the middle. > Magic Numbers and stuff. > (I just wish i knew a few myself) > > > ----- Original Message ----- > From: "JĂłn FrĂ­mann" > To: "PSN-Postlist" > Sent: Monday, June 11, 2007 05:25 > Subject: How many volts ? > > > Hi all > > I got a coil and magnet from Larry today and I was wondering what the > voltage level of the coil is. But the coil is 9000 ohms. -- 73, de Brad KB8UYR/6 __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Opinion on seismometer From: Dave Nelson davenn@............... Date: Wed, 13 Jun 2007 20:59:50 +1000 Hi Jon going by your pic ... It seems you have no mass (weight) at the end of= =20 the arm and that is why the wire line is slack also the terminating of that line=20 at the top end is critical to overcome free swinging problems follow Geffory's ideas= =20 using piano wire and turnbuckles and a good pivot point etc, as shown in= =20 the original Lehman design. a good mass would be ~ 5 - 10 kg of brass or lead My commercial horizonal seismo had 10kg brass mass without any sort of reasonable mass on the arm the seismo isnt going to work I assume you have something planned ... altho you havent commented= =20 on what you are going to use. cheers Dave Nelson Sydney At 10:19 PM 12/06/2007 +0000, you wrote: >Hi Chris. > >The sensor is 95% done, I hopefully am going to finish it in about two >weeks time or around that. The arm is 60 cm long. I am using a simple >wire on the arm, from the top to bottom. > >I plan to use the magnet damping system as it is on that webpage you >pointed to. I just can't set it up at the moment, I am going to get help >in two weeks time to fix that issue and setup the sensor in a decent >way. I am also going to fix few bugs that I currently have. But the arm >goes straigt trugh the holder, it was a mistake that I did when it was >setup up for me, my mistake. It is going to get that corrected, along >with few other things. > >Regards. >-- >J=F3n Fr=EDmann >http://www.jonfr.com >http://www.simnet.is/jonfr500/earthquake/ > >__________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email PSN-L-REQUEST@.............. with >the body of the message (first line only): unsubscribe >See http://www.seismicnet.com/maillist.html for more information. > > > >-- >No virus found in this incoming message. >Checked by AVG Free Edition. >Version: 7.5.472 / Virus Database: 269.8.15/847 - Release Date: 12/06/2007= =20 >9:42 PM __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Opinion on seismometer From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@......... Date: Wed, 13 Jun 2007 12:49:14 +0000 Hi Dave. I have replaced the wire, the one I was using was just a bad wire. The arm has mass, just not big one. The mass is something around 50g at the moment. I am going to try to increase the mass today to 1kg. Regards. --=20 J=F3n Fr=EDmann http://www.jonfr.com http://www.simnet.is/jonfr500/earthquake/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Opinion on seismometer From: Mark Robinson mark.robinson@............... Date: Thu, 14 Jun 2007 01:48:30 +1200 Jón Frímann wrote: > I have replaced the wire, the one I was using was just a bad wire. The > arm has mass, just not big one. The mass is something around 50g at the > moment. I am going to try to increase the mass today to 1kg. Hi Jón, The vertical mast looks a bit dodgy. I expect it will wobble about when you add mass. Using a longer lump of the square tube for the mast and should resolve that issue. Tacking some pieces of square section along the base should also improve rigidity there although I can't tell how thick the base is so it may be fine. Your sensor arrangement doesn't look quite right, especially in the photo of your first mockup. Perhaps you could make a pair of pole pieces to attach to the magnet: one a ring to fit over the outside of the coil attached to one pole and the other a rod sized to fit through the coil. That should give you good output. You have some good parties over there ;) -- regards Mark Robinson __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Opinion on seismometer From: Jan Froom JDarwin@............. Date: Wed, 13 Jun 2007 07:41:43 -0700 I can remember when Pete Rowe and I first started playing around with amateur seismometers... I built a large unit with a long boom with a very heavy mass. Pete built a little unit, with no mass on his boom at all. I had my unit mounted on three massive concrete piers... Pete set his unit on a scrap of 2X4 under his house... Funny thing... we both got about the same results... and Pete didn't have half the problems I had. Pete finally put a small fish weight on the end of his boom... I sure... simply to appease me. I've also come to the conclusion that the antique seismometers I've collected all have large masses and huge coils simply because they had to generate enough power to drive a pen motors directly, with no external amplification. With today's amplifiers and technology you can do a whole lot more with a whole lot less. Since the only response to my query about drum recorders came from Chris... I took his advice and took an aspirin and thought about my problem. I've decided to take advantage of the antique nature of what I have, and capitalize on that. Part of what I've tried to inspire in the kids I've worked with... is the simplicity of a seismic monitoring system... the simplicity of a whole lot of "complex" scientific devices... what better way then to let them see the simple pieces up close... and if it looks a bit "Rube Goldbergish"... well that will be kool too. Jan in Gilroy. I can remember when Pete Rowe and I first started playing around with amateur seismometers... I built a large unit with a long boom with a very heavy mass. Pete built a little unit, with no mass on his boom at all. I had my unit mounted on three massive concrete piers... Pete set his unit on a scrap of 2X4 under his house...
Funny thing... we both got about the same results... and Pete didn't have half the problems I had.
Pete finally put a small fish weight on the end of his boom... I sure... simply to appease me.

I've also come to the conclusion that the antique seismometers I've collected all have large masses and huge coils simply because they had to generate enough power to drive a pen motors directly, with no external amplification. With today's amplifiers and technology you can do a whole lot more with a whole lot less.

Since the only response to my query about drum recorders came from Chris... I took his advice and took an aspirin and thought about my problem. I've decided to take advantage of the antique nature of what I have, and capitalize on that. Part of what I've tried to inspire in the kids I've worked with... is the simplicity of a seismic monitoring system... the simplicity of a whole lot of "complex" scientific devices... what better way then to let them see the simple pieces up close... and if it looks a bit  "Rube Goldbergish"... well that will be kool too.

Jan in Gilroy.
Subject: Re: How many volts ? From: "Geoffrey" gmvoeth@........... Date: Wed, 13 Jun 2007 07:46:37 -0700 You are talking BEEP School, But its more like 2 turns = 2X V and 4 turns is 4X V or something along those lines. Im talking Transformer design and not this stuff. But P=I^2R would tell you the copper losses and for max power transfer the Z in must equal the Z out. ----- Original Message ----- From: "Brad Douglas" To: Sent: Tuesday, June 12, 2007 21:53 Subject: Re: How many volts ? >E = I x R > > E = volts > I = current (Amps) > R = resistance (Ohms) > > There may be a reactance phase shift from the coil/magnet that may or > may not need to be taken into account. > > Hope that helps. > > On Tue, 2007-06-12 at 03:18 -0700, Geoffrey wrote: >> There are formulas for figuring out voltages and turns >> and magnetic fields such as design formulas for >> transformers since most power today is AC. >> But it has been so terribly long ago that I ever >> did such things I can no longer tell the technical detales. >> Plain Old Physics should have an ideal kind of law >> that will answer your questions without being exact >> but give you an excellent idea of what to expect. >> The internet is the best place to start looking >> but out there is some mathematician/physicist that would love >> to share his knowledge with you. >> Possibly an old Electronics book that deals with such things >> as designed for understanding by a layman/noobe. >> Mathematicians must account for all units etc. but i think >> for a laymen experimentation and curve tracing can >> give you good results so long as the goes ins and outs >> are close enough for government work. >> Simply matching a math curve to the data points found >> so you put in the known to get the unknown without >> knowing what goes on in the middle. >> Magic Numbers and stuff. >> (I just wish i knew a few myself) >> >> >> ----- Original Message ----- >> From: "JĂłn FrĂ­mann" >> To: "PSN-Postlist" >> Sent: Monday, June 11, 2007 05:25 >> Subject: How many volts ? >> >> >> Hi all >> >> I got a coil and magnet from Larry today and I was wondering what the >> voltage level of the coil is. But the coil is 9000 ohms. > > > -- > 73, de Brad KB8UYR/6 > > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: How many volts ? From: "Geoffrey" gmvoeth@........... Date: Wed, 13 Jun 2007 07:46:37 -0700 You are talking BEEP School, But its more like 2 turns = 2X V and 4 turns is 4X V or something along those lines. Im talking Transformer design and not this stuff. But P=I^2R would tell you the copper losses and for max power transfer the Z in must equal the Z out. ----- Original Message ----- From: "Brad Douglas" To: Sent: Tuesday, June 12, 2007 21:53 Subject: Re: How many volts ? >E = I x R > > E = volts > I = current (Amps) > R = resistance (Ohms) > > There may be a reactance phase shift from the coil/magnet that may or > may not need to be taken into account. > > Hope that helps. > > On Tue, 2007-06-12 at 03:18 -0700, Geoffrey wrote: >> There are formulas for figuring out voltages and turns >> and magnetic fields such as design formulas for >> transformers since most power today is AC. >> But it has been so terribly long ago that I ever >> did such things I can no longer tell the technical detales. >> Plain Old Physics should have an ideal kind of law >> that will answer your questions without being exact >> but give you an excellent idea of what to expect. >> The internet is the best place to start looking >> but out there is some mathematician/physicist that would love >> to share his knowledge with you. >> Possibly an old Electronics book that deals with such things >> as designed for understanding by a layman/noobe. >> Mathematicians must account for all units etc. but i think >> for a laymen experimentation and curve tracing can >> give you good results so long as the goes ins and outs >> are close enough for government work. >> Simply matching a math curve to the data points found >> so you put in the known to get the unknown without >> knowing what goes on in the middle. >> Magic Numbers and stuff. >> (I just wish i knew a few myself) >> >> >> ----- Original Message ----- >> From: "JĂłn FrĂ­mann" >> To: "PSN-Postlist" >> Sent: Monday, June 11, 2007 05:25 >> Subject: How many volts ? >> >> >> Hi all >> >> I got a coil and magnet from Larry today and I was wondering what the >> voltage level of the coil is. But the coil is 9000 ohms. > > > -- > 73, de Brad KB8UYR/6 > > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Opinion on seismometer From: "tchannel" tchannel@.............. Date: Wed, 13 Jun 2007 08:50:44 -0600 Hi Dave, Do you have a picture of your commercial horizontal seismo, or wed site? Thanks, Ted ----- Original Message ----- From: "Dave Nelson" To: Sent: Wednesday, June 13, 2007 4:59 AM Subject: Re: Opinion on seismometer Hi Jon going by your pic ... It seems you have no mass (weight) at the end of the arm and that is why the wire line is slack also the terminating of that line at the top end is critical to overcome free swinging problems follow Geffory's ideas using piano wire and turnbuckles and a good pivot point etc, as shown in the original Lehman design. a good mass would be ~ 5 - 10 kg of brass or lead My commercial horizonal seismo had 10kg brass mass without any sort of reasonable mass on the arm the seismo isnt going to work I assume you have something planned ... altho you havent commented on what you are going to use. cheers Dave Nelson Sydney At 10:19 PM 12/06/2007 +0000, you wrote: >Hi Chris. > >The sensor is 95% done, I hopefully am going to finish it in about two >weeks time or around that. The arm is 60 cm long. I am using a simple >wire on the arm, from the top to bottom. > >I plan to use the magnet damping system as it is on that webpage you >pointed to. I just can't set it up at the moment, I am going to get help >in two weeks time to fix that issue and setup the sensor in a decent >way. I am also going to fix few bugs that I currently have. But the arm >goes straigt trugh the holder, it was a mistake that I did when it was >setup up for me, my mistake. It is going to get that corrected, along >with few other things. > >Regards. >-- >Jón Frímann >http://www.jonfr.com >http://www.simnet.is/jonfr500/earthquake/ > >__________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email PSN-L-REQUEST@.............. with >the body of the message (first line only): unsubscribe >See http://www.seismicnet.com/maillist.html for more information. > > > >-- >No virus found in this incoming message. >Checked by AVG Free Edition. >Version: 7.5.472 / Virus Database: 269.8.15/847 - Release Date: 12/06/2007 >9:42 PM __________________________________________________________ Public Seismic Network Mailing List (PSN-L) __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Opinion on seismometer From: ChrisAtUpw@....... Date: Wed, 13 Jun 2007 11:28:35 EDT In a message dated 13/06/2007, davenn@............... writes: Hi Jon going by your pic ... It seems you have no mass (weight) at the end of the arm and that is why the wire line is slack also the terminating of that line at the top end is critical to overcome free swinging problems follow Geffory's ideas using piano wire and turnbuckles and a good pivot point etc, as shown in the original Lehman design. a good mass would be ~ 5 - 10 kg of brass or lead My commercial horizontal seismo had 10kg brass mass Hi Jon, You choose your mass to go with the arm. I use either 15 mm SS water pipe for preference, or 3/4" to 1" OD Al tube. The SS pipe weighs ~213 gm per metre, it is quite rigid and works very well for arms of <40 to ~100 cm. You can buy inexpensive brass compression fittings for water tube. SS is more rigid than Al. Use tube, not solid rod, to get longer periods. Another possibility is thin wall brass 'telescope' tube. You used to be able to buy brass curtain rod tube? Do not make the arm or the mass from magnetic material - they tend to pick up magnetic field fluctuations from the Earth and from the power wiring. You don't say what sort of top and bottom bearings you are going to use? SS Ball on a SS plane or crossed cylinders are fine. See _http://pages.prodigy.net/fxc/_ (http://pages.prodigy.net/fxc/) and _http://pages.prodigy.net/fxc/JC.html_ (http://pages.prodigy.net/fxc/JC.html) You put the balls or the vertical rollers on the upright support column. This defines the axis of rotation of the arm, so that once you have set the system up for cross balance, you only need to trim this slightly subsequently. Even if the flats / horizontal rollers move slightly during operation of the seismometer, they have only a small effect on the balance or the period. To get a long period, the '~vertical rotation axis' has to be set at 1/3 degree or less to the true vertical. If you put the ball on the arm and the flat on the vertical, every time that you have to reassemble / adjust the seismometer, you have to completely reset the cross balance and then the period. If the bearing moves slightly during normal operation, the arm will probably get unbalanced / drift. DON'T use a POINT PIVOT or a KNIFE EDGE. I don't know who started using these, but they are UNSATISFACTORY and WILL seriously limit the period that you can achieve. Assuming that your 60 cm arm is light compared to the end mass, you may need ~1 kg mass, not over 2.5 kg ---> most of the mass needs to be at the end of the arm. If you try to use a very heavy mass, you could get into problems with bearing loading and with suspension wire stretch / breakage. The commercial units like Sprengnether used two single short piano wires in tension for the suspension. They use a heavy twin wire V suspension to prevent the arm from rotating / oscillating about it's long axis. See the Sprengnether photos at _http://www.geocities.com/meredithlamb/page023.html_ (http://www.geocities.com/meredithlamb/page023.html) These heavy units were probably designed before the MTQ noise limit had been worked out. Regards, Chris Chapman
In a message dated 13/06/2007, davenn@............... writes:
<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000=20 size=3D2>   Hi Jon

    going by your pic ... It= seems=20 you have no mass (weight) at the end of the arm
and that is why the wir= e=20 line is slack  also the terminating of that line at the top
end is= =20 critical to overcome free swinging problems   follow Geffory's i= deas=20
using piano wire and turnbuckles and a good pivot point etc,  as shown in
the original Lehman design.

&nb= sp; a=20 good mass would be ~ 5 - 10 kg of brass or lead
My commercial horizonta= l=20 seismo had 10kg brass mass
Hi Jon,
 
    You choose your mass to go with the arm. I=20= use=20 either 15 mm SS water pipe for preference, or 3/4" to 1" OD Al tube. Th= e SS=20 pipe weighs ~213 gm per metre, it is quite rigid and works very well for arm= s of=20 <40 to ~100 cm. You can buy inexpensive brass compression fittings for wa= ter=20 tube. SS is more rigid than Al. Use tube, not solid rod, to get longer=20 periods. Another possibility is thin wall brass 'telescope' tube.=20= You=20 used to be able to buy brass curtain rod tube? Do not make the arm or the ma= ss=20 from magnetic material - they tend to pick up magnetic field fluctuations fr= om=20 the Earth and from the power wiring.
 
    You don't say what sort of top and bottom beari= ngs=20 you are going to use? SS Ball on a SS plane or crossed cylinders are fine. S= ee=20 http://pages.prodigy.net/fxc/&nbs= p;and=20 http://pages.prodigy.net/fxc/J= C.html
 
    You put the balls or the vertical rollers on= the=20 upright support column. This defines the axis of rotation of the arm, so= =20 that once you have set the system up for cross balance, you only need to tri= m=20 this slightly subsequently. Even if the flats / horizontal rollers move slig= htly=20 during operation of the seismometer, they have only a small effect on the=20 balance or the period. To get a long period, the '~vertical rotation axis' h= as=20 to be set at 1/3 degree or less to the true vertical.
 
    If you put the ball on the arm and the flat on=20= the=20 vertical, every time that you have to reassemble / adjust the seismomet= er,=20 you have to completely reset the cross balance and then the period. If the=20 bearing moves slightly during normal operation, the arm will probably get=20 unbalanced / drift.
 
    DON'T use a POINT PIVOT or a KNIFE EDGE. I don'= t=20 know who started using these, but they are UNSATISFACTORY and WILL=20 seriously limit the period that you can achieve.   
 
    Assuming that your 60 cm arm is light compared=20= to=20 the end mass, you may need ~1 kg mass, not over 2.5 kg ---> most of=20= the=20 mass needs to be at the end of the arm. If you try to use a very heavy mass,= you=20 could get into problems with bearing loading and with suspension wire stretc= h /=20 breakage. The commercial units like Sprengnether used two single short piano= =20 wires in tension for the suspension. They use a heavy twin wire V suspension= to=20 prevent the arm from rotating / oscillating about it's long axis.
 
    See the Sprengnether photos at http://www.geoci= ties.com/meredithlamb/page023.html These=20 heavy units were probably designed before the MTQ noise limit had been=20 worked out. 
 
    Regards,
 
    Chris Chapman 
    
 
Subject: Re: Opinion on seismometer From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@......... Date: Wed, 13 Jun 2007 15:31:32 +0000 Hi all Here is a new picture of the seismomter with 1kg mass. This build of the lehman type seismoeter is deeply flawed and is going to get scrapped in two weeks time or at last repared. But there are better chances that I am going to build a new one with a help. I don't know what the natrual period of this seismometer is, but my guess is that it is somewhere around 1 or 2Hz. But I do see cultural noise, but it is not as hig as on my geophone. http://www.jonfr.com/myndir/v/geology/seismometer/p6130001.jpg.html http://www.jonfr.com/myndir/v/geology/seismometer/p6130002.jpg.html Regards. --=20 J=F3n Fr=EDmann http://www.jonfr.com http://www.simnet.is/jonfr500/earthquake/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: How many volts ? From: Brad Douglas rez@.................. Date: Wed, 13 Jun 2007 12:34:00 -0700 I gave the best answer with the information I had. I'm not terribly familiar with the hardware you're discussing. I thought you were talking about an inductor, not a transformer. :-) Transformers are simple ratios. For example, let's say we have a (secondary coil:primary coil) 10:1 (step-up) transformer plugged into a USA wall socket. That would yield a result of 1200V (10/1 x 120V). A step-down transformer with the same properties as above (except a 1:10 ratio) would yield 12V (1/10 x 120V). Am I getting closes to what you want? On Wed, 2007-06-13 at 07:46 -0700, Geoffrey wrote: > You are talking BEEP School, But its more like > 2 turns = 2X V and 4 turns is 4X V or something > along those lines. > Im talking Transformer design and not this stuff. > But P=I^2R would tell you the copper losses > and for max power transfer the Z in must equal the Z out. > > ----- Original Message ----- > From: "Brad Douglas" > To: > Sent: Tuesday, June 12, 2007 21:53 > Subject: Re: How many volts ? > > > >E = I x R > > > > E = volts > > I = current (Amps) > > R = resistance (Ohms) > > > > There may be a reactance phase shift from the coil/magnet that may or > > may not need to be taken into account. > > > > Hope that helps. > > > > On Tue, 2007-06-12 at 03:18 -0700, Geoffrey wrote: > >> There are formulas for figuring out voltages and turns > >> and magnetic fields such as design formulas for > >> transformers since most power today is AC. > >> But it has been so terribly long ago that I ever > >> did such things I can no longer tell the technical detales. > >> Plain Old Physics should have an ideal kind of law > >> that will answer your questions without being exact > >> but give you an excellent idea of what to expect. > >> The internet is the best place to start looking > >> but out there is some mathematician/physicist that would love > >> to share his knowledge with you. > >> Possibly an old Electronics book that deals with such things > >> as designed for understanding by a layman/noobe. > >> Mathematicians must account for all units etc. but i think > >> for a laymen experimentation and curve tracing can > >> give you good results so long as the goes ins and outs > >> are close enough for government work. > >> Simply matching a math curve to the data points found > >> so you put in the known to get the unknown without > >> knowing what goes on in the middle. > >> Magic Numbers and stuff. > >> (I just wish i knew a few myself) > >> > >> > >> ----- Original Message ----- > >> From: "JĂłn FrĂ­mann" > >> To: "PSN-Postlist" > >> Sent: Monday, June 11, 2007 05:25 > >> Subject: How many volts ? > >> > >> > >> Hi all > >> > >> I got a coil and magnet from Larry today and I was wondering what the > >> voltage level of the coil is. But the coil is 9000 ohms. -- Brad Douglas KB8UYR/6 Address: 37.493,-121.924 / WGS84 National Map Corps #TNMC-3785 __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Guatemala earthquake From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@......... Date: Wed, 13 Jun 2007 20:51:17 +0000 Hi all Emsc did report a mw 6.9 earthquake offshore Guatemala. But for some strange reason I don't think I did record that earthquake on my test lehman type seismometer. However I did see it on my geophone, but mostly on the Z axis for some reason, but not so clear on N-S axis and E-W axis. Any ideas why I might not have recorded the Mw 6.9 earthquake on my test lehman sensor. Besides the obivus flaws in it. Regards. --=20 J=F3n Fr=EDmann http://www.jonfr.com http://www.simnet.is/jonfr500/earthquake/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Guatemala earthquake From: ChrisAtUpw@....... Date: Wed, 13 Jun 2007 17:36:56 EDT In a message dated 13/06/2007, jonfr@......... writes: Any ideas why I might not have recorded the Mw 6.9 earthquake on my test lehman sensor. Besides the obvious flaws in it. Hi Jon, What period is it set at? Put some marker at the end of the boom, push it 10 mm to one side and time the intervals between complete oscillation cycles. If it does not have any damping, it should swing freely. What sort of suspensions have you used? Regards, Chris Chapman
In a message dated 13/06/2007, jonfr@......... writes:
<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size= =3D2>Any=20 ideas why I might not have recorded the Mw 6.9 earthquake on my test
le= hman=20 sensor. Besides the obvious flaws in it.
Hi Jon,
 
    What period is it set at? Put some marker at th= e=20 end of the boom, push it 10 mm to one side and time the intervals between=20 complete oscillation cycles. If it does not have any damping, it should swin= g=20 freely.
 
    What sort of suspensions have you used?
 
    Regards,
 
    Chris Chapman
Subject: Re: Drum Recorders From: "meredith lamb" paleoartifact@......... Date: Wed, 13 Jun 2007 15:52:22 -0600 Hi Jan and all, I suppose the "drummers" will shudder with this suggestion for finding a new use out of the parts. I've only actually tore one up to find out what is actually in one; so, the age, model, will probably vary in what one finds...or....can re-utilize. It was actually the drum itself which offered up the most high value parts. The drum "could" house a fitting size seismometer, and 3 screws could be installed for leveling. Inside, the model I had was acouple brass masses, (balance?) which "could be" utiltized in a seismometer. The frame can offer up a variety of aluminum pieces. Even the molded large frame itself, could be utilized as a strong seismometer brace/frame. What the heck......at least it could be salavaged for such seismology use. I did not find the actually penmotors to be of much value....but they were interesting to see. Actually (yes more), some of the very old "seismoscopes" also look like they could be re-utilized, into a variety of S-G's; or, hanging mass seismometers. Of course by now most are either metal salvaged or in a multitude of dumps here and there....too bad. Meredith Lamb On 6/11/07, Jan Froom wrote: > > Does anyone know where one might find the newer type drum recorders. > > I have a whole shed full of the old ones which move laterally as the drum > turns, > but I've been asked to set up a seismic display in a public area and I'm > just > not happy using the old drum recorders. > And I think the giant pen motors I have... must be 80 years old... if not > older. > > Jan in Gilroy.... >
Hi Jan and all,
 
I suppose the "drummers" will shudder with this suggestion for finding a new
use out of the parts.  I've only actually tore one up to find out what is actually
in one; so, the age, model, will probably vary in what one finds...or....can
re-utilize.  It was actually the drum itself which offered up the most high value parts.
The drum "could" house a fitting size seismometer, and 3 screws could be 
installed for leveling.  Inside, the model I had was acouple brass masses, (balance?) which
"could be" utiltized in a seismometer.  The frame can offer up a variety of aluminum
pieces.  Even the molded large frame itself, could be utilized as a strong seismometer
brace/frame.  What the heck......at least it could be salavaged for such seismology use.  I
did not find the actually penmotors to be of much value....but they were interesting
to see.
 
Actually (yes more), some of the very old "seismoscopes" also look like they could
be re-utilized, into a variety of S-G's; or, hanging mass seismometers.  Of course by
now most are either metal salvaged or in a multitude of dumps here and there....too bad. 
 
Meredith Lamb 
 
 
On 6/11/07, Jan Froom <JDarwin@.............> wrote:
Does anyone know where one might find the newer type drum recorders.

I have a whole shed full of the old ones which move laterally as the drum turns,
but I've been asked to set up a seismic display in a public area and I'm just
not happy using the old drum recorders. 
And I think the giant pen motors I have... must be 80 years old... if not older.

Jan in Gilroy....

Subject: Re: Guatemala earthquake From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@......... Date: Wed, 13 Jun 2007 21:55:54 +0000 Hi Chris This test sensor has a period of close to 1,7Hz (2Hz). I have normal wire to hold up the arm. There is no damping system on this sensor, since I will get a help to build a new one in two to three weeks (or about that). Regards. --=20 J=F3n Fr=EDmann http://www.jonfr.com http://www.simnet.is/jonfr500/earthquake/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Guatemala earthquake From: Angel sismos@.............. Date: Wed, 13 Jun 2007 23:33:30 +0000 Hello J=F3n, Congrats on your lehman! From=20my experiences a lehman like that would wander all over the place if you did not put in a box. The drafts and air currents would drive it loco. I suspect that main reason your lehman is deaf is that heavy cable coming off the coil, I bet it renders the boom motionless. I also agree with other who say the upright is too weak and that the upper pivot is just as important as the lower one. I also made my first lehamn HUGE and it was less better that the very smaller ones I made. My first one was over a meter long with a BIG mass. BTW here is what I reported 5 minutes after the event, I nailed it! www.volcanbaru.com/OSOP/1181762985.html Regards, Angel Wednesday, June 13, 2007, 8:51:17 PM, you wrote: > Hi all > Emsc did report a mw 6.9 earthquake offshore Guatemala. But for some > strange reason I don't think I did record that earthquake on my test > lehman type seismometer. However I did see it on my geophone, but mostly > on the Z axis for some reason, but not so clear on N-S axis and E-W > axis. > Any ideas why I might not have recorded the Mw 6.9 earthquake on my test > lehman sensor. Besides the obivus flaws in it. > Regards. --=20 Best regards, Angel __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Guatemala earthquake From: "Michael Kimzey" mckimzey@........... Date: Wed, 13 Jun 2007 19:59:39 -0400 Hi all. I believe that * I * am responsible for the recent earthquake. Things have been quiet for the past month while I've had my 4 sensors running. Last PM I took them * all * off-line to service components and ....WHAM...less that 12 hours later we get a 6.9 mag. Life's funny that way... - Mike __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Opinion on seismometer From: Pete Rowe ptrowe@......... Date: Wed, 13 Jun 2007 17:04:02 -0700 (PDT) Hi all I sent the following message with a pdf of my recording but it bounced back as too large for the group. I'm not sure how to send it any other way. Pete Here is my recording of the Guatemalan quake today. As Jan mentioned, my seismometer is the size of a shoebox, has a three second period, is critically damped with a resistor across the coil, has almost no weight on the boom, and I can see a 7.0 anywhere on earth. The suspension is two fine steel wires (violin E string) both of which are in tension. This sits on the dirt under my house. The noise level is higher than normal today due to wind in the trees. Normally, I have a very quiet baseline. It has been running almost untouched since 1988. regards, Pete Rowe San Jose, CA --- Jan Froom wrote: > I can remember when Pete Rowe and I first started > playing around with > amateur seismometers... I built a large unit with a > long boom with a > very heavy mass. Pete built a little unit, with no > mass on his boom at > all. I had my unit mounted on three massive concrete > piers... Pete set > his unit on a scrap of 2X4 under his house... > Funny thing... we both got about the same results... > and Pete didn't > have half the problems I had. > Pete finally put a small fish weight on the end of > his boom... I sure... > simply to appease me. > > I've also come to the conclusion that the antique > seismometers I've > collected all have large masses and huge coils > simply because they had > to generate enough power to drive a pen motors > directly, with no > external amplification. With today's amplifiers and > technology you can > do a whole lot more with a whole lot less. > > Since the only response to my query about drum > recorders came from > Chris... I took his advice and took an aspirin and > thought about my > problem. I've decided to take advantage of the > antique nature of what I > have, and capitalize on that. Part of what I've > tried to inspire in the > kids I've worked with... is the simplicity of a > seismic monitoring > system... the simplicity of a whole lot of "complex" > scientific > devices... what better way then to let them see the > simple pieces up > close... and if it looks a bit "Rube > Goldbergish"... well that will be > kool too. > > Jan in Gilroy. > ____________________________________________________________________________________ Need Mail bonding? Go to the Yahoo! Mail Q&A for great tips from Yahoo! Answers users. http://answers.yahoo.com/dir/?link=list&sid=396546091 __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: RE: Guatemala earthquake From: "Paul Cianciolo" Paulc@........ Date: Wed, 13 Jun 2007 20:27:46 -0400 SO Mike... Um... whets your next off line period?? So we can get ready PC -----Original Message----- From: psn-l-request@.............. [mailto:psn-l-request@................. Behalf Of Michael Kimzey Sent: Wednesday, June 13, 2007 8:00 PM To: psn-l@.............. Subject: Re: Guatemala earthquake Hi all. I believe that * I * am responsible for the recent earthquake. Things have been quiet for the past month while I've had my 4 sensors running. Last PM I took them * all * off-line to service components and ....WHAM...less that 12 hours later we get a 6.9 mag. Life's funny that way... - Mike __________________________________________________________ Public Seismic Network Mailing List (PSN-L) __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Guatemala earthquake From: "tchannel" tchannel@.............. Date: Wed, 13 Jun 2007 18:38:56 -0600 Hi Mike, I believe you! Thanks, Ted ----- Original Message ----- From: "Michael Kimzey" To: Sent: Wednesday, June 13, 2007 5:59 PM Subject: Re: Guatemala earthquake > Hi all. > > I believe that * I * am responsible for the recent earthquake. Things > have been quiet for the past month while I've had my 4 sensors running. > Last PM I took them * all * off-line to service components and > ...WHAM...less that 12 hours later we get a 6.9 mag. Life's funny that > way... > > - Mike > > > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with the body of the > message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Opinion on seismometer From: John Lahr johnjan@........ Date: Wed, 13 Jun 2007 17:59:57 -0700 Hi Pete, This sounds like a very compact design. What sort of amplifier and recording system are you using? Do you have any photographs of the instrument that you could post, along with the PDF that was too large for the PSN? There are a number of free sites where images can be posted. See: http://familyinternet.about.com/od/sharingonline/tp/sharephotos.htm Then just let us know the URL. Thanks, John __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Opinion on seismometer From: Larry Cochrane lcochrane@.............. Date: Wed, 13 Jun 2007 18:58:58 -0700 Hi All, This is a reminder that you can not send attachments to the PSN-L list. If you have a file you would like to share with the group you will need to place it on a web/ftp server somewhere and send the link to the file to the list. If you do not have access to a web server I can place the file on my system. If you have a PSN event file you would like to share with the group you can send them to event@.............. as attachments. The event file(s) will show up on this page http://www.seismicnet.com/cgi-dos/event.exe a few minutes after my mail server receives the message. Regards, Larry Cochrane Redwood City, PSN Pete Rowe wrote: > Hi all > I sent the following message with a pdf of my > recording but it bounced back as too large for the > group. I'm not sure how to send it any other way. > Pete > > > Here is my recording of the Guatemalan quake today. As > Jan mentioned, my seismometer is the size of a > shoebox, has a three second period, is critically > damped with a resistor across the coil, has almost no > weight on the boom, and I can see a 7.0 anywhere on > earth. The suspension is two fine steel wires (violin > E string) both of which are in tension. This sits on > the dirt under my house. The noise level is higher > than normal today due to wind in the trees. Normally, > I have a very quiet baseline. It has been running > almost untouched since 1988. > > regards, > Pete Rowe > San Jose, CA > --- Jan Froom wrote: > >> I can remember when Pete Rowe and I first started >> playing around with >> amateur seismometers... I built a large unit with a >> long boom with a >> very heavy mass. Pete built a little unit, with no >> mass on his boom at >> all. I had my unit mounted on three massive concrete >> piers... Pete set >> his unit on a scrap of 2X4 under his house... >> Funny thing... we both got about the same results... >> and Pete didn't >> have half the problems I had. >> Pete finally put a small fish weight on the end of >> his boom... I sure... >> simply to appease me. >> >> I've also come to the conclusion that the antique >> seismometers I've >> collected all have large masses and huge coils >> simply because they had >> to generate enough power to drive a pen motors >> directly, with no >> external amplification. With today's amplifiers and >> technology you can >> do a whole lot more with a whole lot less. >> >> Since the only response to my query about drum >> recorders came from >> Chris... I took his advice and took an aspirin and >> thought about my >> problem. I've decided to take advantage of the >> antique nature of what I >> have, and capitalize on that. Part of what I've >> tried to inspire in the >> kids I've worked with... is the simplicity of a >> seismic monitoring >> system... the simplicity of a whole lot of "complex" >> scientific >> devices... what better way then to let them see the >> simple pieces up >> close... and if it looks a bit "Rube >> Goldbergish"... well that will be >> kool too. >> >> Jan in Gilroy. >> > > > > > > ____________________________________________________________________________________ > Need Mail bonding? > Go to the Yahoo! Mail Q&A for great tips from Yahoo! Answers users. > http://answers.yahoo.com/dir/?link=list&sid=396546091 > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. > > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Opinion on seismometer From: Pete Rowe ptrowe@......... Date: Wed, 13 Jun 2007 20:11:30 -0700 (PDT) OK, thanks larry. I sent it to seismicnet. If all is well, everyone should be able to see it at: http://www.seismicnet.com/cgi-dos/event.exe Pete --- Larry Cochrane wrote: > Hi All, > > This is a reminder that you can not send attachments > to the PSN-L list. If you have a > file you would like to share with the group you will > need to place it on a web/ftp > server somewhere and send the link to the file to > the list. If you do not have access > to a web server I can place the file on my system. > > If you have a PSN event file you would like to share > with the group you can send them > to event@.............. as attachments. The event > file(s) will show up on this page > http://www.seismicnet.com/cgi-dos/event.exe a few > minutes after my mail server > receives the message. > > Regards, > Larry Cochrane > Redwood City, PSN > > Pete Rowe wrote: > > Hi all > > I sent the following message with a pdf of my > > recording but it bounced back as too large for the > > group. I'm not sure how to send it any other way. > > Pete > > > > > > Here is my recording of the Guatemalan quake > today. As > > Jan mentioned, my seismometer is the size of a > > shoebox, has a three second period, is critically > > damped with a resistor across the coil, has almost > no > > weight on the boom, and I can see a 7.0 anywhere > on > > earth. The suspension is two fine steel wires > (violin > > E string) both of which are in tension. This sits > on > > the dirt under my house. The noise level is higher > > than normal today due to wind in the trees. > Normally, > > I have a very quiet baseline. It has been running > > almost untouched since 1988. > > > > regards, > > Pete Rowe > > San Jose, CA > > --- Jan Froom wrote: > > > >> I can remember when Pete Rowe and I first started > >> playing around with > >> amateur seismometers... I built a large unit with > a > >> long boom with a > >> very heavy mass. Pete built a little unit, with > no > >> mass on his boom at > >> all. I had my unit mounted on three massive > concrete > >> piers... Pete set > >> his unit on a scrap of 2X4 under his house... > >> Funny thing... we both got about the same > results... > >> and Pete didn't > >> have half the problems I had. > >> Pete finally put a small fish weight on the end > of > >> his boom... I sure... > >> simply to appease me. > >> > >> I've also come to the conclusion that the antique > >> seismometers I've > >> collected all have large masses and huge coils > >> simply because they had > >> to generate enough power to drive a pen motors > >> directly, with no > >> external amplification. With today's amplifiers > and > >> technology you can > >> do a whole lot more with a whole lot less. > >> > >> Since the only response to my query about drum > >> recorders came from > >> Chris... I took his advice and took an aspirin > and > >> thought about my > >> problem. I've decided to take advantage of the > >> antique nature of what I > >> have, and capitalize on that. Part of what I've > >> tried to inspire in the > >> kids I've worked with... is the simplicity of a > >> seismic monitoring > >> system... the simplicity of a whole lot of > "complex" > >> scientific > >> devices... what better way then to let them see > the > >> simple pieces up > >> close... and if it looks a bit "Rube > >> Goldbergish"... well that will be > >> kool too. > >> > >> Jan in Gilroy. > >> > > > > > > > > > > > > > ____________________________________________________________________________________ > > Need Mail bonding? > > Go to the Yahoo! Mail Q&A for great tips from > Yahoo! Answers users. > > > http://answers.yahoo.com/dir/?link=list&sid=396546091 > > > __________________________________________________________ > > > > Public Seismic Network Mailing List (PSN-L) > > > > To leave this list email > PSN-L-REQUEST@.............. with > > the body of the message (first line only): > unsubscribe > > See http://www.seismicnet.com/maillist.html for > more information. > > > > > > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email > PSN-L-REQUEST@.............. with > the body of the message (first line only): > unsubscribe > See http://www.seismicnet.com/maillist.html for more > information. > ____________________________________________________________________________________ TV dinner still cooling? Check out "Tonight's Picks" on Yahoo! TV. http://tv.yahoo.com/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Guatemala earthquake From: Tangazazen@....... Date: Thu, 14 Jun 2007 00:36:20 EDT Hi Jon, The Guatemala quake signal was suprisingly small for a 6.8 - 6.9 event. I registered about 2.5 to 3 times the background level, that's for a vertical broadband operating at 0.1 to 0.05 Hz 2nd order Butterworth. I note that Beal School recorded nothing and the BGS is not particularly great in amplitude for an event of this magnitude at a distance of 10500Km. Regards Martin
Hi Jon,
 
     The Guatemala quake signal was suprisingl= y=20 small for a 6.8 - 6.9  event. I registered about 2.5 to 3 times the=20 background level, that's for a vertical broadband operating at 0.1 to 0.05 H= z=20 2nd order Butterworth.
I note that Beal School recorded nothing and the BGS is not=20 particularly great in amplitude for an event of this magnitude at a distance= of=20 10500Km.
 
Regards Martin
 Subject: Re: Guatemala earthquake From: John Lahr johnjan@........ Date: Wed, 13 Jun 2007 21:59:32 -0700 Hi Martin, The Guatemala event was recorded quiet well by the AS-1 instruments in the US. http://jclahr.com/science/psn/as1/heli/allas1.php I think that Beal school did record the event but they will need to run a low pass filter with a corner of about 12 seconds to bring out the longer periods. Within the event window, this filter can be applied twice to even more greatly reduce the higher frequency noise. For some reason the coordinates that they provide at the top of their seismogram page don't agree with those entered into AmaSeis, and it would be helpful to install the latest version of AmaSeis. http://www.geo-world.org/bhuk.html They got a very good recording of the recent, rare event near Kent. http://jclahr.com/science/psn/as1/heli/kent_earthquake.doc Cheers, John At 09:36 PM 6/13/2007, you wrote: >Hi Jon, > > The Guatemala quake signal was suprisingly small for a 6.8 - > 6.9 event. I registered about 2.5 to 3 times the background level, > that's for a vertical broadband operating at 0.1 to 0.05 Hz 2nd > order Butterworth. >I note that Beal School recorded nothing and the BGS is not >particularly great in amplitude for an event of this magnitude at a >distance of 10500Km. > >Regards Martin __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Guatemala earthquake From: Tangazazen@....... Date: Thu, 14 Jun 2007 01:13:45 EDT Hi John, I also got a good signal from the Kent quake. As it was on my backdoor, I didn't need the seismometer to tell me ! Martin
Hi John,
 
 I also got a good signal from the Kent quake. As it was on my=20 backdoor, I didn't need the seismometer to tell me !
 
Martin 
 Subject: Is Seismicnet down From: "Paul Cianciolo" Paulc@........ Date: Thu, 14 Jun 2007 12:22:25 -0400 Hello All, Can anyone tell me if the Seismicnet.com is currently down. I am trying to post an event and not sure if I am doing something wrong. PauLC W1VLF __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Is Seismicnet down From: "Thomas Dick" dickthomas01@............. Date: Thu, 14 Jun 2007 12:46:33 -0500 Paul I sent a file and got confirmation __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Opinion on seismometer From: "Dale Hardy" photon1@........... Date: Fri, 15 Jun 2007 10:09:38 +1000 Hi Pete, what is the image filename please thanks Dale ----- Original Message ----- From: "Pete Rowe" To: Sent: Thursday, June 14, 2007 1:11 PM Subject: Re: Opinion on seismometer > OK, thanks larry. I sent it to seismicnet. If all is > well, everyone should be able to see it at: > http://www.seismicnet.com/cgi-dos/event.exe > > Pete > --- Larry Cochrane wrote: > >> Hi All, >> >> This is a reminder that you can not send attachments >> to the PSN-L list. If you have a >> file you would like to share with the group you will >> need to place it on a web/ftp >> server somewhere and send the link to the file to >> the list. If you do not have access >> to a web server I can place the file on my system. >> >> If you have a PSN event file you would like to share >> with the group you can send them >> to event@.............. as attachments. The event >> file(s) will show up on this page >> http://www.seismicnet.com/cgi-dos/event.exe a few >> minutes after my mail server >> receives the message. >> >> Regards, >> Larry Cochrane >> Redwood City, PSN >> >> Pete Rowe wrote: >> > Hi all >> > I sent the following message with a pdf of my >> > recording but it bounced back as too large for the >> > group. I'm not sure how to send it any other way. >> > Pete >> > >> > >> > Here is my recording of the Guatemalan quake >> today. As >> > Jan mentioned, my seismometer is the size of a >> > shoebox, has a three second period, is critically >> > damped with a resistor across the coil, has almost >> no >> > weight on the boom, and I can see a 7.0 anywhere >> on >> > earth. The suspension is two fine steel wires >> (violin >> > E string) both of which are in tension. This sits >> on >> > the dirt under my house. The noise level is higher >> > than normal today due to wind in the trees. >> Normally, >> > I have a very quiet baseline. It has been running >> > almost untouched since 1988. >> > >> > regards, >> > Pete Rowe >> > San Jose, CA >> > --- Jan Froom wrote: >> > >> >> I can remember when Pete Rowe and I first started >> >> playing around with >> >> amateur seismometers... I built a large unit with >> a >> >> long boom with a >> >> very heavy mass. Pete built a little unit, with >> no >> >> mass on his boom at >> >> all. I had my unit mounted on three massive >> concrete >> >> piers... Pete set >> >> his unit on a scrap of 2X4 under his house... >> >> Funny thing... we both got about the same >> results... >> >> and Pete didn't >> >> have half the problems I had. >> >> Pete finally put a small fish weight on the end >> of >> >> his boom... I sure... >> >> simply to appease me. >> >> >> >> I've also come to the conclusion that the antique >> >> seismometers I've >> >> collected all have large masses and huge coils >> >> simply because they had >> >> to generate enough power to drive a pen motors >> >> directly, with no >> >> external amplification. With today's amplifiers >> and >> >> technology you can >> >> do a whole lot more with a whole lot less. >> >> >> >> Since the only response to my query about drum >> >> recorders came from >> >> Chris... I took his advice and took an aspirin >> and >> >> thought about my >> >> problem. I've decided to take advantage of the >> >> antique nature of what I >> >> have, and capitalize on that. Part of what I've >> >> tried to inspire in the >> >> kids I've worked with... is the simplicity of a >> >> seismic monitoring >> >> system... the simplicity of a whole lot of >> "complex" >> >> scientific >> >> devices... what better way then to let them see >> the >> >> simple pieces up >> >> close... and if it looks a bit "Rube >> >> Goldbergish"... well that will be >> >> kool too. >> >> >> >> Jan in Gilroy. >> >> >> > >> > >> > >> > >> > >> > >> > ____________________________________________________________________________________ >> > Need Mail bonding? >> > Go to the Yahoo! Mail Q&A for great tips from >> Yahoo! Answers users. >> > >> > http://answers.yahoo.com/dir/?link=list&sid=396546091 >> > >> > __________________________________________________________ >> > >> > Public Seismic Network Mailing List (PSN-L) >> > >> > To leave this list email >> PSN-L-REQUEST@.............. with >> > the body of the message (first line only): >> unsubscribe >> > See http://www.seismicnet.com/maillist.html for >> more information. >> > >> > >> >> > __________________________________________________________ >> >> Public Seismic Network Mailing List (PSN-L) >> >> To leave this list email >> PSN-L-REQUEST@.............. with >> the body of the message (first line only): >> unsubscribe >> See http://www.seismicnet.com/maillist.html for more >> information. >> > > > > > ____________________________________________________________________________________ > TV dinner still cooling? > Check out "Tonight's Picks" on Yahoo! TV. > http://tv.yahoo.com/ > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. > > > -- > No virus found in this incoming message. > Checked by AVG Free Edition. > Version: 7.5.472 / Virus Database: 269.8.15/848 - Release Date: 13/06/2007 > 12:50 PM > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: How Pivotal is the pivotal relationship? From: "Paul Cianciolo" Paulc@........ Date: Fri, 15 Jun 2007 12:19:46 -0400 Hello Folks, Now that I have my instrument somewhat operational, there are another few "improvement" Here is the deal. When constructing my first experimental Lehman units I used a piece of steel channel iron mounted in a vice at the vertical member. The idea being it would for an experimental platform for different pendulum lengths, weights, suspension wires, bearing surfaces, material etc. etc. The first bearing surface was the head of # 5 bolt polished, and mounted into a holed drilled into the vertical member. The arm had a similar bolt mounted in the end of an aluminum tube. This bolt had a hole in the center of the head and a hard stainless ball glued into it. The suspension was a .020 piano wire and the mass was a 5 Lbs roll of copper wire slide over the end of the aluminum pipe. The top of the suspension wire was simply drooped over the top of the vertical member and "C" clamped to it in order to made the pendulum as close as possible to horizontal. By moving the pivots laterally I could see the effect, and cause the mass to stop where ever I wanted within reason. OK comes the problem. After putting guitar tensioner on the top of the vertical member, so I could adjust the pendulum level, I could no longer cause the mass to stop anywhere. It seemed that no combination of level the pendulum, changing the mass position moving the bottom pivot would allow the pendulum to stop. After a couple hours of messing around, I reverted back to the original setup and Bingo... perfect balance. So... blah. blah, blah, Finally I realized that the adjustment apparatus had moved the top wire suspension point back slightly so that it was a bit behind the vertical member. No longer directly vertical of the bottom pivot. I find that I need to have the top pivot just slightly forward of the bottom pivot to get any pendulum I build to balance. Is there some rule of thumb... It seems the closer to 90 degrees the angle between pendulum and vertical becomes the easier the pendulum will shift off balance. Currently my bottom pivot is crossed hard cylinders, and I want to do the top this way, but I would like to know more about the "Pivotal Relationship" before I construct the bearing. Phew!!!.. I hope this makes sense to someone. Thank you PauLC W1VLF
Hello Folks,
 
Now that I have my instrument = somewhat=20 operational, there are another few "improvement"
 
Here is the deal.
 
When constructing my first = experimental=20 Lehman units I used a piece of steel channel iron mounted in a vice at = the=20 vertical member.
The idea being it would for an = experimental=20 platform for different pendulum lengths, weights, suspension wires, = bearing=20 surfaces, material  etc. etc.
 
The first bearing surface was the = head=20 of  # 5 bolt polished, and mounted into a holed drilled into the=20 vertical member. The arm had a similar bolt mounted in = the end of=20 an aluminum tube. This bolt had a hole in the center of the head and = a hard=20 stainless ball glued into it.
 
The suspension was a .020 piano = wire and the=20 mass was a 5 Lbs roll of copper wire slide over the end of the aluminum=20 pipe.
The top of the suspension wire was = simply=20 drooped over the top of the vertical member and  "C" clamped = to it in=20 order to made the pendulum as close as possible to=20 horizontal. 
 
By moving the pivots laterally I = could see=20 the effect, and cause the mass to stop where ever I wanted within=20 reason.
 
OK  comes the problem.  = After=20 putting guitar tensioner on the top of the vertical member, so I could = adjust=20 the pendulum level, I could no longer cause the mass to stop=20 anywhere.
It seemed that no combination of = level the=20 pendulum, changing the mass position moving the bottom pivot would allow = the=20 pendulum to stop.
 
After a couple hours of messing = around, I=20 reverted back to the original setup and Bingo... perfect = balance.
 
So... blah. blah, blah, =
 
Finally I realized that the = adjustment=20 apparatus had moved the top wire suspension point back slightly so that = it was a=20 bit behind the vertical member.
No longer directly vertical of the = bottom=20 pivot.
 
I find that I need to have the top = pivot=20 just slightly forward of the bottom pivot to get any pendulum I build to = balance.
 
Is there some rule of = thumb...  It=20 seems the closer to 90 degrees the angle between pendulum and vertical = becomes=20 the easier the pendulum will shift off balance.
 
Currently my bottom pivot is = crossed hard=20 cylinders, and I want to do the top this way, but I would like to know = more=20 about the "Pivotal Relationship" before I construct the = bearing.
 
Phew!!!.. I hope this makes sense = to=20 someone.
Thank you
 
PauLC
W1VLF
 
 
Subject: TeeShirt From: "tchannel" tchannel@.............. Date: Fri, 15 Jun 2007 10:51:42 -0600 Hi Folks, I wanted to let you see the Tee-Shirts the IMMG Boise Idaho, = created to sell at a fund raiser for the Museum. I am not trying to sell anything, but if you just got to have one, email = me. They wanted to bring attention to their new Seismic Sensor Station, and = ask for a .jpg of a recorded earthquake using their new sensor. =20 We really own the success of this sensor you all of you, who were, and = are, so helpful in its development and construction. " Someone was asking what Earthquake is on the Tee Shirts. It is a = 5.7M 01/09/07 at 15:49:02 UTC from Southeastern Alaska, 2.9 km depth, = 1404 miles from IMMG." I posted the picture on a, new-for-me picture posting site.....so I hope = it works and you can see it at http://www.superfilehosting.com/download.php?file=3D209IdahoMuseumTeeshir= t.jpg Many Thanks, Ted
Hi Folks,  I wanted to let you see = the=20 Tee-Shirts the IMMG Boise Idaho, created to sell at a fund raiser for = the=20 Museum.
I am not trying to sell anything, but = if you just=20 got to have one, email me.
 
They wanted to bring attention to their = new Seismic=20 Sensor Station, and ask for a .jpg of a recorded earthquake using their = new=20 sensor.  
 
 We really own the success of this = sensor you=20 all of you, who were, and are, so helpful in its development and=20 construction.
 

" Someone was asking what = Earthquake is on=20 the Tee Shirts.   It = is a=20 5.7M  01/09/07 at 15:49:02 = UTC from=20 Southeastern Alaska, 2.9 km depth, =20 1404 miles from IMMG."

 

I posted=20 the picture on a, new-for-me picture posting site.....so I hope it works = and you=20 can see it at

http://www.superfilehosting.com/download.php?file=3D209Ida= hoMuseumTeeshirt.jpg

 

Many=20 Thanks, Ted

Subject: Re: How Pivotal is the pivotal relationship? From: Mark Robinson mark.robinson@............... Date: Sat, 16 Jun 2007 04:57:05 +1200 Paul Cianciolo wrote: > > Hello Folks, > > Now that I have my instrument somewhat operational, there are another > few "improvement" > > Here is the deal. > > When constructing my first experimental Lehman units I used a piece of > steel channel iron mounted in a vice at the vertical member. > The idea being it would for an experimental platform for different > pendulum lengths, weights, suspension wires, bearing surfaces, material > etc. etc. > > The first bearing surface was the head of # 5 bolt polished, and > mounted into a holed drilled into the vertical member. The arm had a > similar bolt mounted in the end of an aluminum tube. This bolt had a > hole in the center of the head and a hard stainless ball glued into it. > > The suspension was a .020 piano wire and the mass was a 5 Lbs roll of > copper wire slide over the end of the aluminum pipe. > The top of the suspension wire was simply drooped over the top of the > vertical member and "C" clamped to it in order to made the pendulum as > close as possible to horizontal. > > By moving the pivots laterally I could see the effect, and cause the > mass to stop where ever I wanted within reason. > > OK comes the problem. After putting guitar tensioner on the top of the > vertical member, so I could adjust the pendulum level, I could no longer > cause the mass to stop anywhere. > It seemed that no combination of level the pendulum, changing the mass > position moving the bottom pivot would allow the pendulum to stop. > > After a couple hours of messing around, I reverted back to the original > setup and Bingo... perfect balance. > > So... blah. blah, blah, > > Finally I realized that the adjustment apparatus had moved the top wire > suspension point back slightly so that it was a bit behind the vertical > member. > No longer directly vertical of the bottom pivot. > > I find that I need to have the top pivot just slightly forward of the > bottom pivot to get any pendulum I build to balance. > > Is there some rule of thumb... It seems the closer to 90 degrees the > angle between pendulum and vertical becomes the easier the pendulum will > shift off balance. > > Currently my bottom pivot is crossed hard cylinders, and I want to do > the top this way, but I would like to know more about the "Pivotal > Relationship" before I construct the bearing. > > Phew!!!.. I hope this makes sense to someone. > Thank you > > PauLC > W1VLF Hi Paul, You discoveries are spot on. As the line through the pivots approaches vertical the period gets longer and the system becomes less stable. The first is a Good Thing, the second isn't. Most people use three fine pitched bolts through the base to make this adjustment. One at the centre of one end and the others either side at the other. cheers Mark zl2tod __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: RE: How Pivotal is the pivotal relationship? From: "Paul Cianciolo" Paulc@........ Date: Fri, 15 Jun 2007 13:22:13 -0400 Hi Mark, Thank you for that information. So one should strive for a level pendulum, and a near vertical as feasible support points? PauLC W1VLF -----Original Message----- From: psn-l-request@.............. [mailto:psn-l-request@................. Behalf Of Mark Robinson Sent: Friday, June 15, 2007 12:57 PM To: psn-l@.............. Subject: Re: How Pivotal is the pivotal relationship? Paul Cianciolo wrote: > > Hello Folks, > > Now that I have my instrument somewhat operational, there are another > few "improvement" > > Here is the deal. > > When constructing my first experimental Lehman units I used a piece of > steel channel iron mounted in a vice at the vertical member. > The idea being it would for an experimental platform for different > pendulum lengths, weights, suspension wires, bearing surfaces, material > etc. etc. > > The first bearing surface was the head of # 5 bolt polished, and > mounted into a holed drilled into the vertical member. The arm had a > similar bolt mounted in the end of an aluminum tube. This bolt had a > hole in the center of the head and a hard stainless ball glued into it. > > The suspension was a .020 piano wire and the mass was a 5 Lbs roll of > copper wire slide over the end of the aluminum pipe. > The top of the suspension wire was simply drooped over the top of the > vertical member and "C" clamped to it in order to made the pendulum as > close as possible to horizontal. > > By moving the pivots laterally I could see the effect, and cause the > mass to stop where ever I wanted within reason. > > OK comes the problem. After putting guitar tensioner on the top of the > vertical member, so I could adjust the pendulum level, I could no longer > cause the mass to stop anywhere. > It seemed that no combination of level the pendulum, changing the mass > position moving the bottom pivot would allow the pendulum to stop. > > After a couple hours of messing around, I reverted back to the original > setup and Bingo... perfect balance. > > So... blah. blah, blah, > > Finally I realized that the adjustment apparatus had moved the top wire > suspension point back slightly so that it was a bit behind the vertical > member. > No longer directly vertical of the bottom pivot. > > I find that I need to have the top pivot just slightly forward of the > bottom pivot to get any pendulum I build to balance. > > Is there some rule of thumb... It seems the closer to 90 degrees the > angle between pendulum and vertical becomes the easier the pendulum will > shift off balance. > > Currently my bottom pivot is crossed hard cylinders, and I want to do > the top this way, but I would like to know more about the "Pivotal > Relationship" before I construct the bearing. > > Phew!!!.. I hope this makes sense to someone. > Thank you > > PauLC > W1VLF Hi Paul, You discoveries are spot on. As the line through the pivots approaches vertical the period gets longer and the system becomes less stable. The first is a Good Thing, the second isn't. Most people use three fine pitched bolts through the base to make this adjustment. One at the centre of one end and the others either side at the other. cheers Mark zl2tod __________________________________________________________ Public Seismic Network Mailing List (PSN-L) __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: How Pivotal is the pivotal relationship? From: ChrisAtUpw@....... Date: Fri, 15 Jun 2007 14:09:47 EDT In a message dated 15/06/2007, Paulc@........ writes: When constructing my first experimental Lehman units I used a piece of steel channel iron mounted in a vice at the vertical member. The first bearing surface was the head of # 5 bolt polished, and mounted into a holed drilled into the vertical member. The arm had a similar bolt mounted in the end of an aluminum tube. This bolt had a hole in the center of the head and a hard stainless ball glued into it. Hi Paul, You have two viable choices for a counterface for your SS ball bearing - another piece of very hard SS - like a bit of a blade off a SS craft knife - you can get break off blades - or a triangular tungsten carbide lathe tool tip - the plain ones are not expensive. I polish mine with diamond paste. Use Devweld 531, Devcon Plastic Welder, Loctite Multibond, Permabond Quickbond or any other two component acrylic adhesive, NOT an Epoxy. The acrylic glues have exceptional strength and are 'tough'. The suspension was a .020 piano wire and the mass was a 5 Lbs roll of copper wire slide over the end of the aluminum pipe. The top of the suspension wire was simply drooped over the top of the vertical member and "C" clamped to it in order to made the pendulum as close as possible to horizontal. You need to control any tendency of the arm to rotate about it's long axis. The easy way to do this is to put a 6" crossbar just behind the mass and have a V suspension to the top bearing. 7 strand SS fishing trace is great for this and it comes with crimp tube fittings. 30 to 50 lbs line is OK. You are better with a solid chunk of metal for the mass, like a slice off a 3" to 4" OD brass rod. You may find a mass of ~ 1 kg is easier, for both the suspensions. You need to provide a fixed / clamped top hinge point. By moving the pivots laterally I could see the effect, and cause the mass to stop where ever I wanted within reason. OK comes the problem. After putting guitar tensioner on the top of the vertical member, so I could adjust the pendulum level, I could no longer cause the mass to stop anywhere. It seemed that no combination of level the pendulum, changing the mass position moving the bottom pivot would allow the pendulum to stop. Finally I realized that the adjustment apparatus had moved the top wire suspension point back slightly so that it was a bit behind the vertical member. No longer directly vertical of the bottom pivot. I find that I need to have the top pivot just slightly forward of the bottom pivot to get any pendulum I build to balance. Is there some rule of thumb... It seems the closer to 90 degrees the angle between pendulum and vertical becomes the easier the pendulum will shift off balance. Currently my bottom pivot is crossed hard cylinders, and I want to do the top this way, but I would like to know more about the "Pivotal Relationship" before I construct the bearing. Tungsten Carbide drills are not expensive and the shafts make very good bearings. You can also buy tungsten carbide needle rollers. You can also use shoulder bolts type 435 from McMaster Carr. If you use a guitar tensioner, lead the wire through a hole in a horizontal bolt and two washers and clamp them to define the top flex point of the wire accurately - you need precisely defined clamp edges. I 'dish' the washers slightly with a conical punch on a wood block. If the length between the bearing and the balance point of the arm close to the mass is L, the period T = 2 x Pi x Sqrt( L / (g x sinA)), where A is the angle between the true vertical and the line joining the centres of rotation of the top and bottom bearings. It is typically ~1/3 degree, maybe less - a very small angle. If you have a ball or a vertical roller on the vertical support column, the centre of rotation is the centre of the ball or the roller. If your ball or vertical roller is on the end of the arm ---> change it! g = 9.81 if L is in metres, g = 32.2 if L is in feet. Make the seismometer base a bit longer than the arm and make the crossbar at the support end about 1/2 the base length ---> make a single unit supporting everything on the three screws. If you try to use separate units, as described on psn, you will get never ending problems. Set the height / position of the mass, taking account of the sensor and damping systems. You set up the suspension angles with three levelling screws on the base of the seismometer. Set up the cross balance first, then set up the period and re-trim the cross balance as necessary. Then set the damping to ~0.7 critical. If you push the arm 10mm to one side and release it, it should swing ~1/2 mm past the balance point. Hope that this helps! Regards, Chris Chapman
In a message dated 15/06/2007, Paulc@........ writes:
<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size= =3D2>
When constructing my first experimen= tal=20 Lehman units I used a piece of steel channel iron mounted in a vice at the= =20 vertical member.
 
The first bearing surface was the he= ad of=20 # 5 bolt polished, and mounted into a holed drilled into the=20 vertical member. The arm had a similar bolt mounted in the=20= end=20 of an aluminum tube. This bolt had a hole in the center of the head and=20 a hard stainless ball glued into it.
Hi Paul,
 
    You have two viable choices for a counterface f= or=20 your SS ball bearing - another piece of very hard SS - like a bit of a=20 blade off a SS craft knife - you can get break off blades - or a triangular=20 tungsten carbide lathe tool tip - the plain ones are not expensive. I polish= =20 mine with diamond paste. Use Devweld 531, Devcon Plastic Welder, Loctit= e=20 Multibond, Permabond Quickbond or any other two component acrylic adhesive,=20= NOT=20 an Epoxy. The acrylic glues have exceptional strength and are=20 'tough'. 
 
<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size= =3D2>
The suspension was a .020 piano wire= and=20 the mass was a 5 Lbs roll of copper wire slide over the end of the aluminu= m=20 pipe.
The top of the suspension wire was s= imply=20 drooped over the top of the vertical member and  "C" clamped to = it=20 in order to made the pendulum as close as possible to=20 horizontal. 
    You need to control any tendency of the arm to=20 rotate about it's long axis. The easy way to do this is to put a 6" crossbar= =20 just behind the mass and have a V suspension to the top bearing. 7 strand SS= =20 fishing trace is great for this and it comes with crimp tube fittings. 30 to= 50=20 lbs line is OK.
    You are better with a solid chunk of met= al=20 for the mass, like a slice off a 3" to 4" OD brass rod.
    You may find a mass of ~ 1 kg is easier, for bo= th=20 the suspensions.
    You need to provide a fixed / clamped top hinge= =20 point.
<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size= =3D2>
By moving the pivots laterally I cou= ld see=20 the effect, and cause the mass to stop where ever I wanted within=20 reason.
 
OK comes the problem.  After pu= tting=20 guitar tensioner on the top of the vertical member, so I could adjust the=20 pendulum level, I could no longer cause the mass to stop=20 anywhere.
It seemed that no combination of lev= el the=20 pendulum, changing the mass position moving the bottom pivot would allow t= he=20 pendulum to stop.
 
Finally I realized that the adjustme= nt=20 apparatus had moved the top wire suspension point back slightly so that it= was=20 a bit behind the vertical member.
No longer directly vertical of the b= ottom=20 pivot.
 
I find that I need to have the top p= ivot=20 just slightly forward of the bottom pivot to get any pendulum I build to=20 balance.
 
Is there some rule of thumb... = It=20 seems the closer to 90 degrees the angle between pendulum and vertical bec= omes=20 the easier the pendulum will shift off balance.
 
Currently my bottom pivot is crossed= hard=20 cylinders, and I want to do the top this way, but I would like to know mor= e=20 about the "Pivotal Relationship" before I construct the=20 bearing.
    Tungsten Carbide drills are not expensiv= e=20 and the shafts make very good bearings. You can also buy tungsten carbide ne= edle=20 rollers. You can also use shoulder bolts type 435 from McMaster Carr.
 
    If you use a guitar tensioner, lead the wire=20 through a hole in a horizontal bolt and two washers and clamp them to=20 define the top flex point of the wire accurately - you need precisely define= d=20 clamp edges. I 'dish' the washers slightly with a conical punch on a wo= od=20 block.
 
    If the length between the bearing and the balan= ce=20 point of the arm close to the mass is L, the period T =3D 2 x Pi x Sqrt( L /= (g x=20 sinA)), where A is the angle between the true vertical and the line joining=20= the=20 centres of rotation of the top and bottom bearings. It is typically ~1/3 deg= ree,=20 maybe less - a very small angle. If you have a ball or a vertical rolle= r on=20 the vertical support column, the centre of rotation is the centre of the bal= l or=20 the roller. If your ball or vertical roller is on the end of the arm --->= =20 change it!  g =3D 9.81 if L is in metres, g =3D 32.2 if L is in=20 feet.
 
    Make the seismometer base a bit longer than the= arm=20 and make the crossbar at the support end about 1/2 the base length --->=20 make a single unit supporting everything on the three screws. If you=20= try=20 to use separate units, as described on psn, you will get never ending=20 problems. Set the height / position of the mass, taking account of the=20 sensor and damping systems. You set up the suspension angles with=20 three levelling screws on the base of the seismometer. Set up the cross= =20 balance first, then set up the period and re-trim the cross balance as=20 necessary. Then set the damping to ~0.7 critical. If you push the arm 10mm t= o=20 one side and release it, it should swing ~1/2 mm past the balance point.
 
    Hope that this helps!
 
    Regards,
 
    Chris Chapman
 
Subject: Re: TeeShirt From: Pete Rowe ptrowe@......... Date: Fri, 15 Jun 2007 11:16:53 -0700 (PDT) WOW!, nice job, Ted. Congratulations on your community support. Regards, Pete --- tchannel wrote: > Hi Folks, I wanted to let you see the Tee-Shirts > the IMMG Boise Idaho, created to sell at a fund > raiser for the Museum. > I am not trying to sell anything, but if you just > got to have one, email me. > > They wanted to bring attention to their new Seismic > Sensor Station, and ask for a .jpg of a recorded > earthquake using their new sensor. > > We really own the success of this sensor you all of > you, who were, and are, so helpful in its > development and construction. > > " Someone was asking what Earthquake is on the Tee > Shirts. It is a 5.7M 01/09/07 at 15:49:02 UTC > from Southeastern Alaska, 2.9 km depth, 1404 miles > from IMMG." > > > > I posted the picture on a, new-for-me picture > posting site.....so I hope it works and you can see > it at > > http://www.superfilehosting.com/download.php?file=209IdahoMuseumTeeshirt.jpg > > > > Many Thanks, Ted > ____________________________________________________________________________________ Take the Internet to Go: Yahoo!Go puts the Internet in your pocket: mail, news, photos & more. http://mobile.yahoo.com/go?refer=1GNXIC __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Opinion on seismometer From: Pete Rowe ptrowe@......... Date: Fri, 15 Jun 2007 11:26:12 -0700 (PDT) Hi Dale Here it is: http://www.seismicnet.com/quakes/0706/070613.192941.prn.psn Pete --- Dale Hardy wrote: > Hi Pete, what is the image filename please > thanks > Dale > > > ----- Original Message ----- > From: "Pete Rowe" > To: > Sent: Thursday, June 14, 2007 1:11 PM > Subject: Re: Opinion on seismometer > > > > OK, thanks larry. I sent it to seismicnet. If all > is > > well, everyone should be able to see it at: > > http://www.seismicnet.com/cgi-dos/event.exe > > > > Pete > > --- Larry Cochrane > wrote: > > > >> Hi All, > >> > >> This is a reminder that you can not send > attachments > >> to the PSN-L list. If you have a > >> file you would like to share with the group you > will > >> need to place it on a web/ftp > >> server somewhere and send the link to the file to > >> the list. If you do not have access > >> to a web server I can place the file on my > system. > >> > >> If you have a PSN event file you would like to > share > >> with the group you can send them > >> to event@.............. as attachments. The event > >> file(s) will show up on this page > >> http://www.seismicnet.com/cgi-dos/event.exe a few > >> minutes after my mail server > >> receives the message. > >> > >> Regards, > >> Larry Cochrane > >> Redwood City, PSN > >> > >> Pete Rowe wrote: > >> > Hi all > >> > I sent the following message with a pdf of my > >> > recording but it bounced back as too large for > the > >> > group. I'm not sure how to send it any other > way. > >> > Pete > >> > > >> > > >> > Here is my recording of the Guatemalan quake > >> today. As > >> > Jan mentioned, my seismometer is the size of a > >> > shoebox, has a three second period, is > critically > >> > damped with a resistor across the coil, has > almost > >> no > >> > weight on the boom, and I can see a 7.0 > anywhere > >> on > >> > earth. The suspension is two fine steel wires > >> (violin > >> > E string) both of which are in tension. This > sits > >> on > >> > the dirt under my house. The noise level is > higher > >> > than normal today due to wind in the trees. > >> Normally, > >> > I have a very quiet baseline. It has been > running > >> > almost untouched since 1988. > >> > > >> > regards, > >> > Pete Rowe > >> > San Jose, CA > >> > --- Jan Froom wrote: > >> > > >> >> I can remember when Pete Rowe and I first > started > >> >> playing around with > >> >> amateur seismometers... I built a large unit > with > >> a > >> >> long boom with a > >> >> very heavy mass. Pete built a little unit, > with > >> no > >> >> mass on his boom at > >> >> all. I had my unit mounted on three massive > >> concrete > >> >> piers... Pete set > >> >> his unit on a scrap of 2X4 under his house... > >> >> Funny thing... we both got about the same > >> results... > >> >> and Pete didn't > >> >> have half the problems I had. > >> >> Pete finally put a small fish weight on the > end > >> of > >> >> his boom... I sure... > >> >> simply to appease me. > >> >> > >> >> I've also come to the conclusion that the > antique > >> >> seismometers I've > >> >> collected all have large masses and huge coils > >> >> simply because they had > >> >> to generate enough power to drive a pen motors > >> >> directly, with no > >> >> external amplification. With today's > amplifiers > >> and > >> >> technology you can > >> >> do a whole lot more with a whole lot less. > >> >> > >> >> Since the only response to my query about drum > >> >> recorders came from > >> >> Chris... I took his advice and took an aspirin > >> and > >> >> thought about my > >> >> problem. I've decided to take advantage of the > >> >> antique nature of what I > >> >> have, and capitalize on that. Part of what > I've > >> >> tried to inspire in the > >> >> kids I've worked with... is the simplicity of > a > >> >> seismic monitoring > >> >> system... the simplicity of a whole lot of > >> "complex" > >> >> scientific > >> >> devices... what better way then to let them > see > >> the > >> >> simple pieces up > >> >> close... and if it looks a bit "Rube > >> >> Goldbergish"... well that will be > >> >> kool too. > >> >> > >> >> Jan in Gilroy. > >> >> > >> > > >> > > >> > > >> > > >> > > >> > > >> > > > ____________________________________________________________________________________ > >> > Need Mail bonding? > >> > Go to the Yahoo! Mail Q&A for great tips from > >> Yahoo! Answers users. > >> > > >> > > > http://answers.yahoo.com/dir/?link=list&sid=396546091 > >> > > >> > > > __________________________________________________________ > >> > > >> > Public Seismic Network Mailing List (PSN-L) > >> > > >> > To leave this list email > >> PSN-L-REQUEST@.............. with > >> > the body of the message (first line only): > >> unsubscribe > >> > See http://www.seismicnet.com/maillist.html for > >> more information. > >> > > >> > > >> > >> > > > __________________________________________________________ > >> > >> Public Seismic Network Mailing List (PSN-L) > >> > >> To leave this list email > >> PSN-L-REQUEST@.............. with > >> the body of the message (first line only): > >> unsubscribe > >> See http://www.seismicnet.com/maillist.html for > more > >> information. > >> > > > > > > > > > > > ____________________________________________________________________________________ > === message truncated === ____________________________________________________________________________________ Finding fabulous fares is fun. Let Yahoo! FareChase search your favorite travel sites to find flight and hotel bargains. http://farechase.yahoo.com/promo-generic-14795097 __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: TeeShirt From: "Bob Hammond" propgrinder@......... Date: Fri, 15 Jun 2007 10:44:12 -0800 Ted, where's the event located and it's magnitude as depicted on the T-shirt? Bob On 6/15/07, tchannel wrote: > > Hi Folks, I wanted to let you see the Tee-Shirts the IMMG Boise Idaho, > created to sell at a fund raiser for the Museum. > I am not trying to sell anything, but if you just got to have one, email > me. > > They wanted to bring attention to their new Seismic Sensor Station, and > ask for a .jpg of a recorded earthquake using their new sensor. > > We really own the success of this sensor you all of you, who were, and > are, so helpful in its development and construction. > > > " Someone was asking what Earthquake is on the Tee Shirts. It is a 5.7M > 01/09/07 at 15:49:02 UTC from Southeastern Alaska, 2.9 km depth, 1404 > miles from IMMG." > > > > I posted the picture on a, new-for-me picture posting site.....so I hope > it works and you can see it at > > > http://www.superfilehosting.com/download.php?file=209IdahoMuseumTeeshirt.jpg > > > > Many Thanks, Ted >
Ted,  where's the event located and it's magnitude as depicted on the T-shirt?
 
Bob

 
On 6/15/07, tchannel <tchannel@..............> wrote:
Hi Folks,  I wanted to let you see the Tee-Shirts the IMMG Boise Idaho, created to sell at a fund raiser for the Museum.
I am not trying to sell anything, but if you just got to have one, email me.
 
They wanted to bring attention to their new Seismic Sensor Station, and ask for a .jpg of a recorded earthquake using their new sensor.  
 
 We really own the success of this sensor you all of you, who were, and are, so helpful in its development and construction.
 

" Someone was asking what Earthquake is on the Tee Shirts.   It is a 5.7M  01/09/07 at 15:49:02 UTC from Southeastern Alaska, 2.9 km depth,   1404 miles from IMMG."

 

I posted the picture on a, new-for-me picture posting site.....so I hope it works and you can see it at

http://www.superfilehosting.com/download.php?file=209IdahoMuseumTeeshirt.jpg

 

Many Thanks, Ted


Subject: Re: TeeShirt From: "tchannel" tchannel@.............. Date: Fri, 15 Jun 2007 13:25:53 -0600 HI Bob, Here is the event as shown on the teeshirt.=20 =3D=3D PRELIMINARY EARTHQUAKE REPORT =3D=3D ***This event supersedes event AT00498817. Region: SOUTHEASTERN ALASKA Geographic coordinates: 59.486N, 137.081W Magnitude: 5.7 Mb Depth: 4 km Universal Time (UTC): 9 Jan 2007 15:49:33 Time near the Epicenter: 9 Jan 2007 06:49:33 Local time in your area: 9 Jan 2007 08:49:33 Location with respect to nearby cities: 52 km (32 miles) W (278 degrees) of Mosquito Lake, AK 58 km (36 miles) W (280 degrees) of Covenant Life, AK 68 km (42 miles) W (279 degrees) of Klukwan, AK 722 km (448 miles) E (100 degrees) of Anchorage, AK ----- Original Message -----=20 From: Bob Hammond=20 To: psn-l@................. Sent: Friday, June 15, 2007 12:44 PM Subject: Re: TeeShirt Ted, where's the event located and it's magnitude as depicted on the = T-shirt? Bob =20 On 6/15/07, tchannel wrote:=20 Hi Folks, I wanted to let you see the Tee-Shirts the IMMG Boise = Idaho, created to sell at a fund raiser for the Museum. I am not trying to sell anything, but if you just got to have one, = email me. They wanted to bring attention to their new Seismic Sensor Station, = and ask for a .jpg of a recorded earthquake using their new sensor. =20 We really own the success of this sensor you all of you, who were, = and are, so helpful in its development and construction. " Someone was asking what Earthquake is on the Tee Shirts. It is a = 5.7M 01/09/07 at 15:49:02 UTC from Southeastern Alaska, 2.9 km depth, = 1404 miles from IMMG." I posted the picture on a, new-for-me picture posting site.....so I = hope it works and you can see it at = http://www.superfilehosting.com/download.php?file=3D209IdahoMuseumTeeshir= t.jpg=20 Many Thanks, Ted
HI Bob,  Here is the event as = shown on=20 the teeshirt.
 
 =3D=3D=20 PRELIMINARY EARTHQUAKE REPORT =3D=3D

***This event supersedes = event=20 AT00498817.


Region:       &= nbsp;           &n= bsp;   =20 SOUTHEASTERN ALASKA
Geographic=20 coordinates:        59.486N,=20 137.081W
Magnitude:        &nb= sp;          =20 5.7=20 Mb
Depth:          &= nbsp;           &n= bsp;=20 4 km
Universal Time=20 (UTC):          9 Jan = 2007 =20 15:49:33
Time near the Epicenter:       = 9 Jan=20 2007  06:49:33
Local time in your=20 area:       9 Jan 2007 =20 08:49:33

Location with respect to nearby cities:
  52 km = (32=20 miles) W (278 degrees) of Mosquito Lake, AK
  58 km (36 miles) W = (280=20 degrees) of Covenant Life, AK
  68 km (42 miles) W (279 degrees) = of=20 Klukwan, AK
 722 km (448 miles) E (100 degrees) of Anchorage,=20 AK

----- Original Message -----
From:=20 Bob=20 Hammond
Sent: Friday, June 15, 2007 = 12:44=20 PM
Subject: Re: TeeShirt

Ted,  where's the event located and it's magnitude as = depicted on=20 the T-shirt?
 
Bob

 
On 6/15/07, tchannel <tchannel@..............>=20 wrote:=20
Hi Folks,  I wanted to let you = see the=20 Tee-Shirts the IMMG Boise Idaho, created to sell at a fund raiser = for the=20 Museum.
I am not trying to sell anything, = but if you=20 just got to have one, email me.
 
They wanted to bring attention to = their new=20 Seismic Sensor Station, and ask for a .jpg of a recorded earthquake = using=20 their new sensor.  
 
 We really own the success of = this sensor=20 you all of you, who were, and are, so helpful in its development and = construction.
 

" Someone was = asking what=20 Earthquake is on the Tee Shirts.   It is a=20 5.7M  01/09/07 at 15:49:02 UTC from Southeastern = Alaska,=20 2.9 km depth,   1404 miles from IMMG."

 

I = posted the picture=20 on a, new-for-me picture posting site.....so I hope it works and you = can see=20 it at

http://www.superfilehosting.com/download.php?file=3D209Id= ahoMuseumTeeshirt.jpg=20

 

Many = Thanks,=20 = Ted


Subject: RE: TeeShirt From: "Steve Hammond" shammon1@............. Date: Fri, 15 Jun 2007 19:24:07 -0700 =20 -----Original Message----- From: psn-l-request@.............. [mailto:psn-l-request@............... = On Behalf Of tchannel Sent: Friday, June 15, 2007 9:52 AM To: psn-l@.............. Subject: TeeShirt Hi Folks, I wanted to let you see the Tee-Shirts the IMMG Boise Idaho, created to sell at a fund raiser for the Museum. I am not trying to sell anything, but if you just got to have one, email = me. =20 They wanted to bring attention to their new Seismic Sensor Station, and = ask for a .jpg of a recorded earthquake using their new sensor. =20 =20 We really own the success of this sensor you all of you, who were, and = are, so helpful in its development and construction. =20 " Someone was asking what Earthquake is on the Tee Shirts. It is a = 5.7M 01/09/07 at 15:49:02 UTC from Southeastern Alaska, 2.9 km depth, 1404 = miles from IMMG." =20 I posted the picture on a, new-for-me picture posting site.....so I hope = it works and you can see it at http://www.superfilehosting.com/download.php?file=3D209IdahoMuseumTeeshir= t.jpg =20 Many Thanks, Ted Message
 
-----Original Message-----
From:=20 psn-l-request@.............. [mailto:psn-l-request@............... = On=20 Behalf Of tchannel
Sent: Friday, June 15, 2007 9:52=20 AM
To: psn-l@..............
Subject:=20 TeeShirt

Hi Folks,  I wanted to let you = see the=20 Tee-Shirts the IMMG Boise Idaho, created to sell at a fund raiser for = the=20 Museum.
I am not trying to sell anything, but = if you just=20 got to have one, email me.
 
They wanted to bring attention to = their new=20 Seismic Sensor Station, and ask for a .jpg of a recorded earthquake = using=20 their new sensor.  
 
 We really own the success of = this sensor=20 you all of you, who were, and are, so helpful in its development and=20 construction.
 

" Someone was asking what = Earthquake is=20 on the Tee Shirts.   = It is a=20 5.7M  01/09/07 at = 15:49:02 UTC=20 from Southeastern Alaska, 2.9 km depth, =20 1404 miles from IMMG."

 

I=20 posted the picture on a, new-for-me picture posting site.....so I hope = it=20 works and you can see it at

http://www.superfilehosting.com/download.php?file=3D209Ida= hoMuseumTeeshirt.jpg

 

Many=20 Thanks, Ted

Subject: RE: How Pivotal is the pivotal relationship? From: "Paul Cianciolo" Paulc@........ Date: Sat, 16 Jun 2007 17:12:51 -0400 Chris, I have changed from the ball bearing, with wire suspension to crossed cylinders for both the top and bottom bearing surfaces. The wire suspension seems to cause noise when ever the the frame was touched. I wanted to get rid of the resonance of the wire so both the horizontal boom, and the suspension are now tubes. No more rotational problem around the horizontal mass axis either. The last step was building the interface between the tubular suspension and the vertical support, so I could use the crossed cylinders there as well. -----Original Message----- From: psn-l-request@.............. [mailto:psn-l-request@................. Behalf Of ChrisAtUpw@....... Sent: Friday, June 15, 2007 2:10 PM To: psn-l@.............. Subject: Re: How Pivotal is the pivotal relationship? In a message dated 15/06/2007, Paulc@........ writes: When constructing my first experimental Lehman units I used a piece of steel channel iron mounted in a vice at the vertical member. The first bearing surface was the head of # 5 bolt polished, and mounted into a holed drilled into the vertical member. The arm had a similar bolt mounted in the end of an aluminum tube. This bolt had a hole in the center of the head and a hard stainless ball glued into it. Hi Paul, You have two viable choices for a counterface for your SS ball bearing - another piece of very hard SS - like a bit of a blade off a SS craft knife - you can get break off blades - or a triangular tungsten carbide lathe tool tip - the plain ones are not expensive. I polish mine with diamond paste. Use Devweld 531, Devcon Plastic Welder, Loctite Multibond, Permabond Quickbond or any other two component acrylic adhesive, NOT an Epoxy. The acrylic glues have exceptional strength and are 'tough'. The suspension was a .020 piano wire and the mass was a 5 Lbs roll of copper wire slide over the end of the aluminum pipe. The top of the suspension wire was simply drooped over the top of the vertical member and "C" clamped to it in order to made the pendulum as close as possible to horizontal. You need to control any tendency of the arm to rotate about it's long axis. The easy way to do this is to put a 6" crossbar just behind the mass and have a V suspension to the top bearing. 7 strand SS fishing trace is great for this and it comes with crimp tube fittings. 30 to 50 lbs line is OK. You are better with a solid chunk of metal for the mass, like a slice off a 3" to 4" OD brass rod. I have since gone with a lead mass You may find a mass of ~ 1 kg is easier, for both the suspensions. You need to provide a fixed / clamped top hinge point. This is exactly what I was using before the crossed cylinders. By moving the pivots laterally I could see the effect, and cause the mass to stop where ever I wanted within reason. OK comes the problem. After putting guitar tensioner on the top of the vertical member, so I could adjust the pendulum level, I could no longer cause the mass to stop anywhere. It seemed that no combination of level the pendulum, changing the mass position moving the bottom pivot would allow the pendulum to stop. Finally I realized that the adjustment apparatus had moved the top wire suspension point back slightly so that it was a bit behind the vertical member. No longer directly vertical of the bottom pivot. I find that I need to have the top pivot just slightly forward of the bottom pivot to get any pendulum I build to balance. Is there some rule of thumb... It seems the closer to 90 degrees the angle between pendulum and vertical becomes the easier the pendulum will shift off balance. Currently my bottom pivot is crossed hard cylinders, and I want to do the top this way, but I would like to know more about the "Pivotal Relationship" before I construct the bearing. Tungsten Carbide drills are not expensive and the shafts make very good bearings. You can also buy tungsten carbide needle rollers. You can also use shoulder bolts type 435 from McMaster Carr. If you use a guitar tensioner, lead the wire through a hole in a horizontal bolt and two washers and clamp them to define the top flex point of the wire accurately - you need precisely defined clamp edges. I 'dish' the washers slightly with a conical punch on a wood block. If the length between the bearing and the balance point of the arm close to the mass is L, the period T = 2 x Pi x Sqrt( L / (g x sinA)), where A is the angle between the true vertical and the line joining the centres of rotation of the top and bottom bearings. It is typically ~1/3 degree, maybe less - a very small angle. If you have a ball or a vertical roller on the vertical support column, the centre of rotation is the centre of the ball or the roller. If your ball or vertical roller is on the end of the arm ---> change it! g = 9.81 if L is in metres, g = 32.2 if L is in feet. All of these considerations have been taken care of in my new sensor. Make the seismometer base a bit longer than the arm and make the crossbar at the support end about 1/2 the base length ---> make a single unit supporting everything on the three screws. If you try to use separate units, as described on psn, you will get never ending problems. Set the height / position of the mass, taking account of the sensor and damping systems. You set up the suspension angles with three levelling screws on the base of the seismometer. Set up the cross balance first, then set up the period and re-trim the cross balance as necessary. Then set the damping to ~0.7 critical. If you push the arm 10mm to one side and release it, it should swing ~1/2 mm past the balance point. Hope that this helps! Yes it does immensely, and validates some of the ideas I thought of myself. Regards, Chris Chapman Thank you again Chris. PauLC W1VLF
Chris,
 
I have changed from the ball = bearing, with=20 wire suspension to crossed cylinders for both the top and bottom bearing = surfaces.
The wire suspension seems to cause = noise=20 when ever the the frame was touched.
I wanted to get rid of the = resonance of the=20 wire so both the horizontal boom, and the suspension are now = tubes.
 
No more rotational problem around = the=20 horizontal mass axis either.
 
The last step was building the = interface=20 between the tubular suspension and the vertical support, so I could use = the=20 crossed cylinders there as well.
 
 
-----Original Message-----
From:=20 psn-l-request@.............. = [mailto:psn-l-request@...............On Behalf=20 Of ChrisAtUpw@.......
Sent: Friday, June 15, 2007 2:10=20 PM
To: psn-l@..............
Subject: Re: How = Pivotal is=20 the pivotal relationship?

In a message dated 15/06/2007, Paulc@........ writes:
When constructing my first = experimental=20 Lehman units I used a piece of steel channel iron mounted in a vice = at the=20 vertical member.
 
The first bearing surface was = the head=20 of # 5 bolt polished, and mounted into a holed drilled into the=20 vertical member. The arm had a similar bolt mounted = in the=20 end of an aluminum tube. This bolt had a hole in the center of the = head and=20 a hard stainless ball glued into it.
Hi Paul,
 
    You have two viable choices for a = counterface for=20 your SS ball bearing - another piece of very hard SS - like a bit = of a=20 blade off a SS craft knife - you can get break off blades - or a = triangular=20 tungsten carbide lathe tool tip - the plain ones are not expensive. I = polish=20 mine with diamond paste. Use Devweld 531, Devcon Plastic = Welder, Loctite=20 Multibond, Permabond Quickbond or any other two component acrylic = adhesive,=20 NOT an Epoxy. The acrylic glues have exceptional strength and are=20 'tough'. 
 
The suspension was a .020 = piano wire and=20 the mass was a 5 Lbs roll of copper wire slide over the end of the = aluminum=20 pipe.
The top of the suspension wire = was=20 simply drooped over the top of the vertical member and  "C" = clamped=20 to it in order to made the pendulum as close as possible to=20 horizontal. 
    You need to control any tendency of the = arm to=20 rotate about it's long axis. The easy way to do this is to put a 6" = crossbar=20 just behind the mass and have a V suspension to the top bearing. 7 = strand SS=20 fishing trace is great for this and it comes with crimp tube fittings. = 30 to=20 50 lbs line is OK.
    You are better with a solid chunk = of metal=20 for the mass, like a slice off a 3" to 4" OD brass rod. 
 
I have = since gone with=20 a lead mass 
 
    You may find a mass of ~ 1 kg is easier, = for both=20 the suspensions.
    You need to provide a fixed / clamped top = hinge=20 point. 
 
This is = exactly what I=20 was using before the crossed cylinders. 
By moving the pivots laterally = I could=20 see the effect, and cause the mass to stop where ever I wanted = within=20 reason.
 
OK comes the problem.  = After=20 putting guitar tensioner on the top of the vertical member, so I = could=20 adjust the pendulum level, I could no longer cause the mass to stop=20 anywhere.
It seemed that no combination = of level=20 the pendulum, changing the mass position moving the bottom pivot = would allow=20 the pendulum to stop.
 
Finally I realized that the = adjustment=20 apparatus had moved the top wire suspension point back slightly so = that it=20 was a bit behind the vertical member.
No longer directly vertical of = the=20 bottom pivot.
 
I find that I need to have the = top pivot=20 just slightly forward of the bottom pivot to get any pendulum I = build to=20 balance.
 
Is there some rule of = thumb...  It=20 seems the closer to 90 degrees the angle between pendulum and = vertical=20 becomes the easier the pendulum will shift off balance.
 
Currently my bottom pivot is = crossed=20 hard cylinders, and I want to do the top this way, but I would like = to know=20 more about the "Pivotal Relationship" before I construct the=20 bearing.
    Tungsten Carbide drills are not = expensive=20 and the shafts make very good bearings. You can also buy tungsten = carbide=20 needle rollers. You can also use shoulder bolts type 435 from McMaster = Carr.
 
    If you use a guitar tensioner, lead the = wire=20 through a hole in a horizontal bolt and two washers and clamp = them to=20 define the top flex point of the wire accurately - you need precisely = defined=20 clamp edges. I 'dish' the washers slightly with a conical punch = on a wood=20 block.
 
    If the length between the bearing and the = balance=20 point of the arm close to the mass is L, the period T =3D 2 x Pi x = Sqrt( L / (g=20 x sinA)), where A is the angle between the true vertical and the line = joining=20 the centres of rotation of the top and bottom bearings. It is = typically ~1/3=20 degree, maybe less - a very small angle. If you have a ball or a = vertical=20 roller on the vertical support column, the centre of rotation is the = centre of=20 the ball or the roller. If your ball or vertical roller is on the end = of the=20 arm ---> change it!  g =3D 9.81 if L is in metres, g =3D = 32.2 if L is=20 in feet. 
 
 All = of these=20 considerations have been taken care of in my new = sensor.
 
    Make the seismometer base a bit longer = than the=20 arm and make the crossbar at the support end about 1/2 the base length = --->=20 make a single unit supporting everything on the three screws. = If you=20 try to use separate units, as described on psn, you will get = never ending=20 problems. Set the height / position of the mass, taking account = of the=20 sensor and damping systems. You set up the suspension angles with=20 three levelling screws on the base of the seismometer. Set up the = cross=20 balance first, then set up the period and re-trim the cross balance as = necessary. Then set the damping to ~0.7 critical. If you push the arm = 10mm to=20 one side and release it, it should swing ~1/2 mm past the balance = point.
 
    Hope that this helps!  
 
Yes it = does immensely,=20 and validates some of the ideas I thought of = myself. 
 
    Regards,
 
    Chris Chapman 
 
Thank you = again=20 Chris.
 
PauLC
W1VLF 
 
Subject: Slinky Sensor From: "tchannel" tchannel@.............. Date: Sat, 16 Jun 2007 15:30:47 -0600 Slinky Sensor June 16, 2007 =20 I just finished a sensor made from a "Slinky Spring" The toy spring kids = and some adults play with. I used the "Slinky Jr." ? Which is a = metal spring smaller than the full size Slinky. I think they call it = the Jr. and it measures about 1 =BE" in dia. If you hold the spring by = the end it expands to about 3'. When you add weight it expands to = about 7' and has a period of about 2 seconds. This is a not-too-serious = attempt, its just for fun. =20 The basic concept ; =20 Use a Slinky spring. From the end of the spring hang a =BC" x 12" brass = threaded rod. On the rod place three =BC" thick x =BE " od ring = magnets separated by brass nuts Two magnets for the coil, one magnet = lower on the rod for the damper. Using the 4 brass nuts, you can = position the magnets up and down the 12" brass rod for vertical = adjustments. =20 The rod and magnets pass thru and are centered to float inside a donut = coil, and a damper made from a 1" x 2" long copper pipe, which is split = into three parts. These three parts each have a brass screw for adj how = close or far they get to the damping magnet. =20 There are two 3" pvc tees one on top of the other, which act as = housings. The top tee houses the coil. The bottom tee houses the = damper. =20 The two tees attach to a 3" toilet flange, and the toilet flange is = bolted to a concrete block. The concrete block has three adj leveling legs. =20 The spring, rod, and magnets are all lowered into a 3" x 48" pvc pipe, = and hang from a 3" pvc end cap. =20 I plugged the two tee openings with tee plugs with windows. =20 The entire system is inside the enclosed pvc pipe to isolate from air = currents. =20 All in all it work okay, I have recorded several earthquakes with it, = and it seem to work as well as my other vertical. They are posted on = PSN as TCIDzS (z for vertical S for slinky) =20 I have a concept sketch and picts to send if anyone is = interested.........I tried to post on the web. but had problems. Thanks, Ted

Slinky=20 Sensor           &n= bsp;           &nb= sp;           &nbs= p;  =20 June 16, 2007

 

I just finished a sensor made from a =93Slinky Spring=94 The = toy spring kids=20 and some adults play with.  = I used=20 the =93Slinky Jr.=94  = ?   Which is a metal spring = smaller=20 than the full size Slinky.   I=20 think they call it the Jr. and it measures about 1 =BE=94 in dia.  If you hold the spring by the = end it=20 expands to about 3=92.   = When you=20 add weight it expands to about 7=92 and has a period of about 2 = seconds. =20 This is a not-too-serious attempt, its just for fun.

 

The basic concept ;

 

Use a Slinky spring.  = From=20 the end of the spring hang a =BC=94 x 12=94 brass threaded rod.  On the rod place three =BC=94 = thick x  =BE =93 od ring magnets = separated by brass=20 nuts  Two magnets for the = coil, one=20 magnet lower on the rod for the damper.   Using the 4 brass nuts, = you can=20 position the magnets up and down the 12=94 brass rod for vertical=20 adjustments.

 

The rod and magnets pass thru and are centered to float inside = a donut=20 coil, and a damper made from a 1=94 x 2=94 long copper pipe, which is = split into=20 three parts.  These three = parts each=20 have a brass screw for adj how close or far they get to the damping=20 magnet.

 

There are two 3=94 pvc tees one on top of the other, which act = as housings.=20 The top tee houses the coil.  = The=20 bottom tee houses the damper.

 

The two tees attach to a 3=94 toilet flange, and the toilet = flange is=20 bolted to a concrete block.

The concrete block has three adj leveling legs.

 

The spring, rod, and magnets are all lowered into a 3=94 x  48=94 pvc pipe, and hang from = a 3=94 pvc end=20 cap.

 

I plugged the two tee openings with tee plugs with = windows.

 

The entire system is inside the enclosed pvc pipe to isolate = from air=20 currents.

 

All in all it work okay, I have recorded several earthquakes = with it, and=20 it seem to work as well as my other vertical.  They are posted on PSN as = TCIDzS     (z for = vertical S for=20 slinky)

 

I have a concept sketch and picts to send if = anyone is=20 interested.........I tried to post on the web. but had=20 problems.

 

Thanks,=20 Ted

Subject: Re: How Pivotal is the pivotal relationship? From: ChrisAtUpw@....... Date: Sat, 16 Jun 2007 23:38:46 EDT In a message dated 16/06/2007 22:13:22 GMT Daylight Time, Paulc@........ writes: Chris, I have changed from the ball bearing, with wire suspension to crossed cylinders for both the top and bottom bearing surfaces. The wire suspension seems to cause noise when ever the the frame was touched. I wanted to get rid of the resonance of the wire so both the horizontal boom, and the suspension are now tubes. No more rotational problem around the horizontal mass axis either. The last step was building the interface between the tubular suspension and the vertical support, so I could use the crossed cylinders there as well. Hi Paul, Sounds fine. The cylinders on the vertical support should be vertical. The arm carries the horizontal cylinders. This makes set up and operation much easier. You can buy solid tungsten carbide drills up to 1/8". The McMaster Carr pins are what John Cole uses. Twin tubes should give a rigid suspension. To get good performance out of a V suspension, the cable need to be fairly heavy. You just use the fine piano wire for the top 1/2". Regards, Chris Chapman
In a message dated 16/06/2007 22:13:22 GMT Daylight Time, Paulc@........ t=20 writes:
<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size= =3D2>
Chris,
I have changed from the ball bearing= , with=20 wire suspension to crossed cylinders for both the top and bottom bearing=20 surfaces.
The wire suspension seems to cause n= oise=20 when ever the the frame was touched.
I wanted to get rid of the resonance= of=20 the wire so both the horizontal boom, and the suspension are now=20 tubes.
No more rotational problem around th= e=20 horizontal mass axis either.
The last step was building the inter= face=20 between the tubular suspension and the vertical support, so I could use th= e=20 crossed cylinders there as well.
Hi Paul,
 
    Sounds fine. The cylinders on the vertical supp= ort=20 should be vertical. The arm carries the horizontal cylinders. This makes set= up=20 and operation much easier. You can buy solid tungsten carbide drills up to 1= /8".=20 The McMaster Carr pins are what John Cole uses.
 
    Twin tubes should give a rigid suspension.= To=20 get good performance out of a V suspension, the cable need to be fairly heav= y.=20 You just use the fine piano wire for the top 1/2".
 
    Regards,
 
    Chris Chapman
Subject: Is something cooking in Hawaii??? From: "Paul Cianciolo" Paulc@........ Date: Mon, 18 Jun 2007 18:54:37 -0400 Hello, Ok ... So what is going on in Hawaii? If you follow this link.... http://earthquake.usgs.gov/eqcenter/recenteqsww/Quakes/quakes_all.php And look at the previous 2 weeks of data, you can find a earth quake or two in there. Then look at the data from yesterday 6-17-07 and today 6-18-07. Over 50 on 6-17-07 alone? Is this normal? I have heard of earthquake clusters, but this?? Is there some volcanic action going on, or is it a big Luau ???? Maybe lava rolling into the sea. PauLC W1VLF
Hello,
 
Ok ...=20 So what is going on in Hawaii?
 
If you=20 follow this link....   http://earthquake.usgs.gov/eqcenter/recenteqsww/Quakes/quakes_all.p= hp
 
And=20 look at the previous 2 weeks of data, you can find a earth quake or two = in=20 there.
 
Then=20 look at the data from yesterday 6-17-07 and today = 6-18-07.
Over=20 50 on 6-17-07 alone?
 
Is=20 this normal?   I have heard of earthquake clusters, but=20 this??
 
Is=20 there some volcanic action going on, or is it a big Luau =20 ????
Maybe=20 lava rolling into the sea.
 
PauLC
W1VLF
 
 
 
Subject: Re: Is something cooking in Hawaii??? From: Terence Dowling dowling@......... Date: Mon, 18 Jun 2007 16:47:54 -0700 Paul Cianciolo wrote: > Hello, > > Ok ... So what is going on in Hawaii? > > If you follow this link.... > http://earthquake.usgs.gov/eqcenter/recenteqsww/Quakes/quakes_all.php > > And look at the previous 2 weeks of data, you can find a earth quake > or two in there. > > Then look at the data from yesterday 6-17-07 and today 6-18-07. > Over 50 on 6-17-07 alone? > > Is this normal? I have heard of earthquake clusters, but this?? See: http://volcano.wr.usgs.gov/hvostatus.php > > Is there some volcanic action going on, or is it a big Luau ???? > Maybe lava rolling into the sea. > > PauLC > W1VLF > > > -- Terence Dowling Senior Computer Scientist Adobe Systems Incorporated 345 Park Avenue, MS W08-508 San Jose, CA 95110-2704 USA 408.536.3856 phone, 408.537.4022 fax dowling@.........

Paul Cianciolo wrote:
Hello,
 
Ok ... So what is going on in Hawaii?
 
 
And look at the previous 2 weeks of data, you can find a earth quake or two in there.
 
Then look at the data from yesterday 6-17-07 and today 6-18-07.
Over 50 on 6-17-07 alone?
 
Is this normal?   I have heard of earthquake clusters, but this??
See:

         http://volcano.wr.usgs.gov/hvostatus.php
 
Is there some volcanic action going on, or is it a big Luau  ????
Maybe lava rolling into the sea.
 
PauLC
W1VLF
 
 
 

-- 
Terence Dowling
Senior Computer Scientist
Adobe Systems Incorporated
345 Park Avenue, MS W08-508
San Jose, CA 95110-2704 USA
408.536.3856 phone, 408.537.4022 fax
dowling@.........
Subject: RE: Is something cooking in Hawaii??? From: "Paul Cianciolo" Paulc@........ Date: Mon, 18 Jun 2007 19:51:51 -0400 Wow Terrence, OK Thanks for that link.. Great reading!! -----Original Message----- From: psn-l-request@.............. [mailto:psn-l-request@................. Behalf Of Terence Dowling Sent: Monday, June 18, 2007 7:48 PM To: psn-l@.............. Subject: Re: Is something cooking in Hawaii??? Paul Cianciolo wrote: Hello, Ok ... So what is going on in Hawaii? If you follow this link.... http://earthquake.usgs.gov/eqcenter/recenteqsww/Quakes/quakes_all.php And look at the previous 2 weeks of data, you can find a earth quake or two in there. Then look at the data from yesterday 6-17-07 and today 6-18-07. Over 50 on 6-17-07 alone? Is this normal? I have heard of earthquake clusters, but this?? See: http://volcano.wr.usgs.gov/hvostatus.php Is there some volcanic action going on, or is it a big Luau ???? Maybe lava rolling into the sea. PauLC W1VLF -- Terence Dowling Senior Computer Scientist Adobe Systems Incorporated 345 Park Avenue, MS W08-508 San Jose, CA 95110-2704 USA 408.536.3856 phone, 408.537.4022 fax dowling@.........
Wow  Terrence,
 
OK=20 Thanks for that link..
Great=20 reading!!
-----Original Message-----
From: = psn-l-request@................. [mailto:psn-l-request@...............On Behalf Of Terence=20 Dowling
Sent: Monday, June 18, 2007 7:48 PM
To:=20 psn-l@..............
Subject: Re: Is something cooking in=20 Hawaii???



Paul Cianciolo wrote:
Hello,
 
Ok=20 ... So what is going on in Hawaii?
 
If=20 you follow this link....   http://earthquake.usgs.gov/eqcenter/recenteqsww/Quakes/quakes_all.p= hp
 
And look at the previous 2 weeks of data, = you can=20 find a earth quake or two in there.
 
Then look at the data from yesterday = 6-17-07 and=20 today 6-18-07.
Over 50 on 6-17-07 = alone?
 
Is=20 this normal?   I have heard of earthquake clusters, but=20 = this??
See:

   &nbs= p;    =20 http://volcano.wr.usgs.= gov/hvostatus.php
 
Is=20 there some volcanic action going on, or is it a big Luau =20 ????
Maybe lava rolling into the=20 sea.
 
PauLC
W1VLF
 
 
 

--=20 Terence Dowling Senior Computer Scientist Adobe Systems Incorporated 345 Park Avenue, MS W08-508 San Jose, CA 95110-2704 USA 408.536.3856 phone, 408.537.4022 fax dowling@.........
Subject: Is this another case of "cut and paste" or earthquake frequencies From: "Paul Cianciolo" Paulc@........ Date: Wed, 20 Jun 2007 15:26:53 -0400 Guys, Gals, This might take a while to make my point, but I am going to try anyway. They say a turtle make no progress unless he sticks his head out of his shell. There are similarities between Radio wave propagation and say waves in a pool. IE the drop a stone into a pool and watch the omni directional waves propagate from the source. Does it seem to you that when "they" designed physics... the same principles got cut and pasted into different disciplines? Sound waves versus light waves, have similarities. Lots of disciplines deal with phase relationships, compression, dilatation, etc. Physical length of an object, the medium, the atmosphere its in, temperature etc. all play a role with a given object resonating. So... Here is one of my questions.. Is an earthquake an event that imparts a huge amount of energy in to the earth? For instance as a rubber mallet strikes a tuning fork? The fork resonates at it's fundamental freq. and harmonics etc. SO is the earth resonating with the impact of the rubber mallet earthquake? And it does this at frequencies of 1/50 of Hertz to say 10 Hertz or so. The earth is not a homogenous unit so there is probably all sorts of reflection and refraction going on internally. I want to try to apply some of the basic ideas from Radio Wave propagation for earthquake propagation. Boy, this is not making sense..... Better I should think about this more.. PauLC W1VLF __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Is this another case of "cut and paste" or earthquake frequencies From: ChrisAtUpw@....... Date: Wed, 20 Jun 2007 16:56:00 EDT In a message dated 20/06/2007, Paulc@........ writes: I want to try to apply some of the basic ideas from Radio Wave propagation for earthquake propagation. Boy, this is not making sense..... Hi Paul, Sound wave propagation in the Earth is more complex than radio waves in the Atmosphere. You have the two direct sound waves, the P or pressure waves for which the motion is in the direction of propagation and the S or shear waves for which the motion is perpendicular to the direction of propagation. These propagate from the quake in all directions, but S waves cannot travel through the Earth's liquid core. Whenever these are reflected or refracted by a layer which gives a sharp change in the refractive index (velocity), new pairs of waves types are generated. Then you have the Rayleigh surface waves for which the motion is vertical and the Love waves for which the motion is in the surface plane, both at right angles to the direction of propagation. These are generated by interactions with the P and S waves. Their amplitude can depend on the surface rocks and on resonance effects - like shaking a jelly. The 2D surface waves decrease in amplitude with distance at a lower rate than 3D body waves. The Earth's massive surface plates are in continual very slow motion. The rock deforms and strain energy is stored, until the local fracture stress is reached, when you get the sudden massive movement which we call an earthquake. You get a wide range of frequencies generated at the fracture site, but above about 2 Hz the sound waves are progressively absorbed, so what a distant observer sees depends on the distance, both vertically and horizontally. The relative amplitudes of the body and surface waves depend on the physical depth of the fracture. Since the surface waves are generated by the body waves, a very deep earthquake is likely to have low amplitude surface waves. The magnitude of a quake is related to the length of the fracture. The time taken for a quake to 'happen' is also related to the physical length. High magnitude quakes are long and 'slow'. Very large quakes generate many complex eigenmode (natural vibration mode) oscillations of the whole earth, which can be observed at very low frequencies. The lowest frequency is about 0.0003 Hz. These may continue for several days. Surface waves from large quakes can travel several times around the Earth. Internal body waves may also be reflected on the far side of the Earth. Go to _http://web.ics.purdue.edu/~braile/edumod/svintro/svintro.htmand_ (http://web.ics.purdue.edu/~braile/edumod/svintro/svintro.htmand) download and play Seisvole for several recorded examples of differing amplitude and depth. Regards, Chris Chapman
In a message dated 20/06/2007, Paulc@........ writes:
<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size= =3D2>I want=20 to try to apply some of the basic ideas from Radio Wave propagation
for= =20 earthquake propagation.

Boy, this is not making=20 sense.....
Hi Paul,
 
    Sound wave propagation in the Earth is more com= plex=20 than radio waves in the Atmosphere.
 
    You have the two direct sound waves, the P= or=20 pressure waves for which the motion is in the direction of propagation and t= he S=20 or shear waves for which the motion is perpendicular to the direction of=20 propagation. These propagate from the quake in all directions, but S wa= ves=20 cannot travel through the Earth's liquid core.
 
    Whenever these are reflected or refracted = by a=20 layer which gives a sharp change in the refractive index (velocity= ),=20 new pairs of waves types are generated.
 
    Then you have the Rayleigh surface waves for wh= ich=20 the motion is vertical and the Love waves for which the motion is in th= e=20 surface plane, both at right angles to the direction of propagation. Th= ese=20 are generated by interactions with the P and S waves. Their amplitude can de= pend=20 on the surface rocks and on resonance effects - like shaking a jelly.
 
    The 2D surface waves decrease in amplitude with= =20 distance at a lower rate than 3D body waves.  
 
    The Earth's massive surface plates are in conti= nual=20 very slow motion. The rock deforms and strain energy is stored, until the lo= cal=20 fracture stress is reached, when you get the sudden massive movement wh= ich=20 we call an earthquake. You get a wide range of frequencies generated at the=20 fracture site, but above about 2 Hz the sound waves are progressively absorb= ed,=20 so what a distant observer sees depends on the distance, both vertically and= =20 horizontally. The relative amplitudes of the body and surface waves depend o= n=20 the physical depth of the fracture. Since the surface waves are generated by= the=20 body waves, a very deep earthquake is likely to have low amplitude surface=20 waves.
    The magnitude of a quake is related to the leng= th=20 of the fracture. The time taken for a quake to 'happen' is also related to t= he=20 physical length. High magnitude quakes are long and 'slow'. 
 
    Very large quakes generate many complex eigenmo= de=20 (natural vibration mode) oscillations of the whole earth, which can be obser= ved=20 at very low frequencies. The lowest frequency is about 0.0003 Hz. These= may=20 continue for several days. 
    Surface waves from large quakes can travel seve= ral=20 times around the Earth. Internal body waves may also be reflected=20= on=20 the far side of the Earth.
 
    Go to htt= p://web.ics.purdue.edu/~braile/edumod/svintro/svintro.htmand=20 download and play Seisvole for several recorded examples of differing amplit= ude=20 and depth.
 
    Regards,
 
    Chris Chapman
 
 
Subject: Weather Noise From: "tchannel" tchannel@.............. Date: Wed, 20 Jun 2007 17:31:41 -0600 Hi All, Today in Boise, the weather noise on the sensor is very, very = bad. Over the last few days, is has not been good, but today it is = offal. I will check the weather summary tonight to see what has moved = into the valley. I live in a valley about 5 miles from the mountains, to the North. To = the South it is flat, East and West flat for many miles. I have heard that cold air can roll into the area, causing noise, and I = have seen that on the screen. I don't see wind, rain or things that you = would think would cause noise. Just fronts. Not winds. At night everything fall down to nothing, nice flat lines, but as soon = as the sun come up I get the noise. Most days its not too bad. I notice it more on a vertical sensor than a = horz sensor. I think, it is the air warming and moving down the valley and up into = the mountains, at night it stops. On cloudy days it less, but still noticeable, at night it is gone. Today it was sunny and partly cloudy, the clouds gathered over the = mountains as if it might rain up there. No wind or rain here, just a nice hot day. But the screen is a mess. Anyone live next to the mountain, with similar issues? Thanks, Ted
Hi All,  Today in Boise, the = weather noise on=20 the sensor is very, very bad.  Over the last few days, is has = not been=20 good, but today it is offal.   I will check the weather = summary=20 tonight to see what has moved into the valley.
 
I live in a valley about 5 miles from = the=20 mountains, to the North.  To the South it is flat, East and West = flat for=20 many miles.
I have heard that cold air can roll = into the area,=20 causing noise, and I have seen that on the screen.  I don't see = wind, rain=20 or things that you would think would cause noise.  Just = fronts.  Not=20 winds.
 
At night everything fall down to = nothing, nice flat=20 lines, but as soon as the sun come up I get the noise.
Most days its not too bad.  I = notice it more=20 on a vertical sensor than a horz sensor.
 
I think, it is the air warming and = moving down the=20 valley and up into the mountains, at night it stops.
On cloudy days it less, but still=20 noticeable, at night it is gone.
 
Today it was sunny and partly cloudy, = the clouds=20 gathered over the mountains as if it might rain up there.
No wind or rain here, just a nice hot=20 day.   But the screen is a mess.
 
Anyone live next to the mountain, with = similar=20 issues?
 
Thanks, Ted
 
Subject: Re: Weather Noise From: ChrisAtUpw@....... Date: Wed, 20 Jun 2007 21:22:30 EDT In a message dated 2007/06/21, tchannel@.............. writes: > At night everything fall down to nothing, nice flat lines, but as soon as > the sun come up I get the noise. > Most days its not too bad. I notice it more on a vertical sensor than a > horz sensor. Hi Ted, This sounds much more like convection noise due to air movement. What sorts of seismometer cases are you using? The recommended is 2" Celotex glued airtight with polyurethene foam grouting. This thick board has a polystyrene core covered by glass scrim and Al foil. You can add double layer mylar windows. You buy clear copy film for use with laser printers. See http://pages.prodigy.net/fxc/seiscoverslg.jpg Regards, Chris Chapman In a me= ssage dated 2007/06/21, tchannel@.............. writes:

At night everything fall down t= o nothing, nice flat lines, but as soon as the sun come up I get the noise.<= /FONT>=
Most days its not too bad.  I notice it more on a vertical sensor than= a horz sensor.


Hi Ted,

       This sounds much more like convection n= oise due to air movement. What sorts of seismometer cases are you using? The= recommended  is 2" Celotex glued airtight with polyurethene foam grout= ing. This thick board has a polystyrene core covered by glass scrim and Al f= oil. You can add double layer mylar windows. You buy clear copy film for use= with laser printers.
       See http://pages.prodigy.net/fxc/seisco= verslg.jpg

       Regards,

       Chris Chapman Subject: Re: Weather Noise From: "tchannel" tchannel@.............. Date: Wed, 20 Jun 2007 21:35:54 -0600 Hi Chris, Yes it would seem so.....and I have seen just that = phenomenon, before and after enclosing my first sensor. The enclosure = made a big different. However This occurs mostly on my enclosed = verticals, a little bit on the Horz. All three operate in the same = room. All three are fully enclosed. The room does not vary in temp. much at all. It is a basement living = area and stays about 68 day and night. The room might vary 5 degrees. I = have even put a heater in the room to raise the temp. with no affect on = the noise. Also a fan in the room, with no increase in noise. The noise = is timed perfectly with the rising and setting of the sun, it starts = with the sun rise, 7:00am, and ends at 4:00pm. =20 Most days, it is noticeable, but not problematic. Today it was quiet a = mess. Today's temp was 94, and a weather front moving thru. Tomorrow = will be hot, but with a high pressure area. I will see if the = pattern changes. The temp should change in a few days, so I will see if it is temperature = related. Thanks, Ted ----- Original Message -----=20 From: ChrisAtUpw@.......... To: psn-l@................. Sent: Wednesday, June 20, 2007 7:22 PM Subject: Re: Weather Noise In a message dated 2007/06/21, tchannel@.............. writes: At night everything fall down to nothing, nice flat lines, but as = soon as the sun come up I get the noise. Most days its not too bad. I notice it more on a vertical sensor = than a horz sensor. Hi Ted, This sounds much more like convection noise due to air = movement. What sorts of seismometer cases are you using? The recommended = is 2" Celotex glued airtight with polyurethene foam grouting. This = thick board has a polystyrene core covered by glass scrim and Al foil. = You can add double layer mylar windows. You buy clear copy film for use = with laser printers.=20 See http://pages.prodigy.net/fxc/seiscoverslg.jpg=20 Regards, Chris Chapman
Hi Chris,   Yes it would seem = so.....and=20 I have seen just that phenomenon, before and after enclosing my first=20 sensor.  The enclosure made a big different.   However = This=20 occurs mostly on my enclosed verticals, a little bit on the=20 Horz.  All three operate in the same room.  All three are = fully=20 enclosed.
  The room does not vary in temp. = much at=20 all.  It is a basement living area and stays about 68 day and=20 night. The room might vary 5 degrees.  I have even put a = heater=20 in the room to raise the temp. with no affect on the noise. Also a fan = in the=20 room, with no increase in noise. The noise is timed perfectly with = the=20 rising and setting of the sun,  it starts with the sun rise, = 7:00am, and=20 ends at 4:00pm.  
 
Most days, it is noticeable, but not=20 problematic.   Today it was quiet a mess.  Today's temp = was 94,=20 and a weather front moving thru.    Tomorrow = will be=20 hot, but with a high pressure area.     I will see = if the=20 pattern changes.
The temp should change in a few days, = so I will see=20 if it is temperature related.
 
Thanks, Ted
 
 
----- Original Message -----
From:=20 ChrisAtUpw@.......
Sent: Wednesday, June 20, 2007 = 7:22=20 PM
Subject: Re: Weather = Noise

In a=20 message dated 2007/06/21, tchannel@..............=20 writes:

At night everything fall down to nothing, nice flat = lines, but=20 as soon as the sun come up I get the noise.
Most days its = not too=20 bad.  I notice it more on a vertical sensor than a horz=20 sensor.

Hi=20 Ted,

       This sounds much more = like=20 convection noise due to air movement. What sorts of seismometer cases = are you=20 using? The recommended  is 2" Celotex glued airtight with = polyurethene=20 foam grouting. This thick board has a polystyrene core covered by = glass scrim=20 and Al foil. You can add double layer mylar windows. You buy clear = copy film=20 for use with laser printers.
       = See=20 http://pages.prodigy.net/fxc/seiscoverslg.jpg=20

      =20 Regards,

       Chris = Chapman=20 Subject: GEOTECH TELDYNE 1051 VARIABLE RELUCTANCE SEISMOMETER From: Jan Froom JDarwin@............. Date: Thu, 21 Jun 2007 19:34:56 -0700 Kind of sad to see a GEOTECH TELDYNE 1051 VARIABLE RELUCTANCE VERTICAL SEISMOMETER... all rusty and laying on its side... on e-bay $500 bucks... plus shipping. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: GEOTECH TELDYNE 1051 VARIABLE RELUCTANCE SEISMOMETER From: ChrisAtUpw@....... Date: Thu, 21 Jun 2007 23:04:53 EDT In a message dated 2007/06/22, JDarwin@............. writes: > < > http://cgi.ebay.com/GEOTECH-TELDYNE-1051-VARIABLE-RELUCTANCE-SEISMOMETER_W0QQitemZ7612230484QQihZ017QQcategoryZ1504QQrdZ1QQssPageNameZWD1VQQcmdZViewItem > > > $500 bucks... plus shipping. Think of a silly price and hope that some mug will pay it - the whole website seems overpriced. Remember that you would be buying SCRAP METAL! Regards, Chris In a me= ssage dated 2007/06/22, JDarwin@............. writes:

<http://cgi.ebay.com/GEOTECH= -TELDYNE-1051-VARIABLE-RELUCTANCE-SEISMOMETER_W0QQitemZ7612230484QQihZ017QQc= ategoryZ1504QQrdZ1QQssPageNameZWD1VQQcmdZViewItem> 
$500 bucks... plus shipping.


       Think of a silly price and hope that so= me mug will pay it - the whole website seems overpriced.
       Remember that you would be buying SC= RAP METAL!

       Regards,

       Chris Subject: Re: GEOTECH TELDYNE 1051 VARIABLE RELUCTANCE SEISMOMETER From: "Jerry Payton" gpayton880@....... Date: Thu, 21 Jun 2007 22:11:36 -0500 Come on, Chris! That is a 250 lbs. Boat Anchor. Regards, Jerry ----- Original Message ----- From: ChrisAtUpw@....... To: psn-l@.............. Sent: Thursday, June 21, 2007 10:04 PM Subject: Re: GEOTECH TELDYNE 1051 VARIABLE RELUCTANCE SEISMOMETER In a message dated 2007/06/22, JDarwin@............. writes: $500 bucks... plus shipping. Think of a silly price and hope that some mug will pay it - the whole website seems overpriced. Remember that you would be buying SCRAP METAL! Regards, Chris
Come on, Chris!  That is a 250 lbs. Boat Anchor.
 
Regards,
Jerry
----- Original Message -----
From:=20 ChrisAtUpw@.......
Sent: Thursday, June 21, 2007 = 10:04=20 PM
Subject: Re: GEOTECH TELDYNE = 1051=20 VARIABLE RELUCTANCE SEISMOMETER

In a=20 message dated 2007/06/22, JDarwin@............. = writes:

<http://cgi.ebay.com/GEOTECH-TELDYNE-1051-VARIABLE-RELUCTA= NCE-SEISMOMETER_W0QQitemZ7612230484QQihZ017QQcategoryZ1504QQrdZ1QQssPageN= ameZWD1VQQcmdZViewItem> =20
$500 bucks... plus=20 shipping.

       = Think of a=20 silly price and hope that some mug will pay it - the whole website = seems=20 overpriced.
       Remember that = you=20 would be buying SCRAP = METAL!

      =20 Regards,

       Chris=20 Subject: Re: Predictions From: "James L. Gundersen" jgundie@....... Date: Sat, 23 Jun 2007 06:33:39 -0700 Hi, Going through mail I had not read. Though you might wish to try 9:00 PM = for the Jan 26, 1700 time. = http://alt.pep.sfu.ca/cascadia_1700/cascadia_1700.html I believe this time was derived from records of the tsunamis that hit = Japan.=20 Jim PS My thoughts are the earth tides will trigger some earthquakes but not = all. The direct change in acceleration is relatively small (3 E-7 g's = max ??) from the moon and sun but the forces associated with a shift in = a large body of water (tide) I would think are a significant factor = along with perhaps the relative direction and distance from the "ocean" = for the fault. ----- Original Message -----=20 From: Stephen & Kathy=20 To: psn-l@................. Sent: Friday, April 20, 2007 11:12 PM Subject: Re: Predictions FYI,, Following this little introduction, is a simple study I did a = few years ago!! Since then I have tried to correlate the events to = Solid Earth Tide,,, so far I have found no correlation!! My = conclusion at this point is that I think there may be a moon and or sun = tide connection, but like trying to predict the position in the bending = cycle where a wire will finally break, that you bend with your fingers, = there appears to be a similar problem with trying to tie a tidal phase = point to quakes???? It simply breaks when it is ready, no matter where = in the tidal cycle of bending it happens to be???? The complexity of = water tides may also contribute to the problem for events that happen in = the vicinity of ocean tides????? The reason I feel that there may be a = phase connection, becomes clear from the following study where we see = that the time of the new moon, where we have the greatest tidal motion, = also favors the greatest number of quakes?????? I am open to = correction, other studies, other data, and or other conclusions!!!! Stephen PSN Station #55 Subject: Large quakes (mag. 8 and above) and their relationship to Moon phases, = using data found over the web at the following links: http://en.wikipedia.org/wiki/List_of_earthquakes = http://www.fourmilab.ch/cgi-bin/uncgi/Earth/action?opt=3D-m&img=3DMoon.ev= if Using the top link to find quake times and mag., then using the bottom = link to compare them to moon phases, I found 38 quakes of mag. 8 or = greater since 1556, of which I used 35 because the first three did not = have times listed. Where local times were listed I converted them to = UTC time for compatibility with the Moon phase link. After finding the data, the next problem is determining how to = illustrate it with statistics! Statistics can be used in many ways to = manipulate data! Do we use only one or two days around the new and = full moon and compare that to the total, or should we divide it into = approx. 4 equal quadrants? For my simple analysis I will use 4 = quadrants. The moon link above uses approx. 29.4 days for a complete = cycle, so I will use approx. 7.35 days per quadrant, which when related = to the phases works out to about the following: New moon quadrant equals 0 to 15 % Full moon quadrant equals 85 to 100 % first and last quarter quadrant equals 16 to 86 % When we sort the 35 phase data into their quadrants we get the = following: Quakes during New moon =3D 15 Quakes during Full moon =3D 7 Quakes during First & Last quarter =3D 13 When we combine the New and Full quarters to compare with First and = Last quarters we get: Quakes during New & Full moon =3D 22 Conclusion: The New moon quadrant favors the Full moon quadrant by a little more = than double! The combined New and Full quadrants favor the First and Last quadrants = by not quite double! Interesting!!!!! I was led to believe that there was no statistical = correlation between quakes and Moon phases??? Perhaps if we added = the mag. 6 and 7 quakes we would find different conclusions,,,, that = is for someone else to do!!! List of mag. 8 quakes or greater,, With percent of Moon Phase listed 0% =3D New Moon, 100% =3D Full Moon, 50% =3D either First or Last = Quarter Please forgive any TYPOs=20 # Moon Year Mo. Day UTC Place Approx. Phase Time Mag. 1 ??% 1556 Jan. 23 ?? China 8 2 ??% 1668 Aug. 17 ?? Turkey 8 3 ??% 1700 Jan. 26 ?? Vancouver 9 ************************************************ 4 10% 1755 Nov. 1 10:16 Portugal 8.7 5 0% 1811 Dec. 16 08:00 Missouri 8.1 6 33% 1812 Feb. 7 09:45 Missouri 8 7 43% 1855 Jan. 24 10:11 New Zealand 8 8 20% 1891 Oct. 27 21:38 Japan 8 9 21% 1896 Jun. 15 19:32 Japan 8.5 10 91% 1897 Jun. 12 11:06 India 8.3 11 29% 1899 Sep. 10 21:41 Alaska 8 12 8% 1905 Jul. 5 09:40 Mongolia 8.4 13 41% 1906 Jan. 31 15:36 Colombia 8.8 14 9% 1906 Aug. 17 00:40 Chile 8.2 15 29% 1920 Dec. 16 12:05 China 8.6 16 34% 1933 Mar. 2 17:31 Japan 8.4 17 0% 1934 Jan. 15 08:43 India 8.1 18 88% 1938 Nov. 10 20:18 Alaska 8.2 19 54% 1944 Dec. 7 04:35 Japan 8.1 20 48% 1946 Aug. 4 17:51 Dom. Repub. 8.0 21 6% 1946 Dec. 20 19:19 Japan 8.1 22 5% 1949 Aug. 22 04:01 Q. Charlo. Is. 8.1 23 4% 1950 Aug. 15 14:09 Tibet 8.6 24 91% 1952 Nov. 4 16:58 Russia 9 25 51% 1957 Mar. 9 14:22 Alaska 9.1 26 90% 1957 Dec. 4 03:37 Mongolia 8.1 27 6% 1960 May 22 19:11 Chile 9.5 28 99% 1964 Mar. 28 03:36 Alaska 9.2 29 5% 1965 Feb. 4 05:01 Alaska 8.7 30 2% 1970 Jul. 31 17.08 Colombia 8 31 28% 1985 Sep. 19 13:17 Mexico 8 32 0% 1986 May 7 22:47 Alaska 8 33 0% 1994 Jun. 9 00:33 Bolivia 8.2 34 76% 2000 Nov. 16 04:54 New Ireland 8 35 7% 2001 Jun. 23 20:33 Peru 8.4 36 0% 2003 Sep. 25 19:50 Japan 8.3 37 91% 2004 Dec. 23 14:59 Macquarie 8.1 38 99% 2004 Dec. 26 00:59 Sumatra 9.0 tchannel wrote:=20 Hi Folks, Just curious about the subject of Earthquake Predictions. = We all can predict earthquakes, if we keep the "when" and "where" = nonspecific. But on a serious note, are there any scientific tools = used? Do the phases of the moon and the tides play a part? I have = asked this question to several people and received just as many = opinions. Thanks, Ted
Hi,
 
Going through mail I had not = read.  Though you=20 might wish to try 9:00 PM for the Jan 26, 1700 time.  http://al= t.pep.sfu.ca/cascadia_1700/cascadia_1700.html
I believe this time was derived = from records=20 of the tsunamis that hit Japan. 
 
Jim
 
PS My thoughts are the earth tides will = trigger=20 some earthquakes but not all.  The direct change in acceleration is = relatively small (3 E-7 g's max ??) from the moon and sun but the forces = associated with a shift in a large body of water (tide) I would = think are=20 a significant factor along with perhaps the relative direction and = distance=20 from the "ocean" for the fault.
----- Original Message -----
From:=20 Stephen &=20 Kathy
Sent: Friday, April 20, 2007 = 11:12=20 PM
Subject: Re: Predictions

FYI,,  Following this = little=20 introduction, is a simple study I did a few years ago!!   = Since then=20 I have tried to correlate the events to Solid Earth = Tide,,,   so far=20 I have found no correlation!!    My conclusion at this point = is that=20 I think there may be a moon and or sun tide connection, but like = trying to=20 predict the position in the bending cycle where a wire will finally = break,=20 that you bend with your fingers, there appears to be a similar problem = with=20 trying to tie a tidal phase point to quakes????  It simply breaks = when it=20 is ready, no matter where in the tidal cycle of bending it happens to = be????=20   The complexity of water tides may also contribute to the = problem for=20 events that happen in the vicinity of ocean tides?????   The = reason=20 I feel that there may be a phase connection, becomes clear from the = following=20 study where we see that the time of the new moon, where we have the = greatest=20 tidal motion, also favors the greatest number of=20 quakes??????    I am open to correction, other studies, = other=20 data, and or other conclusions!!!!
  Stephen
  PSN = Station=20 #55


Subject:
Large quakes (mag. 8 and = above) and=20 their relationship to Moon phases, using data found over the web at = the=20 following links:

http://en.wikip= edia.org/wiki/List_of_earthquakes

http://www.fourmilab.ch/cgi-bin/uncgi/Earth/action?opt=3D= -m&img=3DMoon.evif

Using=20 the top link to find quake times and mag., then using the bottom link = to=20 compare them to moon phases, I found 38 quakes of mag. 8 or greater = since=20 1556, of which I used 35 because the first three did not have times=20 listed.  Where local times were listed I converted them to UTC = time for=20 compatibility with the Moon phase link.

After finding the data, = the=20 next problem is determining how to illustrate it with = statistics! =20 Statistics can be used in many ways to manipulate data!   Do = we use=20 only one or two days around the new and full moon and compare that to = the=20 total, or should we divide it into approx. 4 equal = quadrants?   For=20 my simple analysis I will use 4 quadrants.   The moon link = above=20 uses approx. 29.4 days for a complete cycle, so I will use approx. = 7.35 days=20 per quadrant, which when related to the phases works out to about the=20 following:
New moon quadrant=20 = equals           &= nbsp;     =20 0 to 15 %
Full moon quadrant=20 = equals           &= nbsp;    =20 85 to 100 %
first and last quarter quadrant = equals    16 to=20 86 %
When we sort the 35 phase data into their quadrants we get the = following:
Quakes during New=20 = moon           &nb= sp;  =20 =3D   15
Quakes during Full=20 = moon           &nb= sp; =20 =3D    7
Quakes during First & Last = quarter  =20 =3D   13
When we combine the New and Full quarters to = compare with=20 First and Last quarters we get:
Quakes during New & Full=20 moon        =3D  =20 22
Conclusion:
The New moon quadrant favors the Full moon = quadrant by a=20 little more than double!
The combined New and Full quadrants favor = the=20 First and Last quadrants by not quite=20 double!
Interesting!!!!!    I was led to believe = that there=20 was no statistical correlation between quakes and Moon=20 phases???     Perhaps if we added the mag. 6 and 7 = quakes=20 we would find different conclusions,,,,   that is for = someone else=20 to do!!!

List of mag. 8 quakes or greater,,   With = percent of=20 Moon Phase listed
0% =3D New Moon,  100% =3D Full = Moon,   =20 50% =3D either First or Last=20 = Quarter
          &n= bsp;           &nb= sp;=20 Please forgive any TYPOs

 #   Moon =20 Year    Mo.  Day   =20 UTC     =20 Place       =20 Approx.
    =20 = Phase           &n= bsp;        =20 = Time           &nb= sp;       =20 Mag.
 1    ??%   1556  = Jan.  =20 23     ??     =20 China          =20 8
 2    ??%   1668  = Aug.  =20 17     ??     =20 Turkey         =20 8
 3    ??%   1700  = Jan.  =20 26     ??     =20 Vancouver      =20 = 9
************************************************
 4 &nb= sp; =20 10%   1755   Nov.   1   =20 10:16    = Portugal       =20 8.7
 5     0%   1811   = Dec.  16    08:00   =20 Missouri       =20 8.1
 6    33%   1812  =20 Feb.   7    09:45   =20 Missouri       =20 8
 7    43%   1855   = Jan. =20 24    10:11    New=20 Zealand     8
 8    = 20%  =20 1891   Oct.  27    = 21:38   =20 Japan          =20 8
 9    21%   1896   = Jun. =20 15    19:32   =20 Japan          =20 8.5
10    91%   1897   = Jun. =20 12    11:06   =20 India          =20 8.3
11    29%   1899   = Sep. =20 10    21:41   =20 Alaska         =20 8
12     8%   1905  =20 Jul.   5    09:40   =20 Mongolia        = 8.4
13   =20 41%   1906   Jan.  31   =20 15:36    = Colombia       =20 8.8
14     9%   1906   = Aug. =20 17    00:40   =20 Chile          =20 8.2
15    29%   1920   = Dec. =20 16    12:05    China=20          =20 8.6
16    34%   1933   = Mar.  =20 2    17:31   =20 Japan          =20 8.4
17     0%   1934   = Jan. =20 15    08:43   =20 India          =20 8.1
18    88%   1938   = Nov. =20 10    20:18   =20 Alaska         =20 8.2
19    54%   1944   = Dec.  =20 7    04:35   =20 Japan          =20 8.1
20    48%   1946   = Aug.  =20 4    17:51    Dom.=20 Repub.     8.0
21    =20 6%   1946   Dec.  20   =20 19:19   =20 Japan          =20 8.1
22     5%   1949   = Aug. =20 22    04:01    Q. Charlo. Is. =20 8.1
23     4%   1950   = Aug. =20 15    14:09   =20 Tibet          =20 8.6
24    91%   1952   = Nov.  =20 4    16:58   =20 Russia         =20 9
25    51%   1957   = Mar.  =20 9    14:22   =20 Alaska         =20 9.1
26    90%   1957   = Dec.  =20 4    03:37   =20 Mongolia       =20 8.1
27     6%   1960  =20 May   22    19:11   =20 Chile          =20 9.5
28    99%   1964   = Mar. =20 28    03:36   =20 Alaska         =20 9.2
29     5%   1965  =20 Feb.   4    05:01   =20 Alaska         =20 8.7
30     2%   1970   = Jul. =20 31    17.08   =20 Colombia        = 8
31   =20 28%   1985   Sep.  19   =20 13:17   =20 Mexico         =20 8
32     0%   1986  =20 May    7    22:47   =20 Alaska         =20 8
33     0%   1994  =20 Jun.   9    00:33   =20 Bolivia        =20 8.2
34    76%   2000   = Nov. =20 16    04:54    New=20 Ireland     8
35     = 7%  =20 2001   Jun.  23    = 20:33   =20 Peru            = 8.4
36     0%   2003   = Sep. =20 25    19:50   =20 Japan          =20 8.3
37    91%   2004   = Dec. =20 23    14:59   =20 Macquarie       = 8.1
38   =20 99%   2004   Dec.  26   =20 00:59   =20 Sumatra        =20 9.0


tchannel wrote:=20
Hi Folks,  Just curious about = the subject=20 of Earthquake Predictions.   We all can predict = earthquakes, if we=20 keep the "when" and "where" nonspecific.   But on a = serious=20 note, are there any scientific tools used?   Do the = phases of=20 the moon and the tides play a part?   I have asked this = question=20 to several people and received just as many opinions.
 
Thanks,=20 Ted
Subject: Lehman advantages From: "tchannel" tchannel@.............. Date: Sun, 24 Jun 2007 09:54:20 -0600 Hi Folks, I am thinking about building another Lehman style Horz = Pendulum sensor. I don't really need to build another, but I have some construction ideas I wanted to try. Before I start, = could you describe the benefits of these points. 1 FIRMLY ATTACHED THE SENSOR THE THE EARTH. I wish to make the contact = between the earth, and the sensor as firm as possible, in this case the = concrete slab setting on the earth and the sensor. Presently the = sensor has three feet which just set on the concrete slab. I know some = people use adhesive to the concrete. If I found a way to bolt all three = feet into the concrete, and a new way to make the necessary adjustments, = what benefits would be derived? I understand that even the concrete floor floats on the earth. I am = just talking about the benefits of a tighter connection between the = sensor and the floor. 2 A RIDGED VERTICAL SUPPORT FOR THE UPRIGHT. I know that on a typical = Lehman the vertical needs to be ridged and minimize the flex between the = vertical and the horz members. If I found a way to minimize this flex, = what benefits might I see? The one I have has no flex that I can see, = but If I added addition braces so the vertical was at 90 to the horz = with the minimum of flex, What benefit would there be? 3 USING A LONGER ARM. I used a normal length arm, and I understand if = space was not an issue a very long 100 meters arm would result in a = longer period. I am just asking if space was avail would a 5 foot arm = result in any benefits, over a 3 foot arm? The last question is, if I had a sensor which was firmly attached to the = floor, with a very ridged vertical, and a longer arm. (with all the other important factors aside) What kind of improvements = might I expect? I think I could build a new and improved sensor, = addressing these three issues. But would these three issues make much = different. If I would, see improvements would they only be for = teleseimic events, or would the improvements be evident in recording = regional as well. Thanks, Ted
Hi Folks,  I am thinking about = building=20 another Lehman style Horz Pendulum sensor.  I don't really need to=20 build another,
but I have some construction ideas I = wanted to=20 try.  Before I start, could you describe the benefits of these=20 points.
 
1 FIRMLY ATTACHED THE SENSOR THE = THE=20 EARTH.   I wish to make the contact between the earth, and the = sensor=20 as firm as possible, in this case the concrete slab setting on the = earth=20 and the sensor.   Presently the sensor has three feet which = just set=20 on the concrete slab. I know some people use adhesive to the = concrete.=20  If I found a way to bolt all three feet into the concrete, and a = new way=20 to make the necessary adjustments, what benefits would be = derived?
I understand that even the concrete = floor floats on=20 the earth.  I am just talking about the benefits of a tighter = connection=20 between the sensor and the floor.
 
2 A RIDGED VERTICAL SUPPORT FOR THE = UPRIGHT. =20 I know that on a typical Lehman the vertical needs to be ridged and = minimize the=20 flex between the vertical and the horz members.   If I found a = way=20 to minimize this flex, what benefits might I see?  The = one I have=20 has no flex that I can see, but If I added addition braces so the = vertical was=20 at 90 to the horz with the minimum of flex, What benefit would there=20 be?
 
3 USING A LONGER ARM.  I = used  a normal=20 length arm, and I understand if space was not an issue a very long 100 = meters=20 arm would result in a longer period.  I am just asking if space was = avail=20 would a 5 foot arm result in any benefits, over a 3 foot = arm?
 
The last question is, if I had a sensor = which was=20 firmly attached to the floor, with a very ridged vertical, and a longer=20 arm.
(with all the other important factors = aside) What=20 kind of improvements might I expect?  I think I could = build a new=20 and improved sensor, addressing these three issues.  But would = these three=20 issues make much different.  If I would, see improvements would = they only=20 be for teleseimic events, or would the improvements be evident in = recording=20 regional as well.
 
Thanks, Ted
Subject: Re: Lehman advantages From: ChrisAtUpw@....... Date: Sun, 24 Jun 2007 17:46:42 EDT In a message dated 2007/06/24, tchannel@.............. writes: > Subj:Lehman advantages > > Hi Folks, I am thinking about building another Lehman style Horz Pendulum > sensor. I have some construction ideas I wanted to try. Before I start, could > you describe the benefits of these points. > > 1 FIRMLY ATTACHED THE SENSOR THE EARTH. I wish to make the contact between > the earth, and the sensor as firm as possible, in this case the concrete slab > setting on the earth and the sensor. Presently the sensor has three feet > which just set on the concrete slab. I know some people use adhesive to the > concrete. If I found a way to bolt all three feet into the concrete, and a new > way to make the necessary adjustments, what benefits would be derived? > I understand that even the concrete floor floats on the earth. I am just > talking about the benefits of a tighter connection between the sensor and the > floor. Hi Ted, Bolting the seismometer mounts to the floor may give problems when the seismometer expands with temperature at a different rate or at a different time to the floor. They are very unlikely to match. I use three 2" square x 1/8" SS squares glued to the concrete floor. You can also use >5mm glass or even glazed tiles. The benefit is that you have a grit free, dead flat surface. Your level settings should not show drift either with temperature or over time, or be effected by large quakes. You can use pool cement to glue the plates. The mounting bolts need to be rigidly attached to the frame. To avoid thermal drift, I glue SS nuts to the underside of the arm with acrylic glue. On top of the arm I glue a 1/2" SS tube pillar and add a wavy washer. The SS set bolt has a SS ball bearing glued to a V in the end, to provide a central rotating contact with mounting plate. The set bolt also has a nut at the top end. After setting the correct height, I partly compress the wavy washer with the top nut. This keeps the thread in tension. The vertical alignment / side slop is controlled by the SS pillar and the tension. > 2 A RIGID VERTICAL SUPPORT FOR THE UPRIGHT. I know that on a typical > Lehman the vertical needs to be rigid and minimise the flex between the vertical > and the horz members. If I found a way to minimise this flex, what benefits > might I see? The one I have has no flex that I can see, but If I added > addition braces so the vertical was at 90 to the horz with the minimum of flex, > What benefit would there be? The vertical and horizontal arms need to be connected quite rigidly. This can be done conveniently with large triangular reinforcing plates at the T joint or ~ 45 deg bracing members to both the main beam and to the cross beam. This will minimise any cross alignment drift and tend to suppress arm oscillations, due to the vertical + arm + mass flexing. Unless you do this you are likely to pick up spurious resonant signals. The original Lehman design was inadequate in this respect. Thump the mass vertically and what do you see on the output? You need to eliminate any oscillations. > 3 USING A LONGER ARM. I used a normal length arm, and I understand if > space was not an issue a very long 100 meters arm would result in a longer > period. I am just asking if space was avail would a 5 foot arm result in any > benefits, over a 3 foot arm? You can provide reasonable temperature and air motion control for a 2 to 3 ft arm, but not for anything much larger. A 1 m long pendulum has a period of about 2 sec. To get a 4 sec period you need a 4 m pendulum. A 20 sec period would require a 100m pendulum. The main factor you need to consider is the ratio between the natural period of an arm of length L and the desired seismometer period - the 1/sinA factor. If you try to get greater than x10 period extension, A becomes a very small angle. You may need fine thread adjustment screws or a slow motion drive. A folded pendulum design is likely to be more satisfactory / easier to construct for mechanical periods over about 30 sec. An alternative method is to provide position and velocity force feedback to stabilise the position of the arm, but the electronics gets more complicated. Using electronic feedback control can run into noise and stability problems, but you can turn a 20 sec pendulum into a 200 sec sensor. See http://www.keckec.com/seismo/ What period do you want? The Rayleigh and Love surface waves tend to have periods of about 20 seconds and few are over 40 sec. For very long extension periods you need to measure the position of the arm, not it's velocity, or you just see noise. > The last question is, if I had a sensor which was firmly attached to the > floor, with a very ridged vertical, and a longer arm. > (with all the other important factors aside) What kind of improvements might > I expect? I think I could build a new and improved sensor, addressing these > three issues. But would these three issues make much different. If I > would, see improvements would they only be for teleseismic events, or would the > improvements be evident in recording regional as well. You should see the true ground motion. There should be NO artefacts from the apparatus. You are more likely to be bothered by short period signals, but the P and S waves that you want to detect are above 0.5 Hz, often 1 to 5 Hz. Remember that IT IS THE EARTH WHICH MOVES ---> NOT THE SEISMOMETER ARM !! You have missed out some important considerations. You need to suppress, damp, or be insensitive to the natural oscillations / modes of the apparatus. Earthquakes are transient pulse type signals and can excite any natural oscillation modes. The arm and the suspension need to be rigid. The arm should be prevented from rotating around it's long axis. There will inevitably be some vertical bounce at the end of the arm, but the frequency should be above that of the low pass electronic filter and the sensor should be designed to have a low sensitivity to vertical motion. You also need to design the sensor to have a constant and linear sensor voltage output for mass position drifts of ~ +/-1/2". You ALWAYS get some position drift with a Lehman. They are very sensitive to tiny shifts in the local ground plane due to temperature, rain and seasonal changes. You need NdFeB bar magnets and rectangular coils to do this, or alternatively long cylindrical coils with many turns + magnets, similar to a loudspeaker, but with clearance gaps and coil lengths which allow for a 1/2" mass drift. The damping force should act ~on the line between the centre of mass and the lower bearing, otherwise it will try to rotate the arm about it's long axis. Also, place the centre of the pickup coil close to this axis. Have a look at http://jclahr.com/science/psn/chapman/school/MKII/index.html The top wire suspension was changed to either a V cable or to a 1/2" tube. Both worked OK. Both hinges were altered to be crossed rods, although a ball on a plane works equally well. You mount the vertical rods or balls on the vertical support column, NOT on the arm. The horizontal rods or the flats are mounted on the moving arm. Also have a look at the Sprengnether at http://www.geocities.com/meredithlamb/ Have a look at 416 SS 'shoulder screws' 93985A205 or similar from www.mcmaster.com. Alternatively, buy solid tungsten carbide drills and use the shank. They are sold for drilling fibreglass circuit board and other hard materials. See www.DigiKey.com or www.smallparts.com. Smallparts also sell bearings. You can buy flat triangular Tungsten Carbide tips for lathe tools quite cheaply with ~ 0.3" sides. Alternatively, you can use a bit of a SS knife blade glued to the end of the arm. Regards, Chris Chapman In a me= ssage dated 2007/06/24, tchannel@.............. writes:

Subj:Lehman advantages <= BR>
Hi Folks, I am thinking about building another Lehman style Horz Pendulum se= nsor.  I have some construction ideas I wanted to try.  Before I s= tart, could you describe the benefits of these points.

1 FIRMLY ATTACHED THE SENSOR THE EARTH.  I wish to make the contact be= tween the earth, and the sensor as firm as possible, in this case the concre= te slab setting on the earth and the sensor.  Presently the sensor has=20= three feet which just set on the concrete slab. I know some people use adhes= ive to the concrete.  If I found a way to bolt all three feet into the=20= concrete, and a new way to make the necessary adjustments, what benefits wou= ld be derived?
I understand that even the concrete floor floats on the earth.  I am j= ust talking about the benefits of a tighter connection between the sensor an= d the floor.


Hi Ted,

    Bolting the seismometer mounts to the floor may give pro= blems when the seismometer expands with temperature at a different rate or a= t a different time to the floor. They are very unlikely to match.

       I use three 2" square x 1/8" SS squares= glued to the concrete floor. You can also use >5mm glass or even glazed=20= tiles. The benefit is that you have a grit free, dead flat surface. Your lev= el settings should not show drift either with temperature or over time, or b= e effected by large quakes. You can use pool cement to glue the plates.

       The mounting bolts need to be rigidly a= ttached to the frame. To avoid thermal drift, I glue SS nuts to the undersid= e of the arm with acrylic glue. On top of the arm I glue a 1/2" SS tube pill= ar and add a wavy washer. The SS set bolt has a SS ball bearing glued to a V= in the end, to provide a central rotating contact with mounting plate. The=20= set bolt also has a nut at the top end. After setting the correct height, I=20= partly compress the wavy washer with the top nut. This keeps the thread in t= ension. The vertical alignment / side slop is controlled by the SS pillar an= d the tension.

2 A RIGID VERTICAL SUPPORT FO= R THE UPRIGHT.  I know that on a typical Lehman the vertical needs to b= e rigid and minimise the flex between the vertical and the horz members.&nbs= p; If I found a way to minimise this flex, what benefits might I see? =20= The one I have has no flex that I can see, but If I added addition braces so= the vertical was at 90 to the horz with the minimum of flex, What benefit w= ould there be?


       The vertical and horizontal arms need=20= to be connected quite rigidly. This can be done conveniently with large tria= ngular reinforcing plates at the T joint or ~ 45 deg bracing members to both= the main beam and to the cross beam. This will minimise any cross alignment= drift and tend to suppress arm oscillations, due to the vertical + arm + ma= ss flexing. Unless you do this you are likely to pick up spurious resonant s= ignals. The original Lehman design was inadequate in this respect.

       Thump the mass vertically and what do y= ou see on the output? You need to eliminate any oscillations.

3 USING A LONGER ARM.  I=20= used a normal length arm, and I understand if space was not an issue a very=20= long 100 meters arm would result in a longer period.  I am just asking=20= if space was avail would a 5 foot arm result in any benefits, over a 3 foot=20= arm?


       You can provide reasonable temperature= and air motion control for a 2 to 3 ft arm, but not for anything much large= r. A 1 m long pendulum has a period of about 2 sec. To get a 4 sec period yo= u need a 4 m pendulum. A 20 sec period would require a 100m pendulum.
       The main factor you need to consider is= the ratio between the natural period of an arm of length L and the desired=20= seismometer period - the 1/sinA factor. If you try to get greater than x10 p= eriod extension, A becomes a very small angle. You may need fine thread adju= stment screws or a slow motion drive. 
       A folded pendulum design is likely to b= e more satisfactory / easier to construct for mechanical periods over about=20= 30 sec.
       An alternative method is to provide pos= ition and velocity force feedback to stabilise the position of the arm, but=20= the electronics gets more complicated. Using electronic feedback control can= run into noise and stability problems, but you can turn a 20 sec pendulum i= nto a 200 sec sensor. See http://www.keckec.com/seismo/

       What period do you want?  The Rayl= eigh and Love surface waves tend to have periods of about 20 seconds and few= are over 40 sec. For very long extension periods you need to measure the po= sition of the arm, not it's velocity, or you just see noise.

The last question is, if I had= a sensor which was firmly attached to the floor, with a very ridged vertica= l, and a longer arm.
(with all the other important factors aside) What kind of improvements migh= t I expect?  I think I could build a new and improved sensor, addressin= g these three issues.  But would these three issues make much different= ..  If I would, see improvements would they only be for teleseismic even= ts, or would the improvements be evident in recording regional as well.

    You should see the true ground motion. There should b= e NO artefacts from the apparatus. You are more likely to be bothered by sho= rt period signals, but the P and S waves that you want to detect are above 0= ..5 Hz, often 1 to 5 Hz.

    Remember that IT IS THE EARTH WHICH MOVES ---> NOT THE= SEISMOMETER ARM !!

    You have missed out some important considerations. You n= eed to suppress, damp, or be insensitive to the natural oscillations / modes= of the apparatus. Earthquakes are transient pulse type signals and can exci= te any natural oscillation modes.
    The arm and the suspension need to be rigid. The arm shou= ld be prevented from rotating around it's long axis. There will inevitably b= e some vertical bounce at the end of the arm, but the frequency should be ab= ove that of the low pass electronic filter and the sensor should be designed= to have a low sensitivity to vertical motion. You also need to design the s= ensor to have a constant and linear sensor voltage output for mass positi= on drifts of ~ +/-1/2". You ALWAYS get some position drift with a Lehman= .. They are very sensitive to tiny shifts in the local ground plane due to te= mperature, rain and seasonal changes. You need NdFeB bar magnets and rectang= ular coils to do this, or alternatively long cylindrical coils with many tur= ns + magnets, similar to a loudspeaker, but with clearance gaps and coil len= gths which allow for a 1/2" mass drift.
    The damping force should act ~on the line between the cen= tre of mass and the lower bearing, otherwise it will try to rotate the arm a= bout it's long axis. Also, place the centre of the pickup coil close to this= axis.
    Have a look at http://jclahr.com/science/psn/chapman/scho= ol/MKII/index.html The top wire suspension was changed to either a V cable o= r to a 1/2" tube. Both worked OK. Both hinges were altered to be crossed rod= s, although a ball on a plane works equally well. You mount the vertical=20= rods or balls on the vertical support column, NOT on the arm.  The=20= horizontal rods or the flats are mounted on the moving arm.
    Also have a look at the Sprengnether at http://www.geocit= ies.com/meredithlamb/

       Have a look at 416 SS 'shoulder screws= ' 93985A205 or similar= from www.mcmaster.com.
       Alternatively, buy solid tungsten carbi= de drills and use the shank. They are sold for drilling fibreglass circuit b= oard and other hard materials. See www.DigiKey.com or www.smallparts.com. Sm= allparts also sell bearings. You can buy flat triangular Tungsten Carbide ti= ps for lathe tools quite cheaply with ~ 0.3" sides. Alternatively, you can u= se a bit of a SS knife blade glued to the end of the arm.

    Regards,

    Chris Chapman Subject: Re: Lehman advantages From: "tchannel" tchannel@.............. Date: Sun, 24 Jun 2007 16:54:58 -0600 Hi Chris, Thanks for this information. =20 A Folded Pendulum seismometer by David H. Youden.......I found this = article, is there other articles, which show the construction details of = the folded pendulum? I will go over all your points in detail. Thanks, Ted ----- Original Message -----=20 From: ChrisAtUpw@.......... To: psn-l@................. Sent: Sunday, June 24, 2007 3:46 PM Subject: Re: Lehman advantages In a message dated 2007/06/24, tchannel@.............. writes: Subj:Lehman advantages=20 Hi Folks, I am thinking about building another Lehman style Horz = Pendulum sensor. I have some construction ideas I wanted to try. = Before I start, could you describe the benefits of these points. 1 FIRMLY ATTACHED THE SENSOR THE EARTH. I wish to make the contact = between the earth, and the sensor as firm as possible, in this case the = concrete slab setting on the earth and the sensor. Presently the sensor = has three feet which just set on the concrete slab. I know some people = use adhesive to the concrete. If I found a way to bolt all three feet = into the concrete, and a new way to make the necessary adjustments, what = benefits would be derived? I understand that even the concrete floor floats on the earth. I am = just talking about the benefits of a tighter connection between the = sensor and the floor. Hi Ted, Bolting the seismometer mounts to the floor may give problems when = the seismometer expands with temperature at a different rate or at a = different time to the floor. They are very unlikely to match.=20 I use three 2" square x 1/8" SS squares glued to the concrete = floor. You can also use >5mm glass or even glazed tiles. The benefit is = that you have a grit free, dead flat surface. Your level settings should = not show drift either with temperature or over time, or be effected by = large quakes. You can use pool cement to glue the plates. The mounting bolts need to be rigidly attached to the frame. To = avoid thermal drift, I glue SS nuts to the underside of the arm with = acrylic glue. On top of the arm I glue a 1/2" SS tube pillar and add a = wavy washer. The SS set bolt has a SS ball bearing glued to a V in the = end, to provide a central rotating contact with mounting plate. The set = bolt also has a nut at the top end. After setting the correct height, I = partly compress the wavy washer with the top nut. This keeps the thread = in tension. The vertical alignment / side slop is controlled by the SS = pillar and the tension. 2 A RIGID VERTICAL SUPPORT FOR THE UPRIGHT. I know that on a = typical Lehman the vertical needs to be rigid and minimise the flex = between the vertical and the horz members. If I found a way to minimise = this flex, what benefits might I see? The one I have has no flex that I = can see, but If I added addition braces so the vertical was at 90 to the = horz with the minimum of flex, What benefit would there be? The vertical and horizontal arms need to be connected quite = rigidly. This can be done conveniently with large triangular reinforcing = plates at the T joint or ~ 45 deg bracing members to both the main beam = and to the cross beam. This will minimise any cross alignment drift and = tend to suppress arm oscillations, due to the vertical + arm + mass = flexing. Unless you do this you are likely to pick up spurious resonant = signals. The original Lehman design was inadequate in this respect. Thump the mass vertically and what do you see on the output? = You need to eliminate any oscillations. 3 USING A LONGER ARM. I used a normal length arm, and I understand = if space was not an issue a very long 100 meters arm would result in a = longer period. I am just asking if space was avail would a 5 foot arm = result in any benefits, over a 3 foot arm? You can provide reasonable temperature and air motion control = for a 2 to 3 ft arm, but not for anything much larger. A 1 m long = pendulum has a period of about 2 sec. To get a 4 sec period you need a 4 = m pendulum. A 20 sec period would require a 100m pendulum.=20 The main factor you need to consider is the ratio between the = natural period of an arm of length L and the desired seismometer period = - the 1/sinA factor. If you try to get greater than x10 period = extension, A becomes a very small angle. You may need fine thread = adjustment screws or a slow motion drive. =20 A folded pendulum design is likely to be more satisfactory / = easier to construct for mechanical periods over about 30 sec. An alternative method is to provide position and velocity force = feedback to stabilise the position of the arm, but the electronics gets = more complicated. Using electronic feedback control can run into noise = and stability problems, but you can turn a 20 sec pendulum into a 200 = sec sensor. See http://www.keckec.com/seismo/ What period do you want? The Rayleigh and Love surface waves = tend to have periods of about 20 seconds and few are over 40 sec. For = very long extension periods you need to measure the position of the arm, = not it's velocity, or you just see noise. The last question is, if I had a sensor which was firmly attached to = the floor, with a very ridged vertical, and a longer arm. (with all the other important factors aside) What kind of = improvements might I expect? I think I could build a new and improved = sensor, addressing these three issues. But would these three issues = make much different. If I would, see improvements would they only be = for teleseismic events, or would the improvements be evident in = recording regional as well. You should see the true ground motion. There should be NO = artefacts from the apparatus. You are more likely to be bothered by = short period signals, but the P and S waves that you want to detect are = above 0.5 Hz, often 1 to 5 Hz. Remember that IT IS THE EARTH WHICH MOVES ---> NOT THE SEISMOMETER = ARM !! You have missed out some important considerations. You need to = suppress, damp, or be insensitive to the natural oscillations / modes of = the apparatus. Earthquakes are transient pulse type signals and can = excite any natural oscillation modes. The arm and the suspension need to be rigid. The arm should be = prevented from rotating around it's long axis. There will inevitably be = some vertical bounce at the end of the arm, but the frequency should be = above that of the low pass electronic filter and the sensor should be = designed to have a low sensitivity to vertical motion. You also need to = design the sensor to have a constant and linear sensor voltage output = for mass position drifts of ~ +/-1/2". You ALWAYS get some position = drift with a Lehman. They are very sensitive to tiny shifts in the local = ground plane due to temperature, rain and seasonal changes. You need = NdFeB bar magnets and rectangular coils to do this, or alternatively = long cylindrical coils with many turns + magnets, similar to a = loudspeaker, but with clearance gaps and coil lengths which allow for a = 1/2" mass drift. The damping force should act ~on the line between the centre of = mass and the lower bearing, otherwise it will try to rotate the arm = about it's long axis. Also, place the centre of the pickup coil close to = this axis.=20 Have a look at = http://jclahr.com/science/psn/chapman/school/MKII/index.html The top = wire suspension was changed to either a V cable or to a 1/2" tube. Both = worked OK. Both hinges were altered to be crossed rods, although a ball = on a plane works equally well. You mount the vertical rods or balls on = the vertical support column, NOT on the arm. The horizontal rods or the = flats are mounted on the moving arm. Also have a look at the Sprengnether at = http://www.geocities.com/meredithlamb/ Have a look at 416 SS 'shoulder screws' 93985A205 or similar = from www.mcmaster.com.=20 Alternatively, buy solid tungsten carbide drills and use the = shank. They are sold for drilling fibreglass circuit board and other = hard materials. See www.DigiKey.com or www.smallparts.com. Smallparts = also sell bearings. You can buy flat triangular Tungsten Carbide tips = for lathe tools quite cheaply with ~ 0.3" sides. Alternatively, you can = use a bit of a SS knife blade glued to the end of the arm. Regards, Chris Chapman
Hi Chris, Thanks for this=20 information.   

A Folded Pendulum seismometer by = David H. Youden.......I found = this=20 article, is there other articles, which show the construction details of = the=20 folded pendulum?

I will go over = all your=20 points in detail.  Thanks, Ted

 

----- Original Message -----
From:=20 ChrisAtUpw@.......
Sent: Sunday, June 24, 2007 = 3:46 PM
Subject: Re: Lehman = advantages

In a=20 message dated 2007/06/24, tchannel@..............=20 writes:

Subj:Lehman advantages

Hi Folks, I am = thinking=20 about building another Lehman style Horz Pendulum sensor.  I = have some=20 construction ideas I wanted to try.  Before I start, could you = describe=20 the benefits of these points.

1 FIRMLY = ATTACHED THE SENSOR=20 THE EARTH.  I wish to make the contact between the earth, and = the=20 sensor as firm as possible, in this case the concrete slab setting = on the=20 earth and the sensor.  Presently the sensor has three feet = which just=20 set on the concrete slab. I know some people use adhesive to the=20 concrete.  If I found a way to bolt all three feet into the = concrete,=20 and a new way to make the necessary adjustments, what benefits would = be=20 derived?
I understand that even the concrete floor floats on = the=20 earth.  I am just talking about the benefits of a tighter = connection=20 between the sensor and the floor.


Hi Ted,

    Bolting the = seismometer=20 mounts to the floor may give problems when the seismometer expands = with=20 temperature at a different rate or at a different time to the floor. = They are=20 very unlikely to match.

       I = use=20 three 2" square x 1/8" SS squares glued to the concrete floor. You can = also=20 use >5mm glass or even glazed tiles. The benefit is that you have a = grit=20 free, dead flat surface. Your level settings should not show drift = either with=20 temperature or over time, or be effected by large quakes. You can use = pool=20 cement to glue the plates.

       = The=20 mounting bolts need to be rigidly attached to the frame. To avoid = thermal=20 drift, I glue SS nuts to the underside of the arm with acrylic glue. = On top of=20 the arm I glue a 1/2" SS tube pillar and add a wavy washer. The SS set = bolt=20 has a SS ball bearing glued to a V in the end, to provide a central = rotating=20 contact with mounting plate. The set bolt also has a nut at the top = end. After=20 setting the correct height, I partly compress the wavy washer with the = top=20 nut. This keeps the thread in tension. The vertical alignment / side = slop is=20 controlled by the SS pillar and the tension.

2 A RIGID=20 VERTICAL SUPPORT FOR THE UPRIGHT.  I know that on a typical = Lehman the=20 vertical needs to be rigid and minimise the flex between the = vertical and=20 the horz members.  If I found a way to minimise this flex, what = benefits might I see?  The one I have has no flex that I can = see, but=20 If I added addition braces so the vertical was at 90 to the horz = with the=20 minimum of flex, What benefit would there be?

       The=20 vertical and horizontal arms need to be connected quite rigidly. This = can be=20 done conveniently with large triangular reinforcing plates at the T = joint or ~=20 45 deg bracing members to both the main beam and to the cross beam. = This will=20 minimise any cross alignment drift and tend to suppress arm = oscillations, due=20 to the vertical + arm + mass flexing. Unless you do this you are = likely to=20 pick up spurious resonant signals. The original Lehman design was = inadequate=20 in this respect.

       Thump the = mass=20 vertically and what do you see on the output? You need to eliminate = any=20 oscillations.

 3 USING A LONGER ARM.  I used a normal length arm, = and I=20 understand if space was not an issue a very long 100 meters arm = would result=20 in a longer period.  I am just asking if space was avail would = a 5 foot=20 arm result in any benefits, over a 3 foot arm?

       You can=20 provide reasonable temperature and air motion control for a 2 to 3 ft = arm, but=20 not for anything much larger. A 1 m long pendulum has a period of = about 2 sec.=20 To get a 4 sec period you need a 4 m pendulum. A 20 sec period would = require a=20 100m pendulum.
       The main = factor you=20 need to consider is the ratio between the natural period of an arm of = length L=20 and the desired seismometer period - the 1/sinA factor. If you try to = get=20 greater than x10 period extension, A becomes a very small angle. You = may need=20 fine thread adjustment screws or a slow motion drive. =20
       A folded pendulum design is = likely to=20 be more satisfactory / easier to construct for mechanical periods over = about=20 30 sec.
       An alternative method = is to=20 provide position and velocity force feedback to stabilise the position = of the=20 arm, but the electronics gets more complicated. Using electronic = feedback=20 control can run into noise and stability problems, but you can turn a = 20 sec=20 pendulum into a 200 sec sensor. See=20 = http://www.keckec.com/seismo/

      = What=20 period do you want?  The Rayleigh and Love surface waves tend to = have=20 periods of about 20 seconds and few are over 40 sec. For very long = extension=20 periods you need to measure the position of the arm, not it's = velocity, or you=20 just see noise.

 The last question is, if I had a sensor which was firmly = attached to the floor, with a very ridged vertical, and a longer=20 arm.
(with all the other important factors aside) What = kind of=20 improvements might I expect?  I think I could build a new and = improved=20 sensor, addressing these three issues.  But would these three = issues=20 make much different.  If I would, see improvements would they = only be=20 for teleseismic events, or would the improvements be evident in = recording=20 regional as well.

    = You should see the true ground = motion. There=20 should be NO artefacts from the apparatus. You are more likely to be = bothered=20 by short period signals, but the P and S waves that you want to detect = are=20 above 0.5 Hz, often 1 to 5 Hz.

    Remember that = IT IS=20 THE EARTH WHICH MOVES ---> NOT THE SEISMOMETER ARM = !!

    You have = missed out some=20 important considerations. You need to suppress, damp, or be = insensitive to the=20 natural oscillations / modes of the apparatus. Earthquakes are = transient pulse=20 type signals and can excite any natural oscillation=20 modes.
    The arm and the suspension need to be = rigid. The=20 arm should be prevented from rotating around it's long axis. There = will=20 inevitably be some vertical bounce at the end of the arm, but the = frequency=20 should be above that of the low pass electronic filter and the sensor = should=20 be designed to have a low sensitivity to vertical motion. You also = need to=20 design the sensor to have a constant and linear sensor voltage = output for=20 mass position drifts of ~ +/-1/2". You ALWAYS get some position = drift with=20 a Lehman. They are very sensitive to tiny shifts in the local ground = plane due=20 to temperature, rain and seasonal changes. You need NdFeB bar magnets = and=20 rectangular coils to do this, or alternatively long cylindrical coils = with=20 many turns + magnets, similar to a loudspeaker, but with clearance = gaps and=20 coil lengths which allow for a 1/2" mass drift.
    = The=20 damping force should act ~on the line between the centre of mass and = the lower=20 bearing, otherwise it will try to rotate the arm about it's long axis. = Also,=20 place the centre of the pickup coil close to this axis. =
   =20 Have a look at = http://jclahr.com/science/psn/chapman/school/MKII/index.html=20 The top wire suspension was changed to either a V cable or to a 1/2" = tube.=20 Both worked OK. Both hinges were altered to be crossed rods, although = a ball=20 on a plane works equally well. You mount the vertical rods or balls = on the=20 vertical support column, NOT on the arm.  The horizontal rods = or the=20 flats are mounted on the moving arm.
    Also have a = look at=20 the Sprengnether at = http://www.geocities.com/meredithlamb/

       Have a=20 look at 416 SS 'shoulder screws' 93985A205=20 or similar from www.mcmaster.com. =
      =20 Alternatively, buy solid tungsten carbide drills and use the shank. = They are=20 sold for drilling fibreglass circuit board and other hard materials. = See=20 www.DigiKey.com or www.smallparts.com. Smallparts also sell bearings. = You can=20 buy flat triangular Tungsten Carbide tips for lathe tools quite = cheaply with ~=20 0.3" sides. Alternatively, you can use a bit of a SS knife blade glued = to the=20 end of the arm.

    Regards,

    Chris=20 Chapman Subject: Re: Lehman advantages From: "tchannel" tchannel@.............. Date: Sun, 24 Jun 2007 17:51:36 -0600 Hi Chris, I found this one, but maybe you know of other pictures or = sites http://jclahr.com/science/psn/epics/reports/folded/ I find this real interesting, have you tried it? Anyone? Thanks, Ted ----- Original Message -----=20 From: ChrisAtUpw@.......... To: psn-l@................. Sent: Sunday, June 24, 2007 3:46 PM Subject: Re: Lehman advantages In a message dated 2007/06/24, tchannel@.............. writes: Subj:Lehman advantages=20 Hi Folks, I am thinking about building another Lehman style Horz = Pendulum sensor. I have some construction ideas I wanted to try. = Before I start, could you describe the benefits of these points. 1 FIRMLY ATTACHED THE SENSOR THE EARTH. I wish to make the contact = between the earth, and the sensor as firm as possible, in this case the = concrete slab setting on the earth and the sensor. Presently the sensor = has three feet which just set on the concrete slab. I know some people = use adhesive to the concrete. If I found a way to bolt all three feet = into the concrete, and a new way to make the necessary adjustments, what = benefits would be derived? I understand that even the concrete floor floats on the earth. I am = just talking about the benefits of a tighter connection between the = sensor and the floor. Hi Ted, Bolting the seismometer mounts to the floor may give problems when = the seismometer expands with temperature at a different rate or at a = different time to the floor. They are very unlikely to match.=20 I use three 2" square x 1/8" SS squares glued to the concrete = floor. You can also use >5mm glass or even glazed tiles. The benefit is = that you have a grit free, dead flat surface. Your level settings should = not show drift either with temperature or over time, or be effected by = large quakes. You can use pool cement to glue the plates. The mounting bolts need to be rigidly attached to the frame. To = avoid thermal drift, I glue SS nuts to the underside of the arm with = acrylic glue. On top of the arm I glue a 1/2" SS tube pillar and add a = wavy washer. The SS set bolt has a SS ball bearing glued to a V in the = end, to provide a central rotating contact with mounting plate. The set = bolt also has a nut at the top end. After setting the correct height, I = partly compress the wavy washer with the top nut. This keeps the thread = in tension. The vertical alignment / side slop is controlled by the SS = pillar and the tension. 2 A RIGID VERTICAL SUPPORT FOR THE UPRIGHT. I know that on a = typical Lehman the vertical needs to be rigid and minimise the flex = between the vertical and the horz members. If I found a way to minimise = this flex, what benefits might I see? The one I have has no flex that I = can see, but If I added addition braces so the vertical was at 90 to the = horz with the minimum of flex, What benefit would there be? The vertical and horizontal arms need to be connected quite = rigidly. This can be done conveniently with large triangular reinforcing = plates at the T joint or ~ 45 deg bracing members to both the main beam = and to the cross beam. This will minimise any cross alignment drift and = tend to suppress arm oscillations, due to the vertical + arm + mass = flexing. Unless you do this you are likely to pick up spurious resonant = signals. The original Lehman design was inadequate in this respect. Thump the mass vertically and what do you see on the output? = You need to eliminate any oscillations. 3 USING A LONGER ARM. I used a normal length arm, and I understand = if space was not an issue a very long 100 meters arm would result in a = longer period. I am just asking if space was avail would a 5 foot arm = result in any benefits, over a 3 foot arm? You can provide reasonable temperature and air motion control = for a 2 to 3 ft arm, but not for anything much larger. A 1 m long = pendulum has a period of about 2 sec. To get a 4 sec period you need a 4 = m pendulum. A 20 sec period would require a 100m pendulum.=20 The main factor you need to consider is the ratio between the = natural period of an arm of length L and the desired seismometer period = - the 1/sinA factor. If you try to get greater than x10 period = extension, A becomes a very small angle. You may need fine thread = adjustment screws or a slow motion drive. =20 A folded pendulum design is likely to be more satisfactory / = easier to construct for mechanical periods over about 30 sec. An alternative method is to provide position and velocity force = feedback to stabilise the position of the arm, but the electronics gets = more complicated. Using electronic feedback control can run into noise = and stability problems, but you can turn a 20 sec pendulum into a 200 = sec sensor. See http://www.keckec.com/seismo/ What period do you want? The Rayleigh and Love surface waves = tend to have periods of about 20 seconds and few are over 40 sec. For = very long extension periods you need to measure the position of the arm, = not it's velocity, or you just see noise. The last question is, if I had a sensor which was firmly attached to = the floor, with a very ridged vertical, and a longer arm. (with all the other important factors aside) What kind of = improvements might I expect? I think I could build a new and improved = sensor, addressing these three issues. But would these three issues = make much different. If I would, see improvements would they only be = for teleseismic events, or would the improvements be evident in = recording regional as well. You should see the true ground motion. There should be NO = artefacts from the apparatus. You are more likely to be bothered by = short period signals, but the P and S waves that you want to detect are = above 0.5 Hz, often 1 to 5 Hz. Remember that IT IS THE EARTH WHICH MOVES ---> NOT THE SEISMOMETER = ARM !! You have missed out some important considerations. You need to = suppress, damp, or be insensitive to the natural oscillations / modes of = the apparatus. Earthquakes are transient pulse type signals and can = excite any natural oscillation modes. The arm and the suspension need to be rigid. The arm should be = prevented from rotating around it's long axis. There will inevitably be = some vertical bounce at the end of the arm, but the frequency should be = above that of the low pass electronic filter and the sensor should be = designed to have a low sensitivity to vertical motion. You also need to = design the sensor to have a constant and linear sensor voltage output = for mass position drifts of ~ +/-1/2". You ALWAYS get some position = drift with a Lehman. They are very sensitive to tiny shifts in the local = ground plane due to temperature, rain and seasonal changes. You need = NdFeB bar magnets and rectangular coils to do this, or alternatively = long cylindrical coils with many turns + magnets, similar to a = loudspeaker, but with clearance gaps and coil lengths which allow for a = 1/2" mass drift. The damping force should act ~on the line between the centre of = mass and the lower bearing, otherwise it will try to rotate the arm = about it's long axis. Also, place the centre of the pickup coil close to = this axis.=20 Have a look at = http://jclahr.com/science/psn/chapman/school/MKII/index.html The top = wire suspension was changed to either a V cable or to a 1/2" tube. Both = worked OK. Both hinges were altered to be crossed rods, although a ball = on a plane works equally well. You mount the vertical rods or balls on = the vertical support column, NOT on the arm. The horizontal rods or the = flats are mounted on the moving arm. Also have a look at the Sprengnether at = http://www.geocities.com/meredithlamb/ Have a look at 416 SS 'shoulder screws' 93985A205 or similar = from www.mcmaster.com.=20 Alternatively, buy solid tungsten carbide drills and use the = shank. They are sold for drilling fibreglass circuit board and other = hard materials. See www.DigiKey.com or www.smallparts.com. Smallparts = also sell bearings. You can buy flat triangular Tungsten Carbide tips = for lathe tools quite cheaply with ~ 0.3" sides. Alternatively, you can = use a bit of a SS knife blade glued to the end of the arm. Regards, Chris Chapman
Hi Chris,  I found this one, but = maybe you=20 know of other pictures or sites http://jclah= r.com/science/psn/epics/reports/folded/
I find this real interesting, have you = tried it?=20 Anyone?
Thanks, Ted
 
----- Original Message -----
From:=20 ChrisAtUpw@.......
Sent: Sunday, June 24, 2007 = 3:46 PM
Subject: Re: Lehman = advantages

In a=20 message dated 2007/06/24, tchannel@..............=20 writes:

Subj:Lehman advantages

Hi Folks, I am = thinking=20 about building another Lehman style Horz Pendulum sensor.  I = have some=20 construction ideas I wanted to try.  Before I start, could you = describe=20 the benefits of these points.

1 FIRMLY = ATTACHED THE SENSOR=20 THE EARTH.  I wish to make the contact between the earth, and = the=20 sensor as firm as possible, in this case the concrete slab setting = on the=20 earth and the sensor.  Presently the sensor has three feet = which just=20 set on the concrete slab. I know some people use adhesive to the=20 concrete.  If I found a way to bolt all three feet into the = concrete,=20 and a new way to make the necessary adjustments, what benefits would = be=20 derived?
I understand that even the concrete floor floats on = the=20 earth.  I am just talking about the benefits of a tighter = connection=20 between the sensor and the floor.

Hi Ted,

    Bolting the = seismometer=20 mounts to the floor may give problems when the seismometer expands = with=20 temperature at a different rate or at a different time to the floor. = They are=20 very unlikely to match.

       I = use=20 three 2" square x 1/8" SS squares glued to the concrete floor. You can = also=20 use >5mm glass or even glazed tiles. The benefit is that you have a = grit=20 free, dead flat surface. Your level settings should not show drift = either with=20 temperature or over time, or be effected by large quakes. You can use = pool=20 cement to glue the plates.

       = The=20 mounting bolts need to be rigidly attached to the frame. To avoid = thermal=20 drift, I glue SS nuts to the underside of the arm with acrylic glue. = On top of=20 the arm I glue a 1/2" SS tube pillar and add a wavy washer. The SS set = bolt=20 has a SS ball bearing glued to a V in the end, to provide a central = rotating=20 contact with mounting plate. The set bolt also has a nut at the top = end. After=20 setting the correct height, I partly compress the wavy washer with the = top=20 nut. This keeps the thread in tension. The vertical alignment / side = slop is=20 controlled by the SS pillar and the tension.

2 A RIGID=20 VERTICAL SUPPORT FOR THE UPRIGHT.  I know that on a typical = Lehman the=20 vertical needs to be rigid and minimise the flex between the = vertical and=20 the horz members.  If I found a way to minimise this flex, what = benefits might I see?  The one I have has no flex that I can = see, but=20 If I added addition braces so the vertical was at 90 to the horz = with the=20 minimum of flex, What benefit would there be?

       The=20 vertical and horizontal arms need to be connected quite rigidly. This = can be=20 done conveniently with large triangular reinforcing plates at the T = joint or ~=20 45 deg bracing members to both the main beam and to the cross beam. = This will=20 minimise any cross alignment drift and tend to suppress arm = oscillations, due=20 to the vertical + arm + mass flexing. Unless you do this you are = likely to=20 pick up spurious resonant signals. The original Lehman design was = inadequate=20 in this respect.

       Thump the = mass=20 vertically and what do you see on the output? You need to eliminate = any=20 oscillations.

 3 USING A LONGER ARM.  I used a normal length arm, = and I=20 understand if space was not an issue a very long 100 meters arm = would result=20 in a longer period.  I am just asking if space was avail would = a 5 foot=20 arm result in any benefits, over a 3 foot arm?

       You can=20 provide reasonable temperature and air motion control for a 2 to 3 ft = arm, but=20 not for anything much larger. A 1 m long pendulum has a period of = about 2 sec.=20 To get a 4 sec period you need a 4 m pendulum. A 20 sec period would = require a=20 100m pendulum.
       The main = factor you=20 need to consider is the ratio between the natural period of an arm of = length L=20 and the desired seismometer period - the 1/sinA factor. If you try to = get=20 greater than x10 period extension, A becomes a very small angle. You = may need=20 fine thread adjustment screws or a slow motion drive. =20
       A folded pendulum design is = likely to=20 be more satisfactory / easier to construct for mechanical periods over = about=20 30 sec.
       An alternative method = is to=20 provide position and velocity force feedback to stabilise the position = of the=20 arm, but the electronics gets more complicated. Using electronic = feedback=20 control can run into noise and stability problems, but you can turn a = 20 sec=20 pendulum into a 200 sec sensor. See=20 = http://www.keckec.com/seismo/

      = What=20 period do you want?  The Rayleigh and Love surface waves tend to = have=20 periods of about 20 seconds and few are over 40 sec. For very long = extension=20 periods you need to measure the position of the arm, not it's = velocity, or you=20 just see noise.

 The last question is, if I had a sensor which was firmly = attached to the floor, with a very ridged vertical, and a longer=20 arm.
(with all the other important factors aside) What = kind of=20 improvements might I expect?  I think I could build a new and = improved=20 sensor, addressing these three issues.  But would these three = issues=20 make much different.  If I would, see improvements would they = only be=20 for teleseismic events, or would the improvements be evident in = recording=20 regional as well.

    = You should see the true ground = motion. There=20 should be NO artefacts from the apparatus. You are more likely to be = bothered=20 by short period signals, but the P and S waves that you want to detect = are=20 above 0.5 Hz, often 1 to 5 Hz.

    Remember that = IT IS=20 THE EARTH WHICH MOVES ---> NOT THE SEISMOMETER ARM = !!

    You have = missed out some=20 important considerations. You need to suppress, damp, or be = insensitive to the=20 natural oscillations / modes of the apparatus. Earthquakes are = transient pulse=20 type signals and can excite any natural oscillation=20 modes.
    The arm and the suspension need to be = rigid. The=20 arm should be prevented from rotating around it's long axis. There = will=20 inevitably be some vertical bounce at the end of the arm, but the = frequency=20 should be above that of the low pass electronic filter and the sensor = should=20 be designed to have a low sensitivity to vertical motion. You also = need to=20 design the sensor to have a constant and linear sensor voltage = output for=20 mass position drifts of ~ +/-1/2". You ALWAYS get some position = drift with=20 a Lehman. They are very sensitive to tiny shifts in the local ground = plane due=20 to temperature, rain and seasonal changes. You need NdFeB bar magnets = and=20 rectangular coils to do this, or alternatively long cylindrical coils = with=20 many turns + magnets, similar to a loudspeaker, but with clearance = gaps and=20 coil lengths which allow for a 1/2" mass drift.
    = The=20 damping force should act ~on the line between the centre of mass and = the lower=20 bearing, otherwise it will try to rotate the arm about it's long axis. = Also,=20 place the centre of the pickup coil close to this axis. =
   =20 Have a look at = http://jclahr.com/science/psn/chapman/school/MKII/index.html=20 The top wire suspension was changed to either a V cable or to a 1/2" = tube.=20 Both worked OK. Both hinges were altered to be crossed rods, although = a ball=20 on a plane works equally well. You mount the vertical rods or balls = on the=20 vertical support column, NOT on the arm.  The horizontal rods = or the=20 flats are mounted on the moving arm.
    Also have a = look at=20 the Sprengnether at = http://www.geocities.com/meredithlamb/

       Have a=20 look at 416 SS 'shoulder screws' 93985A205=20 or similar from www.mcmaster.com. =
      =20 Alternatively, buy solid tungsten carbide drills and use the shank. = They are=20 sold for drilling fibreglass circuit board and other hard materials. = See=20 www.DigiKey.com or www.smallparts.com. Smallparts also sell bearings. = You can=20 buy flat triangular Tungsten Carbide tips for lathe tools quite = cheaply with ~=20 0.3" sides. Alternatively, you can use a bit of a SS knife blade glued = to the=20 end of the arm.

    Regards,

    Chris=20 Chapman Subject: Sample rate on Amaseis?? From: "Paul Cianciolo" Paulc@........ Date: Tue, 26 Jun 2007 16:00:29 -0400 Hello Folks, I was just thinking about the sample rate for Amaseis. The preamp board I have from Larry Cochrane is set to 10 HZ -3db point low pass filter. This means that a minimum sample rate of at least 2x should be used, I think according to Mr Nyquist. My Amaseis is set to sample at 6 SPS. This should lead to some interesting aliasing results. In the config file I changed the sample rate to 20 SPS and now the Winquake FFT window shows out to 10 Hz. I have not tested an upload to the PSN yet. Any thoughts out there. PauLC W1VLF
Hello=20 Folks,
I was=20 just thinking about the sample rate for Amaseis.
 
The=20 preamp board I have from Larry Cochrane is set to 10 HZ -3db point low = pass=20 filter.
This=20 means that a minimum sample rate of at least  2x should be used, I = think=20 according to Mr Nyquist.
 
My=20 Amaseis is set to sample at 6 SPS.  This should lead to some = interesting=20 aliasing results.
 
In the=20 config file I changed the sample rate to 20 SPS and now the Winquake FFT = window=20 shows  out to 10 Hz.
 
I have=20 not tested an upload to the PSN yet.
 
Any=20 thoughts out there.
 
PauLC
W1VLF
 
 
 
Subject: Re: Sample rate on Amaseis?? From: ChrisAtUpw@....... Date: Tue, 26 Jun 2007 17:40:23 EDT In a message dated 2007/06/26, Paulc@........ writes: > The preamp board I have from Larry Cochrane is set to 10 HZ -3db point low > pass filter. This means that a minimum sample rate of at least 2x should be > used, I think according to Mr Nyquist. > > My Amaseis is set to sample at 6 SPS. This should lead to some interesting > aliasing results. Hi Paul, It is only the AS1 electronics box which is set to 6.15 SPS. The AS1 has a resonance at 0.67 Hz, so the output falls off sharply above about 2 - 3 Hz If you are using a Dataq ADC for instance, you can set the sample rate to any rate that the board offers, by altering the config file value.. > In the config file I changed the sample rate to 20 SPS and now the > Winquake FFT window shows out to 10 Hz. This should be OK, if the ADC can provide it. Regards, Chris Chapman In a me= ssage dated 2007/06/26, Paulc@........ writes:


The preamp board I have from L= arry Cochrane is set to 10 HZ -3db point low pass filter. This means that a=20= minimum sample rate of at least 2x should be used, I think according to Mr N= yquist.

My Amaseis is set to sample at 6 SPS.  This should lead to some intere= sting aliasing results.


Hi Paul,

       It is only the AS1 electronics box whic= h is set to 6.15 SPS. The AS1 has a resonance at 0.67 Hz, so the output fall= s off sharply above about 2 - 3 Hz

       If you are using a Dataq ADC for instan= ce, you can set the sample rate to any rate that the board offers, by alteri= ng the config file value..

In the config file I changed=20= the sample rate to 20 SPS and now the Winquake FFT window shows out to 10 Hz= ..


       This should be OK, if the ADC can provi= de it.
      
       Regards,

       Chris Chapman Subject: RE: Sample rate on Amaseis?? From: "Paul Cianciolo" Paulc@........ Date: Tue, 26 Jun 2007 18:04:47 -0400 Thank you Chris, Yes. The ADC can go well above this so all is OK. I am now set to 20 SPS and will see how I make out. Thanks Again!! PauLC -----Original Message----- From: psn-l-request@.............. [mailto:psn-l-request@................. Behalf Of ChrisAtUpw@....... Sent: Tuesday, June 26, 2007 5:40 PM To: psn-l@.............. Subject: Re: Sample rate on Amaseis?? In a message dated 2007/06/26, Paulc@........ writes: The preamp board I have from Larry Cochrane is set to 10 HZ -3db point low pass filter. This means that a minimum sample rate of at least 2x should be used, I think according to Mr Nyquist. My Amaseis is set to sample at 6 SPS. This should lead to some interesting aliasing results. Hi Paul, It is only the AS1 electronics box which is set to 6.15 SPS. The AS1 has a resonance at 0.67 Hz, so the output falls off sharply above about 2 - 3 Hz If you are using a Dataq ADC for instance, you can set the sample rate to any rate that the board offers, by altering the config file value.. In the config file I changed the sample rate to 20 SPS and now the Winquake FFT window shows out to 10 Hz. This should be OK, if the ADC can provide it. Regards, Chris Chapman
Thank=20 you Chris,
 
Yes.=20 The ADC can go well above this so all is OK.
I am=20 now set to 20 SPS and will see how I make out.
 
Thanks=20 Again!!
 
PauLC
 
 
 
 
 
 -----Original = Message-----
From:=20 psn-l-request@.............. [mailto:psn-l-request@...............On = Behalf=20 Of ChrisAtUpw@.......
Sent: Tuesday, June 26, 2007 5:40=20 PM
To: psn-l@..............
Subject: Re: Sample rate = on=20 Amaseis??

In = a message=20 dated 2007/06/26, Paulc@........ writes:


 The preamp board I have from Larry Cochrane is set to 10 = HZ -3db=20 point low pass filter. This means that a minimum sample rate of at = least 2x=20 should be used, I think according to Mr Nyquist.

My Amaseis is = set to sample at=20 6 SPS.  This should lead to some interesting aliasing=20 results.


Hi=20 Paul,

       It is only the AS1=20 electronics box which is set to 6.15 SPS. The AS1 has a resonance at = 0.67 Hz,=20 so the output falls off sharply above about 2 - 3=20 Hz

       If you are using a = Dataq ADC=20 for instance, you can set the sample rate to any rate that the board = offers,=20 by altering the config file value..

In the=20 config file I changed the sample rate to 20 SPS and now the Winquake = FFT=20 window shows out to 10 Hz.

      = ; This=20 should be OK, if the ADC can provide=20 it.
      =20
      =20 Regards,

       Chris = Chapman=20 Subject: Re: Sample rate on Amaseis?? From: Bobhelenmcclure@....... Date: Tue, 26 Jun 2007 22:31:07 EDT Hi Paul, Both the Dataq software and Amaseis actually run the Dataq 194 at its maximum rate of 240 samples per second, and then average the samples down to the user selected rate. This largely eliminates any problem of aliasing. You are free to select whatever recording rate you need to capture the highest frequency you want to capture from seismic events. I live on Long Island, New York, and get only teleseisms here, so my recording rate of 5 samples per second has been adequate. The use of Amaseis limits you to one channel. If you ever want to record more than one channel using the Dataq ADC, I urge the use of my software. See _http://www.jclahr.com/science/psn/mcclure/wdq_utilities/index.html_ (http://www.jclahr.com/science/psn/mcclure/wdq_utilities/index.html) Bob McClure On 26 Jun 2007, Paul Cianciolo wrote: I was just thinking about the sample rate for Amaseis. The preamp board I have from Larry Cochrane is set to 10 HZ -3db point low pass filter. This means that a minimum sample rate of at least 2x should be used, I think according to Mr Nyquist. My Amaseis is set to sample at 6 SPS. This should lead to some interesting aliasing results. In the config file I changed the sample rate to 20 SPS and now the Winquake FFT window shows out to 10 Hz. I have not tested an upload to the PSN yet. Any thoughts out there. ************************************** See what's free at http://www.aol.com.
Hi Paul,
 
  Both the Dataq software and Amaseis actually run the Dataq=20= 194=20 at its maximum rate of 240 samples per second, and then average the samples=20= down=20 to the user selected rate. This largely eliminates any problem of aliasing.=20= You=20 are free to select whatever recording rate you need to capture the highest=20 frequency you want to capture from seismic events. I live on Long Island, Ne= w=20 York, and get only teleseisms here, so my recording rate of 5 samples per se= cond=20 has been adequate.
 
  The use of Amaseis limits you to one channel. If you ever want t= o=20 record more than one channel using the Dataq ADC, I urge the use of my softw= are.=20 See
 
= http://www.jclahr.com/science/psn/mcclure/wdq_utilities/index.html
 
Bob McClure
 
On 26 Jun 2007, Paul Cianciolo wrote:
 
I was just thinking about the sample rate for Amaseis.

The pream= p=20 board I have from Larry Cochrane is set to 10 HZ -3db point low
pass=20 filter.
This means that a minimum sample rate of at least  2x should= be=20 used, I
think according to Mr Nyquist.

My Amaseis is set to sample= at=20 6 SPS.  This should lead to some interesting
aliasing results.
In=20 the config file I changed the sample rate to 20 SPS and now the Winquake
= FFT=20 window shows  out to 10 Hz.

I have not tested an upload to the P= SN=20 yet.

Any thoughts out there.



See what's free at AOL.com.
Subject: Folded Pendulum From: tchannel1@............ Date: Tue, 26 Jun 2007 22:18:39 -0600 I have seen a few descriptions of the "Folded Pendulum" sensor concept. = Here is one http://jclahr.com/science/psn/youden/ from this one and = others I get the general idea. I made a mock up using two pendulums 16" long and a cross member of = about 15" By moving the mass L and R on the cross member beam, I could = get up to 12 seconds period. I guess the longer the pendulums the longer the period, so If I use 24" = It could be more than 12 secs. This design by David H. Youden, uses = 6.47" pendulums, and I did not see what period it produced. The overall = dim of it, is 10.27" tall....So perhaps it has a shorter period. Have any of you built or tried this approach? Thanks, Ted
I have seen a few descriptions of the = "Folded=20 Pendulum" sensor concept.  Here is one http://jclahr.com/science/= psn/youden/ =20 from this one and others I get the general idea.
 
I made a mock up using two pendulums = 16" long and a=20 cross member of about 15"  By moving the mass L and R on the cross = member=20 beam, I could get up to 12 seconds period.
 
I guess the longer the pendulums the = longer the=20 period, so If I use 24" It could be more than 12 secs.  This design = by=20 David H. Youden, uses 6.47" pendulums, and I did not see what period it=20 produced.  The overall dim of it, is 10.27" tall....So perhaps it = has a=20 shorter period.
 
Have any of you built or tried this=20 approach?
 
Thanks, Ted
 
 
Subject: Multi-Dimensional-Sensor, First Time Of Arrival Only From: "Geoffrey" gmvoeth@........... Date: Wed, 27 Jun 2007 02:31:57 -0700 I was just wondering if you connected a strain guage or other sensor type unknown to me where the vertical pendumlum wire joins at the upper support if you could possibly measure weight changes that might result from motion in any of the three axises ? The point here is to look only at first time of arrival of the various phases and not worry about direction in any one plane. I am unable to experiment with thesse ideas but i imagine I can not imagine anything that has not already been tried elsewhere before. Can someone more knowledgeable please give me more ideas along this line. The sensor would be the single most critical component in this system and not the other hardware. It seems to me the only damping you would need is of the horizontal pendulum motion. When I experimented many years ago with a XY single horizontal only pendulum I had quite good results with first time of arrivals but since I was only interested actually in the vertical I did not look at it any closer. I could not tell the other fancy data the rest of you are looking for like NS or EW motion just that there was motion at this point in time. At that time I was under instruction by a geophysicist at Golden on how to read seismic waves and all he wanted to see, ever, was first time of arrivals of the vertical waves regardless of the other features. In this modern day there must be a decent strain guage with the necessary sensitivity etc...usw... to take an 8 lb pendulum or so. Regards; geoff __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Folded Pendulum From: ChrisAtUpw@....... Date: Wed, 27 Jun 2007 18:39:50 EDT In a message dated 2007/06/27, tchannel1@............ writes: > I have seen a few descriptions of the "Folded Pendulum" sensor concept. > Here is one http://jclahr.com/science/psn/youden/ from this one and others I > get the general idea. > > I made a mock up using two pendulums 16" long and a cross member of about > 15" By moving the mass L and R on the cross member beam, I could get up to 12 > seconds period. Hi Ted, A 16" pendulum has a period of 1.28 seconds. A factor of x10 increase in period should be quite easy. We can get >30 sec from a 1.4 sec Lehman, no problems. The limitation is likely to be in your suspension system. The Australians managed to get a period of 90 sec from a 1 sec folded pendulum without feedback, if my memory is correct. > I guess the longer the pendulums the longer the period, so If I use 24" It > could be more than 12 secs. This design by David H. Youden, uses 6.47" > pendulums, and I did not see what period it produced. The overall dim of it, is > 10.27" tall....So perhaps it has a shorter period. Dave Youden's pendulums are 0.8 seconds. Since it is a feedback instrument, the period will depend on the electronics. It looks as if this corresponds to about 6 seconds. However, the SG pendulums can be extended to ~50 seconds. What happens as you trim the mass closer to the balance point? Do you have a trim mass set by a screw thread? Regards, Chris Chapman In a me= ssage dated 2007/06/27, tchannel1@............ writes:

I have seen a few descriptions=20= of the "Folded Pendulum" sensor concept.  Here is one http://jclahr.com/science/psn/youden/&n= bsp; from this one and others I get the general idea.

I made a mock up using two pendulums 16" long and a cross member of about 1= 5"  By moving the mass L and R on the cross member beam, I could get up= to 12 seconds period.


Hi Ted,

       A 16" pendulum has a period of 1.28 sec= onds. A factor of x10 increase in period should be quite easy. We can get &g= t;30 sec from a 1.4 sec Lehman, no problems. The limitation is likely to be=20= in your suspension system.

       The Australians managed to get a period= of 90 sec from a 1 sec folded pendulum without feedback, if my memory is co= rrect.

I guess the longer the pendul= ums the longer the period, so If I use 24" It could be more than 12 secs.&nb= sp; This design by David H. Youden, uses 6.47" pendulums, and I did not see=20= what period it produced.  The overall dim of it, is 10.27" tall....So p= erhaps it has a shorter period.


       Dave Youden's pendulums are 0.8 seconds= .. Since it is a feedback instrument, the period will depend on the electroni= cs. It looks as if this corresponds to about 6 seconds. However, the SG pend= ulums can be extended to ~50 seconds.

       What happens as you trim the mass close= r to the balance point? Do you have a trim mass set by a screw thread?

       Regards,

       Chris Chapman Subject: Re: Multi-Dimensional-Sensor, First Time Of Arrival Only From: ChrisAtUpw@....... Date: Wed, 27 Jun 2007 19:05:35 EDT In a message dated 2007/06/27, gmvoeth@........... writes: > I was just wondering if you connected a strain guage or > other sensor type unknown to me where the vertical pendumlum > wire joins at the upper support if you could possibly > measure weight changes that might result from motion in any > of the three axises ? Hi Geoff, You are unlikely to have much success with Strain Gauges. The likely problems are with sensitivity and noise. They tend to have quite a low sensitivity. It might be interesting to try suspending a pendulum using 1/2 a piezo disk? Regards, Chris Chapman In a me= ssage dated 2007/06/27, gmvoeth@........... writes:

I was just wondering if you con= nected a strain guage or
other sensor type unknown to me where the vertical pendumlum
wire joins at the upper support if you could possibly
measure weight changes that might result from motion in any
of the three axises ?


Hi Geoff,

       You are unlikely to have much success w= ith Strain Gauges. The likely problems are with sensitivity and noise. They=20= tend to have quite a low sensitivity. It might be interesting to try suspend= ing a pendulum using 1/2 a piezo disk?

       Regards,

       Chris Chapman Subject: Re: Folded Pendulum From: tchannel1@............ Date: Wed, 27 Jun 2007 18:16:43 -0600 Hi Chris, Thanks, that answered several questions. >What happens as you trim the mass closer to the balance point? Do you = have a trim mass set by a screw thread? I got about 12 second, with just a block for a mass, When I do it for = real I will use a threaded rod and moveable mass. Thanks, TEd ----- Original Message -----=20 From: ChrisAtUpw@.......... To: psn-l@................. Sent: Wednesday, June 27, 2007 4:39 PM Subject: Re: Folded Pendulum In a message dated 2007/06/27, tchannel1@............ writes: I have seen a few descriptions of the "Folded Pendulum" sensor = concept. Here is one http://jclahr.com/science/psn/youden/ from this = one and others I get the general idea. I made a mock up using two pendulums 16" long and a cross member of = about 15" By moving the mass L and R on the cross member beam, I could = get up to 12 seconds period. Hi Ted, A 16" pendulum has a period of 1.28 seconds. A factor of x10 = increase in period should be quite easy. We can get >30 sec from a 1.4 = sec Lehman, no problems. The limitation is likely to be in your = suspension system. The Australians managed to get a period of 90 sec from a 1 sec = folded pendulum without feedback, if my memory is correct.=20 I guess the longer the pendulums the longer the period, so If I use = 24" It could be more than 12 secs. This design by David H. Youden, uses = 6.47" pendulums, and I did not see what period it produced. The overall = dim of it, is 10.27" tall....So perhaps it has a shorter period. Dave Youden's pendulums are 0.8 seconds. Since it is a feedback = instrument, the period will depend on the electronics. It looks as if = this corresponds to about 6 seconds. However, the SG pendulums can be = extended to ~50 seconds. What happens as you trim the mass closer to the balance point? = Do you have a trim mass set by a screw thread? Regards, Chris Chapman
Hi Chris,   Thanks, that = answered several=20 questions.
 
>What happens as you trim the mass = closer to the=20 balance point? Do you have a trim mass set by a screw = thread?
 
I got about 12 second, with just a = block for a=20 mass,  When I do it for real I will use a threaded rod and moveable = mass.
Thanks, TEd
 
----- Original Message -----
From:=20 ChrisAtUpw@.......
Sent: Wednesday, June 27, 2007 = 4:39=20 PM
Subject: Re: Folded = Pendulum

In a=20 message dated 2007/06/27, tchannel1@............=20 writes:

I have seen a few descriptions of the "Folded Pendulum" = sensor=20 concept.  Here is one http://jclahr.com/science/= psn/youden/ =20 from this one and others I get the general idea.

I made a mock up = using two=20 pendulums 16" long and a cross member of about 15"  By moving = the mass=20 L and R on the cross member beam, I could get up to 12 seconds=20 period.

Hi=20 Ted,

       A 16" pendulum has a = period=20 of 1.28 seconds. A factor of x10 increase in period should be quite = easy. We=20 can get >30 sec from a 1.4 sec Lehman, no problems. The limitation = is=20 likely to be in your suspension=20 system.

       The Australians = managed to=20 get a period of 90 sec from a 1 sec folded pendulum without feedback, = if my=20 memory is correct.

I guess=20 the longer the pendulums the longer the period, so If I use 24" It = could be=20 more than 12 secs.  This design by David H. Youden, uses 6.47"=20 pendulums, and I did not see what period it produced.  The = overall dim=20 of it, is 10.27" tall....So perhaps it has a shorter = period.

       Dave = Youden's=20 pendulums are 0.8 seconds. Since it is a feedback instrument, the = period will=20 depend on the electronics. It looks as if this corresponds to about 6 = seconds.=20 However, the SG pendulums can be extended to ~50=20 seconds.

       What happens as = you trim=20 the mass closer to the balance point? Do you have a trim mass set by a = screw=20 thread?

      =20 Regards,

       Chris = Chapman=20 Subject: 2007-06-28 02:52 (Mw 6.7) BOUGAINVILLE REGION, P.N.G. -7.9 154. From: John Lahr johnjan@........ Date: Wed, 27 Jun 2007 22:30:52 -0700 This is the largest event in some time. If you didn't record it, you probaby have a problem with your station! Almost all of the educational AS-1 systems picked it up. http://jclahr.com/science/psn/as1/heli/allas1.php Cheers, John __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Multi-Dimensional-Sensor, First Time Of Arrival Only From: "Geoffrey" gmvoeth@........... Date: Thu, 28 Jun 2007 03:54:50 -0700 Thanks Chris, Surely there are new high tech sensors we amateures may not be aware of that possibly we may obtain. It seems there has been no advancements in the sensor area. I had great troubles with the piezo idea because it has such a high impedence. Whatever i do I must use a balanced preamp system with most of the gain in the front end or the drifting of the class "A" baseline is unacceptable. Isnt there a varible resistor that might work over a range of a few mm for full scale ?? The key is most probably the range of operation and these special kind of devices are just not normally made available to the general public. At the moment only a magnet coil seems to fill the billit since I am unwilling to use home built AC devices like capacitive (moving plates) or inductive (moving cores) sensors. If I had an fcc license I might try those AC devices but since i do not i will not. Right now only baseband and DC are my options. Low impedance front ends have always been best for me. Is there any way for the layman to realistically research the new sensors that might be out there ? Regards; geoff ----- Original Message ----- From: To: Sent: Wednesday, June 27, 2007 16:05 Subject: Re: Multi-Dimensional-Sensor, First Time Of Arrival Only > In a message dated 2007/06/27, gmvoeth@........... writes: > >> I was just wondering if you connected a strain guage or >> other sensor type unknown to me where the vertical pendumlum >> wire joins at the upper support if you could possibly >> measure weight changes that might result from motion in any >> of the three axises ? > > Hi Geoff, > > You are unlikely to have much success with Strain Gauges. The likely > problems are with sensitivity and noise. They tend to have quite a low > sensitivity. It might be interesting to try suspending a pendulum using 1/2 a piezo > disk? > > Regards, > > Chris Chapman > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Multi-Dimensional-Sensor, First Time Of Arrival Only From: "Thomas Dick" dickthomas01@............. Date: Thu, 28 Jun 2007 12:40:37 -0500 Geoff, you go time to look at this and comment ... This is a long time coming. I haven't created the bibliography yet. It is 5 megs.PHF file at http://i.bachcottage.com/Evv-Nov6-Tornado.pdf word doc file at http://i.bachcottage.com/TornadoAnalysisForTheEvansvilleIndianaNovember6.doc __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: 2007-06-28 02:52 (Mw 6.7) BOUGAINVILLE REGION, P.N.G. -7.9 154. From: Pete Rowe ptrowe@......... Date: Thu, 28 Jun 2007 10:58:11 -0700 (PDT) Thanks John it was loud and clear here in San Jose. Pete --- John Lahr wrote: > This is the largest event in some time. If you > didn't record it, you > probaby have a problem > with your station! Almost all of the educational > AS-1 systems picked it up. > http://jclahr.com/science/psn/as1/heli/allas1.php > > Cheers, > John > > > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email > PSN-L-REQUEST@.............. with > the body of the message (first line only): > unsubscribe > See http://www.seismicnet.com/maillist.html for more > information. > ____________________________________________________________________________________ Get your own web address. Have a HUGE year through Yahoo! Small Business. http://smallbusiness.yahoo.com/domains/?p=BESTDEAL __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Multi-Dimensional-Sensor, First Time Of Arrival Only From: ChrisAtUpw@....... Date: Thu, 28 Jun 2007 14:23:14 EDT In a message dated 2007/06/28, gmvoeth@........... writes: > Surely there are new high tech sensors we amateurs may not be aware of that > possibly we may obtain. It seems there has been no advancements in the > sensor area. I had great troubles with the piezo idea because it has such a high > impedance. Hi Geoff, I have no significant problems with piezo devices, but I build them into the screened sensor unit itself. You can realistically get periods out to about 3 seconds. This is OK for making 0.5 / 1 Hz and up sensors to replace 1 Hz geophones, which cost >$1,500. Whatever I do I must use > a balanced preamp system with most of the gain > in the front end or the drifting of the class "A" baseline is unacceptable. > Isn't there a variable resistor that might work over a range of > a few mm for full scale? Not that I know of. The only type that I can think of are the tunnelling mode pressure pads / coax cable. These are fine for making intruder alarms or pressure controls for joysticks, but they do not have the temperature stability suitable for a seismometer. It is usual with amateur sensors to provide a 30 to 60 second high pass filter to remove 1/f noise and baseline drift. The key is most probably the > range of operation and these special kind of > devices > are just not normally made available to the general public. Just what are these mysterious devices and how do they work? > At the moment only a magnet coil seems to fill the billit > since I am unwilling to use home built AC devices like capacitive (moving > plates) or > inductive (moving cores) sensors. If you are unwilling to use either of the two most common distance measuring techniques, you have severely restricted yourself. One of the sensors that I use has a 10 cm ferrite aerial rod and a resolution of about 7 nano metres. It cost about $60 for the kit. Capacitor systems are not difficult to make or to use and amateur designs are available. I can see no logical reason to reject these. If I had an fcc license I might try > those AC devices but since I do not I > will not. So, what sort of device needs a FCC Licence? Certainly NOT LCDT or LVDT sensors!! > Right now only baseband and DC are my options. > Low impedance front ends have always been best for me. > > Is there any way for the layman to realistically research the new sensors > that might be out there ? I know of three other options. One is a twin Silicon photodiode sensor with a moving shutter and a filament bulb. You can design these for deflections up to +/-10 mm at quite low cost and you may get the 15 nano metre resolution that I measured. Another is a Hall effect magnetic detector with a quad NdFeB magnet block to drive it. These only have a working range of +/-1/2 mm at maybe 20 nano metres resolution, but they are OK for simple pendulums, e.g. SG type. The third is to use a conducting water manometer / tiltmeter type of device. It is not too difficult to make these horizontal sensors work out to over 20 seconds. See Gile, WW, Geophys. J. Roy. Astro. Soc. vol 36 1974 pp 153-165 "A Mercury Pendulum Seismometer" very good but a bit too large for amateurs. (You don't have to make them anything like so large! - you just have to be more clever!) If you know of any other sensor technologies, do tell me! I am aware of some of the MEMs devices, but the only ones that I have seen had a lousy noise performance. Regards, Chris Chapman In a me= ssage dated 2007/06/28, gmvoeth@........... writes:

Surely there are new high tech=20= sensors we amateurs may not be aware of that possibly we may obtain. It seem= s there has been no advancements in the sensor area. I had great troubles wi= th the piezo idea because it has such a high impedance.


Hi Geoff,

       I have no significant problems with pie= zo devices, but I build them into the screened sensor unit itself. You can r= ealistically get periods out to about 3 seconds. This is OK for making 0.5 /= 1 Hz and up sensors to replace 1 Hz geophones, which cost >$1,500.

Whatever I do I must use
a bala= nced preamp system with most of the gain
in the front end or the drifting of the class "A" baseline is unacceptable.<= BR> Isn't there a variable resistor that might work over a range of
a few mm for full scale?


       Not that I know of. The only type that= I can think of are the tunnelling mode pressure pads / coax cable. These ar= e fine for making intruder alarms or pressure controls for joysticks, but th= ey do not have the temperature stability suitable for a seismometer. &n= bsp;

       It is usual with amateur sensors to pro= vide a 30 to 60 second high pass filter to remove 1/f noise and baseline dri= ft.

The key is most probably the
r= ange of operation and these special kind of devices
are just not normally made available to the general public.

       Just what are these mysterious devices= and how do they work?

At the moment only a magnet coi= l seems to fill the billit
since I am unwilling to use home built AC devices like capacitive (moving pl= ates) or
inductive (moving cores) sensors.


       If you are unwilling to use either of=20= the two most common distance measuring techniques, you have severely restric= ted yourself. One of the sensors that I use has a 10 cm ferrite aerial rod a= nd a resolution of about 7 nano metres. It cost about $60 for the kit. Capac= itor systems are not difficult to make or to use and amateur designs are ava= ilable. I can see no logical reason to reject these.

If I had an fcc license I might try
those AC devices but since I do not I will not.


       So, what sort of device needs a FCC Li= cence?
       Certainly NOT LCDT or LVDT sensors!!
Right now only baseband and DC=20= are my options.
Low impedance front ends have always been best for me.

Is there any way for the layman to realistically research the new sensors th= at might be out there ?


       I know of three other options.

       One is a twin Silicon photodiode sensor= with a moving shutter and a filament bulb. You can design these for deflect= ions up to +/-10 mm at quite low cost and you may get the 15 nano metre reso= lution that I measured.

       Another is a Hall effect magnetic detec= tor with a quad NdFeB magnet block to drive it. These only have a working ra= nge of +/-1/2 mm at maybe 20 nano metres resolution, but they are OK for sim= ple pendulums, e.g. SG type.

       The third is to use a conducting water=20= manometer / tiltmeter type of device. It is not too difficult to make these=20= horizontal sensors work out to over 20 seconds. See Gile, WW, Geophys. J. Ro= y. Astro. Soc. vol 36 1974 pp 153-165 "A Mercury Pendulum Seismometer= " very good but a bit too large for amateurs. (You don't have to make them a= nything like so large! - you just have to be more clever!)

       If you know of any other sensor t= echnologies, do tell me! I am aware of some of the MEMs devices, but= the only ones that I have seen had a lousy noise performance.

       Regards,

       Chris Chapman Subject: Re: Multi-Dimensional-Sensor, First Time Of Arrival Only From: Dave Nelson davenn@............... Date: Fri, 29 Jun 2007 06:49:32 +1000 Thomas, cant access either of those links cant you check the address please :) Dave N At 12:40 PM 28/06/2007 -0500, you wrote: >Geoff, you go time to look at this and comment ... >This is a long time coming. I haven't created the bibliography yet. It is >5 megs.PHF file at http://i.bachcottage.com/Evv-Nov6-Tornado.pdf >word doc file at >http://i.bachcottage.com/TornadoAnalysisForTheEvansvilleIndianaNovember6.doc >__________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email PSN-L-REQUEST@.............. with the body of the >message (first line only): unsubscribe >See http://www.seismicnet.com/maillist.html for more information. > > >-- >No virus found in this incoming message. >Checked by AVG Free Edition. Version: 7.5.476 / Virus Database: >269.9.10/875 - Release Date: 27/06/2007 9:08 PM __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Multi-Dimensional-Sensor, First Time Of Arrival Only From: "Thomas Dick" dickthomas01@............. Date: Thu, 28 Jun 2007 16:44:28 -0500 I access it OK. There have been no local outages that I know of. Try again. Let me know. It IS 5 megs...lots of graphics. Your comments would be appreciated. ----- Original Message ----- From: "Dave Nelson" To: Sent: Thursday, June 28, 2007 3:49 PM Subject: Re: Multi-Dimensional-Sensor, First Time Of Arrival Only > Thomas, > cant access either of those links > cant you check the address please :) > > Dave N > > At 12:40 PM 28/06/2007 -0500, you wrote: >>Geoff, you go time to look at this and comment ... >>This is a long time coming. I haven't created the bibliography yet. It is >>5 megs.PHF file at http://i.bachcottage.com/Evv-Nov6-Tornado.pdf >>word doc file at >>http://i.bachcottage.com/TornadoAnalysisForTheEvansvilleIndianaNovember6.doc >>__________________________________________________________ >> >>Public Seismic Network Mailing List (PSN-L) >> >>To leave this list email PSN-L-REQUEST@.............. with the body of the >>message (first line only): unsubscribe >>See http://www.seismicnet.com/maillist.html for more information. >> >> >>-- >>No virus found in this incoming message. >>Checked by AVG Free Edition. Version: 7.5.476 / Virus Database: >>269.9.10/875 - Release Date: 27/06/2007 9:08 PM > > > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with the body of the > message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Multi-Dimensional-Sensor, First Time Of Arrival Only From: "Geoffrey" gmvoeth@........... Date: Thu, 28 Jun 2007 21:19:32 -0700 There is one called (not sure of spelling) michaelson Interferometer that uses a laser interference pattern to count the patterns and use this to tell the deflection of whatever. Have you ever seen anything relating to bouyancy or levitation ? I have the awareness that it might be possible with the aid of a PID loop (Proportional/Integral/Derivative) feedback like the cruise control in a car used in conjunction with a hall effect sensor to fix a mass at a stable point and measure the energy used to keep it at the refrence point. PID is commonly used in industrial control to fix settings like temperature and flow rates. Any Ideas Here ? Regards; geoff __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Multi-Dimensional-Sensor, First Time Of Arrival Only From: "Geoffrey" gmvoeth@........... Date: Thu, 28 Jun 2007 21:28:02 -0700 I downloaded the PDF file using Free Download Manager had Five connections going at once for various parts of the file and still got only 1.2KB/s download. I did get it tho. Thanx Will look at it later. Regards; geoff ----- Original Message ----- From: "Thomas Dick" To: Sent: Thursday, June 28, 2007 10:40 Subject: Re: Multi-Dimensional-Sensor, First Time Of Arrival Only > Geoff, you go time to look at this and comment ... > This is a long time coming. I haven't created the bibliography yet. It is 5 > megs.PHF file at http://i.bachcottage.com/Evv-Nov6-Tornado.pdf > word doc file at > http://i.bachcottage.com/TornadoAnalysisForTheEvansvilleIndianaNovember6.doc > > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Multi-Dimensional-Sensor, First Time Of Arrival Only From: ChrisAtUpw@....... Date: Fri, 29 Jun 2007 00:50:51 EDT In a message dated 2007/06/29, gmvoeth@........... writes: > There is one called (not sure of spelling) michaelson Interferometer > that uses a laser interference pattern to count the patterns > and use this to tell the deflection of whatever. Hi Geoff, The problem with these is that the wavelength of light is about 1/2 micron, which is LARGE in seismic terms. You can measure to small fractions of a wavelenght but it is both difficult and expensive. A couple of Si photocells and a filament lamp will give you much better seismic performance. MIs have 'been around' for about 100 years. > Have you ever seen anything relating to bouyancy or levitation ? I can't think of anything. > I have the awareness that it might be possible with the aid > of a PID loop (Proportional/Integral/Derivative) feedback > like the cruise control in a car used in conjunction with > a hall effect sensor to fix a mass at a stable point and measure > the energy used to keep it at the refrence point. > PID is commonly used in industrial control to fix settings > like temperature and flow rates. > Any Ideas Here ? > Sounds like a standard wide band seismic sensor to me. They use 3 component feedback. What were those other sensors you were talking about? Regards, Chris Chapman In a me= ssage dated 2007/06/29, gmvoeth@........... writes:

There is one called (not sure o= f spelling) michaelson Interferometer
that uses a laser interference pattern to count the patterns
and use this to tell the deflection of whatever.


Hi Geoff,

       The problem with these is that the wave= length of light is about 1/2 micron, which is LARGE in seismic terms. You ca= n measure to small fractions of a wavelenght but it is both difficult and ex= pensive. A couple of Si photocells and a filament lamp will give you much be= tter seismic performance.

       MIs have 'been around' for about 100 ye= ars.

Have you ever seen anything rel= ating to bouyancy or levitation ?


       I can't think of anything.

I have the awareness that it mi= ght be possible with the aid
of a PID loop (Proportional/Integral/Derivative) feedback
like the cruise control in a car used in conjunction with
a hall effect sensor to fix a mass at a stable point and measure
the energy used to keep it at the refrence point.
PID is commonly used in industrial control to fix settings
like temperature and flow rates.
Any Ideas Here ?

    Sounds like a standard wide band seismic sensor to me. Th= ey use 3 component feedback.

    What were those other sensors you were talking about?&nbs= p;

    Regards,

    Chris Chapman
 Subject: Re: Multi-Dimensional-Sensor, First Time Of Arrival Only From: "Geoffrey" gmvoeth@........... Date: Thu, 28 Jun 2007 22:26:44 -0700 > What were those other sensors you were talking about? > > Regards, > > Chris Chapman > > None that you do not already know but I was thinking if you could use buoyancy to offset gravity it may be possible to get longer periods using very small springs with large masses and the fluid providing the bouyancy would possible provide the damping. I think such a thing might be too sensitive to temp or pressure changes tho. But you need a specific gravity for the mass in the range of 1.1 to 1.05 that of the fluid to be used. Possibly with the science of fluidics you might make a pressure amplifier that will amplify static pressures caused by a moving container holding a liquid that acts as the stationary mass. Fluidics is a science like electronics that was invented to make circuits that are immune to RFI but they are limited to under 40KHz. The Mass would be slightly denser then the fluid used. Mercury as a liquid is out of the question due to poisonous effects. Possibly Salt water or some other relatively safe solution to increase density. Regards; geoff __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Multi-Dimensional-Sensor, First Time Of Arrival Only From: Dave Nelson davenn@............... Date: Fri, 29 Jun 2007 17:57:47 +1000 hi again, nope, jst come up with the usual ... The page cannot be displayed The page you are looking for is currently unavailable. The Web site might be experiencing technical difficulties, or you may need to adjust your browser settings. hmmmmm strange accessing other pages ok Is anyone else having problems with those 2 page addy's or is it just me ??? you may be loading out of your own cache, Thomas lets see if anyone else makes comments cheers Dave At 04:44 PM 28/06/2007 -0500, you wrote: >I access it OK. There have been no local outages that I know of. Try >again. Let me know. It IS 5 megs...lots of graphics. Your comments would >be appreciated. >----- Original Message ----- From: "Dave Nelson" >To: >Sent: Thursday, June 28, 2007 3:49 PM >Subject: Re: Multi-Dimensional-Sensor, First Time Of Arrival Only hi again,

    nope,  jst come up with the usual ...

The page cannot be displayed
The page you are looking for is currently unavailable. The Web site might be experiencing technical difficulties, or you may need to adjust your browser settings.

 hmmmmm strange   accessing other pages ok

Is anyone else having problems with those 2 page addy's or is it just me  ???

you may be loading out of your own cache,  Thomas   lets see if
anyone else makes comments

cheers
Dave


At 04:44 PM 28/06/2007 -0500, you wrote:
I access it OK. There have been no local outages that I know of. Try again. Let me know. It IS 5 megs...lots of graphics. Your comments would be appreciated.
----- Original Message ----- From: "Dave Nelson" <davenn@...............>
To: <psn-l@..............>
Sent: Thursday, June 28, 2007 3:49 PM
Subject: Re: Multi-Dimensional-Sensor, First Time Of Arrival Only

Subject: Seismic sensors From: Tangazazen@....... Date: Fri, 29 Jun 2007 04:26:29 EDT Hi, I note the recent interest in sensors for seismic use. I have used full bridge capacitive sensors for a vertical broadband unit which though work well, are time consuming to put together and test as well as being rather bulky. The quadrant photo cell is a better ready made precision device. A spot of light from an LED modulated at 10KHz is projected onto the cell and diametrically opposite quadrants are phase inverted to produce an X-Y signal that change phase and falls to zero as they cross the null point. The output signals are processed by phase sensitive detectors. Since these sorts of sensors are high impedance, the first stage needs a device with a high noise equivalent resistance such as an FET. Unfortunate the flicker noise appears in the noise voltage generator which is equal to the shot noise at 1 or 2 KHz. By operating at 10KHz and a narrow band filter ( phase lock loop time constant) the flicker noise becomes insignificant. The output in volt/ meter depend a lot on the support electronics but in general the quad photo cell approach seems to offer a high output. The LED is somewhat temperature sensitive (approx. -0.7% C ) but by summing the four quadrant and applying this as feedback this temperature dependence can be made negligible. For a single axis, pairs of quadrants could be used. This technique is more if a development that a new idea but might be of interest. Martin
Hi,
 
  I note the recent interest in sensors for seismic use. I ha= ve=20 used full bridge capacitive sensors for a vertical broadband unit which thou= gh=20 work well, are time consuming to put together and test as well as being rath= er=20 bulky. The quadrant photo cell is a better ready made precision device. = ;A=20 spot of light from an LED modulated at 10KHz is projected onto the cell and=20 diametrically opposite quadrants are phase inverted to produce an X-Y signal= =20 that change phase and falls to zero as they cross the null point. The output= =20 signals are processed by phase sensitive detectors. Since these sorts of sen= sors=20 are high impedance, the first stage needs a device with a high noise equival= ent=20 resistance such as an FET. Unfortunate the flicker noise appears in the= =20 noise voltage generator which is equal to the shot noise at 1 or 2 KHz. By=20 operating at 10KHz and a narrow band filter ( phase lock loop time=20 constant) the flicker noise becomes insignificant. The output in volt/=20 meter depend a lot on the support electronics but in general the quad p= hoto=20 cell approach seems to offer a high output. The LED is somewhat temperature=20 sensitive (approx. -0.7% C ) but by summing the four quadrant and applying t= his=20 as feedback this temperature dependence can be made negligible.  For a=20 single axis, pairs of quadrants could be used.=20       
  This technique is more if a development that a new idea but= =20 might be of interest. 
 
 
Martin
 Subject: Re: Multi-Dimensional-Sensor, First Time Of Arrival Only From: "Dale Hardy" photon1@........... Date: Fri, 29 Jun 2007 21:00:23 +1000 Nope, same here Dave, can't access either page, just times out, cannot = display, running IE7 regards Dale ----- Original Message -----=20 From: Dave Nelson=20 To: psn-l@................. Sent: Friday, June 29, 2007 5:57 PM Subject: Re: Multi-Dimensional-Sensor, First Time Of Arrival Only hi again, nope, jst come up with the usual ... The page cannot be displayed The page you are looking for is currently unavailable. The Web site = might be experiencing technical difficulties, or you may need to adjust = your browser settings. hmmmmm strange accessing other pages ok Is anyone else having problems with those 2 page addy's or is it just = me ??? you may be loading out of your own cache, Thomas lets see if anyone else makes comments cheers Dave At 04:44 PM 28/06/2007 -0500, you wrote: I access it OK. There have been no local outages that I know of. Try = again. Let me know. It IS 5 megs...lots of graphics. Your comments would = be appreciated. ----- Original Message ----- From: "Dave Nelson" = To: Sent: Thursday, June 28, 2007 3:49 PM Subject: Re: Multi-Dimensional-Sensor, First Time Of Arrival Only -------------------------------------------------------------------------= ----- No virus found in this incoming message. Checked by AVG Free Edition.=20 Version: 7.5.476 / Virus Database: 269.9.12/878 - Release Date: = 28/06/2007 5:57 PM
Nope, same here Dave, can't access = either page,=20 just times out, cannot display, running IE7
regards
Dale
----- Original Message -----
From:=20 Dave=20 Nelson
Sent: Friday, June 29, 2007 = 5:57 PM
Subject: Re: = Multi-Dimensional-Sensor,=20 First Time Of Arrival Only

hi again,

    nope,  jst = come up=20 with the usual ...

The page cannot be=20 displayed
The page you are looking for is currently = unavailable.=20 The Web site might be experiencing technical difficulties, or you may = need to=20 adjust your browser settings.

 hmmmmm strange  =20 accessing other pages ok

Is anyone else having problems with = those 2=20 page addy's or is it just me  ???

you may be loading out = of your=20 own cache,  Thomas   lets see if
anyone else makes=20 comments

cheers
Dave


At 04:44 PM 28/06/2007 = -0500, you=20 wrote:
I access it OK. There = have been=20 no local outages that I know of. Try again. Let me know. It IS 5 = megs...lots=20 of graphics. Your comments would be appreciated.
----- Original = Message=20 ----- From: "Dave Nelson" <davenn@...............>
To:=20 <psn-l@..............>
Sent: Thursday, June 28, 2007 3:49=20 PM
Subject: Re: Multi-Dimensional-Sensor, First Time Of Arrival=20 Only

No virus found in this incoming message.
Checked by AVG Free = Edition.
Version: 7.5.476 / Virus Database: 269.9.12/878 - Release = Date:=20 28/06/2007 5:57 PM
Subject: Re: Multi-Dimensional-Sensor, First Time Of Arrival Only From: ChrisAtUpw@....... Date: Fri, 29 Jun 2007 09:10:44 EDT In a message dated 2007/06/29 , photon1@........... writes: > Nope, same here Dave, can't access either page, just times out, cannot > display, running IE7, regards, Dale Hi All, I have just downloaded the pdf file, but it is ~3 Mb, so this takes several minutes unless you have a high speed broadband. Regards, Chris Chapman In a me= ssage dated 2007/06/29 , photon1@........... writes:

Nope, same here Dave, can't acc= ess either page, just times out, cannot display, running IE7, regards, Dale<= /FONT>=


Hi All,

       I have just downloaded the pdf file, bu= t it is ~3 Mb, so this takes several minutes unless you have a high speed br= oadband.

       Regards,

       Chris Chapman Subject: Re: Seismic sensors From: ChrisAtUpw@....... Date: Fri, 29 Jun 2007 09:57:37 EDT In a message dated 2007/06/29, Tangazazen@....... writes: > I note the recent interest in sensors for seismic use. The quadrant photo > cell is a better ready made precision device. A spot of light from an LED > modulated at 10KHz is projected onto the cell and diametrically opposite > quadrants are phase inverted to produce an X-Y signal that change phase and falls to > zero as they cross the null point. The output signals are processed by phase > sensitive detectors. Since these sorts of sensors are high impedance, the > first stage needs a device with a high noise equivalent resistance such as an > FET. Unfortunate the flicker noise appears in the noise voltage generator which > is equal to the shot noise at 1 or 2 KHz. By operating at 10KHz and a narrow > band filter (phase lock loop time constant) the flicker noise becomes > insignificant. The output in volt / meter depends a lot on the support electronics > but in general the quad photo cell approach seems to offer a high output. The > LED is somewhat temperature sensitive (approx. -0.7% C ) but by summing the > four quadrants and applying this as feedback this temperature dependence can > be made negligible. For a single axis, pairs of quadrants could be used. > > This technique is more of a development that a new idea but might be of > interest. Hi Martin, At what sort of current are you running your photo detectors? I used about 100 micro A and got a noise level of about 14 nano metres. The noise that you see is inversely proportional to the SQRT of the current. You do need to use large area photocells to get the noise down. CAZ opamps can be useful here, especially MAX430 or LTC1150. You can use a genuine chopper amplifier to reduce this further, maybe by x10. How 'quiet' or otherwise is your LED? The metal cased IR types are quite good, a lot of the others, much less so. I would call a drift of 0.7% / C Deg quite sensitive. Is this a measured figure? Most LEDs show maybe a factor of ~ x5 over 0 to 100 C? (You may need to read the small print in the spec sheet - LED manufacturers seem to be quite shy about the drift in their products) This is which is why I have used a filament lamp with a stable voltage regulator and a bypass transistor to handle the power. It is also relatively easy to stabilise the output signal level further using another Si photocell and a reference voltage. Regards, Chris Chapman In a me= ssage dated 2007/06/29, Tangazazen@....... writes:

I note the recent interest in s= ensors for seismic use. The quadrant photo cell is a better ready made preci= sion device. A spot of light from an LED modulated at 10KHz is projected ont= o the cell and diametrically opposite quadrants are phase inverted to produc= e an X-Y signal that change phase and falls to zero as they cross the null p= oint. The output signals are processed by phase sensitive detectors. Since t= hese sorts of sensors are high impedance, the first stage needs a device wit= h a high noise equivalent resistance such as an FET. Unfortunate the flicker= noise appears in the noise voltage generator which is equal to the shot noi= se at 1 or 2 KHz. By operating at 10KHz and a narrow band filter (phase lock= loop time constant) the flicker noise becomes insignificant. The output in=20= volt / meter depends a lot on the support electronics but in general the qua= d photo cell approach seems to offer a high output. The LED is somewhat temp= erature sensitive (approx. -0.7% C ) but by summing the four quadrants and a= pplying this as feedback this temperature dependence can be made negligible.=   For a single axis, pairs of quadrants could be used.   = ;   
  This technique is more of a development that a new idea but might be=20= of interest.


Hi Martin,

       At what sort of current are you running= your photo detectors? I used about 100 micro A and got a noise level of abo= ut 14 nano metres. The noise that you see is inversely proportional to the S= QRT of the current. You do need to use large area photocells to get the nois= e down. CAZ opamps can be useful here, especially MAX430 or LTC1150. You can= use a genuine chopper amplifier to reduce this further, maybe by x10.

       How 'quiet' or otherwise is your LED? T= he metal cased IR types are quite good, a lot of the others, much less so. I= would call a drift of 0.7% / C Deg quite sensitive. Is this a measured figu= re? Most LEDs show maybe a factor of ~ x5 over 0 to 100 C?  (You may ne= ed  to read the small print in the spec sheet - LED manufacturers seem=20= to be quite shy about the drift in their products)
       This is which is why I have used a fila= ment lamp with a stable voltage regulator and a bypass transistor to handle=20= the power. It is also relatively easy to stabilise the output signal level f= urther using another Si photocell and a reference voltage.

       Regards,

       Chris Chapman Subject: folded pendulum From: tchannel1@............ Date: Fri, 29 Jun 2007 10:27:58 -0600 Hi Folks, I am still experimenting with the basic structure of the = folded Pendulum linkage. One normal pendulum, one inverted pendulum and = a horz connecting arm. 1 I am assuming the length of the two pendulums should be the same and = as long a practical. I am thinking of 12 to 18" which would make the = sensor about 24" to 36" tall. I may go shorter........ 2 I gather the length of the horz connecting arm, should be a long a = practical. In that, a longer arm would allow more room along the horz = plane, on which to tweak the balance. A too short arm, would make the = balance point too small. I would be using a fine threaded rod with a threaded mass and a threaded = smaller mass, for extra fine adj. 3 Would such a device still require the same type of enclosure as a = Lehman or Vertical? 4 Would the size of the mass be critical? I would be using brass or SS = shim stock at all points for hinges. Thanks, Ted
Hi Folks,  I am still = experimenting with the=20 basic structure of the folded Pendulum linkage. One normal pendulum, one = inverted pendulum and a horz connecting arm.
 
1  I am assuming the length of the = two=20 pendulums should be the same and as long a practical.  I am = thinking of 12=20 to 18" which would make the sensor about 24" to 36" tall.  I may go = shorter........
 
2 I gather the length of the horz = connecting arm,=20 should be a long a practical.  In that, a longer arm would allow = more room=20 along the horz plane, on which to tweak the balance.  A too short = arm,=20 would make the balance point too small.
I would be using a fine threaded rod = with a=20 threaded mass and a threaded smaller mass, for extra fine = adj.
 
3  Would such a device still = require the same=20 type of enclosure as a Lehman or Vertical?
4  Would the size of the mass be=20 critical?  I would be using brass or SS shim stock at all points = for=20 hinges.
 
Thanks, Ted
Subject: Re: Seismic sensors From: Tangazazen@....... Date: Fri, 29 Jun 2007 13:52:18 EDT Hi Chris, Each of the photo detector quadrants generate about 0.7 microamp which are fed into virtual earth charge sensitive amplifiers. There are numerous noise sources but as you point out the shot noise associated with the photo current is dominant. The quadrant detector is 8mm dia, in fact a larger detector means a larger capacitance which in turn increases the noise. It is the 'lock-in amplifier' approach that controls the noise level. For an integration time of a few milliseconds the effective bandwidth at 10KHz is 100 - 200 or so Hz. Lock-in systems can pull out a signal that is substantially less than the noise level. The noise level of the LED has not been noticeable. The random conversion to photons is offset by the use of a diffuse encapsulation, a bit like an integrating sphere. The important requirement of the LED is uniformity of the light spot and reasonable linearity when modulated. The feedback from the sum of the quad elements is dynamic but there is a limit to how much the amplifier loop can correct for nonlinearity. LED temperature dependence under constant current conditions is non linear but -0.7% over 20C to 80C is an approximate figure for a Gallium Arsenide Phosphide at 670nm. The feedback loop as mentioned overcomes any temperature dependance. Interestingly LED temperature coefficients seems to get smaller at the shorter wavelength but the quantum yield of the LED and the response of the Silicon diode decrease, it's a question of optimisation. If I had to choose between full capacitive bridge and a quad photo detector I would choose the latter, It's a much more elegant solution. Regards Martin
Hi Chris,
 
      Each of the photo detector quadrants=20 generate about 0.7 microamp which are fed into virtual earth charge=20 sensitive amplifiers.
There are numerous noise sources but as you point out the shot noise=20 associated with the photo current is dominant. The quadrant detector is 8mm=20= dia,=20 in fact a larger detector means a larger capacitance which in turn increases= the=20 noise. It is the  'lock-in amplifier'  approach that controls the=20 noise level. For an integration time of a few milliseconds the effective=20 bandwidth at 10KHz is 100 - 200 or so Hz. Lock-in systems can pull out a sig= nal=20 that is substantially less than the noise level.
 
The noise level of the LED has not been noticeable. The=20 random conversion to photons is offset by the use of a diffuse=20 encapsulation, a bit like an integrating sphere. The important requirement o= f=20 the LED is uniformity of the light spot and reasonable linearity when modula= ted.=20 The feedback from the sum of the quad elements is dynamic but there is a lim= it=20 to how much the amplifier loop can correct for nonlinearity.
 
LED temperature dependence under constant current conditions is no= n=20 linear but -0.7% over 20C to 80C is an approximate figure for a Gallium Arse= nide=20 Phosphide at 670nm. The feedback loop as mentioned overcomes any=20 temperature dependance. Interestingly LED temperature coefficients= =20 seems to get smaller at the shorter wavelength but the quantum yield of the=20= LED=20 and the response of the Silicon diode decrease, it's a question of=20 optimisation.  
 
If I had to choose between full capacitive bridge and a quad photo dete= ctor=20 I would choose the latter, It's a much more elegant solution.
 
 
Regards Martin
 
 Subject: Re: Multi-Dimensional-Sensor, First Time Of Arrival Only From: "Thomas Dick" dickthomas01@............. Date: Fri, 29 Jun 2007 13:31:32 -0500 ----- Original Message ----- From: "Geoffrey" To: Sent: Thursday, June 28, 2007 11:28 PM Subject: Re: Multi-Dimensional-Sensor, First Time Of Arrival Only >I downloaded the PDF file using Free Download Manager had Five > connections going at once for various parts of the file and still got only > 1.2KB/s download. I did get it tho. > Thanx > Will look at it later. > > Regards; > geoff > ----- Original Message ----- > From: "Thomas Dick" > To: > Sent: Thursday, June 28, 2007 10:40 > Subject: Re: Multi-Dimensional-Sensor, First Time Of Arrival Only > > >> Geoff, you go time to look at this and comment ... >> This is a long time coming. I haven't created the bibliography yet. It is >> 5 megs.PHF file at http://i.bachcottage.com/Evv-Nov6-Tornado.pdf >> word doc file at >> http://i.bachcottage.com/TornadoAnalysisForTheEvansvilleIndianaNovember6.doc >> __________________________________________________________ >> >> Public Seismic Network Mailing List (PSN-L) >> >> To leave this list email PSN-L-REQUEST@.............. with the body of >> the message (first line only): unsubscribe >> See http://www.seismicnet.com/maillist.html for more information. >> > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with the body of the > message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: A little Friday coolness From: "Paul Cianciolo" Paulc@........ Date: Fri, 29 Jun 2007 16:06:52 -0400 Folks, With all the talk about pendulums, it reminded me of a article I saw in a magazine once. The article was about a Harmonograph. I won't even think about the math involved that would be Chris's department. It seems to me like a mechanical pendulum adding machine. Where the length, decay, friction.. all play a roll in drawing not a seismogram, but a ...? Early predecessor to the Spirograph toy?? Interesting, and not too far off topic. PauLC W1VLF http://physics.kenyon.edu/EarlyApparatus/Oscillations_and_Waves/Harmonograph s/Harmonographs.html
Folks,
 
With=20 all the talk about pendulums, it reminded me of a article I saw in a = magazine=20 once.
 
The=20 article was about a Harmonograph. 
 
I=20 won't even think about the math involved that would be Chris's=20 department.
 
It=20 seems to me like a mechanical pendulum adding = machine.
Where=20 the length, decay, friction.. all play a roll in drawing not a = seismogram, but a=20 ....?
 
Early=20 predecessor to the Spirograph toy??  Interesting, and not too far = off=20 topic.
 
PauLC
W1VLF
 
http://physics.kenyon.edu/EarlyApparatus= /Oscillations_and_Waves/Harmonographs/Harmonographs.html
 
 
Subject: Re: folded pendulum From: ChrisAtUpw@....... Date: Fri, 29 Jun 2007 20:45:18 EDT In a message dated 2007/06/29, tchannel1@............ writes: > Hi Folks, I am still experimenting with the basic structure of the folded > Pendulum linkage. One normal pendulum, one inverted pendulum and a horz > connecting arm. > > 1 I am assuming the length of the two pendulums should be the same and as > long a practical. I am thinking of 12 to 18" which would make the sensor about > 24" to 36" tall. I may go shorter........ Hi Ted, It very much depends on what maximum period you want? This is often 25 to 30 seconds for amateur equipment? I suggest that the shortest you consider should be 1 second at about 9.8". Above that, what is the maximum framesize that you can easily make? Maybe 2 ft square with 3" U channel? With your trial setup, you got a period extension of x10. You could probably get x20 fairly easily. > 2 I gather the length of the horz connecting arm, should be a long a > practical. In that, a longer arm would allow more room along the horz plane, on > which to tweak the balance. A too short arm, would make the balance point too > small. > I would be using a fine threaded rod with a threaded mass and a threaded > smaller mass, for extra fine adj. I suggest that you make the horizontal connecting arm out of brass to form the main mass. Then mount a small 'trim' mass just off centre. I don't think that the horizontal arm needs to be more than the pendulum length. You are critically dependant on the position of the mass to extend the period. Mount the main mass rgidly fixed. Don't mount it on threaded rod. > 3 Would such a device still require the same type of enclosure as a Lehman > or Vertical? Yes. It may be convenient to use 1/8" or 3/16" Al alloy plate to form the two sides and connect them together with either square rod or U channel to support the arms and to give an enclosed box structure. Maybe cut a hole in the centre of one plate to mount and adjust the sensor and damping components and provide a cover plate? > 4 Would the size of the mass be critical? I would be using brass or SS > shim stock at all points for hinges. Don't use Brass shim. SS or bronze should be fine. You are very dependant on getting good bearings to be able to extend the period. The load bearing capacity of the shim stock should be considered when deciding on the mass. Don't go above 1/10 the max. rated load stress. Consider the handling stresses. Don't make the arms very long and narrow - max about 5:1, maybe less? Design in stops to prevent the arm moving more than about 1/2" either way. Regards, Chris Chapman In a me= ssage dated 2007/06/29, tchannel1@............ writes:

Hi Folks, I am still experiment= ing with the basic structure of the folded Pendulum linkage. One normal pend= ulum, one inverted pendulum and a horz connecting arm.

1 I am assuming the length of the two pendulums should be the same and as l= ong a practical.  I am thinking of 12 to 18" which would make the senso= r about 24" to 36" tall.  I may go shorter........


Hi Ted,

       It very much depends on what maximum pe= riod you want? This is often 25 to 30 seconds for amateur equipment?

       I suggest that the shortest you conside= r should be 1 second at about 9.8". Above that, what is the maximum framesiz= e that you can easily make? Maybe 2 ft square with 3" U channel? With your t= rial setup, you got a period extension of x10. You could probably get x20 fa= irly easily.

2 I gather the length of the=20= horz connecting arm, should be a long a practical.  In that, a longer a= rm would allow more room along the horz plane, on which to tweak the balance= ..  A too short arm, would make the balance point too small.
I would be using a fine threaded rod with a threaded mass and a threaded sm= aller mass, for extra fine adj.


       I suggest that you make the horizontal= connecting arm out of brass to form the main mass. Then mount a small 'trim= ' mass just off centre. I don't think that the horizontal arm needs to be mo= re than the pendulum length. You are critically dependant on the position of= the mass to extend the period. Mount the main mass rgidly fixed. Don't moun= t it on threaded rod.

3 Would such a device still re= quire the same type of enclosure as a Lehman or Vertical?


       Yes. It may be convenient to use 1/8"=20= or 3/16" Al alloy plate to form the two sides and connect them together with= either square rod or U channel to support the arms and to give an enclosed=20= box structure. Maybe cut a hole in the centre of one plate to mount and adju= st the sensor and damping components and provide a cover plate?

4 Would the size of the mass b= e critical?  I would be using brass or SS shim stock at all points for=20= hinges.


       Don't use Brass shim. SS or bronze shou= ld be fine. You are very dependant on getting good bearings to be able to ex= tend the period. The load bearing capacity of the shim stock should be consi= dered when deciding on the mass. Don't go above 1/10 the max. rated load str= ess. Consider the handling stresses. Don't make the arms very long and narro= w - max about 5:1, maybe less? Design in stops to prevent the arm moving mor= e than about 1/2" either way.

       Regards,

       Chris Chapman Subject: Re: folded pendulum From: tchannel1@............ Date: Fri, 29 Jun 2007 21:38:17 -0600 Hi Chris, All good suggestions! If I understand you would use the = Arm for the Mass or the Arm also acts as the mass, With the mass already centered, you would only need a small amount of = mass on a threaded rod to tweak the period? Thank You, Ted ----- Original Message -----=20 From: ChrisAtUpw@.......... To: psn-l@................. Sent: Friday, June 29, 2007 6:45 PM Subject: Re: folded pendulum In a message dated 2007/06/29, tchannel1@............ writes: Hi Folks, I am still experimenting with the basic structure of the = folded Pendulum linkage. One normal pendulum, one inverted pendulum and = a horz connecting arm. 1 I am assuming the length of the two pendulums should be the same = and as long a practical. I am thinking of 12 to 18" which would make = the sensor about 24" to 36" tall. I may go shorter........ Hi Ted, It very much depends on what maximum period you want? This is = often 25 to 30 seconds for amateur equipment? I suggest that the shortest you consider should be 1 second at = about 9.8". Above that, what is the maximum framesize that you can = easily make? Maybe 2 ft square with 3" U channel? With your trial setup, = you got a period extension of x10. You could probably get x20 fairly = easily. 2 I gather the length of the horz connecting arm, should be a long a = practical. In that, a longer arm would allow more room along the horz = plane, on which to tweak the balance. A too short arm, would make the = balance point too small. I would be using a fine threaded rod with a threaded mass and a = threaded smaller mass, for extra fine adj. I suggest that you make the horizontal connecting arm out of = brass to form the main mass. Then mount a small 'trim' mass just off = centre. I don't think that the horizontal arm needs to be more than the = pendulum length. You are critically dependant on the position of the = mass to extend the period. Mount the main mass rgidly fixed. Don't mount = it on threaded rod. 3 Would such a device still require the same type of enclosure as a = Lehman or Vertical? Yes. It may be convenient to use 1/8" or 3/16" Al alloy plate = to form the two sides and connect them together with either square rod = or U channel to support the arms and to give an enclosed box structure. = Maybe cut a hole in the centre of one plate to mount and adjust the = sensor and damping components and provide a cover plate? 4 Would the size of the mass be critical? I would be using brass or = SS shim stock at all points for hinges. Don't use Brass shim. SS or bronze should be fine. You are very = dependant on getting good bearings to be able to extend the period. The = load bearing capacity of the shim stock should be considered when = deciding on the mass. Don't go above 1/10 the max. rated load stress. = Consider the handling stresses. Don't make the arms very long and narrow = - max about 5:1, maybe less? Design in stops to prevent the arm moving = more than about 1/2" either way. Regards, Chris Chapman
Hi Chris,  All good=20 suggestions!    If I understand you would use = the Arm for=20 the Mass or the Arm also acts as the mass,
With the mass already centered, you = would only need=20 a small amount of mass on a threaded rod to tweak the = period?
Thank You, Ted
----- Original Message -----
From:=20 ChrisAtUpw@.......
Sent: Friday, June 29, 2007 = 6:45 PM
Subject: Re: folded = pendulum

In a=20 message dated 2007/06/29, tchannel1@............=20 writes:

Hi Folks, I am still experimenting with the basic = structure of=20 the folded Pendulum linkage. One normal pendulum, one inverted = pendulum and=20 a horz connecting arm.

1 I am assuming the length of the two pendulums = should be the=20 same and as long a practical.  I am thinking of 12 to 18" which = would=20 make the sensor about 24" to 36" tall.  I may go=20 shorter........

Hi=20 Ted,

       It very much depends = on what=20 maximum period you want? This is often 25 to 30 seconds for amateur=20 equipment?

       I suggest that = the=20 shortest you consider should be 1 second at about 9.8". Above that, = what is=20 the maximum framesize that you can easily make? Maybe 2 ft square with = 3" U=20 channel? With your trial setup, you got a period extension of x10. You = could=20 probably get x20 fairly easily.

2 I=20 gather the length of the horz connecting arm, should be a long a=20 practical.  In that, a longer arm would allow more room along = the horz=20 plane, on which to tweak the balance.  A too short arm, would = make the=20 balance point too small.
I would be using = a fine=20 threaded rod with a threaded mass and a threaded smaller mass, for = extra=20 fine adj.

       I=20 suggest that you make the horizontal connecting arm out of brass to = form the=20 main mass. Then mount a small 'trim' mass just off centre. I don't = think that=20 the horizontal arm needs to be more than the pendulum length. You are=20 critically dependant on the position of the mass to extend the period. = Mount=20 the main mass rgidly fixed. Don't mount it on threaded = rod.

 3 Would such a device still require the same type of = enclosure=20 as a Lehman or Vertical?

       Yes. It=20 may be convenient to use 1/8" or 3/16" Al alloy plate to form the two = sides=20 and connect them together with either square rod or U channel to = support the=20 arms and to give an enclosed box structure. Maybe cut a hole in the = centre of=20 one plate to mount and adjust the sensor and damping components and = provide a=20 cover plate?

 4 Would the size of the mass be critical?  I would = be using=20 brass or SS shim stock at all points for hinges.

       Don't use = Brass shim.=20 SS or bronze should be fine. You are very dependant on getting good = bearings=20 to be able to extend the period. The load bearing capacity of the shim = stock=20 should be considered when deciding on the mass. Don't go above 1/10 = the max.=20 rated load stress. Consider the handling stresses. Don't make the arms = very=20 long and narrow - max about 5:1, maybe less? Design in stops to = prevent the=20 arm moving more than about 1/2" either=20 way.

      =20 Regards,

       Chris = Chapman=20 Subject: Re: folded pendulum From: ChrisAtUpw@....... Date: Sat, 30 Jun 2007 02:13:58 EDT In a message dated 2007/06/30, tchannel1@............ writes: > Hi Chris, If I understand, you would use the Arm for the Mass or the Arm > also acts as the mass. > With the mass already centered, you would only need a small amount of mass > on a threaded rod to tweak the period? > Thank You, Ted Hi Ted, That is correct. Making the horizontal arm fairly heavy to act as the mass should give it a very high position stability and symmetry. There should be minimal thermal expansion problems. You would then just move the period trim mass, which might be only a few % of the total mass. A small error in the position of the trim mass should be tiny in comparison to the total mass. The lateral forces from the two pendulums subtract, hence you need very high stability. I suggest that you first make the frame, the pendulums and the arm and then slide a trim block along the arm. You might start with about 5% and see if this is adequate or if it could be reduced. You will likely need to fit a magnetic damper from the start. Remember that the damping required decreases as the period increases. If you make the main mass, the trim mass, the mounting fittings and the threaded adjuster all out of brass, all the thermal expansions should match. The Australians chemically machined a complete square form seismometer, including the flexures, out of a solid block of bronze to get very high dimensional stability. There are several interesting papers on seismometers and flexures in the publications list at http://www.gravity.uwa.edu.au/ There used to be some on line both there and a LIGO in the USA. Regards, Chris Chapman In a me= ssage dated 2007/06/30, tchannel1@............ writes:

Hi Chris,  If I understand= , you would use the Arm for the Mass or the Arm also acts as the mass.
With the mass already centered, you would only need a small amount of mass=20= on a threaded rod to tweak the period?
Thank You, Ted


Hi Ted,

       That is correct. Making the horizontal=20= arm fairly heavy to act as the mass should give it a very high position stab= ility and symmetry. There should be minimal thermal expansion problems. You=20= would then just move the period trim mass, which might be only a few % of th= e total mass. A small error in the position of the trim mass should be tiny=20= in comparison to the total mass.

       The lateral forces from the two pendulu= ms subtract, hence you need very high stability. I suggest that you first ma= ke the frame, the pendulums and the arm and then slide a trim block along th= e arm. You might start with about 5% and see if this is adequate or if it co= uld be reduced. You will likely need to fit a magnetic damper from the start= .. Remember that the damping required decreases as the period increases.

       If you make the main mass, the trim mas= s, the mounting fittings and the threaded adjuster all out of brass, all the= thermal expansions should match. The Australians chemically machined a comp= lete square form seismometer, including the flexures, out of a solid block o= f bronze to get very high dimensional stability.

       There are several interesting papers on= seismometers and flexures in the publications list at http://www.gravity.uw= a.edu.au/ There used to be some on line both there and a LIGO in the USA.
       Regards,

       Chris Chapman Subject: Re: Multi-Dimensional-Sensor, First Time Of Arrival Only From: Ben Bradley benbradley@............... Date: Sat, 30 Jun 2007 08:02:54 -0500 Geoffrey wrote: > There is one called (not sure of spelling) michaelson Interferometer > that uses a laser interference pattern to count the patterns > and use this to tell the deflection of whatever. > > Have you ever seen anything relating to bouyancy or levitation ? > > I have the awareness that it might be possible with the aid > of a PID loop (Proportional/Integral/Derivative) feedback > like the cruise control in a car used in conjunction with > a hall effect sensor to fix a mass at a stable point and measure > the energy used to keep it at the refrence point. > PID is commonly used in industrial control to fix settings > like temperature and flow rates. > Any Ideas Here ? Yes, the PID "force feedback" thing has been done. Here's an example: http://www.keckec.com/seismo/ > > Regards; > geoff __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: folded pendulum From: tchannel1@............ Date: Sat, 30 Jun 2007 06:51:42 -0600 Chris, This may be hard to answer. In this case, the mass would only = be an amount required to do the job. I have read that some people use very little mass, others a lot. On a = vertical and on a horz one gets the idea of how much to use. This a = bit different, and here is where I could use some direction. 1 If I added no mass, simply the connecting arm, made of the same = material as the pendulums, and the same length or maybe longer. This = arm is the mass, and as such is not much of a stress on the SS? shims = used as hinges. My mock up was made like this. Then I added a large mass, everything = seemed to work the same. But using a large mass would put a lot of = strain on the hinges. 2 About the only advantage I can see with a large mass is that air = currents would be less likely to move it. 3 It would be easy to construct it either way, Perhaps no addition mass = is too little, and an amount which stressed the hinges is too much? Is = 1/2 that amount proper? I understand your suggest about the 5% trim = weight. Thanks, Ted ----- Original Message -----=20 From: ChrisAtUpw@.......... To: psn-l@................. Sent: Saturday, June 30, 2007 12:13 AM Subject: Re: folded pendulum In a message dated 2007/06/30, tchannel1@............ writes: Hi Chris, If I understand, you would use the Arm for the Mass or = the Arm also acts as the mass. With the mass already centered, you would only need a small amount = of mass on a threaded rod to tweak the period? Thank You, Ted Hi Ted,=20 That is correct. Making the horizontal arm fairly heavy to act = as the mass should give it a very high position stability and symmetry. = There should be minimal thermal expansion problems. You would then just = move the period trim mass, which might be only a few % of the total = mass. A small error in the position of the trim mass should be tiny in = comparison to the total mass.=20 The lateral forces from the two pendulums subtract, hence you = need very high stability. I suggest that you first make the frame, the = pendulums and the arm and then slide a trim block along the arm. You = might start with about 5% and see if this is adequate or if it could be = reduced. You will likely need to fit a magnetic damper from the start. = Remember that the damping required decreases as the period increases. If you make the main mass, the trim mass, the mounting fittings = and the threaded adjuster all out of brass, all the thermal expansions = should match. The Australians chemically machined a complete square form = seismometer, including the flexures, out of a solid block of bronze to = get very high dimensional stability.=20 There are several interesting papers on seismometers and = flexures in the publications list at http://www.gravity.uwa.edu.au/ = There used to be some on line both there and a LIGO in the USA. Regards, Chris Chapman
Chris,    This may be = hard to=20 answer.  In this case, the mass would only be  an amount = required to=20 do the job.
I have read that some people use = very little=20 mass, others a lot.  On a vertical and on a horz one gets the idea = of how=20 much to use.   This a bit different, and here is where I could = use=20 some direction.
 
1  If I added no mass, simply the = connecting=20 arm, made of the same material as the pendulums, and the same length or = maybe=20 longer.   This arm is the mass, and as such is not much of a = stress on=20 the SS? shims used as hinges.
My mock up was made like = this.   Then I=20 added a large mass, everything seemed to work the same. But using a = large mass=20 would  put a lot of strain on the hinges.
 
2  About the only advantage I can = see with a=20 large mass is that air currents would be less likely to move = it.
 
3 It would be easy to construct it = either=20 way,  Perhaps no addition mass is too little, and an amount which = stressed=20 the hinges is too much?  Is 1/2 that amount = proper?    I=20 understand your suggest about the 5% trim weight.
 
Thanks, Ted
 
 
----- Original Message -----
From:=20 ChrisAtUpw@.......
Sent: Saturday, June 30, 2007 = 12:13=20 AM
Subject: Re: folded = pendulum

In a=20 message dated 2007/06/30, tchannel1@............=20 writes:

Hi Chris,  If I understand, you would use the Arm = for the=20 Mass or the Arm also acts as the mass.
With the mass = already=20 centered, you would only need a small amount of mass on a threaded = rod to=20 tweak the period?
Thank You, Ted

Hi Ted,=20

       That is correct. Making = the=20 horizontal arm fairly heavy to act as the mass should give it a very = high=20 position stability and symmetry. There should be minimal thermal = expansion=20 problems. You would then just move the period trim mass, which might = be only a=20 few % of the total mass. A small error in the position of the trim = mass should=20 be tiny in comparison to the total mass.=20

       The lateral forces from = the two=20 pendulums subtract, hence you need very high stability. I suggest that = you=20 first make the frame, the pendulums and the arm and then slide a trim = block=20 along the arm. You might start with about 5% and see if this is = adequate or if=20 it could be reduced. You will likely need to fit a magnetic damper = from the=20 start. Remember that the damping required decreases as the period=20 increases.

       If you make the = main=20 mass, the trim mass, the mounting fittings and the threaded adjuster = all out=20 of brass, all the thermal expansions should match. The Australians = chemically=20 machined a complete square form seismometer, including the flexures, = out of a=20 solid block of bronze to get very high dimensional stability.=20

       There are several = interesting=20 papers on seismometers and flexures in the publications list at=20 http://www.gravity.uwa.edu.au/ There used to be some on line both = there and a=20 LIGO in the USA.

      =20 Regards,

       Chris = Chapman=20 Subject: Period From: tchannel1@............ Date: Sat, 30 Jun 2007 07:07:19 -0600 Hi All, I just did a side by side comparison of an Earthquake recorded = by a Vertical with a 2? second period and a Horz Pendulum with a 10? = second period. The different on this 6.7M at 10000km was very = pronounced, showing all the advantages of the Horz. However, using the Vertical, I record many more Earthquake, and smaller = ones. If the event is large, both sensors are impressive (to me). In planning my next sensor, I need to pick a target period. I already = see the advantage of each. What period might be the best target? Or = is it just better to pick one end of the spectrum and not the center? Thanks, Ted
Hi All,  I just did a side by side = comparison=20 of an Earthquake recorded by a Vertical with a 2? second period and a = Horz=20 Pendulum with a 10? second period.  The different on this 6.7M at = 10000km=20 was very pronounced, showing all the advantages of the = Horz.
 
However, using the Vertical, I record = many more=20 Earthquake, and smaller ones.  If the event is large, both sensors = are=20 impressive (to me).
 
In planning my next sensor, I need to = pick a target=20 period.   I already see the advantage of each.  What = period might=20 be the best target?   Or is it just better to pick one = end of the=20 spectrum and not the center?
 
Thanks, Ted
Subject: Re: Period From: ChrisAtUpw@....... Date: Sat, 30 Jun 2007 11:00:18 EDT In a message dated 2007/06/30, tchannel1@............ writes: > Hi All, I just did a side by side comparison of an Earthquake recorded by > a Vertical with a 2? second period and a Horz Pendulum with a 10? second > period. The different on this 6.7M at 10000km was very pronounced, showing all > the advantages of the Horz. > > However, using the Vertical, I record many more Earthquake, and smaller > ones. If the event is large, both sensors are impressive (to me). > > In planning my next sensor, I need to pick a target period. I already see > the advantage of each. What period might be the best target? Or is it just > better to pick one end of the spectrum and not the center? Hi Ted, The 'old type' seismic systems used short and long period sensors to avoid the ocean background signals between 4 and 10 seconds. With computer data capture and analysis, this is no longer necessary, but you may choose to use a twin Tee reject filter operating at about 6 seconds. The P waves tend to roll in from 0.5 to 10 Hz, with frequencies over 3.3 Hz associated with quakes less than 1000 km away. You often look for P waves from 1 to 3 Hz. The S waves roll in at 0.2 to 10 Hz, with frequencies over 2 Hz assocoiated with quakes less than 1000 km away. The frequency is slightly more than half the associated P wave. The Love and Rayleigh waves may have periods from 2 to 500 sec, but many have periods ~20 seconds, occasionally over 40 seconds. It is fairly easy to makea vertical sensor with a period of 0.5 to 0.67 Hz and above. This can be extended to 1/10 th electronically. Lehman horizontal types are fairly easy to make out to 20 to 30 seconds. Above this they tend to be very sensitive to ground tilt changes / instability. Adding feedback can help a lot. Regards, Chris Chapman In a me= ssage dated 2007/06/30, tchannel1@............ writes:

Hi All,  I just did a side= by side comparison of an Earthquake recorded by a Vertical with a 2? second= period and a Horz Pendulum with a 10? second period.  The different on= this 6.7M at 10000km was very pronounced, showing all the advantages of the= Horz.

However, using the Vertical, I record many more Earthquake, and smaller one= s.  If the event is large, both sensors are impressive (to me).<= FONT COLOR=3D"#000000" BACK=3D"#ffffff" style=3D"BACKGROUND-COLOR: #ffffff"= SIZE=3D3 PTSIZE=3D12 FAMILY=3D"SANSSERIF" FACE=3D"Arial" LANG=3D"0">

In planning my next sensor, I need to pick a target period. I already see t= he advantage of each.  What period might be the best target?  Or i= s it just better to pick one end of the spectrum and not the center?<= FONT COLOR=3D"#000000" BACK=3D"#ffffff" style=3D"BACKGROUND-COLOR: #ffffff"= SIZE=3D3 PTSIZE=3D12 FAMILY=3D"SANSSERIF" FACE=3D"Arial" LANG=3D"0">

Hi Ted,

       The 'old type' seismic systems used sho= rt and long period sensors to avoid the ocean background signals between 4 a= nd 10 seconds. With computer data capture and analysis, this is no longer ne= cessary, but you may choose to use a twin Tee reject filter operating at abo= ut 6 seconds.
       The P waves tend to roll in from 0.5 to= 10 Hz, with frequencies over 3.3 Hz associated with quakes less than 1000 k= m away. You often look for P waves from 1 to 3 Hz.
       The S waves roll in at 0.2 to 10 Hz, wi= th frequencies over 2 Hz assocoiated with quakes less than 1000 km away. The= frequency is slightly more than half the associated P wave.
       The Love and Rayleigh waves may have pe= riods from 2 to 500 sec, but many have periods ~20 seconds, occasionally ove= r 40 seconds.
       It is fairly easy to makea vertical sen= sor with a period of 0.5 to 0.67 Hz and above. This can be extended to 1/10=20= th electronically.
       Lehman horizontal types are fairly easy= to make out to 20 to 30 seconds. Above this they tend to be very sensitive=20= to ground tilt changes / instability. Adding feedback can help a lot.

       Regards,

       Chris Chapman Subject: Re: folded pendulum From: ChrisAtUpw@....... Date: Sat, 30 Jun 2007 14:36:42 EDT In a message dated 2007/06/30, tchannel1@............ writes: > Chris, This may be hard to answer. In this case, the mass would only be > an amount required to do the job. > I have read that some people use very little mass, others a lot. On a > vertical and on a horz one gets the idea of how much to use. This a bit different, > and here is where I could use some direction. > > 1 If I added no mass, simply the connecting arm, made of the same material > as the pendulums, and the same length or maybe longer. This arm is the mass, > and as such is not much of a stress on the SS? shims used as hinges. > My mock up was made like this. Then I added a large mass, everything seemed > to work the same. But using a large mass would put a lot of strain on the > hinges. Hi Ted, If you had a very light central arm, the period of the end pendulums would be reduced to about 1/4 - the CofG of a vertical bar is half way along it. Actually, it is the radius of gyration about the end of the bar which is the critical factor. You need a mass over 10x the mass of the vertical arms. I would design for something between 1 and 5 Lbs, depending on the vertical weights. This hinge shims should cope with this quite easily. > 2 About the only advantage I can see with a large mass is that air > currents would be less likely to move it. A large mass is less effected by air currents, but you will still see them. You will need an enclosure. This is another reason why I was suggesting sheet Al side plates. They would tend to conduct heat quite well and would minimise any internal temperature variations. > 3 It would be easy to construct it either way, Perhaps no addition mass > is too little, and an amount which stressed the hinges is too much? Is 1/2 > that amount proper? I understand your suggest about the 5% trim weight. 1 Lbf/sq in = 6895 Pa. The strength of chromenickel steel is listed as 1000 to 1500 Mega Pa. Taking the lower figure and assuming that you are using 2 thou x 1" total width hinges gives a max load of about 290 lbs, so a 29 lbs working load should be OK. You are unlikely to have a load problem. Before WWII, seismometers often had to move high ratio mechanical pen arms, with gains up to over 100, so they needed a large mass to overcome friction. This heavy thinking sort of 'carried over' into amateur equipment. Some of the early Lehman equipment used a solid steel arm, so you needed an end mass which was large compared to this to get a long period. A 1/2" steel bar weighs ~0.665 Lb per foot. 3ft weighs ~2 Lbs, so an end mass of 10 lbs is not excessive. I use 1/2" nominal = 15mm OD SS water pipe, which weighs 0.143 Lb per foot, so a 2.2 lb end mass is fine. The large pipe diameter makes it sufficiently rigid. Regards, Chris Chapman In a me= ssage dated 2007/06/30, tchannel1@............ writes:

Chris,    This m= ay be hard to answer. In this case, the mass would only be an amount require= d to do the job.
I have read that some people use very little mass, others a lot. On a verti= cal and on a horz one gets the idea of how much to use. This a bit different= , and here is where I could use some direction.

1  If I added no mass, simply the connecting arm, made of the same mat= erial as the pendulums, and the same length or maybe longer. This arm is the= mass, and as such is not much of a stress on the SS? shims used as hinges.<= /FONT>=
My mock up was made like this. Then I added a large mass, everything seemed= to work the same. But using a large mass would  put a lot of strain on= the hinges.


Hi Ted,

       If you had a very light central arm, th= e period of the end pendulums would be reduced to about 1/4 - the CofG of a=20= vertical bar is half way along it. Actually, it is the radius of gyration ab= out the end of the bar which is the critical factor.
       You need a mass over 10x the mass of th= e vertical arms. I would design for something between 1 and 5 Lbs, depending= on the vertical weights. This hinge shims should cope with this quite easil= y.

2  About the only advanta= ge I can see with a large mass is that air currents would be less likely to=20= move it.


       A large mass is less effected by air c= urrents, but you will still see them. You will need an enclosure. This is an= other reason why I was suggesting sheet Al side plates. They would tend to c= onduct heat quite well and would minimise any internal temperature variation= s.

3 It would be easy to constru= ct it either way,  Perhaps no addition mass is too little, and an amoun= t which stressed the hinges is too much?  Is 1/2 that amount proper? I=20= understand your suggest about the 5% trim weight.


       1 Lbf/sq in =3D 6895 Pa. The strength o= f chromenickel steel is listed as 1000 to 1500 Mega Pa. Taking the lower fig= ure and assuming that you are using 2 thou x 1" total width hinges gives a m= ax load of about 290 lbs, so a 29 lbs working load should be OK. You are unl= ikely to have a load problem.

       Before WWII, seismometers often had to=20= move high ratio mechanical pen arms, with gains up to over 100, so they need= ed a large mass to overcome friction. This heavy thinking sort of 'carried o= ver' into amateur equipment.
       Some of the early Lehman equipment used= a solid steel arm, so you needed an end mass which was large compared to th= is to get a long period. A 1/2" steel bar weighs ~0.665 Lb per foot. 3ft wei= ghs ~2 Lbs, so an end mass of 10 lbs is not excessive.
       I use 1/2" nominal =3D 15mm OD SS water= pipe, which weighs 0.143 Lb per foot, so a 2.2 lb end mass is fine. The lar= ge pipe diameter makes it sufficiently rigid.

       Regards,

       Chris Chapman