Subject: Leap Second From: "Robert McClure" bobmcclure90@......... Date: Thu, 1 Jan 2009 21:32:55 -0500 Data loggers, did you observe that 12-31-2008 was one second longer than ususal? See http://tf.nist.gov/pubs/bulletin/leapsecond.htm I keep my timing manually aligned with WWVB. My clocks self-adjusted their timing backward one second to accomodate the leap-second. I do not know how Larry's GPS timing accommodated the change. Not to says that it all matters much. I have never seen microseisms as strong as they have been so far this winter. I cannot see anything but major events, of which there have not been any lately. I live on Long Island, NY, on the Atlantic coast, and am exposed to both ocean microseisms and the shorter period land microseisms from weather fronts. I did pick up a rare local event on 12/27/2008, an M3.4 from southeastern Pennsylvania. See 081227.050500.rem.psn. Happy New Year to all, Bob   Data loggers, did you observe that 12-31-2008 was one second longer than ususal? See

http://tf.nist.gov/pubs/bulletin/leapsecond.htm

  I keep my timing manually aligned with WWVB. My clocks self-adjusted their timing backward one second to accomodate the leap-second. I do not know how Larry's GPS timing accommodated the change.

  Not to says that it all matters much. I have never seen microseisms as strong as they have been so far this winter. I cannot see anything but major events, of which there have not been any lately. I live on Long Island, NY, on the Atlantic coast, and am exposed to both ocean microseisms and the shorter period land microseisms from weather fronts. I did pick up a rare local event on 12/27/2008, an M3.4 from southeastern Pennsylvania. See 081227.050500.rem.psn.

  Happy New Year to all,

Bob
Subject: Could An Electric Guitar String Pickup Be used to sense Earthquakes ? From: "Geoff" gmvoeth@........... Date: Tue, 20 Jan 2009 19:16:43 -0700 I was just watching this show on how it works and they dissected an electric guitar it uses magnets to set up a steady field which is disrupted by a vibrating string. Has anyone tried using such a pickup for sensing the motion of a pendulum ?? They say there is a considerable amount of copper wire used in the pickup...it may be more sensitive than the common magnet and coil ?? I'm always looking for a new CHEAP passive way to sense seismic waves. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: home made vertical seismometer From: "rog@........... rog@eipi10.org Date: Sat, 24 Jan 2009 13:10:25 -0800 I have just joined the list and am looking for suggestions for good examples and instructions for home made vertical seismometers. I have a Lowes and Home Depot near by. I have purchased the electronic elements from Larry. Robert __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: home made vertical seismometer From: ChrisAtUpw@....... Date: Sat, 24 Jan 2009 17:49:46 EST In a message dated 24/01/2009, rog@.......... writes: I have just joined the list and am looking for suggestions for good examples and instructions for home made vertical seismometers. Hi Robert, It is only possible to make a simple vertical seismometer with a stable period of less than about 6 seconds. This is due to the large temperature coefficient of Young's Modulus for steel. If you try to make one with a much longer period, it simply collapses as the room temperature rises a few degrees. Elinvar and Ni-SpanC springs were developed to overcome the problem, but you also need a quite critical design, first described in 1934 by LaCoste. See the references on _http://psn.quake.net/infoequip.html_ (http://psn.quake.net/infoequip.html) Another approach is to make a simple seismometer with a period of maybe 1.5 to 2 seconds and then selectively compensate the F^2 signal response drop off below resonance with a 1/F^2 amplifier. You can extend the period by up to about x20 this way, but you need to design very low noise electronics. See _http://jclahr.com/science/psn/hill/index.html_ (http://jclahr.com/science/psn/hill/index.html) but DO use magnetic damping, NOT oil! The other approach to get longer stable periods is to use a similar setup, but to provide a 3 element force feedback system. Look at the STM-8 on psn, designed by Sean Morrissey _http://www.eas.slu.edu/People/STMorrissey/index.html_ (http://www.eas.slu.edu/People/STMorrissey/index.html) and _http://www.bryantlabs.net/seismo.html_ (http://www.bryantlabs.net/seismo.html) I don't want to discourage you, but it is MUCH easier to make a good horizontal seismometer with a period of up to 30 seconds. See _http://www.bgs.ac.uk/schoolseismology/_ (http://www.bgs.ac.uk/schoolseismology/) and click on 'seismometer'. See also the Volksmeter at _http://www.rllinstruments.com/_ (http://www.rllinstruments.com/) Regards, Chris Chapman
In a message dated 24/01/2009, rog@.......... writes:
<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size= =3D2>I have=20 just joined the list and am looking for suggestions for good
examples=20= and=20 instructions for home made vertical seismometers.
<= /DIV>
Hi Robert,
 
    It is only possible to make a simple vertical=20 seismometer with a stable period of less than about 6 seconds. This is due t= o=20 the large temperature coefficient of Young's Modulus for steel. If you try t= o=20 make one with a much longer period, it simply collapses as the room temperat= ure=20 rises a few degrees. Elinvar and Ni-SpanC springs were developed to overcome= the=20 problem, but you also need a quite critical design, first described in 1934=20= by=20 LaCoste. See the references on http://psn.quake.net/infoequip.= html
 
    Another approach is to make a simple seismomete= r=20 with a period of maybe 1.5 to 2 seconds and then selectively compensate the=20= F^2=20 signal response drop off below resonance with a 1/F^2 amplifier. You ca= n=20 extend the period by up to about x20 this way, but you need to design very l= ow=20 noise electronics. See http://jclahr.com/sci= ence/psn/hill/index.html  but=20 DO use magnetic damping, NOT oil!
 
    The other approach to get longer stable periods= is=20 to use a similar setup, but to provide a 3 element force feedback=20 system. Look at the STM-8 on psn, designed by Sean Morrissey http://www.eas= ..slu.edu/People/STMorrissey/index.html and=20 http://www.bryantlabs.net/sei= smo.html
 
    I don't want to discourage you, but it is MUCH=20 easier to make a good horizontal seismometer with a period of up to 30 secon= ds.=20 See http://www.bgs.ac.uk/schools= eismology/ and=20 click on 'seismometer'. See also the Volksmeter at http://www.rllinstruments.com/
 
    Regards,
 
    Chris Chapman
    
Subject: Re: home made vertical seismometer From: "tchannel" tchannel@............ Date: Sat, 24 Jan 2009 16:48:37 -0700 Hi Folks, Thanks Chris for the links below, the UK School project was = very nice. =20 Here is an unrelated question, except the UK site explained the use of = the software, Amaseis..........which I have use and I am still using it = at some stations. It has a feature which allow you to "replay" the = recorded helicorder, trace and speed it up. The result is impressive = as you can replay and watch the event unfold in just a few seconds. My = question is there a way to capture this 10 or 15 second screen event and = save it as some kind of movie file which could be emailed to others. = I do not see this "replay" feature in WinSDR. So this feature may only = be on Amaseis. Thanks, Ted ----- Original Message -----=20 From: ChrisAtUpw@.......... To: psn-l@................. Sent: Saturday, January 24, 2009 3:49 PM Subject: Re: home made vertical seismometer In a message dated 24/01/2009, rog@.......... writes: I have just joined the list and am looking for suggestions for good=20 examples and instructions for home made vertical seismometers. Hi Robert, It is only possible to make a simple vertical seismometer with a = stable period of less than about 6 seconds. This is due to the large = temperature coefficient of Young's Modulus for steel. If you try to make = one with a much longer period, it simply collapses as the room = temperature rises a few degrees. Elinvar and Ni-SpanC springs were = developed to overcome the problem, but you also need a quite critical = design, first described in 1934 by LaCoste. See the references on = http://psn.quake.net/infoequip.html Another approach is to make a simple seismometer with a period of = maybe 1.5 to 2 seconds and then selectively compensate the F^2 signal = response drop off below resonance with a 1/F^2 amplifier. You can extend = the period by up to about x20 this way, but you need to design very low = noise electronics. See http://jclahr.com/science/psn/hill/index.html = but DO use magnetic damping, NOT oil! The other approach to get longer stable periods is to use a = similar setup, but to provide a 3 element force feedback system. Look at = the STM-8 on psn, designed by Sean Morrissey = http://www.eas.slu.edu/People/STMorrissey/index.html and = http://www.bryantlabs.net/seismo.html I don't want to discourage you, but it is MUCH easier to make a = good horizontal seismometer with a period of up to 30 seconds. See = http://www.bgs.ac.uk/schoolseismology/ and click on 'seismometer'. See = also the Volksmeter at http://www.rllinstruments.com/ Regards, Chris Chapman
Hi Folks,  Thanks Chris for the links below, the UK School = project was=20 very nice.  
 
Here is an unrelated question, except the UK site explained the use = of the=20 software, Amaseis..........which I have use and I am still using it at = some=20 stations.   It has a feature which allow you to "replay" the = recorded=20 helicorder, trace and speed it up.   The result is impressive = as you=20 can replay and watch the event unfold in just a few seconds.   = My=20 question is there a way to capture this 10 or 15 second screen event and = save it=20 as some kind of movie file which could be emailed to = others.    I=20 do not see this "replay" feature in WinSDR.  So this feature may = only be on=20 Amaseis.
 
Thanks, Ted
----- Original Message -----
From:=20 ChrisAtUpw@.......
To: psn-l@..............
Sent: Saturday, January 24, = 2009 3:49=20 PM
Subject: Re: home made vertical = seismometer

In a message dated 24/01/2009, rog@.......... writes:
I have=20 just joined the list and am looking for suggestions for good =
examples=20 and instructions for home made vertical=20 seismometers.
Hi Robert,
 
    It is only possible to make a simple = vertical=20 seismometer with a stable period of less than about 6 seconds. This is = due to=20 the large temperature coefficient of Young's Modulus for steel. If you = try to=20 make one with a much longer period, it simply collapses as the room=20 temperature rises a few degrees. Elinvar and Ni-SpanC springs were = developed=20 to overcome the problem, but you also need a quite critical design, = first=20 described in 1934 by LaCoste. See the references on http://psn.quake.net/infoequ= ip.html
 
    Another approach is to make a simple = seismometer=20 with a period of maybe 1.5 to 2 seconds and then selectively = compensate the=20 F^2 signal response drop off below resonance with a = 1/F^2 amplifier. You=20 can extend the period by up to about x20 this way, but you need to = design very=20 low noise electronics. See http://jclahr.com/= science/psn/hill/index.html  but=20 DO use magnetic damping, NOT oil!
 
    The other approach to get longer stable = periods=20 is to use a similar setup, but to provide a 3 element force = feedback=20 system. Look at the STM-8 on psn, designed by Sean Morrissey http://www.= eas.slu.edu/People/STMorrissey/index.html and=20 http://www.bryantlabs.net/= seismo.html
 
    I don't want to discourage you, but it is = MUCH=20 easier to make a good horizontal seismometer with a period of up to 30 = seconds. See http://www.bgs.ac.uk/scho= olseismology/ and=20 click on 'seismometer'. See also the Volksmeter at http://www.rllinstruments.com/
 
    Regards,
 
    Chris Chapman
    
Subject: video screen capture From: "tchannel" tchannel@............ Date: Sun, 25 Jan 2009 11:40:51 -0700 I found this site and software to do what I wanted...... http://www.smallvideosoft.com/download.php = http://www.smallvideosoft.com/ .....I tried it on this computer and it seems to work great. It is call = Freez Screen Video Capture. I have not tried it on the Amaseis window = because I don't have Amaseis on this computer. I will need to load it = and try it out..............Again here is what I wanted to do. 1. Using Amaseis, record an earthquake, highlight the event, use the = play back feature in Amaseis, increase the playback speed to complete in = about 15 second, record the screen in motion, (using this software) and = save the video. 2. This software should do this and it saves it as a .avi 3. I could then email the .avi and explain this is what the earthquake = looked like as it arrived, but speeded up many times. I have Amaseis at one of the school, and they use this playback = feature a lot. Thanks, Ted Hi Folks, Thanks Chris for the links below, the UK School project was = very nice. =20 Here is an unrelated question, except the UK site explained the use of = the software, Amaseis..........which I have use and I am still using it = at some stations. It has a feature which allow you to "replay" the = recorded helicorder, trace and speed it up. The result is impressive = as you can replay and watch the event unfold in just a few seconds. My = question is there a way to capture this 10 or 15 second screen event and = save it as some kind of movie file which could be emailed to others. = I do not see this "replay" feature in WinSDR. So this feature may only = be on Amaseis. Thanks, Ted
I found this site and software to do = what I=20 wanted......
http://www.smallvideo= soft.com/download.php        =             &= nbsp;           &n= bsp; =20  http://www.smallvideosoft.com/
....I=20 tried it on this computer and it seems to work great.  It is call = Freez=20 Screen Video Capture.   I have not tried it on the Amaseis = window=20 because I don't have Amaseis on this computer.   I will need = to load=20 it and try it out..............Again here is what I wanted to = do.
 
1. Using Amaseis, record an earthquake, = highlight=20 the event, use the play back feature in Amaseis, increase the playback = speed to=20 complete in about 15 second, record the screen in motion, (using this=20 software) and save the video.
2. This software should do this and it = saves it as=20 a .avi
3.  I could then email the .avi=20 and explain  this is what the earthquake looked like as it = arrived,=20 but speeded up many times.
     I have Amaseis at = one of the=20 school, and they use this playback feature a lot.
 
Thanks, Ted
 
Hi Folks,  Thanks Chris for the links below, the = UK School=20 project was very nice.  
 
Here is an unrelated question, except the UK site = explained the=20 use of the software, Amaseis..........which I have use and I am still = using it=20 at some stations.   It has a feature which allow you to = "replay" the=20 recorded helicorder, trace and speed it up.   The result is = impressive=20 as you can replay and watch the event unfold in just a few = seconds.  =20 My question is there a way to capture this 10 or 15 second screen event = and save=20 it as some kind of movie file which could be emailed to=20 others.    I do not see this "replay" feature in = WinSDR.  So=20 this feature may only be on Amaseis.
 
Thanks, Ted
 
 
 
 
Subject: Steel vs. other materials From: JimT nyponen@......... Date: Sun, 25 Jan 2009 11:07:13 -0800 I'm a newbie and have never built seismometer. I'm wondering why steel is used so much in seismometer construction when other materials have much less thermal expansion. Spruce wood, for example, has about 1/7 the thermal expansion of steel. Other materials expand even less, quartz, graphite, some glasses and ceramics, etc. Some of the materials with low CTEs (Coefficient of Thermal Expansion) are expensive (invar, tungsten, polyimide, diamond), but others are affordable. Spruce is inexpensive and widely available. Here are a couple of sources of graphite rods and other shapes: http://www.waleapparatus.com/catalog.asp?prodid=548212&showprevnext=1 http://www.graphitestore.com/items_list.asp/action/prod/prd_id/25/cat_id/22 Simax glass is cheap and has an extremely low CTE. I wonder what kind of seismometer a good glassblower would make? Jim Turner __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Steel vs. other materials From: "Geoff" gmvoeth@........... Date: Sun, 25 Jan 2009 12:45:41 -0700 I believe the Well Educated science peoples have resources the average citizen does not so people like myself who live on social security must use the cheapest materials that will get the job done. I have found simple piano wire very difficult to obtain it is like a controlled substance just like absolute barometers in millibars or whatever. I think here in the USA we are fighting a paranoid national security peoples to obtain some tools and materials of the sciences. they want to watch and control who can have what. Pleasure through the sciences is being watched much more closely than is pleasure for the arts otherwise the materials WE seek might be easier to obtain. I must settle for what's in the local hardware stores. Most all else is too expensive. I like your wood and ceramic and mineral ideas. ----- Original Message ----- From: "JimT" To: Sent: Sunday, January 25, 2009 12:07 PM Subject: Steel vs. other materials > I'm a newbie and have never built seismometer. I'm wondering why > steel is used so much in seismometer construction when other materials > have much less thermal expansion. Spruce wood, for example, has about > 1/7 the thermal expansion of steel. Other materials expand even less, > quartz, graphite, some glasses and ceramics, etc. Some of the > materials with low CTEs (Coefficient of Thermal Expansion) are > expensive (invar, tungsten, polyimide, diamond), but others are > affordable. Spruce is inexpensive and widely available. Here are a > couple of sources of graphite rods and other shapes: > http://www.waleapparatus.com/catalog.asp?prodid=548212&showprevnext=1 > http://www.graphitestore.com/items_list.asp/action/prod/prd_id/25/cat_id/22 > > Simax glass is cheap and has an extremely low CTE. I wonder what kind > of seismometer a good glassblower would make? > > Jim Turner > __________________________________________________________ > > 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: Steel vs. other materials From: Brett Nordgren brett3nt@............. Date: Sun, 25 Jan 2009 17:25:29 -0500 Jim, You didn't mention Aluminum, which is my favorite. With wood, I'd be more concerned with its response to humidity, which can be extremely large. It's largely in the vertical designs where thermal effects are most severe, and there the main problem is not thermal expansion, but the change in spring stiffness (elastic modulus), about 20x larger than the expansion number. A good feedback design can greatly reduce those thermal effects. There had been some testing being done on a graphite leaf spring, but I haven't heard anything recently. Regards, Brett At 11:07 AM 1/25/2009 -0800, you wrote: >I'm a newbie and have never built seismometer. I'm wondering why >steel is used so much in seismometer construction when other materials >have much less thermal expansion. Spruce wood, for example, has about >1/7 the thermal expansion of steel. Other materials expand even less, >quartz, graphite, some glasses and ceramics, etc. Some of the >materials with low CTEs (Coefficient of Thermal Expansion) are >expensive (invar, tungsten, polyimide, diamond), but others are >affordable. Spruce is inexpensive and widely available. Here are a >couple of sources of graphite rods and other shapes: >http://www.waleapparatus.com/catalog.asp?prodid=548212&showprevnext=1 >http://www.graphitestore.com/items_list.asp/action/prod/prd_id/25/cat_id/22 > >Simax glass is cheap and has an extremely low CTE. I wonder what kind >of seismometer a good glassblower would make? > >Jim Turner __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Steel vs. other materials From: ChrisAtUpw@....... Date: Sun, 25 Jan 2009 21:55:46 EST In a message dated 25/01/2009 19:07:35 GMT Standard Time, nyponen@......... writes: I'm a newbie and have never built seismometer. I'm wondering why steel is used so much in seismometer construction when other materials have much less thermal expansion. Spruce wood, for example, has about 1/7 the thermal expansion of steel. Other materials expand even less, quartz, graphite, some glasses and ceramics, etc. Some of the materials with low CTEs (Coefficient of Thermal Expansion) are expensive (invar, tungsten, polyimide, diamond), but others are affordable. Spruce is inexpensive and widely available. Here are a couple of sources of graphite rods and other shapes: http://www.waleapparatus.com/catalog.asp?prodid=548212&showprevnext=1 http://www.graphitestore.com/items_list.asp/action/prod/prd_id/25/cat_id/22 Hi Jim, Thermal expansion is not generally a serious problem in seismometers, although you may need to allow for it. Wood is not used for professional seismometers since it is sensitive to humidity and it tends to warp. It also tends to take a 'set' under stress, particularly at elevated temperatures. The thermal expansion is only small along the grain, otherwise it may be quite large. It can be protected with adhesive + metal film, but while helping, organic varnishes and paints do not completely exclude moisture. Mild steel is readily available, has a high rigidity, has the same properties in all directions and is not expensive. But it does need to be protected from corrosion with one of the 'special' paints available. Do NOT use any ferromagnetic material for the arm or the mass. It will pick up magnetic noise from the house wiring, from the Earth and from passing trains, trucks and cars. Aluminum is more expensive and it is much less rigid, but it is fairly resistant to corrosion. It can be varnished / painted with advantage. Use only Stainless Steel, Al alloy or nylon bolts. Aluminum in contact with mild steel corrodes rapidly. Brass is not much better. I have used 3" x 1" Al U channel sections for amateur type seismometers, but you can also use Aluminum bar. Check _http://www.bgs.ac.uk/education/school_seismology/seismometer.html_ (http://www.bgs.ac.uk/education/school_seismology/seismometer.html) Some of the materials you quoted are GRAPHITE. Graphite is a LOW strength solid, NOT suitable for constructing seismometers. You probably meant to refer to Carbon Fibre / Monofilament. This is a very high strength material with a near zero expansion coefficient along the filaments. The expansion perpendicular to the filaments depends on the properties of the binding adhesive / resin and the filling factor of the material. Both epoxy and vinyl adhesives may be used. The properties of woven fabrics depend on the orientation of the filaments. In general, the construction of seismometers needs to be very rigid and moisture / corrosion resistant, whether this is achieved by the material or by the sections used. I use brass for the mass. You can buy it in a wide range of sections and sizes. I use a SS scalpel blade rolling on a fixed 3/8" SS ball bearing for the bottom bearing on a Lehman, cost about 50c. You can also buy Tungsten Carbide needle rollers. Epoxy adhesives are very sensitive to surface moisture and oil / grease. They don't stick soft metals like Al, Zn, Cu etc. very well and most of the common resins cure brittle hard. The flexible types may only be available in industrial packs and they may have reduced strength. Two component acrylic adhesives are tough, not brittle and are much less effected by surface moisture or grease. I use Holdtite ST3295. It is a thick liquid, but it mixes / spreads very easily and sets quickly. It does not stick to polythene unless you oxidise the surface. I prefer it to Devcon Plastic Weld or Bondloc Plastic Weld, which are thick pastes. Loctite also make a wide range of these adhesives, as do Dow Corning. Regards, Chris Chapman
In a message dated 25/01/2009 19:07:35 GMT Standard Time, nyponen@gmail= ..com=20 writes:
<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size= =3D2>I'm a=20 newbie and have never built seismometer.  I'm wondering why
steel=20= is=20 used so much in seismometer construction when other materials
have much= =20 less thermal expansion.  Spruce wood, for example, has about
1/7 t= he=20 thermal expansion of steel.  Other materials expand even less,
qua= rtz,=20 graphite, some glasses and ceramics, etc.  Some of the
materials w= ith=20 low CTEs (Coefficient of Thermal Expansion) are
expensive (invar, tungs= ten,=20 polyimide, diamond), but others are
affordable.  Spruce is inexpen= sive=20 and widely available.  Here are a
couple of sources of graphite ro= ds=20 and other=20 shapes:
http://www.waleapparatus.com/catalog.asp?prodid=3D548212&sh= owprevnext=3D1
http://www.graphitestore.com/items_list.asp/action/prod/pr= d_id/25/cat_id/22
Hi Jim,
 
    Thermal expansion is not generally a serious=20 problem in seismometers, although you may need to allow for it. Wood is not=20= used=20 for professional seismometers since it is sensitive to humidity and it tends= to=20 warp. It also tends to take a 'set' under stress, particularly at eleva= ted=20 temperatures. The thermal expansion is only small along the grain, otherwise= it=20 may be quite large. It can be protected with adhesive + metal film= ,=20 but while helping, organic varnishes and paints do not completely exclu= de=20 moisture.
    Mild steel is readily available, has a high=20 rigidity, has the same properties in all directions and is not=20 expensive. But it does need to be protected from corrosion with one of the=20 'special' paints available. Do NOT use any ferromagnetic material for=20 the arm or the mass. It will pick up magnetic noise from the house wiri= ng,=20 from the Earth and from passing trains, trucks and cars.
    Aluminum is more expensive and it is much=20= less=20 rigid, but it is fairly resistant to corrosion. It can be varnished / painte= d=20 with advantage. Use only Stainless Steel, Al alloy or nylon bolts. Aluminum=20= in=20 contact with mild steel corrodes rapidly. Brass is not much better. I have u= sed=20 3" x 1" Al U channel sections for amateur type seismometers, but you can als= o=20 use Aluminum bar.  Check h= ttp://www.bgs.ac.uk/education/school_seismology/seismometer.html
    Some of the materials you quoted are=20 GRAPHITE. Graphite is a LOW strength solid, NOT suitable for=20 constructing seismometers. You probably meant to refer to Carbon Fibre=20= /=20 Monofilament. This is a very high strength material with a near zero expansi= on=20 coefficient along the filaments. The expansion perpendicular to the=20 filaments depends on the properties of the binding adhesive / resin and the=20 filling factor of the material. Both epoxy and vinyl adhesives may be used.=20= The=20 properties of woven fabrics depend on the orientation of the filaments.
    In general, the construction of seismometers ne= eds=20 to be very rigid and moisture / corrosion resistant, whether this is achieve= d by=20 the material or by the sections used. I use brass for the mass. You can buy=20= it=20 in a wide range of sections and sizes. I use a SS scalpel blade rolling = ;on=20 a fixed 3/8" SS ball bearing for the bottom bearing on a Lehman, cost a= bout=20 50c. You can also buy Tungsten Carbide needle rollers.
    Epoxy adhesives are very sensitive to surface=20 moisture and oil / grease. They don't stick soft metals like Al, Zn, Cu= =20 etc. very well and most of the common resins cure brittle hard. Th= e=20 flexible types may only be available in industrial packs and they may have=20 reduced strength.
    Two component acrylic adhesives are tough, not=20 brittle and are much less effected by surface moisture or grease. = I=20 use Holdtite ST3295. It is a thick liquid, but it mixes / spreads very=20 easily and sets quickly. It does not stick to polythene unless you oxidise t= he=20 surface. I prefer it to Devcon Plastic Weld or Bondloc Plastic Weld, which a= re=20 thick pastes. Loctite also make a wide range of these adhesives, as do Dow=20 Corning.
 
    Regards,
 
    Chris Chapman
Subject: Re: Steel vs. other materials From: Barry Lotz barry_lotz@............. Date: Tue, 27 Jan 2009 06:24:35 -0800 (PST) Brett What about carbon fiber leaf springs? I Googled graphite sheets and a brief= look indicated they might be to thin.=20 Regards Barry=A0=20 --- On Sun, 1/25/09, Brett Nordgren wrote: From: Brett Nordgren Subject: Re: Steel vs. other materials To: psn-l@.............. Date: Sunday, January 25, 2009, 2:25 PM Jim, You didn't mention Aluminum, which is my favorite. With wood, I'd be more=20 concerned with its response to humidity, which can be extremely large. It's largely in the vertical designs where thermal effects are most severe, and there the main problem is not thermal expansion, but the change in=20 spring stiffness (elastic modulus), about 20x larger than the expansion=20 number. A good feedback design can greatly reduce those thermal effects. There had been some testing being done on a graphite leaf spring, but I=20 haven't heard anything recently. Regards, Brett At 11:07 AM 1/25/2009 -0800, you wrote: >I'm a newbie and have never built seismometer. I'm wondering why >steel is used so much in seismometer construction when other materials >have much less thermal expansion. Spruce wood, for example, has about >1/7 the thermal expansion of steel. Other materials expand even less, >quartz, graphite, some glasses and ceramics, etc. Some of the >materials with low CTEs (Coefficient of Thermal Expansion) are >expensive (invar, tungsten, polyimide, diamond), but others are >affordable. Spruce is inexpensive and widely available. Here are a >couple of sources of graphite rods and other shapes: >http://www.waleapparatus.com/catalog.asp?prodid=3D548212&showprevnext=3D1 >http://www.graphitestore.com/items_list.asp/action/prod/prd_id/25/cat_id/2= 2 > >Simax glass is cheap and has an extremely low CTE. I wonder what kind >of seismometer a good glassblower would make? > >Jim Turner __________________________________________________________ Public Seismic Network Mailing List (PSN-L)
Brett
What about carbon fiber leaf springs? I Googled graphite sheets and a brief look indicated they might be to thin.
Regards
Barry 

--- On Sun, 1/25/09, Brett Nordgren <brett3nt@.............> wrote:
From: Brett Nordgren <brett3nt@.............>
Subject: Re: Steel vs. other materials
To: psn-l@..............
Date: Sunday, January 25, 2009, 2:25 PM

Jim,

You didn't mention Aluminum, which is my favorite. With wood, I'd be
more
concerned with its response to humidity, which can be extremely large.

It's largely in the vertical designs where thermal effects are most severe,

and there the main problem is not thermal expansion, but the change in
spring stiffness (elastic modulus), about 20x larger than the expansion
number. A good feedback design can greatly reduce those thermal effects.

There had been some testing being done on a graphite leaf spring, but I
haven't heard anything recently.

Regards,
Brett


At 11:07 AM 1/25/2009 -0800, you wrote:
>I'm a newbie and have never built seismometer. I'm wondering why
>steel is used so much in seismometer construction when other materials
>have much less thermal expansion. Spruce wood, for example, has about
>1/7 the thermal expansion of steel. Other materials expand even less,
>quartz, graphite, some glasses and ceramics, etc. Some of the
>materials with low CTEs (Coefficient of Thermal Expansion) are
>expensive (invar, tungsten, polyimide, diamond), but others are
>affordable. Spruce is inexpensive and widely available. Here are a
>couple of sources of graphite rods and other shapes:
>http://www.waleapparatus.com/catalog.asp?prodid=548212&showprevnext=1
>http://www.graphitestore.com/items_list.asp/action/prod/prd_id/25/cat_id/22
>
>Simax glass is cheap and has an extremely low CTE. I wonder what kind
>of seismometer a good glassblower would make?
>
>Jim Turner


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Subject: Re: Steel vs. other materials From: Brett Nordgren brett3nt@............. Date: Tue, 27 Jan 2009 10:53:07 -0500 Barry, I'd assumed that carbon fiber composite = graphite fiber composite. Sorry for the confusion. They do need to be pretty thin for ordinary-sized instruments in order to not have them going beyond their yield strength when bending them to the necessary curve. As I recall 0.008" - 0.015" is the range of thickness that usually turns out to be appropriate. You also want to be using one-directional materal, oriented along the spring length. I don't think that woven or mat material works as well. Regards, Brett At 06:24 AM 1/27/2009 -0800, you wrote: >Brett >What about carbon fiber leaf springs? I Googled graphite sheets and a >brief look indicated they might be to thin. >Regards >Barry __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Used equipment From: "tchannel" tchannel@............ Date: Sun, 1 Feb 2009 12:26:20 -0700 Hi Folks, I have a school looking for one of Larry's Amp/Filter boards, = one or three channel. New or used. In the past, I have seen some For = Sale Posting. Not to take up time or space here, but if someone has = one, they would like to sell, please email me tchannel@............ Thanks, Ted
Hi Folks, I have a school looking for = one of=20 Larry's Amp/Filter boards, one or three channel.  New or = used.  =20 In the past, I have seen some For Sale Posting.   Not to take = up time=20 or space here, but if someone has one, they would like to sell, please = email me=20 tchannel@............
 
Thanks, Ted
Subject: 8020 aluminum and approaches to constructing a homemade seismometer From: "Robert O. Green" rog@.......... Date: Tue, 03 Feb 2009 19:56:22 -0800 I have come across a source for cut-to-order 8020 aluminum and brackets. http://www.automation4less.com/store/products.asp?cat=1097 Has anyone tried this approach for homemade seismometers? There seems to be good potential. Are there examples of 8020 seismometers? Are there other good sources for 8020? Robert __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: RE: 8020 aluminum and approaches to constructing a homemade seismometer From: "Gary Lindgren" gel@................. Date: Tue, 3 Feb 2009 21:05:33 -0800 Robert, The most common aluminum is 6061-T6. I have found Metal Supermarkets is a good choice for metal (aluminum and steel) http://www.metalsupermarkets.com/msc-metalguide.aspx?ProductID=8 They have locations in several city's around the US and world. I'm lucky and live only 5 miles from the Redwood City CA location. I can e-mail in a quote and get response in an hour or so, and have material ready to pick up in an hour. Best way to communicate is to send e-mail directly to local facility rather than going through corporate mail server. Good luck, Gary Lindgren Palo Alto -----Original Message----- From: psn-l-request@.............. [mailto:psn-l-request@............... On Behalf Of Robert O. Green Sent: Tuesday, February 03, 2009 7:56 PM To: PSN-L@.............. Subject: 8020 aluminum and approaches to constructing a homemade seismometer I have come across a source for cut-to-order 8020 aluminum and brackets. http://www.automation4less.com/store/products.asp?cat=1097 Has anyone tried this approach for homemade seismometers? There seems to be good potential. Are there examples of 8020 seismometers? Are there other good sources for 8020? Robert __________________________________________________________ Public Seismic Network Mailing List (PSN-L) __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: 8020 aluminum and approaches to constructing a homemade seismometer From: "Robert O. Green" rog@.......... Date: Tue, 03 Feb 2009 21:43:00 -0800 Hi Gary, 8020 is 6061-T6 aluminum in an extruded erector-set like form that seems to be a standard. This type of extruded aluminum seems optimal for stiff seismometer like structures. It is easy to configure and quite inexpensive as well. http://www.automation4less.com/store/categories.asp?cat=1116 I am curious if others have used 8020 in seismometer designs. Robert Gary Lindgren wrote: > Robert, > The most common aluminum is 6061-T6. I have found Metal Supermarkets is a > good choice for metal (aluminum and steel) > http://www.metalsupermarkets.com/msc-metalguide.aspx?ProductID=8 They have > locations in several city's around the US and world. I'm lucky and live only > 5 miles from the Redwood City CA location. I can e-mail in a quote and get > response in an hour or so, and have material ready to pick up in an hour. > Best way to communicate is to send e-mail directly to local facility rather > than going through corporate mail server. > Good luck, > Gary Lindgren > Palo Alto > > > > > -----Original Message----- > From: psn-l-request@.............. [mailto:psn-l-request@............... On > Behalf Of Robert O. Green > Sent: Tuesday, February 03, 2009 7:56 PM > To: PSN-L@.............. > Subject: 8020 aluminum and approaches to constructing a homemade seismometer > > I have come across a source for cut-to-order 8020 aluminum and brackets. > > http://www.automation4less.com/store/products.asp?cat=1097 > > Has anyone tried this approach for homemade seismometers? There seems > to be good potential. > > Are there examples of 8020 seismometers? > > Are there other good sources for 8020? > > Robert > > > > __________________________________________________________ > > 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. > ------------------------------------------------------------------------ > > > Internal Virus Database is out of date. > Checked by AVG - http://www.avg.com > Version: 8.0.176 / Virus Database: 270.10.13/1912 - Release Date: 1/23/2009 6:54 PM > > Hi Gary,

8020 is 6061-T6 aluminum in an extruded erector-set like form that seems to be a standard.  This type of extruded aluminum seems optimal for stiff seismometer like structures.  It is easy to configure and quite inexpensive as well.

http://www.automation4less.com/store/categories.asp?cat=1116

I am curious if others have used 8020 in seismometer designs.

Robert

Gary Lindgren wrote:
Robert,
The most common aluminum is 6061-T6. I have found Metal Supermarkets is a
good choice for metal (aluminum and steel)
http://www.metalsupermarkets.com/msc-metalguide.aspx?ProductID=8 They have
locations in several city's around the US and world. I'm lucky and live only
5 miles from the Redwood City CA location. I can e-mail in a quote and get
response in an hour or so, and have material ready to pick up in an hour.
Best way to communicate is to send e-mail directly to local facility rather
than going through corporate mail server.
Good luck,
Gary Lindgren
Palo Alto




-----Original Message-----
From: psn-l-request@.............. [mailto:psn-l-request@..............] On
Behalf Of Robert O. Green
Sent: Tuesday, February 03, 2009 7:56 PM
To: PSN-L@..............
Subject: 8020 aluminum and approaches to constructing a homemade seismometer

I have come across a source for cut-to-order 8020 aluminum and brackets.

http://www.automation4less.com/store/products.asp?cat=1097

Has anyone tried this approach for homemade seismometers?  There seems 
to be good potential.

Are there examples of 8020 seismometers?

Are there other good sources for 8020?

Robert



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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.

__________________________________________________________

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To leave this list email PSN-L-REQUEST@.............. with 
the body of the message (first line only): unsubscribe
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Internal Virus Database is out of date. Checked by AVG - http://www.avg.com Version: 8.0.176 / Virus Database: 270.10.13/1912 - Release Date: 1/23/2009 6:54 PM

Subject: Re: 8020 aluminum and approaches to constructing a homemade seismometer From: ChrisAtUpw@....... Date: Wed, 4 Feb 2009 09:45:12 EST In a message dated 04/02/2009, rog@.......... writes: 8020 is 6061-T6 aluminum in an extruded erector-set like form that seems to be a standard. This type of extruded aluminum seems optimal for stiff seismometer like structures. It is easy to configure and quite inexpensive as well. _http://www.automation4less.com/store/categories.asp?cat=1116_ (http://www.automation4less.com/store/categories.asp?cat=1116) I am curious if others have used 8020 in seismometer designs. Hi Robert, You would need to use the larger sections, but they may be relatively expensive. You need HT30 triangular plates at the corners to make the structure rigid enough. Aluminum is ~3x as flexible as steel. The EQ1 used 1.5" square from memory. I prefer standard U channel, 3" x 1" x 1/8" for a Lehmanm and 2" x 1" x 1/8" for an AS1 type vertical. These work fine. The corner plates are cut from 5" squares. I put the open U on the inside of the L frame. I use Stainless Steel nuts bolts and washers. If you put mild steel or brass in contact with Aluminum, it corrodes very rapidly. I suggest that you cross check the material prices and let us know? Regards, Chris Chapman
In a message dated 04/02/2009, rog@.......... writes:
<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size= =3D2>8020 is=20 6061-T6 aluminum in an extruded erector-set like form that seems to be a=20 standard.  This type of extruded aluminum seems optimal for stiff=20 seismometer like structures.  It is easy to configure and quite=20 inexpensive as well.

ht= tp://www.automation4less.com/store/categories.asp?cat=3D1116=20

I am curious if others have used 8020 in seismometer=20 designs.
Hi Robert,
 
    You would need to use the larger sections, but=20= they=20 may be relatively expensive. You need HT30 triangular plates at the corners=20= to=20 make the structure rigid enough. Aluminum is ~3x as flexible as steel. The E= Q1=20 used 1.5" square from memory.
 
    I prefer standard U channel, 3" x 1" x 1/8" for= a=20 Lehmanm and  2" x 1" x 1/8" for an AS1 type vertical. These work fine.=20= The=20 corner plates are cut from 5" squares. I put the open U on the inside of the= L=20 frame.
 
    I use Stainless Steel nuts bolts and washers. I= f=20 you put mild steel or brass in contact with Aluminum, it corrodes very=20 rapidly.
 
    I suggest that you cross check the material pri= ces=20 and let us know?
 
    Regards,
 
    Chris Chapman
Subject: Advantages of more ADC bits From: rsparks rsparks@.......... Date: Fri, 06 Feb 2009 19:57:55 -0800 Hello All, I have been considering what advantage the amateur seismologist might see if making an upgrade to more bits in the A/D converter. First, some background. If any of this is incorrect, please offer corrections. A/D converters are also known as ADC devices. Their function is to convert an analog voltage to a digital number. Each device will have a basic range such as +/- 10 volts. That range will be divided into a number of intervals depending upon the number of bits available to the device. Each voltage interval will be assigned a digital number. Bits are a basic division of computer technology and are expressed as powers of two (2^xx). Thus, an 8 bit device will have 2^8 = 256 divisions. Not too accurate if 256 divisions are used to find a point between +/- 10 volts. Also not very sensitive as the each division/count is 20/256 = 0.078125V. Here is a list of devices/seismometers and the sensitivity/accuracy in bits: Volksmeter 24 bit PSN/Cochrane 16 bit Saum Infiltec 16 bit AS1 12 bit Dataq 8/10/12 bit As I wonder about this information, I get to wondering "Why bother to upgrade?", at least for amateur purposes. Two reasons come to mind. You will see more quakes with a more sensitive instrument. You can not really compensate with more amplification because the dynamic range is smaller with the low bit count devices. Yes, you can raise the amplification level so that an 8 bit device will respond to the same voltage signal that the 24 bit device will see, but the 8 bit device will be saturated after only 256 counts while the 24 bit device would have only recorded 256 counts out of 16.7 million possible counts. The second reason is to have better fidelity or accuracy. Any FFT taken of a trace will be more accurate if each individual reading is better placed in the digital data table. An expanded trace of low count signals will look more "sine wave" like. An easier way to make the wave more "sine like" might be increased sample rate. Ultimately, both accuracy and sample rate must be increased for superior results. It is fun to consider upgrades, harder to make them. Roger __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Advantages of more ADC bits From: Brett Nordgren brett3nt@............. Date: Fri, 06 Feb 2009 23:38:59 -0500 Roger, The main advantage of more bits is the *possibility* of greater sensitivity. Very weak signals will appear to be less 'stairstep'-like. When properly set up, the sensor voltage output should clip at the same level as the max A/D count. That means that with a 24-bit A/D, each bit represents a much smaller signal than you would get with a 16-bit device. However, everything depends on the noise level of the sensor and of the site, and only the best require the sensitivity available from 24 bits. The microseism, instrument and cultural noise level at most amateur sites would very likely not justify the additional sensitivity of a 24-bit digitizer. BTW, most 24-bit digitizers actually achieve something less than 24, depending on the sampling rate. Regards, Brett At 07:57 PM 2/6/2009 -0800, you wrote: >Hello All, > >I have been considering what advantage the amateur seismologist might see >if making an upgrade to more bits in the A/D converter. >First, some background. If any of this is incorrect, please offer >corrections. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Advantages of more ADC bits From: ChrisAtUpw@....... Date: Sat, 7 Feb 2009 17:52:20 EST In a message dated 07/02/2009, rsparks@.......... writes: I have been considering what advantage the amateur seismologist might see if making an upgrade to more bits in the A/D converter. Bits are a basic division of computer technology and are expressed as powers of two (2^xx). Thus, an 8 bit device will have 2^8 = 256 divisions, whereas a 16 bit device will have 65,536 divisions. Here is a list of devices/seismometers and the sensitivity/accuracy in bits: Volksmeter 24 bit PSN/Cochrane 16 bit Saum Infiltec 16 bit AS1 12 bit Dataq 8/10/12 bit I get to wondering "Why bother to upgrade?", at least for amateur purposes. Two reasons come to mind. You will see more quakes with a more sensitive instrument. You can not really compensate with more amplification because the dynamic range is smaller with the low bit count devices. Yes, you can raise the amplification level so that an 8 bit device will respond to the same voltage signal that the 24 bit device will see, but the 8 bit device will be saturated after only 256 counts while the 24 bit device would have only recorded 256 counts out of 16.7 million possible counts. The second reason is to have better fidelity or accuracy. Any FFT taken of a trace will be more accurate if each individual reading is better placed in the digital data table. Ultimately, both accuracy and sample rate must be increased for superior results. Hi Roger, Another important question to ask is 'What is the chip background noise level?' The depends on the integration interval and whether a series of signals are averaged. Also ask 'What is your seismic background noise level?' The older 16 bit ADCs used to have 3 to 4 bits of internal digital noise on them. But with a 20 micro second conversion rate you could take and average 64 sequential readings. You need to take 4 readings to average out 1 bit of digital noise, 16 to average out 2 bits etc. You can push signal averaging to about 18 bit accuracy on a 16 bit ADC for single channel low sample rates. 24 bit ADCs may only give about 19 / 20 bits true resolution, or even less if you require a rapid sample rate. The 16 bit Sigma Delta ADCs can give 16 bits true resolution for 20 samples / second, but may be less for greater sample rates. Some 24 bit systems only have +/-2 volts input range, which requires you to use very low noise / costly amplifiers. You also need to check the amplifier noise level and the local seismic noise levels that you detect. The local noise may be mostly due to ~6 second period microseisems. The noise level for P and S waves at 0.5 to 5 Hz and for surface waves at periods over 12 seconds may be much lower, so the amplifier self noise is important. Assuming that you have a 16 bit true ADC with a +/-10 V input range, 1 bit represents 0.305 milli V. You definitely need the amplifier to have a lower noise level than this. 12 bits resolution only gives you +/-2048 signal steps, so even if there is no ADC noise, your practical dynamic range is limited to about 3 Magnitudes. 16 bits gives a more practicable +/-32,768 step range. Remember that Earthquake Magnitudes have a logarithmic scale. Dynamic range may be a serious problem if you live close to say, the New Madrid earthquake zone and experience local quakes. For quake amplitude / distance motions see _http://jclahr.com/science/psn/magnitude.html_ (http://jclahr.com/science/psn/magnitude.html) Amplifiers suffer from several sorts of noise, including resistive, input voltage and current and 1/f noise. The 1/f noise is serious and may be dominant at periods over ~10 seconds. Chopper amplifiers do not suffer from 1/f noise, but they are more expensive to construct. The very low noise levels seen in commercial seismic systems is due to the use of capacitative distance transducers and chopper detection systems. Velocity measuring systems are limited by noise at longer periods. Regards, Chris Chapman
In a message dated 07/02/2009, rsparks@.......... writes:
<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size= =3D2>I have=20 been considering what advantage the amateur seismologist might
see if=20 making an upgrade to more bits in the A/D converter.

Bits are a ba= sic=20 division of computer technology and are expressed as
powers of two=20 (2^xx).  Thus, an 8 bit device will have 2^8 =3D 256
divisions, w= hereas=20 a 16 bit device will have 65,536 divisions. 
Here is a list of=20 devices/seismometers and the sensitivity/accuracy in=20 bits:

Volksmeter         24=20 bit
PSN/Cochrane   16 bit
Saum Infiltec     = ; 16=20 bit
AS1                 &n= bsp;=20 12 bit
Dataq               &nbs= p;=20 8/10/12 bit

 I get to wondering "Why bother to upgrade?", at l= east=20 for amateur purposes.

Two reasons come to mind.  You will see= =20 more quakes with a more
sensitive instrument.  You can not really= =20 compensate with more
amplification because the dynamic range is smalle= r=20 with the low bit
count devices.  Yes, you can raise the amplifica= tion=20 level so that an 8
bit device will respond to the same voltage signal=20= that=20 the 24 bit
device will see,  but the 8 bit device will be saturat= ed=20 after only 256
counts while the 24 bit device would have only recorded= 256=20 counts out
of 16.7 million possible counts.

The second reason i= s to=20 have better fidelity or accuracy.  Any FFT taken
of a trace will=20= be=20 more accurate if each individual reading is better
placed in the digit= al=20 data table. Ultimately, both accuracy and
sample rate must be increase= d=20 for superior results.
Hi Roger,
 
    Another important question to ask is 'What= is=20 the chip background noise level?' The depends on the integration interv= al=20 and whether a series of signals are averaged. Also ask 'What is your=20 seismic background noise level?'
 
    The older 16 bit ADCs used to have 3 to 4 bits=20= of=20 internal digital noise on them. But with a 20 micro second conversion rate y= ou=20 could take and average 64 sequential readings. You need to take 4 readi= ngs=20 to average out 1 bit of digital noise, 16 to average out 2 bits etc. Yo= u=20 can push signal averaging to about 18 bit accuracy on a 16 bit ADC for=20 single channel low sample rates.
 
    24 bit ADCs may only give about 19 / 20 bits tr= ue=20 resolution, or even less if you require a rapid sample rate. The 16 bit Sigm= a=20 Delta ADCs can give 16 bits true resolution for 20 samples / second, but may= be=20 less for greater sample rates. Some 24 bit systems only have +/-2 volts inpu= t=20 range, which requires you to use very low noise / costly=20 amplifiers. 
 
    You also need to check the amplifier noise leve= l=20 and the local seismic noise levels that you detect. The local noise may be=20 mostly due to ~6 second period microseisems. The noise level for P and S wav= es=20 at 0.5 to 5 Hz and for surface waves at periods over 12 seconds ma= y be=20 much lower, so the amplifier self noise is important. Assuming that you= =20 have a 16 bit true ADC with a +/-10 V input range, 1 bit represents 0.305 mi= lli=20 V. You definitely need the amplifier to have a lower noise level than=20 this.
 
    12 bits resolution only gives you +/-2048 signa= l=20 steps, so even if there is no ADC noise, your practical dynamic range is lim= ited=20 to about 3 Magnitudes. 16 bits gives a more practicable +/-32,768 step=20 range. Remember that Earthquake Magnitudes have a logarithmic=20 scale. Dynamic range may be a serious problem if you live close to say,= the=20 New Madrid earthquake zone and experience local quakes. For quake amplitude=20= /=20 distance motions see http://jclahr.com/scie= nce/psn/magnitude.html
 
    Amplifiers suffer from several sorts of noise,=20 including resistive, input voltage and current and 1/f noise. The 1/f n= oise=20 is serious and may be dominant at periods over ~10 seconds. Chopper amplifie= rs=20 do not suffer from 1/f noise, but they are more expensive to construct. The=20= very=20 low noise levels seen in commercial seismic systems is due to the use of=20 capacitative distance transducers and chopper detection systems. Velocity=20 measuring systems are limited by noise at longer periods.
 
    Regards,
 
    Chris Chapman   
 
Subject: Re: Advantages of more ADC bits From: rsparks rsparks@.......... Date: Sun, 08 Feb 2009 12:13:52 -0800 Thanks to both Chris and Brett for their thoughtful replies. I better understand that an upgrade to 24 bits is not a "no brainer" upgrade, but part of design strategy. All the parts must fit together to get superior results and fulfill site goals. There are new devices that may hold promise for future amateur use. One such device is the Cirrus Logic CS5530 24 bit ADC with integrated amplifier. I don't know if this could stand alone with a dedicated computer (or maybe not dedicated) using a serial port, or if it must be combined with a microcontroller. I also don't know if the input must be pre-filtered to prevent aliasing, or if the integrated amplifier is sufficient for amateur seismic work. Thanks for your comments Roger __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Sensor in a jar. From: "tchannel" tchannel@............ Date: Mon, 9 Feb 2009 11:49:52 -0700 This is another project which used the Torsion wire/spring/fiber = approach to produce a short period sensor. Similar, in concept to the = Wood Anderson Torsion spring. http://tinkeringcaveman.googlepages.com/home I made a version, of this approach, it which is about 24" tall x 10"x10" = using a square solid box made of 3/4" melamine material use for cabinet = construction. The reason I used this material was that I had it on = hand, and I just wanted to test the idea. The material worked out = fine, and for that matter so did the sensor. I suspended a thin ss = wire, about 20" long, to the top and bottom of the box, , attached a = magnet and coil assembly, onto a 12" horz arm. This acts like a horz = pendulum on one side of the wire. More information avail to anyone = interested in this, just email me. My system has a 6.5 second period. It records earthquakes as well as = any of my other sensors. I moved recently and found this sensor to be the easiest to move, set = up and level. No ball on plate or other balancing issues. I just = removed the coil, moved the 12" arm to the side of the box, and secured = it. The torsion spring is connect to the top and the bottom of the box, so = it did not need to be disconnected. I plan to build another, this time a bit different. Thought you might like to see this. Thanks, Ted
 
 
This is another project which used the = Torsion=20 wire/spring/fiber approach to produce a short period sensor.   = Similar, in concept to the Wood Anderson Torsion spring.
 
 
http://tinkeringcav= eman.googlepages.com/home
 
 
I made a version, of this = approach, it which=20 is about 24" tall x 10"x10" using a square solid box made of 3/4" = melamine=20 material use for cabinet construction.   The reason I used = this=20 material was that I had it on hand, and I just wanted to test the=20 idea.   The material worked out fine, and for that matter so = did the=20 sensor.   I suspended a thin ss wire, about 20" long, to = the top=20 and bottom of the box, , attached a magnet and coil assembly, onto = a 12"=20 horz arm.   This acts like a horz pendulum on one side of the=20 wire.    More information avail to anyone interested in = this,=20 just email me.
 
 
 
 My system has a 6.5 second=20 period.   It records earthquakes as well as any of my other=20 sensors.
 I moved recently and found this = sensor to be=20 the easiest to move, set up and level.  No ball on plate or other = balancing=20 issues.   I just removed the coil, moved the 12" arm to the = side of=20 the box, and secured it.
 The torsion spring is connect to = the top and=20 the bottom of the box, so it did not need to be = disconnected.
 I plan to build = another, this time a bit=20 different.
 
Thought you might like to see = this.
 
Thanks,
Ted
 
Subject: HAS ANYONE TRIED THIS b4... From: "GMV" gmvoeth@........... Date: Mon, 9 Feb 2009 17:29:51 -0700 hello PSN; build the mechanics to any type of seismometer then use several different sensors to see which produces the best results ? does anyone know what the best would be ?? variable optical, laser, led, etc.. variable capacitive, interleve plates ?? variable inductive ( like the old radio tuning slug in a coil ) velocity sensor ( magnet coil or magnet solinoid [coil plus iron core]) strain guage with a weight attached ? ( like bathroom scales ) are there mechanical ways to damp ( remove energy ) that might work as well as magnetic ? It might be nice to have a chord for a pendulum that will damp as it flexes ??? is it possible to levitate two magnets against each other then measure changes in the field as the two magnets bounce south against south or vice-versa ? hall effect or coil ? it seems to me that whatever sensor you use you need two identical for a proper input into a differential amplifier ?? that alone would increase your output by 6Dbv or X2 ? Comments please ?? Please share your results unless you intend to capitalize on what you have learned. best regards to all; geoff
hello = PSN;
 
build the mechanics to = any type of=20 seismometer
then use several = different sensors=20 to see which
produces the best = results=20 ?
 
does anyone know what = the best=20 would be ??
 
variable optical, = laser, led,=20 etc..
variable capacitive, = interleve=20 plates ??
variable inductive ( = like the old=20 radio tuning slug in a coil )
velocity sensor ( = magnet coil or=20 magnet solinoid [coil plus iron core])
strain guage with a = weight attached=20 ? ( like bathroom scales )
 
are there mechanical = ways to damp (=20 remove energy ) that might work
as well as magnetic=20 ?
 
It might be nice to = have a chord=20 for a pendulum that will
damp as it flexes=20 ???
 
is it possible to = levitate two=20 magnets against each other
then measure changes in = the field=20 as the two magnets
bounce south against = south or=20 vice-versa ?
hall effect or coil=20 ?
 
 
it seems to me that = whatever sensor=20 you use you need two
identical for a proper = input into a=20 differential amplifier ??
that alone would = increase your=20 output by 6Dbv or X2 ?
 
Comments please=20 ??
Please share your = results unless=20 you intend to capitalize
on what you have=20 learned.
 
best regards to=20 all;
geoff
Subject: Re: Advantages of more ADC bits From: "GMV" gmvoeth@........... Date: Mon, 9 Feb 2009 17:47:06 -0700 note on alising alizing ?? It is my understanding that all inputs which are sampled must be low pass filtered at like 0.4 of the sample rate in hertz so if you sample at 100 samples per seconds you need to prefilter prior to input to the a/d with a n4 to preferred(n8 eight stages of a simple rc filter) at like 40 hertz. alizing is kinda a law of physics (math) you must deal with or get phony signals like 50 or 60 hz artifacts in your results. alizing is like with 100 sps: 50 hz wraps back to zero(DC) and 51 becomes one Hz(ac) ?? you must eliminate all freqs above 1/2 the sample rate and since filters are not perfect that means like 0.75/2 instead of 1/2. You want zero Dbv ( x1) or less above 1/2 the sps in hertz. Im no scientist but I do understand this limitation since working with sampled data in the sonar field. I kept getting phony 60hz artifacts just above 5Hz till i filtered my signal before sampling it. geoff ----- Original Message ----- From: "rsparks" To: Sent: Sunday, February 08, 2009 1:13 PM Subject: Re: Advantages of more ADC bits > Thanks to both Chris and Brett for their thoughtful replies. I better > understand that an upgrade to 24 bits is not a "no brainer" upgrade, > but part of design strategy. All the parts must fit together to get > superior results and fulfill site goals. > > There are new devices that may hold promise for future amateur use. One > such device is the Cirrus Logic CS5530 24 bit ADC with integrated > amplifier. I don't know if this could stand alone with a dedicated > computer (or maybe not dedicated) using a serial port, or if it must be > combined with a microcontroller. I also don't know if the input must be > pre-filtered to prevent aliasing, or if the integrated amplifier is > sufficient for amateur seismic work. > > Thanks for your comments > > Roger > __________________________________________________________ > > 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: Coil and Magnets or Led and photo transistor From: "tchannel" tchannel@............ Date: Mon, 9 Feb 2009 17:53:48 -0700 Another question about this site........he uses a LED and Photo = Transistor in place of the coil and magnet. I have never used this. = Is one better than the other? This approach would be smaller and = lighter. =20 http://tinkeringcaveman.googlepages.com/home Thanks, Ted
 Another question about this = site........he=20 uses a LED and Photo Transistor in place of the coil and = magnet.   I=20 have never used this.  Is one better than the other?   = This=20 approach would be smaller and lighter. 
 
 
http://tinkeringcav= eman.googlepages.com/home
 
Thanks, Ted
Subject: need a new fangled low pass filter butterworth ?? From: "GMV" gmvoeth@........... Date: Mon, 9 Feb 2009 17:57:55 -0700 Does anyone know a modern active filter like n8 that one can use at like 3 or 4 hz rolloff ?? I look at the manufacturers sites but like thay are designed for the Khz ranges ? it needs to rolloff butterworth to like -80Db or vin/10000 Im looking for something simpler that a two stage MFB active opamp type to breadboard. they are easy to design but not easy to get matched parts for. thanx geoff
Does anyone know a = modern active=20 filter like n8 that
one can use at like 3 = or 4 hz=20 rolloff ??
 
I look at the = manufacturers sites=20 but like thay
are designed for the = Khz ranges=20 ?
 
it needs to rolloff = butterworth to=20 like -80Db
 or=20 vin/10000
 
Im looking for = something simpler=20 that a two stage
MFB active opamp type = to=20 breadboard.
they are easy to design = but not=20 easy to get matched parts for.
 
thanx
geoff
 
Subject: Re: Coil and Magnets or Led and photo transistor From: ChrisAtUpw@....... Date: Mon, 9 Feb 2009 21:28:26 EST In a message dated 10/02/2009, tchannel@............ writes: Another question about this site.... he uses a LED and Photo Transistor in place of the coil and magnet. I have never used this. Is one better than the other? This approach would be smaller and lighter. _http://tinkeringcaveman.googlepages.com/home_ (http://tinkeringcaveman.googlepages.com/home) Hi Ted, He will get very poor performance out of his proposed LED + Phototransistor system. You can get photo detection systems with resolutions of maybe 10 nano metres, if you design them correctly. Microseisms have a quoted amplitude range between 0.5 and 15 microns. Multiply by 1000 to get nano metres. The manufacturers of LEDs don't often tell you that the light output at a constant cuttent varies by >x10 for substrate temperature changes between 0 and 100 C. Can't think why! The unstabilised drifts are huge and the photo noise is considerable. You can stabilise the output with another Si photocell + a driver amplifier. You need differential large area photocells and an intense photo emitter to give the high photo currents required to get the photo noise and drift down. The current is proportional to the number of electrons in a sample. The photo noise is the square root of this number. You can do it OK with differential Si photocells BPW34 or larger and an under run tungsten filament bulb. Use about 3/4 the rated voltage to give ~infinite filament life. Maybe put the bulb outside the glass jar to keep down the heating / air convection? There is a differential photo amplifier on John's website. Remember that this is a position detector, NOT a velocity detector. If you use a coil + magnet block sensor, you have to get the output current away from the armature. Maybe use the suspension wires? You need very small diameter suspension wires to get the longer periods. The Wood-Anderson seismometers used about 0.8 thou OD Tungsten wire. The smallest that I can get off the shelf is 2.4 thou OD. It is used in laser printers. Check used cartridges? You might also be able to use small diameter NiChrome wire. I have some 2 thou OD. What do _www.smallparts.com_ (http://www.smallparts.com) keep? The smallest steel music wire is about 7 thou diameter - much too large. Smaller diameters are produced, but I don't know of a source. Glass filaments tend to be brittle and don't conduct electric current. S glass is often used for fibreglass construction. Regards, Chris Chapman
In a message dated 10/02/2009, tchannel@............ writes:
<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size= =3D2>
 Another question about this site...= .. he=20 uses a LED and Photo Transistor in place of the coil and magnet. I have ne= ver=20 used this. Is one better than the other? This approach would be smaller an= d=20 lighter. 
http://tinkeringcave= man.googlepages.com/home
Hi Ted,
 
    He will get very poor performance out of his=20 proposed LED + Phototransistor system. You can get photo detection systems w= ith=20 resolutions of maybe 10 nano metres, if you design them correctly. Microseis= ms=20 have a quoted amplitude range between 0.5 and 15 microns. Multiply by 1000 t= o=20 get nano metres.
    The manufacturers of LEDs don't often tell you=20= that=20 the light output at a constant cuttent varies by >x10  for substrate= =20 temperature changes between 0 and 100 C. Can't think why! The unstabili= sed=20 drifts are huge and the photo noise is considerable. You can stabilise the=20 output with another Si photocell + a driver amplifier.
    You need differential large area photocells and= an=20 intense photo emitter to give the high photo currents required to get the ph= oto=20 noise and drift down. The current is proportional to the number of electrons= in=20 a sample. The photo noise is the square root of this number. You can do it O= K=20 with differential Si photocells BPW34 or larger and an under run=20 tungsten filament bulb. Use about 3/4 the rated voltage to give ~infini= te=20 filament life. Maybe put the bulb outside the glass jar to keep down the hea= ting=20 / air convection? There is a differential photo amplifier on John's=20 website.
    Remember that this is a position detector, NOT=20= a=20 velocity detector.
    If you use a coil + magnet block sensor, you ha= ve=20 to get the output current away from the armature. Maybe use the suspension=20 wires?
 
    You need very small diameter suspension wires t= o=20 get the longer periods. The Wood-Anderson seismometers used about 0.8 thou O= D=20 Tungsten wire. The smallest that I can get off the shelf is 2.4 thou OD= .. It=20 is used in laser printers. Check used cartridges? You might also be able to=20= use=20 small diameter NiChrome wire. I have some 2 thou OD. What do www.smallparts.com keep? The smallest= steel=20 music wire is about 7 thou diameter - much too large. Smaller diameters are=20 produced, but I don't know of a source. Glass filaments tend to be brittle a= nd=20 don't conduct electric current. S glass is often used for fibreglass=20 construction.
 
    Regards,
 
    Chris Chapman
Subject: Re: HAS ANYONE TRIED THIS b4... From: ChrisAtUpw@....... Date: Mon, 9 Feb 2009 23:24:14 EST In a message dated 10/02/2009, gmvoeth@........... writes: build the mechanics to any type of seismometer then use several different sensors to see which produces the best results? Hi Geoff, That is not necessary. does anyone know what the best would be? Yes, but they are also sample time and design / range dependant. In sequence of best first Capacitative. LCDT 10^-12 m Inductive. LVDT 10^-10 m Optical. 10^-8 m Hall Magnetic. 3x10^-8 m Wavelength optical is sometimes used, but it gets excessively expensive below 5x10^-7 m The absolute stability may only be better than ~10^-8 m. Velocity sensors tend to be grouped around Inductive, but are frequency dependant. They are not so effective at long periods. I am excluding the operation of superconducting sensors. They can have extremely high stability. are there mechanical ways to damp (remove energy) that might work as well as magnetic? Viscosity methods are difficult to use and strongly temperature dependant. You can use phased electrostatic feedback as well as electromagnetic. It might be nice to have a chord for a pendulum that will damp as it flexes? Not usually necessary. Springs sometimes give problems, particuarly coil springs. It is easier to apply magnetic damping to leaf springs. is it possible to levitate two magnets against each other then measure changes in the field as the two magnets bounce south against south or vice-versa? Yes, but it is non linear and temperature dependant. Solenoid + magnet can be used, but there is still a temperature dependance and a highly stabilised current requirement. it seems to me that whatever sensor you use you need two identical for a proper input into a differential amplifier? that alone would increase your output by 6Dbv or X2? That may not be necessary. A single sensor can often drive a differential amplifier OK. Single sensors drive non differential amplifiers just fine. Regards, Chris Chapman
In a message dated 10/02/2009, gmvoeth@........... writes:
<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size= =3D2>
build the mechanics to an= y type=20 of seismometer
then use several differen= t=20 sensors to see which
produces the best=20 results?
Hi Geoff,
 
    That is not necessary.
<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size= =3D2>
does anyone know what the= best=20 would be?
    Yes, but they are also sample time and design /= =20 range dependant.
 
    In sequence of best first
    Capacitative. LCDT 10^-12 m
    Inductive. LVDT 10^-10 m
    Optical. 10^-8 m
    Hall Magnetic. 3x10^-8 m
 
    Wavelength optical is sometimes used, but it ge= ts=20 excessively expensive below 5x10^-7 m
 
    The absolute stability may only be better than=20 ~10^-8 m.
 
    Velocity sensors tend to be grouped around=20 Inductive, but are frequency dependant. They are not so effective at long=20 periods.
 
    I am excluding the operation of superconducting= =20 sensors. They can have extremely high stability.
<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size= =3D2>
are there mechanical ways= to damp=20 (remove energy) that might work as well as=20 magnetic?
    Viscosity methods are difficult to use and stro= ngly=20 temperature dependant.
    You can use phased electrostatic feedback as we= ll=20 as electromagnetic. 
<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size= =3D2>
It might be nice to have=20= a chord=20 for a pendulum that will <= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size= =3D2>
is it possible to levitat= e two=20 magnets against each other then measure changes in the field as the two magnets=20 bounce south a= gainst=20 south or vice-versa?
    Yes, but it is non linear and temperature=20 dependant. Solenoid + magnet can be used, but there is still a temperature=20 dependance and a highly stabilised current requirement.
<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size= =3D2>
it seems to me that whate= ver=20 sensor you use you need two identical for a proper input into a differential=20 amplifier?
that alone would increase= your=20 output by 6Dbv or X2?
    That may not be necessary. A single sensor can=20 often drive a differential amplifier OK. Single sensors drive non differenti= al=20 amplifiers just fine.
 
    Regards,
 
    Chris Chapman
Subject: Re: HAS ANYONE TRIED THIS b4... From: "GMV" gmvoeth@........... Date: Tue, 10 Feb 2009 06:22:37 -0700 Hello Chris; question below inline like in news groups. Maybe psn should have a public news group no registration is necessary like alt.amateur.seismic.psn ?? maybe I could investigate the creation of such a thing ??? ----- Original Message -----=20 From: ChrisAtUpw@.......... To: psn-l@................. Sent: Monday, February 09, 2009 9:24 PM Subject: Re: HAS ANYONE TRIED THIS b4... In a message dated 10/02/2009, gmvoeth@........... writes: build the mechanics to any type of seismometer then use several different sensors to see which produces the best results? Hi Geoff, That is not necessary. does anyone know what the best would be? Yes, but they are also sample time and design / range dependant. In sequence of best first Capacitative. LCDT 10^-12 m Inductive. LVDT 10^-10 m Optical. 10^-8 m Hall Magnetic. 3x10^-8 m Wavelength optical is sometimes used, but it gets excessively = expensive below 5x10^-7 m The absolute stability may only be better than ~10^-8 m. Velocity sensors tend to be grouped around Inductive, but are = frequency dependant. They are not so effective at long periods. I am excluding the operation of superconducting sensors. They can = have extremely high stability. are there mechanical ways to damp (remove energy) that might work as = well as magnetic? Viscosity methods are difficult to use and strongly temperature = dependant. You can use phased electrostatic feedback as well as = electromagnetic.=20 It might be nice to have a chord for a pendulum that will damp as it = flexes? Not usually necessary. Springs sometimes give problems, = particuarly coil springs. It is easier to apply magnetic damping to leaf = springs. is it possible to levitate two magnets against each other then = measure changes in the field as the two magnets bounce south against = south or vice-versa? Yes, but it is non linear and temperature dependant. Solenoid + = magnet can be used, but there is still a temperature dependance and a = highly stabilised current requirement. it seems to me that whatever sensor you use you need two identical = for a proper input into a differential amplifier? that alone would increase your output by 6Dbv or X2? That may not be necessary. A single sensor can often drive a = differential amplifier OK. Single sensors drive non differential = amplifiers just fine. ***************************** Hello Chris: Yes I understand what you say here but I have learned through = experiences that a differential amp is about the only way to achieve = stability in that you have a phantom null point that lies within a (lets = say here) coil. This is also the best way to get common mode rejection = of unwanted noise. If you use the diff amp as it seems to be intended = with two identical sensors symmetrical about ground the best results = seem to be obtained. you can gang multiple sensors together and enhance = the signal while cancelling 50% of the noise through summation or = correlation of all the individual sensors. Noise is somewhat random but = the signal will affect all sensors identically within a small area like = 1ftsquare (1ft^2). can you further comment on this idea ? (e.g. n^2 (2,4,8) sensors in series or parallel or both all within a = small area together like on a single slab of concrete bonded and = shielded and underground all together) Best regards geoff ******************************** Regards, Chris Chapman
Hello = Chris;
question below inline = like in news=20 groups.
 
Maybe psn should have a = public news=20 group
no registration is = necessary like=20 alt.amateur.seismic.psn ??
maybe I could = investigate the=20 creation of such a thing ???
----- Original Message -----
From:=20 ChrisAtUpw@.......
Sent: Monday, February 09, 2009 = 9:24=20 PM
Subject: Re: HAS ANYONE TRIED = THIS=20 b4...

In a message dated 10/02/2009, gmvoeth@........... = writes:
build the mechanics = to any type=20 of seismometer
then use several = different=20 sensors to see which
produces the best=20 results?
Hi Geoff,
 
    That is not necessary.
does anyone know = what the best=20 would be?
    Yes, but they are also sample time and = design /=20 range dependant.
 
    In sequence of best first
    Capacitative. LCDT 10^-12 m
    Inductive. LVDT 10^-10 m
    Optical. 10^-8 m
    Hall Magnetic. 3x10^-8 m
 
    Wavelength optical is sometimes used, but = it gets=20 excessively expensive below 5x10^-7 m
 
    The absolute stability may only be better = than=20 ~10^-8 m.
 
    Velocity sensors tend to be grouped = around=20 Inductive, but are frequency dependant. They are not so effective at = long=20 periods.
 
    I am excluding the operation of = superconducting=20 sensors. They can have extremely high stability.
are there = mechanical ways to=20 damp (remove energy) that might work as well as=20 magnetic?
    Viscosity methods are difficult to use = and=20 strongly temperature dependant.
    You can use phased electrostatic feedback = as well=20 as electromagnetic. 
It might be nice to = have a=20 chord for a pendulum that will damp as it=20 flexes?
    Not usually necessary. Springs sometimes = give=20 problems, particuarly coil springs. It is easier to apply magnetic = damping to=20 leaf springs.
is it possible to = levitate two=20 magnets against each other then measure changes in the field as the two magnets=20 bounce = south against=20 south or vice-versa?
    Yes, but it is non linear and temperature = dependant. Solenoid + magnet can be used, but there is still a = temperature=20 dependance and a highly stabilised current requirement.
it seems to me that = whatever=20 sensor you use you need two identical for a proper input into a differential=20 amplifier?
that alone would = increase your=20 output by 6Dbv or X2?
    That may not be necessary. A single = sensor can=20 often drive a differential amplifier OK. Single sensors drive non = differential=20 amplifiers just fine.
 
*****************************
Hello=20 Chris:
Yes I understand what = you say=20 here but I have learned through experiences that a differential amp is = about=20 the only way to achieve stability in that you have a phantom null = point that=20 lies within a (lets say here) coil. This is also the best way to get = common=20 mode rejection of unwanted noise. If you use the diff amp as it seems = to be=20 intended with two identical sensors symmetrical about ground the best = results=20 seem to be obtained. you can gang multiple sensors together and = enhance the=20 signal while cancelling 50% of the noise through summation or = correlation of=20 all the individual sensors. Noise is somewhat random but the signal = will=20 affect all sensors identically within a small area like 1ftsquare=20 (1ft^2).
can you further = comment on this=20 idea ?
(e.g. n^2 (2,4,8) = sensors in=20 series or parallel or both all within a small area together like on a = single=20 slab of concrete bonded and shielded and underground all=20 together)
Best=20 regards
geoff
********************************
 
    Regards,
 
    Chris=20 Chapman
Subject: Re: Advantages of more ADC bits From: "GMV" gmvoeth@........... Date: Tue, 10 Feb 2009 06:32:20 -0700 Hello PSN: one thought regarding this is if you use only 8 bits of data you can scale your amplification digitally by which contiguous 8 bits you use out of the 24. for greatest sensitivity you use bits 0 to 7 and for least you use bits 16 to 23. With a bit of scaling you can then control amplification levels through the program and not the hardware. most of you do not like 8 bits but it works just fine for myself since I go for (first time of arrival as well as byte size efficency) and not (signal fidelity or dynamic range). Regards geoff ----- Original Message ----- From: "rsparks" To: Sent: Sunday, February 08, 2009 1:13 PM Subject: Re: Advantages of more ADC bits > Thanks to both Chris and Brett for their thoughtful replies. I better > understand that an upgrade to 24 bits is not a "no brainer" upgrade, > but part of design strategy. All the parts must fit together to get > superior results and fulfill site goals. > > There are new devices that may hold promise for future amateur use. One > such device is the Cirrus Logic CS5530 24 bit ADC with integrated > amplifier. I don't know if this could stand alone with a dedicated > computer (or maybe not dedicated) using a serial port, or if it must be > combined with a microcontroller. I also don't know if the input must be > pre-filtered to prevent aliasing, or if the integrated amplifier is > sufficient for amateur seismic work. > > Thanks for your comments > > Roger > __________________________________________________________ > > 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: using windows VISTA 64 with dos applications From: "GMV" gmvoeth@........... Date: Tue, 10 Feb 2009 07:09:32 -0700 Howdy All from AZ; FYI: I have found you need a dos emulator like DOSBOX to run 16 bit applications under windows vista 64. I have been able to successfully compile older dos exe programs using powerbasic for dos under DOSBOX from within Windows Vista 64. MSDOS is the best program for me to record seismic or whatever data logging needs to be done. The rest of you probably laugh at this but I need a machine dedicated to a single program and it seems the newer OS like windows VISTA will not do this. MSDOS seems the only way. DOSBOX 7.xx is like freeware or donateware right now but I suspect it will not always be so as operating systems refuse to run older softwares. comments welcome. Best regards PSN; geoff
Howdy All from=20 AZ;
 
FYI:
I have found you need a = dos=20 emulator like DOSBOX
to run 16 bit = applications under=20 windows vista 64.
I have been able to = successfully=20 compile older dos
exe programs using = powerbasic for=20 dos under DOSBOX
from within Windows = Vista=20 64.
 
MSDOS is the best = program for me to=20 record seismic or
whatever data logging = needs to be=20 done.
 
The rest of you = probably laugh at=20 this but I need
a machine dedicated to = a single=20 program and it
seems the newer OS like = windows=20 VISTA will not do this.
MSDOS seems the only=20 way.
 
DOSBOX 7.xx is like = freeware or=20 donateware
right now but I suspect = it will not=20 always be so
as operating systems = refuse to run=20 older softwares.
 
comments=20 welcome.
 
Best regards=20 PSN;
geoff
 
Subject: Winquake and Google From: "tchannel" tchannel@............ Date: Wed, 11 Feb 2009 10:03:32 -0700 Hi Folks, For some reason I can no longer use Google with Winquake to = AUTOMATICALLY view my Station or Events........It worked fine before. = I tried opening different .psn in Winquake, different days or months, = and none will show in Google Earth, and they all did before. I get = an error message. "Could not open file C:\Program = Files\WinQuake\GoogleEarth.kml for reading" Google Earth shows a folder under My Places, as before. I can make it work if I manually locate a file called GoogleEarth.kml, = which I found in C:\Users\Ted\App Data\Local|Virtual Store\program = files\WinQuake. In that folder, if I click on GoogleEarth.kml, Google = Earth will launch and show both event and station like it did before. So I think I must have done something in the last day or two to mess it = up. Thanks, Ted
Hi Folks, For some reason I can no = longer use=20 Google with Winquake to AUTOMATICALLY view my Station or = Events........It worked=20 fine before.   I tried opening different .psn in Winquake, = different=20 days or months, and none will show in Google Earth, and they all did=20 before.     I get an error message.   = "Could not=20 open file C:\Program Files\WinQuake\GoogleEarth.kml for = reading"
 
 
Google Earth shows a folder under My = Places, as=20 before.
 
I can make it work if I manually locate = a file=20 called GoogleEarth.kml, which I found in C:\Users\Ted\App = Data\Local|Virtual=20 Store\program files\WinQuake.    In that folder, if I = click on=20 GoogleEarth.kml, Google Earth will launch and show both event and = station like=20 it did before.
 
So I think I must have done something = in the last=20 day or two to mess it up.
 
Thanks, Ted
Subject: Re: Winquake and Google From: Pete Rowe ptrowe@......... Date: Wed, 11 Feb 2009 10:57:38 -0800 (PST) Hi Ted You might try going back to a restore point a few days ago to see if that f= ixes it. This has save me once or twice. I don't have a clue to what you are talking about. How do Winquake and Goog= le earth do something together? How about a short tutorial on how to set th= is up and what it is that is displayed on Google Earth?? Thanks Pete --- On Wed, 2/11/09, tchannel wrote: From: tchannel Subject: Winquake and Google To: "psn" Date: Wednesday, February 11, 2009, 9:03 AM =0A=0A =0A =0A=0AHi Folks, For some reason I can no longer use =0AGoogle wi= th Winquake to AUTOMATICALLY view my Station or Events........It worked =0A= fine before.=A0=A0 I tried opening different .psn in Winquake, different = =0Adays or months, and none will show in Google Earth, and they all did =0A= before.=A0=A0=A0 =A0I get an error message.=A0=A0 "Could not =0Aopen file C= :\Program Files\WinQuake\GoogleEarth.kml for reading"=0A=A0=0A=A0=0AGoogle = Earth shows a folder under My Places, as =0Abefore.=0A=A0=0AI can make it w= ork if I manually locate a file =0Acalled GoogleEarth.kml, which I found in= C:\Users\Ted\App Data\Local|Virtual =0AStore\program files\WinQuake.=A0=A0= =A0 In that folder, if I click on =0AGoogleEarth.kml, Google Earth will lau= nch and show both event and station like =0Ait did before.=0A=A0=0ASo I thi= nk I must have done something in the last =0Aday or two to mess it up.=0A= =A0=0AThanks, Ted=0A=0A=0A
Hi Ted
You might try going back to a restore point a few days ago to see if that fixes it. This has save me once or twice.
I don't have a clue to what you are talking about. How do Winquake and Google earth do something together? How about a short tutorial on how to set this up and what it is that is displayed on Google Earth??
Thanks
Pete

--- On Wed, 2/11/09, tchannel <tchannel@............> wrote:

From: tchannel <tchannel@............>
Subject: Winquake and Google
To: "psn" <psn-l@..............>
Date: Wednesday, February 11, 2009, 9:03 AM

Hi Folks, For some reason I can no longer use Google with Winquake to AUTOMATICALLY view my Station or Events........It worked fine before.   I tried opening different .psn in Winquake, different days or months, and none will show in Google Earth, and they all did before.     I get an error message.   "Could not open file C:\Program Files\WinQuake\GoogleEarth.kml for reading"
 
 
Google Earth shows a folder under My Places, as before.
 
I can make it work if I manually locate a file called GoogleEarth.kml, which I found in C:\Users\Ted\App Data\Local|Virtual Store\program files\WinQuake.    In that folder, if I click on GoogleEarth.kml, Google Earth will launch and show both event and station like it did before.
 
So I think I must have done something in the last day or two to mess it up.
 
Thanks, Ted

Subject: earthquake activity in Indonesia From: Thomas Dick dickthomas01@............. Date: Thu, 12 Feb 2009 10:03:03 -0600 John Search is away. Anybody know whether is activity is volcanic activity? __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: earthquake activity in Indonesia From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@......... Date: Thu, 12 Feb 2009 16:54:12 +0000 Hi There has not been any annocement on the volcano postlist yet. The activie is quite intresting. This might be a pre-earthquake swarm prior to a large earthquake, then I mean earthquake larger then Mw8.5. But only time is going to tell us what is going on there. The area appears to be farly remote. Regards. J=F3n Fr=EDmann. On fim, 2009-02-12 at 10:03 -0600, Thomas Dick wrote: > John Search is away. Anybody know whether is activity is volcanic activit= y? > __________________________________________________________ >=20 > Public Seismic Network Mailing List (PSN-L) >=20 > To leave this list email PSN-L-REQUEST@.............. with=20 > 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: earthquake activity in Indonesia From: JToledo@............. Date: Thu, 12 Feb 2009 11:15:45 -0600 Hi JON : yes it is very interesting the seismic activity takin place since yesterday . even there has been a couple or ORANGE alerts last night on= several events with a 6.4 mag. level. we are monitoring this particular activity,hoping that it will not deve= lop into a higher seismic level , or a big earthquake. tnx for l the information provided by uour site . yours |----------------------------------------------------------------------= ----| | F.Jose Toledo | CONRED | = | | Unidad: OFICIAL DE MONITOREO | Celular: 5-2012109 | E-mail: = | | jtoledo@............. = | | [ Direcci=F3n: Ave. Hincapi=E9 21-72 Zona 13 Tel:2385-4144 ][Guate= mala, | | Guatemala 01013 Guatemala C.A. ] = | |----------------------------------------------------------------------= ----| = __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: earthquake activity in Indonesia From: Thomas Dick dickthomas01@............. Date: Thu, 12 Feb 2009 13:16:23 -0600 Jón Frímann wrote:There has not been any annocement on the volcano postlist yet. Theactivie is quite intresting. This might be a pre-earthquake swarm priorto a large earthquake, then I mean earthquake larger then Mw8.5. Butonly time is going to tell us what is going on there.The area appears to be farly remote. Where is John Search when you need him. I guess he is on summer break. Yes, this is a remote area but fortunately so far the quakes are deep -- (the tsunami threat)-- but near islands. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: John Lahr From: "Kay Wyatt" kwyatt@............. Date: Thu, 12 Feb 2009 11:56:29 -0800 I'm sure that many of you know John Lahr who has been very active in putting seismometers in schools around the country through the IRIS Seismographs in Schools Program. His condition (brain cancer) becomes more grave every day. His wife, Jan, has been posting his progress on John's blog at http://johnsnoggin.blogspot.com/ This morning she posted the note below. If John has touched your life in any way, perhaps you might want to share it by sending an email to seismoedu@.......... John has arranged for me to maintain his seismology website at www.jclahr.com. I plan on posting a tribute to John on his website at the appropriate time. If you wouldn't mind cc'ing me on your email I would be most grateful to hear from you. Remember that replys to this email will go to the PSN listserver, so you might want to just send your email to kwyatt@............. and seismoedu@.......... Kay Wyatt Oregon Shakes Program JAN'S EMAIL FOLLOWS BELOW: Who is out there????? John has touched the lives of so many people. We know the address for this blog has been passed along to people all over the world. I would like to give John a list of people who are following it. Please send an e-mail to let us know you're out there and care about John. Just your name and where you live would be great. The e-mail adress is: seismoedu@......... Of course, it would also be interesting to hear why you are following the blog. Is it because you know John personally? Or because you're familiar with his work or his web site? Or just because you've heard he's a nice guy? Or because you are interested in following someone's brain cancer journey? All of the above or something else? I'll give John a list of names and locations and will print out any longer messages to read to him. This will be fun! Maybe I'll hang a map on the wall and put pins in every location where at least one of you lives. Love to all, Jan __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: earthquake activity in Indonesia From: Bob Hancock icarus@......... Date: Thu, 12 Feb 2009 13:51:12 -0700 A review of the recent events that were magnitude 6 or greater revealed they were all thrust faults orientated on or near a north/ south line. Thrust faults are associated with compressive forces. The earthquake activity appears to be centered west of the southern end of the East Philippine Subduction zone, near the Sangihe Arc, also referred to as the Sangihe Subduction Zone and the Sangihe Volcanic Arc. It is located east of the Halmahera Arc (subduction zone) and the area is referred to as a double subduction zone. Following are some links to articles on the area. http://whatonearth.olehnielsen.dk/molucca.asp http://www.geology.um.maine.edu/geodynamics/AnalogWebsite/UndergradProjects2006/Jennifer%20Bromley/web%20pages/Molucca_sea.html http://www.geology.um.maine.edu/geodynamics/AnalogWebsite/UndergradProjects2006/Jennifer%20Bromley/web%20pages/index.html Bob Hancock On Feb 12, 2009, at 9:03 AM, Thomas Dick wrote:
A review of the recent = events that were magnitude 6 or greater revealed they were all thrust = faults orientated on or near a north/south line.  Thrust faults are = associated with compressive forces.

The = earthquake activity appears to be centered west of the southern end of = the East Philippine Subduction zone, near the Sangihe Arc, also referred = to as the Sangihe Subduction Zone and the Sangihe Volcanic Arc.  It = is located east of the Halmahera Arc (subduction zone) and the area is = referred to as a double subduction zone.  Following are some links = to articles on the area.



http://www.geolog= y.um.maine.edu/geodynamics/AnalogWebsite/UndergradProjects2006/Jennifer%20= Bromley/web%20pages/index.html

Bo= b Hancock

On Feb 12, 2009, at 9:03 AM, Thomas = Dick wrote:

=
= Subject: Re: earthquake activity in Indonesia From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@......... Date: Fri, 13 Feb 2009 04:11:27 +0000 Hi I did check for volcanoes where the current earthquakes are happening. At the island where they earthquakes are happening, there are no volcanoes. There are volcanoes on nearby islands and areas. Giving the pattern, I am not going to be surpriced if there is going to be a earthquake close to Mw8.5 soon in nearby fault zones. When that might happen is harder to say. A link with volcano information on this area. http://www.volcano.si.edu/world/region.cfm?rnum=3D06 Regards. J=F3n Fr=EDmann. On fim, 2009-02-12 at 13:51 -0700, Bob Hancock wrote: > A review of the recent events that were magnitude 6 or greater > revealed they were all thrust faults orientated on or near a > north/south line. Thrust faults are associated with compressive > forces. >=20 >=20 > The earthquake activity appears to be centered west of the southern > end of the East Philippine Subduction zone, near the Sangihe Arc, also > referred to as the Sangihe Subduction Zone and the Sangihe Volcanic > Arc. It is located east of the Halmahera Arc (subduction zone) and > the area is referred to as a double subduction zone. Following are > some links to articles on the area. >=20 >=20 > http://whatonearth.olehnielsen.dk/molucca.asp >=20 >=20 > http://www.geology.um.maine.edu/geodynamics/AnalogWebsite/UndergradProjec= ts2006/Jennifer%20Bromley/web%20pages/Molucca_sea.html >=20 >=20 > http://www.geology.um.maine.edu/geodynamics/AnalogWebsite/UndergradProjec= ts2006/Jennifer%20Bromley/web%20pages/index.html >=20 >=20 > Bob Hancock >=20 >=20 > On Feb 12, 2009, at 9:03 AM, Thomas Dick wrote: >=20 >=20 __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: John Lahr From: meredith lamb paleoartifact@......... Date: Thu, 12 Feb 2009 21:17:27 -0700 PSN members who want to share Kay Wyatt John and Jan Lahr Hi John and Jan Dang! We sure wished you folks hadn't left Colorado afew years back; it was so much fun to be able to go to the variety of get-to-gethers you folks had organized either via you home in Golden and/or at the NEIC building there! There is nothing quite like such to stimulate and share the interest of seismology, seismometry; and of course the personal interlog brings alot with it to make it yet still more stimulating via all the different variations of the subjects! I know you folks really went out of your way to organize, set-up and even brought along a variety of other USGS employees to such, who helped make a number of those events a even bigger success. Your many teaching aids or items that stimulated the physics and instrumentation were quite clever and while most were simple; they taught the viewers and gave understanding to probably hundreds (or perhaps thousands by now) of viewers...and made it more "alive" by demonstration. Am so very glad that your large website will be carryed on via Kay; as I rank it as the very best for anyone with a interest in amateur seismology. I appreciate all the years of work you have done to make it such! It will be a "living" tribute to your teaching skills, enthusiasm and devotion for all those to yet read and view it! The web site is a real information treasure and should be justly preserved for many years to come. My wife, Lee Ann and I both wish to express our big thanks for all you have done! We ourselves have seen cancer in several family members also over time. Its a terrible thing and it is a traumatic event to endure for everyone involved. I wish their were cures for all them....hopefully it will happen in time. Lee Ann herself is a brain cancer survivor of her nearly fatal bout in the early 1960's. Thanks for the notice Jan. Our prayers are with you both, Meredith and Lee Ann Lamb On Thu, Feb 12, 2009 at 12:56 PM, Kay Wyatt wrote: > I'm sure that many of you know John Lahr who has been very active in > putting seismometers in schools around the country through the IRIS > Seismographs in Schools Program. His condition (brain cancer) becomes more > grave every day. > > His wife, Jan, has been posting his progress on John's blog at > http://johnsnoggin.blogspot.com/ > > This morning she posted the note below. If John has touched your life in > any way, perhaps you might want to share it by sending an email to > seismoedu@.......... John has arranged for me to maintain his seismology > website at www.jclahr.com. I plan on posting a tribute to John on his > website at the appropriate time. If you wouldn't mind cc'ing me on your > email I would be most grateful to hear from you. Remember that replys to > this email will go to the PSN listserver, so you might want to just send > your email to kwyatt@............. and seismoedu@.......... > > Kay Wyatt > Oregon Shakes Program > > > JAN'S EMAIL FOLLOWS BELOW: > Who is out there????? > John has touched the lives of so many people. We know the address for this > blog has been passed along to people all over the world. I would like to > give John a list of people who are following it. > > Please send an e-mail to let us know you're out there and care about John. > Just your name and where you live would be great. > > The e-mail adress is: seismoedu@......... > > Of course, it would also be interesting to hear why you are following the > blog. Is it because you know John personally? Or because you're familiar > with his work or his web site? Or just because you've heard he's a nice guy? > Or because you are interested in following someone's brain cancer journey? > All of the above or something else? I'll give John a list of names and > locations and will print out any longer messages to read to him. > > This will be fun! Maybe I'll hang a map on the wall and put pins in every > location where at least one of you lives. > > Love to all, > Jan > > __________________________________________________________ > > 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. >
PSN members who want to share
Kay Wyatt
John and Jan Lahr
 
Hi John and Jan
 
Dang!  We sure wished you folks hadn't left Colorado afew yea= rs back; it was so much fun to be able to go to the variety of
get-to-gethers you folks had organized either via you home in Golden a= nd/or at the NEIC building there!  There is nothing quite
like such to stimulate and share the interest of seismology, seismomet= ry; and of course the personal interlog brings alot with it
to make it yet still more stimulating via all the different varia= tions of the subjects!  I know you folks really went out of your way t= o organize,
set-up and even brought along a variety of other USGS employees to suc= h, who helped make a number of those events a even bigger
success.   Your many teaching aids or items that stimulated = the physics and instrumentation were quite clever and while most were
simple; they taught the viewers and gave understanding to probabl= y hundreds (or perhaps thousands by now) of viewers...and made
it more "alive" by demonstration. 
 
Am so very glad that your large website will be carryed on via Ka= y; as I rank it as the very best for anyone with a interest in
amateur seismology.  I appreciate all the years of work you have = done to make it such!  It will be a "living" tribute to your= teaching
skills, enthusiasm and devotion for all those to yet read and vie= w it!   The web site is a real information treasure and should be= justly
preserved for many years to come.
 
My wife, Lee Ann and I both wish to express our big thanks for all you= have done!
 
We ourselves have seen cancer in several family members also over time= ..  Its a terrible thing and it is a traumatic event to endure
for everyone involved.  I wish their were cures for all them....h= opefully it will happen in time.  Lee Ann herself is a brain=
cancer survivor of her nearly fatal bout in the early 1960's.
 
Thanks for the notice Jan. 
 
Our prayers are with you both,
 
Meredith and Lee Ann Lamb   
 
 
 
 
 
 
 
On Thu, Feb 12, 2009 at 12:56 PM, Kay Wyatt <kwyatt@........... com> wrote:
I'm sure that many of you kn= ow John Lahr who has been very active in putting seismometers in schools ar= ound the country through the IRIS Seismographs in Schools Program.  Hi= s condition (brain cancer) becomes more grave every day.

His wife, Jan, has been posting his progress on John's blog at
<= a href=3D"http://johnsnoggin.blogspot.com/" target=3D"_blank">http://johnsn= oggin.blogspot.com/

This morning she posted the note below. &nbs= p;If John has touched your life in any way, perhaps you might want to share= it by sending an email to seismoedu@..........  John has arranged for me to maintai= n his seismology website at www.jclahr.com.  I plan on posting a tribute to John on his = website at the appropriate time.  If you wouldn't mind cc'ing = me on your email I would be most grateful to hear from you.  Remember = that replys to this email will go to the PSN listserver, so you might want = to just send your email to kwyatt@............. and seismoedu@..........

Kay Wyatt
Oregon Shakes Program


JAN'S EMAIL FOLLOWS B= ELOW:
Who is out there?????
John has touched the lives of so many peo= ple. We know the address for this blog has been passed along to people all = over the world. I would like to give John a list of people who are followin= g it.

Please send an e-mail to let us know you're out there and care abou= t John. Just your name and where you live would be great.

The e-mail= adress is: seismo= edu@.........

Of course, it would also be interesting to hear why you are following t= he blog. Is it because you know John personally? Or because you're fami= liar with his work or his web site? Or just because you've heard he'= ;s a nice guy? Or because you are interested in following someone's bra= in cancer journey? All of the above or something else? I'll give John a= list of names and locations and will print out any longer messages to read= to him.

This will be fun! Maybe I'll hang a map on the wall and put pins in= every location where at least one of you lives.

Love to all,
Jan=

__________________________________________________________

Public Seismic Network Mailing List (PSN-L)

To leave this list email= PSN-L-RE= QUEST@.............. with the body of the message (first line only): un= subscribe
See h= ttp://www.seismicnet.com/maillist.html for more information.

Subject: RE: earthquake activity in Indonesia From: "Gary Lindgren" gel@................. Date: Fri, 13 Feb 2009 16:52:54 -0800 About that Indonesian 7.2 earthquake, I didn't pickup the initial P and S waves, but about 30 minutes or so later I pick up the response showing 16 second sine waves. I assume this is the earth ringing like a bell. The seismometer is a 23 second Lehman, E-W. Gary -----Original Message----- From: psn-l-request@.............. [mailto:psn-l-request@............... On Behalf Of Thomas Dick Sent: Thursday, February 12, 2009 8:03 AM To: psn-l@.............. Subject: earthquake activity in Indonesia John Search is away. Anybody know whether is activity is volcanic activity? __________________________________________________________ Public Seismic Network Mailing List (PSN-L) __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: earthquake activity in Indonesia From: "tchannel" tchannel@............ Date: Fri, 13 Feb 2009 18:31:21 -0700 Hi Gary, Where are you located? I am in Idaho and the epicenter was 106 degrees away. So I was in the shadow zone between 104 and 140, for this earthquake and as a result I could not recieve either the P or S. I did pick other phases, up here, but it was not much to look at. I thought it was around a 6.8m just by looking at it. So I was surrprised when they first called it a 7.5m then a 7.0 then a 7.2 Normally, I would see a bigger signature even if it was a 7.0m The reporting is less then perfect........I was also supprise to see an earthquake here in Idaho, posted on the USGS site two full days after the event. Someone must have been out of town. Thanks, Ted ----- Original Message ----- From: "Gary Lindgren" To: Sent: Friday, February 13, 2009 5:52 PM Subject: RE: earthquake activity in Indonesia > About that Indonesian 7.2 earthquake, I didn't pickup the initial P and S > waves, but about 30 minutes or so later I pick up the response showing 16 > second sine waves. I assume this is the earth ringing like a bell. The > seismometer is a 23 second Lehman, E-W. > Gary > > > > > -----Original Message----- > From: psn-l-request@.............. [mailto:psn-l-request@............... > On > Behalf Of Thomas Dick > Sent: Thursday, February 12, 2009 8:03 AM > To: psn-l@.............. > Subject: earthquake activity in Indonesia > > John Search is away. Anybody know whether is activity is volcanic > activity? > __________________________________________________________ > > 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: earthquake activity in Indonesia From: "Gary Lindgren" gel@................. Date: Fri, 13 Feb 2009 17:44:18 -0800 Hi Ted, I'm in Palo Alto CA. Tell me more about the shadow zone. I guess you saw what I saw. The ringing went on for a hour or so. Gary -----Original Message----- From: psn-l-request@.............. [mailto:psn-l-request@............... On Behalf Of tchannel Sent: Friday, February 13, 2009 5:31 PM To: psn-l@.............. Subject: Re: earthquake activity in Indonesia Hi Gary, Where are you located? I am in Idaho and the epicenter was 106 degrees away. So I was in the shadow zone between 104 and 140, for this earthquake and as a result I could not recieve either the P or S. I did pick other phases, up here, but it was not much to look at. I thought it was around a 6.8m just by looking at it. So I was surrprised when they first called it a 7.5m then a 7.0 then a 7.2 Normally, I would see a bigger signature even if it was a 7.0m The reporting is less then perfect........I was also supprise to see an earthquake here in Idaho, posted on the USGS site two full days after the event. Someone must have been out of town. Thanks, Ted ----- Original Message ----- From: "Gary Lindgren" To: Sent: Friday, February 13, 2009 5:52 PM Subject: RE: earthquake activity in Indonesia > About that Indonesian 7.2 earthquake, I didn't pickup the initial P and S > waves, but about 30 minutes or so later I pick up the response showing 16 > second sine waves. I assume this is the earth ringing like a bell. The > seismometer is a 23 second Lehman, E-W. > Gary > > > > > -----Original Message----- > From: psn-l-request@.............. [mailto:psn-l-request@............... > On > Behalf Of Thomas Dick > Sent: Thursday, February 12, 2009 8:03 AM > To: psn-l@.............. > Subject: earthquake activity in Indonesia > > John Search is away. Anybody know whether is activity is volcanic > activity? > __________________________________________________________ > > 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) __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: RE: earthquake activity in Indonesia From: Robert McClure bobmcclure90@......... Date: Fri, 13 Feb 2009 22:23:17 -0500 Hi Gary, To learn more about earthquake wave propagation, please go to the following link and download "Seismic Waves". http://bingweb.binghamton.edu/~ajones/ * *Seismic Waves is a Windows program which illustrates how wave propagate from an earthquake hypocenter to seismic stations throughout the earth. One sees waves propagating out from the epicenter on a three-dimensional view of the earth at the same time one sees waves propagating through a cross-sectional view of the earth. These two wave propagation views are synchronized with actual event waveforms so that as a particular phase arrives at a station, one sees the effect on the seismogram. * Subject: RE: earthquake activity in Indonesia From: "Gary Lindgren" gel@................. Date: Fri, 13 Feb 2009 16:52:54 -0800 * ------------------------------ About that Indonesian 7.2 earthquake, I didn't pickup the initial P and S waves, but about 30 minutes or so later I pick up the response showing 16 second sine waves. I assume this is the earth ringing like a bell. The seismometer is a 23 second Lehman, E-W. Gary Hi Gary,

  To learn more about earthquake wave propagation, please go to the following link and download "Seismic Waves".

http://bingweb.binghamton.edu/~ajones/

Seismic Waves is a Windows program which illustrates how wave propagate from an earthquake hypocenter to seismic stations throughout the earth. One sees waves propagating out from the epicenter on a three-dimensional view of the earth at the same time one sees waves propagating through a cross-sectional view of the earth. These two wave propagation views are synchronized with actual event waveforms so that as a particular phase arrives at a station, one sees the effect on the seismogram.

Subject: RE: earthquake activity in Indonesia
From: "Gary Lindgren" gel@.................
Date: Fri, 13 Feb 2009 16:52:54 -0800



About that Indonesian 7.2 earthquake, I didn't pickup the initial P and S
waves, but about 30 minutes or so later I pick up the response showing 16
second sine waves. I assume this is the earth ringing like a bell. The
seismometer is a 23 second Lehman, E-W.
Gary

Subject: Re: earthquake activity in Indonesia From: Stephen & Kathy skmort@............ Date: Fri, 13 Feb 2009 20:53:36 -0800 Hi Gary, if you would like to see the shadow zone for a given quake, here is a little process of links. Start at the 7 day USGS link... when you get there, scroll and click on the M5+Earthquake list link: http://earthquake.usgs.gov/eqcenter/recenteqsww/ Click on the date / time link... (example link for the 7.2) http://earthquake.usgs.gov/eqcenter/recenteqsww/Quakes/us2009cybb.php Click on the Scientific & Technical TAB which takes you to the following link: http://neic.usgs.gov/neis/eq_depot/2009/eq_090211_cybb/neic_cybb_t.html Scroll down and click on the Theoretical P-Wave Travel Times link, where you will see a map that shows the approx shadow zone region (outlined by bold black circles), and a short explanation. A Google for surface waves will provide lots of links... here is a link to a short simple explination that I found helpful: http://www.uwm.edu/~bketter/Research/Surface_Theory/Surface.html If you happen to be in the area of the heavy red lines (several red lines bunched together), on the other side of the shadow zone, you can sometimes get reinforced signals that will surprise you on how big the trace is for what you would expect for otherwise smaller quakes. Enjoy, Stephen PSN Station #55 Gary Lindgren wrote: > Hi Ted, > I'm in Palo Alto CA. Tell me more about the shadow zone. I guess you saw > what I saw. The ringing went on for a hour or so. > Gary > Hi Gary, if you would like to see the shadow zone for a given quake, here is a little process of links.  Start at the 7 day USGS link...  when you get there, scroll and click on the M5+Earthquake list link:

http://earthquake.usgs.gov/eqcenter/recenteqsww/

Click on the date / time link...  (example link for the 7.2)

http://earthquake.usgs.gov/eqcenter/recenteqsww/Quakes/us2009cybb.php

Click on the Scientific & Technical TAB which takes you to the following link:

http://neic.usgs.gov/neis/eq_depot/2009/eq_090211_cybb/neic_cybb_t.html  

Scroll down and click on the  Theoretical P-Wave Travel Times link, where you will see a map that shows the approx shadow zone region (outlined by bold black circles), and a short explanation.

A Google for surface waves will provide lots of links...  here is a link to a short simple explination that I found helpful:

http://www.uwm.edu/~bketter/Research/Surface_Theory/Surface.html

If you happen to be in the area of the heavy red lines (several red lines bunched together), on the other side of the shadow zone, you can sometimes get reinforced signals that will surprise you on how big the trace is for what you would expect for otherwise smaller quakes.
  
  Enjoy, Stephen
  PSN Station #55


Gary Lindgren wrote:
Hi Ted,
I'm in Palo Alto CA. Tell me more about the shadow zone. I guess you saw
what I saw. The ringing went on for a hour or so.
Gary
  
Subject: WINQUAKE ( FIRST SAMPLE TIME) From: "GMV" gmvoeth@........... Date: Sat, 14 Feb 2009 18:22:42 -0700 Howdy you Winquake Experts; how in heck does one get winquake to recognize the exact time for the very first sample ? I will put in like 20:45:37.123 for the start time but winquake will show at the higest resolution only 20:45:38 if I put in 20:45:37 it will then report 20:45:37 but thats not the right time, there seems nothing I can do get the exact right time I want the first sample to represent ?? The way I look at my data is the delta time is the span between the samples so I give an exact time to the very first sample as time zero and only count the spans between the samples as equal time increments. Winquake for some strange reason will not accept the time I put into its header as the right time. if i move the mouse to the far left at highest resolution the time at the bottom left corner at the first sample does not show the time I am expecting. The time I expect is placed into the header along with my data by myself in the text form of the psn file. I have tried putting the fraction into the offset but then things are still not right. winquake would ease my analysis but at the moment I must use my own ways to extract times from the data. its sort of like a micrometer if the micrometer does not read zero when the jaws are fully shut you have a bad micrometer. maybe I dont understand how winquake works here ? Haben Sie Any Ideas Bitte?? geoff
Howdy you Winquake=20 Experts;
 
how in heck does one = get winquake=20 to recognize
the exact time for the = very first=20 sample ?
 
I will put in like=20 20:45:37.123
for the start time but = winquake=20 will show at
the higest resolution = only=20 20:45:38
if I put in 20:45:37 it = will then=20 report 20:45:37
but thats not the right = time,
there seems nothing I = can do get=20 the exact right time
I want the first sample = to=20 represent ??
 
The way I look at = my data is=20 the delta time is the span
between the samples so = I give an=20 exact time to
the very first sample = as time zero=20 and only count the
spans between the = samples as equal=20 time increments.
 
Winquake for some = strange reason=20 will not accept
the time I put into its = header as=20 the right time.
if i move the mouse to = the far left=20 at highest resolution
the time at the bottom = left corner=20 at the first sample
does not show the time = I am=20 expecting.
 
The time I expect is = placed into=20 the header along with my data
by myself in the text = form of the=20 psn file.
 
I have tried putting = the fraction=20 into the offset
but then things are = still not=20 right.
 
winquake would ease my = analysis but=20 at the moment I must
use my own ways to = extract times=20 from the data.
 
its sort of like a = micrometer if=20 the micrometer does not read zero
when the jaws are fully = shut you=20 have a bad micrometer.
 
maybe I dont understand = how=20 winquake works here ?
 
Haben Sie Any Ideas=20 Bitte??
 
geoff
 
 
Subject: Re: WINQUAKE ( FIRST SAMPLE TIME) From: Bob Hancock icarus@......... Date: Sat, 14 Feb 2009 23:15:40 -0700 Geoff - The recording of event data is done through WinSDR, not WinQuake. In the replay mode of WinSDR, you can only set the time with one minute accuracy. Once you have recorded an event through WinSDR, you can edit or crop the file with WinQuake, with a one second accuracy. When viewing a file through WinQuake, you can look at timing that is accurate to 0.001 seconds, but I am unaware of anyway to save the data with that accuracy. There are other programs out there, but I am not familiar with them and cannot comment on their accuracy. Bob Hancock On Feb 14, 2009, at 6:22 PM, GMV wrote: > Howdy you Winquake Experts; > > how in heck does one get winquake to recognize > the exact time for the very first sample ? > >
Geoff = -

The recording of event data is done through = WinSDR, not WinQuake.  In the replay mode of WinSDR, you can only = set the time with one minute accuracy.  Once you have recorded an = event through WinSDR, you can edit or crop the file with WinQuake, with = a one second accuracy.  When viewing a file through WinQuake, you = can look at timing that is accurate to 0.001 seconds, but I am unaware = of anyway to save the data with that = accuracy.

There are other programs out there, = but I am not familiar with them and cannot comment on their = accuracy.

Bob = Hancock




On= Feb 14, 2009, at 6:22 PM, GMV wrote:

Howdy you Winquake = Experts;
 
how in heck does one get winquake to = recognize
the exact time for the very first sample = ?
 

= Subject: Re: WINQUAKE ( FIRST SAMPLE TIME) From: "GMV" gmvoeth@........... Date: Sun, 15 Feb 2009 00:17:32 -0700 Hello Bob; Its just that winquake will let you put the right time into its header but it will not compute based upon this time it will choose whatever it wants to do independent of the correct time given to it. This is the fault of the programmer and may be intentional for reasons Im not sure. There is the possibility I do not understand how to place into the header the proper time but then that means everything is not straight foreward and Winquake was programmed by an artist and not a scientist. Just a thought. The capitalist and the programmer may be different human beings so possibly the people you deal with are not able to fix things. Thanks for your reply. geoff ----- Original Message -----=20 From: Bob Hancock=20 To: psn-l@................. Sent: Saturday, February 14, 2009 11:15 PM Subject: Re: WINQUAKE ( FIRST SAMPLE TIME) Geoff - The recording of event data is done through WinSDR, not WinQuake. In = the replay mode of WinSDR, you can only set the time with one minute = accuracy. Once you have recorded an event through WinSDR, you can edit = or crop the file with WinQuake, with a one second accuracy. When = viewing a file through WinQuake, you can look at timing that is accurate = to 0.001 seconds, but I am unaware of anyway to save the data with that = accuracy. There are other programs out there, but I am not familiar with them = and cannot comment on their accuracy. Bob Hancock On Feb 14, 2009, at 6:22 PM, GMV wrote: Howdy you Winquake Experts; how in heck does one get winquake to recognize the exact time for the very first sample ?
Hello = Bob;
 
Its just that winquake = will let you=20 put the right time
into its header but it = will not=20 compute based upon this time
it will choose whatever = it wants to=20 do independent of
the correct time given = to it. This=20 is the fault of the programmer
and may be intentional = for reasons=20 Im not sure.
There is the = possibility I do not=20 understand how to
place into the header = the proper=20 time but then that means
everything is not = straight foreward=20 and Winquake was
programmed by an artist = and not a=20 scientist.
Just a=20 thought.
The capitalist and the = programmer=20 may be different human beings
so possibly the people = you deal=20 with are not able to fix things.
 
Thanks for your=20 reply.
geoff
----- Original Message -----
From:=20 Bob = Hancock=20
Sent: Saturday, February 14, = 2009 11:15=20 PM
Subject: Re: WINQUAKE ( FIRST = SAMPLE=20 TIME)

Geoff -

The recording of event data is done through WinSDR, not WinQuake. =  In the replay mode of WinSDR, you can only set the time with one = minute=20 accuracy.  Once you have recorded an event through WinSDR, you = can edit=20 or crop the file with WinQuake, with a one second accuracy.  When = viewing=20 a file through WinQuake, you can look at timing that is accurate to = 0.001=20 seconds, but I am unaware of anyway to save the data with that = accuracy.

There are other programs out there, but I am not familiar with = them and=20 cannot comment on their accuracy.

Bob Hancock




On Feb 14, 2009, at 6:22 PM, GMV wrote:
Howdy you Winquake=20 Experts;
 
how in heck does = one get=20 winquake to recognize
the exact time for = the very=20 first sample ?
 
=

Subject: Re: WINQUAKE ( FIRST SAMPLE TIME) From: "GMV" gmvoeth@........... Date: Sun, 15 Feb 2009 05:48:50 -0700 hello bob; I think I now understand; Winquake was not designed to look at any old data because it was only designed to be used in conjunction with another program which you need to buy an entire package of both software and hardware. I do believe accuracy and precision can be better than one second but that is very hard for us amateurs to do. In the future I guess I will simply drop the fractions and go with the second when I put data into winquake. since possibly there is delay through my electronics. earlier reference time might compensate a bit for such delays. did you get the two quakes a bit ago ?? Japan/Peru I do not normally report teleseismic events but since I went through the trouble of getting the times I sent them to the usgs. I hope you weather out these economic times in good style. thanks for your replies. best regard; geoff ----- Original Message -----=20 From: Bob Hancock=20 To: psn-l@................. Sent: Saturday, February 14, 2009 11:15 PM Subject: Re: WINQUAKE ( FIRST SAMPLE TIME) Geoff - The recording of event data is done through WinSDR, not WinQuake. In = the replay mode of WinSDR, you can only set the time with one minute = accuracy. Once you have recorded an event through WinSDR, you can edit = or crop the file with WinQuake, with a one second accuracy. When = viewing a file through WinQuake, you can look at timing that is accurate = to 0.001 seconds, but I am unaware of anyway to save the data with that = accuracy. There are other programs out there, but I am not familiar with them = and cannot comment on their accuracy. Bob Hancock On Feb 14, 2009, at 6:22 PM, GMV wrote: Howdy you Winquake Experts; how in heck does one get winquake to recognize the exact time for the very first sample ?
hello = bob;
 
I think I now=20 understand;
Winquake was not = designed to look=20 at
any old data because it = was only=20 designed
to be used in = conjunction with=20 another
program which you need = to buy an=20 entire package
of both software and = hardware. I do=20 believe
accuracy and precision = can be=20 better than
one second but that is = very hard=20 for
us amateurs to do. In = the future I=20 guess I will
simply drop the = fractions and go=20 with the second
when I put data into=20 winquake.
since possibly there is = delay=20 through my electronics.
earlier reference = time might=20 compensate a bit for such delays.
 
did you get the two = quakes a bit=20 ago ??
Japan/Peru
 
I do not normally = report=20 teleseismic events
but since I went = through the=20 trouble of
getting the times I = sent them to=20 the usgs.
 
I hope you weather out = these=20 economic times in good style.
 
thanks for your=20 replies.
 
best = regard;
geoff
----- Original Message -----
From:=20 Bob = Hancock=20
Sent: Saturday, February 14, = 2009 11:15=20 PM
Subject: Re: WINQUAKE ( FIRST = SAMPLE=20 TIME)

Geoff -

The recording of event data is done through WinSDR, not WinQuake. =  In the replay mode of WinSDR, you can only set the time with one = minute=20 accuracy.  Once you have recorded an event through WinSDR, you = can edit=20 or crop the file with WinQuake, with a one second accuracy.  When = viewing=20 a file through WinQuake, you can look at timing that is accurate to = 0.001=20 seconds, but I am unaware of anyway to save the data with that = accuracy.

There are other programs out there, but I am not familiar with = them and=20 cannot comment on their accuracy.

Bob Hancock




On Feb 14, 2009, at 6:22 PM, GMV wrote:
Howdy you Winquake=20 Experts;
 
how in heck does = one get=20 winquake to recognize
the exact time for = the very=20 first sample ?
 
=

Subject: Re: WINQUAKE ( FIRST SAMPLE TIME) From: Robert McClure bobmcclure90@......... Date: Sun, 15 Feb 2009 20:52:26 -0500 The specification for the PSN Type 4 file format is found at: http://www.seismicnet.com/psnformat4.html Note that the DateTime data structure allows the time of the first sample to be entered to the nearest nanosecond. You will have to consult Larry Cochran about whether time from SDR is entered to that precision. My source data comes from Dataq WDQ files, which record starting time only to the second. Bob McClure On Sun, Feb 15, 2009 at 1:15 AM, Bob Hancock wrote: > Geoff - > > The recording of event data is done through WinSDR, not WinQuake. In the > replay mode of WinSDR, you can only set the time with one minute accuracy. > Once you have recorded an event through WinSDR, you can edit or crop the > file with WinQuake, with a one second accuracy. When viewing a file through > WinQuake, you can look at timing that is accurate to 0.001 seconds, but I am > unaware of anyway to save the data with that accuracy. > > There are other programs out there, but I am not familiar with them and > cannot comment on their accuracy. > > Bob Hancock > > > > > On Feb 14, 2009, at 6:22 PM, GMV wrote: > > *Howdy you Winquake Experts;* > ** > *how in heck does one get winquake to recognize* > *the exact time for the very first sample ?* > ** > >   The specification for the PSN Type 4 file format is found at:
http://www.seismicne= t.com/psnformat4.html

  Note that the DateTime data structu= re allows the time of the first sample to be entered to the nearest nanosec= ond. You will have to consult Larry Cochran about whether time from SDR is = entered to that precision. My source data comes from Dataq WDQ files, which= record starting time only to the second.

Bob McClure

On Sun, Feb 15, 2009 at 1= :15 AM, Bob Hancock <icarus@.........> wrote:
Geoff -

The recording of even= t data is done through WinSDR, not WinQuake.  In the replay mode of Wi= nSDR, you can only set the time with one minute accuracy.  Once you ha= ve recorded an event through WinSDR, you can edit or crop the file with Win= Quake, with a one second accuracy.  When viewing a file through WinQua= ke, you can look at timing that is accurate to 0.001 seconds, but I am unaw= are of anyway to save the data with that accuracy.

There are other programs out there, but I am not famili= ar with them and cannot comment on their accuracy.

Bob Hancock




On Feb 14, 2009, at 6:22 PM, GMV wrote:

Howdy you Winquake Experts;
&nb= sp;
how in heck does one= get winquake to recognize
the exact time for the very f= irst sample ?
 


Subject: Re: WINQUAKE ( FIRST SAMPLE TIME) From: "GMV" gmvoeth@........... Date: Sun, 15 Feb 2009 21:37:49 -0700 I am not sure I am using a type four since i use ascii text file type of psn and not the binary form. But I will look closer and possibly modify my data to match the type 4 profile. If you save your data as text then open it in notepad you will something more like type 2!. ----- Original Message ----- From: "Robert McClure" To: Sent: Sunday, February 15, 2009 6:52 PM Subject: Re: WINQUAKE ( FIRST SAMPLE TIME) > The specification for the PSN Type 4 file format is found at: > > http://www.seismicnet.com/psnformat4.html > > Note that the DateTime data structure allows the time of the first sample > to be entered to the nearest nanosecond. You will have to consult Larry > Cochran about whether time from SDR is entered to that precision. My source > data comes from Dataq WDQ files, which record starting time only to the > second. > > Bob McClure > > On Sun, Feb 15, 2009 at 1:15 AM, Bob Hancock wrote: > >> Geoff - >> >> The recording of event data is done through WinSDR, not WinQuake. In the >> replay mode of WinSDR, you can only set the time with one minute accuracy. >> Once you have recorded an event through WinSDR, you can edit or crop the >> file with WinQuake, with a one second accuracy. When viewing a file through >> WinQuake, you can look at timing that is accurate to 0.001 seconds, but I am >> unaware of anyway to save the data with that accuracy. >> >> There are other programs out there, but I am not familiar with them and >> cannot comment on their accuracy. >> >> Bob Hancock >> >> >> >> >> On Feb 14, 2009, at 6:22 PM, GMV wrote: >> >> *Howdy you Winquake Experts;* >> ** >> *how in heck does one get winquake to recognize* >> *the exact time for the very first sample ?* >> ** >> >> > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: seismic amplifier profile (SP) type From: "GMV" gmvoeth@........... Date: Mon, 16 Feb 2009 03:17:06 -0700 Hello PSN; I am thinking of building a new amplifier and was wondering if this profile is correct for a short period (1Hz) type. a N6 low pass mfb three stage filter would go after the stage crating this profile at about 2.5 or 3 Hz. One of you guys must be technical whizz and help me out here in making a decision. I do not expect to fully compensate for the rolloff of the geophone. just trying to get a better picture. http://gmvoeth.home.mchsi.com/seis_amp_01.gif http://gmvoeth.home.mchsi.com/seis_amp_01.bmp these were made using the LT_SPICE_IV simulator program and I will put the models up if you wish to see them. but you need the program to make the models work. www.linear.com best regards; geoff __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Shaking house From: "Robert O. Green" rog@.......... Date: Mon, 16 Feb 2009 07:27:59 -0800 I am a novice and building up a vertical-type seismometer, but live in a wood frame house with a crawl space that shakes considerably with doors closing and the washing machine going, etc. Is it possible to locate the seismometer outside? How should the seismometer be housed? What is the easiest way to run a long cable. I do have massive bedrock on the property about 300 ft from the house. I am using amplifier and digitizer from Larry Cochrane. Robert __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: RE: Shaking house From: "Keith Payea" kpayea@.............. Date: Mon, 16 Feb 2009 09:12:21 -0800 Hi Robert: Not only is it possible, putting the seismometer outside is desirable. The keyword to search for is "Seismic Vault", which is what they call the enclosure in the seismology business. I built a simple dog house type structure in my backyard. Details are here: http://www.bryantlabs.net/SeisVault.html Here are some details of a pro installation: http://seismo.berkeley.edu/seismo/bdsn/instrumentation/guidelines.html which are from a link on Larry's pages. I run analog signals through about 75 feet of shielded twisted pair wire from my vault to the recording equipment. At 300 feet from the sensor to the house, you might want to consider digital transmission of the data. If you are using the digitizer with the serial interface, you could convert the RS-232 to RS-422 at both ends of the cable and it would be transparent to the software and the digitizer. Other people have put a minimal computer near the sensor and then run digital signals of some kind, including wireless, back to their primary computer. If you use cable, bury a conduit (Plastic conduit is cheap) at least twice as big as the wire you want to put in it. I always seem to need to put one more cable in it after it is buried.... Wireless can work, but you still need to figure out how to power it. Cheers. Keith -----Original Message----- From: psn-l-request@.............. [mailto:psn-l-request@............... On Behalf Of Robert O. Green Sent: Monday, February 16, 2009 7:28 AM To: PSN-L@.............. Subject: Shaking house I am a novice and building up a vertical-type seismometer, but live in a wood frame house with a crawl space that shakes considerably with doors closing and the washing machine going, etc. Is it possible to locate the seismometer outside? How should the seismometer be housed? What is the easiest way to run a long cable. I do have massive bedrock on the property about 300 ft from the house. I am using amplifier and digitizer from Larry Cochrane. Robert __________________________________________________________ Public Seismic Network Mailing List (PSN-L) __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Shaking house From: Pete Rowe ptrowe@......... Date: Mon, 16 Feb 2009 09:21:20 -0800 (PST) Hi Robert I have a horizontal instrument in the crawl space under my house and it wor= ks just fine. It is in a metal box to keep the drafts out and just sits on = the ground. I am close to bedrock also. I have a two story wood frame house= .. I do see the washing machine, furnace, and other house related noises but= I don't let that bother me. I would try it under your house since that is = the easiest place to put it. However, as you suspect, the best place to put= it is in the ground far from the noise generating house. I'm sure there wi= ll be others on the list who will share their tips and techniques for doing= this. Where are you located? I'm in San Jose, CA.=20 Pete --- On Mon, 2/16/09, Robert O. Green wrote: From: Robert O. Green Subject: Shaking house To: PSN-L@.............. Date: Monday, February 16, 2009, 7:27 AM I am a novice and building up a vertical-type seismometer, but live in a wo= od frame house with a crawl space that shakes considerably with doors closi= ng and the washing machine going, etc. Is it possible to locate the seismometer outside? How should the seismometer be housed? What is the easiest way to run a long cable.=A0 I do have massive bedrock o= n the property about 300 ft from the house. I am using amplifier and digitizer from Larry Cochrane. Robert __________________________________________________________ Public Seismic Network Mailing List (PSN-L) =0A=0A=0A
Hi Robert
I have a horizontal instrument i= n the crawl space under my house and it works just fine. It is in a metal b= ox to keep the drafts out and just sits on the ground. I am close to bedroc= k also. I have a two story wood frame house. I do see the washing machine, = furnace, and other house related noises but I don't let that bother me. I w= ould try it under your house since that is the easiest place to put it. How= ever, as you suspect, the best place to put it is in the ground far from th= e noise generating house. I'm sure there will be others on the list who wil= l share their tips and techniques for doing this.

Where are you loca= ted? I'm in San Jose, CA.

Pete

--- On Mon, 2/16/09, Rober= t O. Green <rog@..........> wrote:

From: Robert O. Green <rog@..........>
Subject: Shaking= house
To: PSN-L@..............
Date: Monday, February 16, 2009, 7:27= AM

I am a novice and building up a vertica= l-type seismometer, but live in a wood frame house with a crawl space that = shakes considerably with doors closing and the washing machine going, etc.<= br>
Is it possible to locate the seismometer outside?

How should = the seismometer be housed?

What is the easiest way to run a long cab= le.  I do have massive bedrock on the property about 300 ft from the h= ouse.

I am using amplifier and digitizer from Larry Cochrane.
Robert






________________________________________= __________________

Public Seismic Network Mailing List (PSN-L)
To leave this list email PSN-L-REQUEST@SEISM= ICNET.COM with the body of the message (first line only): unsubscribeSee http://www.seismicnet.com/maillist.html for more information.

=0A=0A Subject: Re: Shaking house From: "GMV" gmvoeth@........... Date: Mon, 16 Feb 2009 12:41:56 -0700 Howdy Bob; I dug a 24 inch deep hole in which i placed three surveyor stakes within six inches of the bottom of the hole I took a steel trashcan and punched three holes in bottom to go over the steaks then upon the surface of the three steakes ( already adjusted for level) I glued with goop a granite tile that was one foot square or 12 inches by 12 inches. I made sure the three holes in the trashcan cleared the steaks without touching them so if the wind blew against the can it would not move the geophone platform. The order is important here: 1. dig hole 2. place steaks leveled for granite tile 3. punch holes in trashcan 4. place trashcan in hole over steaks 5. fill dirt around trashcan 6. clean steak heads 7. place goop on all three steakheads 8. place granite tile smooth side up level on glued heads 9. prepare your geophone to be water tight I did this with rubber electricians tape several layers of. 10. wire it up with special underground signal cable that has silicone grease inside a 100% copper shielding. 11. place geophone inside trashcan on top of granite tile. 12. ( cable runs through side of can wherever you want) 12.1 (put goop around the geophone where it contacts the granite tile.) 13. put socks filled with that silica kitty litter in the bottom of the can 14. put can on lid which should be above ground 15. cover entire exposed can with insulating foam ( spray can type) 16. you should be ready to go. 17. prey and forget until something goes terribly wrong. 18. moisture and human activity can be your worst enemies. By far The single hardest thing was driving the steaks into the hole. Second hardest was digging the hole. Most fun was the electronics. I knew where the underground stuff was so blue steaking was no problem before digging the hole. Gut Luk Comrade; geoff ----- Original Message ----- From: "Robert O. Green" To: Sent: Monday, February 16, 2009 8:27 AM Subject: Shaking house >I am a novice and building up a vertical-type seismometer, but live in a > wood frame house with a crawl space that shakes considerably with doors > closing and the washing machine going, etc. > > Is it possible to locate the seismometer outside? > > How should the seismometer be housed? > > What is the easiest way to run a long cable. I do have massive bedrock > on the property about 300 ft from the house. > > I am using amplifier and digitizer from Larry Cochrane. > > Robert > > > > > > > __________________________________________________________ > > 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: Shaking house From: ChrisAtUpw@....... Date: Mon, 16 Feb 2009 19:41:02 EST In a message dated 16/02/2009, rog@.......... writes: I am a novice and building up a vertical-type seismometer, but live in a wood frame house with a crawl space that shakes considerably with doors closing and the washing machine going, etc. Hi Robert, Can you describe your house and the setup in more detail, please? What are the dimensions of the crawl space, the location of the seismometer, the composition of the ground, the ground slope around the house and the depth of the water table? You will not be able to get a low noise seismic signal if the seismometer is supported by a wooden building. Mounting the seismometer on the ground well away from the outer walls usually reduces any noise from the building. It is usual to provide a concrete block on which to mount the seismometer and a suitable draftproof + insulation cover, which may be made from 2" Celotex. You can dig a shallow pit and cast a 50:50 sand and cement plinth. Don't use any gravel. First lay 1" sand and two sheets of damp proof polythene in the bottom of the pit and fold up the corners to above ground level. Staple / tape the top of the folds. Then use a wood surround mould. If you need more height, dig a deeper pit with sloping sides and surround the plinth with cast concrete walls. You leave the plinth covered and wet for up to 4 weeks to allow the cement to cure fully. Then you can dry it out. I stick SS mounting disks to dry concrete with two component acrylic cement. The house wiring and Earth connection should provide significant shielding and protection from lightning. Is it possible to locate the seismometer outside? Certainly, but you need to build a watertight housing for it. Have a look at _http://www.guralp.com/articles/20040400-casestudy-eskdalemuir/support_ (http://www.guralp.com/articles/20040400-casestudy-eskdalemuir/support) You will get lower noise if you make the top nearly flush with the ground / put a vertical bar fence around the site. Maybe wood + wire paling? You may need to consider possible problems with high rainfall and flooding. What is the easiest way to run a long cable? I do have massive bedrock on the property about 300 ft from the house. A 300 ft cable run will very likely require you to provide lightning protection, but this depends on the location. A lot of the US has poor ground conduction and / or a deep water table. Check on the local advice? You can buy power cable with spiral steel wire reinforcing and extra insulation so that it can be laid directly in a trench. This protects it from ground movements, but it won't be cheap. Otherwise you can lay ordinary cable in polythene water pipe. The difficulty is in threading the cable through the pipe. It has a very high total friction. If you have a suitable quarry, cliff, bridge, stairwell, or tower, you can hang the pipe vertically and feed the cable in from the top. Otherwise you need a smooth iron rod and a strong magnet. You use this to pull a cotton or similar strong string through the pipe, then a strong cord and then the cable. You can put talc powder in the pipe to lubricate it. Suck the powder through first with a vacuum cleaner? You can also use Molybdenum Disulphide or Graphite powder, but they are both messy. Hope that this helps, Chris Chapman
In a message dated 16/02/2009, rog@.......... writes:
<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size= =3D2>I am a=20 novice and building up a vertical-type seismometer, but live in a
wood= =20 frame house with a crawl space that shakes considerably with doors
clo= sing=20 and the washing machine going, etc.
Hi Robert,
 
    Can you describe your house and the setup in mo= re=20 detail, please? What are the dimensions of the crawl space, the location of=20= the=20 seismometer, the composition of the ground, the ground slope around the= =20 house and the depth of the water table?
 
    You will not be able to get a low noise seismic= =20 signal if the seismometer is supported by a wooden building. Mounting the=20 seismometer on the ground well away from the outer walls usually=20 reduces any noise from the building.  
    It is usual to provide a concrete block on whic= h to=20 mount the seismometer and a suitable draftproof + insulation cover, which ma= y be=20 made from 2" Celotex. You can dig a shallow pit and cast a 50:50 s= and=20 and cement plinth. Don't use any gravel. First lay 1" sand and two sheets of= =20 damp proof polythene in the bottom of the pit and fold up the corners t= o=20 above ground level. Staple / tape the top of the folds. Then use a wood= =20 surround mould. If you need more height, dig a deeper pit with sloping sides= and=20 surround the plinth with cast concrete walls. You leave the plinth covered a= nd=20 wet for up to 4 weeks to allow the cement to cure fully. Then you can dry it= =20 out. I stick SS mounting disks to dry concrete with two component acrylic=20 cement. 
    The house wiring and Earth connection should=20 provide significant shielding and protection from lightning.
<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size= =3D2>Is it=20 possible to locate the seismometer outside?
    Certainly, but you need to build a watertight=20 housing for it. Have a look at http://www.guralp.com/articles/20040400-casestudy-eskdalemuir/support=  You=20 will get lower noise if you make the top nearly flush with the ground / put=20= a=20 vertical bar fence around the site. Maybe wood + wire paling? You may need t= o=20 consider possible problems with high rainfall and flooding.
<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size= =3D2>What is=20 the easiest way to run a long cable?  I do have massive bedrock
o= n=20 the property about 300 ft from the house.
    A 300 ft cable run will very likely require you= to=20 provide lightning protection, but this depends on the location. A lot of the= US=20 has poor ground conduction and / or a deep water table. Check on t= he=20 local advice? You can buy power cable with spiral steel wire reinforcing and= =20 extra insulation so that it can be laid directly in a trench. This protects=20= it=20 from ground movements, but it won't be cheap.  Otherwise you can=20 lay ordinary cable in polythene water=20 pipe.      
    The difficulty is in threading the cable throug= h=20 the pipe. It has a very high total friction. If you have a=20 suitable quarry, cliff, bridge, stairwell, or tower, you can hang the pipe=20 vertically and feed the cable in from the top. Otherwise you need a smooth i= ron=20 rod and a strong magnet. You use this to pull a cotton or similar strong str= ing=20 through the pipe, then a strong cord and then the cable. You can put talc po= wder=20 in the pipe to lubricate it. Suck the powder through first with a vacuum=20 cleaner? You can also use Molybdenum Disulphide or Graphite powder, but they= are=20 both messy.
 
    Hope that this helps,
 
    Chris Chapman
Subject: Re: Shaking house From: Bob Hancock icarus@......... Date: Mon, 16 Feb 2009 17:44:07 -0700 Robert - I have a seismometer located over 250 feet from my house. However there are some things you might want to consider: 1. How often will you be accessing the instrument - this will determine the type of vault and seismic pier that you set up (think depth and accessibility). For example does you instrument require periodic tweaking, if so, how often will you need to have direct access to the instrument? 2. What are your temperature extremes. Do you live in an excessively wet or dry climate, snow or hot sun? If you have an external seismic vault, is it weather protected, and how hard is it to access the instrument? 2. Regardless of where you place the instrument, temperature stabilization is extremely important. If you have the instrument temperature stabilized, you most likely have it covered, and this begs the question, how easy will it be to access the instrument for tweaking? 3. Does your electronics require a differential receiver at the point where your signal enters your house? This is in addition to and prior to the A/D board. You might want to check if you need something like that. 4. If you use a crawl space under a house, you will most likely pick up tilting ground movement as the house is buffeted by wind, and when people move around the house. However, this is dependent upon the depth of the foundation, firmness of the ground, and external forces that affect the house. 5. When I had my instrument located 75 feet from the house, I could pick up the washing machine. I was able to filter it out when it coincided with a seismic event, but that is something to think about. 6. The previous comment about the cable is very important. Ultra- violet radiation can cut the life of an above ground cable. You definitely want it buried, and placed inside something like PVC piping. 7. If you use some variation of a wireless transmission between the instrument and your receiver, you need to think about the weather and wind again. Do you have blowing dust and dirt where you live. If you have periods of heavy rain, blowing dust or snow, it is likely that you could loose your signal at least during these occurrences. You do not want that to happen during a seismic event. You could get around that with some type of temporary data storage at the instrument site, and if the transmission cannot take place, it could be stored temporarily at the instrument, but like everything else this adds complexity and cost. No simple answers - lots to think about. There are many more factors to consider, but this will get you started in thinking about some of the benefits and problems associated with an external installation. Bob Hancock __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Winquake GoogleEarth and Time Display From: Larry Cochrane lcochrane@.............. Date: Mon, 16 Feb 2009 17:45:02 -0800 Hi Everyone, Sorry for the delay. I have been a little busy with my "day job"... Ted, did you resolve your problem? Regarding Pete Rowe's question on WinQuake and Google Earth. Last year as a fun little project I added to WinQuake the ability to view the event and/or station location in Google Earth. Today I created a new WinQuake setup program that contains this new feature. WinQuake version 3.1.2 can be downloaded from here http://www.seismicnet.com/software.html#WinQuake. The documentation for WinQuake is a little out dated. I'll try and correct that problem soon. Here are the locations in the program for the Google Earth feature: Main Menu under View / Google Earth Event Report Dialog Box has a new button called "Google Earth" Location Map Window - Place mouse cursor on location, right click select Google Earth From geoff, >Howdy you Winquake Experts; >how in heck does one get winquake to recognize >the exact time for the very first sample ? >I will put in like 20:45:37.123 >for the start time but winquake will show at >the higest resolution only 20:45:38 >if I put in 20:45:37 it will then report 20:45:37 >but thats not the right time, >there seems nothing I can do get the exact right time >I want the first sample to represent ?? Geoff, WinQuake starts to display data samples at the top of the second. If the nanosecond field in the event header is zero all samples will be displayed. If the nanosecond field is more then the period of one sample, WinQuake will skip to the next top of the second by skipping the first few samples in the data set. Regards, Larry Cochrane Redwood City, PSN tchannel wrote: > Hi Folks, For some reason I can no longer use Google with Winquake to > AUTOMATICALLY view my Station or Events........It worked fine before. > I tried opening different .psn in Winquake, different days or months, > and none will show in Google Earth, and they all did before. I get > an error message. "Could not open file C:\Program > Files\WinQuake\GoogleEarth.kml for reading" > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Winquake GoogleEarth and Time Display From: "tchannel" tchannel@............ Date: Mon, 16 Feb 2009 20:10:03 -0700 Hi Larry, Ted here, No I still have this problem. For anyone who has not tried this feature, it is great fun..........The kids at the school love it too. After processing your earthquake, in Winquake, I go to the pull down menu Display/Modify.....select GoogleEarth..........select either Station or Event. From there GoogleEarth will launch and fly you to the Station or Event. A great addition to a wonderful program. My set up worked fine, for many months, but For some reason I can no longer use Google with Winquake to AUTOMATICALLY view my Station or Events........It worked fine before. I get an error message. "Could not open file C:\Program Files\WinQuake\GoogleEarth.kml for reading" I can make it work if I manually locate a file called GoogleEarth.kml, which I found in C:\Users\Ted\App Data\Local|Virtual Store\program files\WinQuake. In that folder, if I click on GoogleEarth.kml, Google Earth will launch and show both event and station like it did before. GoogleEarth will launch, but this error is displayed. I did try uninstalling and reinstalling Winquake, but that did not fix it. Thanks, Ted ----- Original Message ----- From: "Larry Cochrane" To: Sent: Monday, February 16, 2009 6:45 PM Subject: Winquake GoogleEarth and Time Display > Hi Everyone, > > Sorry for the delay. I have been a little busy with my "day job"... > > Ted, did you resolve your problem? > > Regarding Pete Rowe's question on WinQuake and Google Earth. Last year as > a fun little project I added to WinQuake the ability to view the event > and/or station location in Google Earth. Today I created a new WinQuake > setup program that contains this new feature. WinQuake version 3.1.2 can > be downloaded from here http://www.seismicnet.com/software.html#WinQuake. > The documentation for WinQuake is a little out dated. I'll try and correct > that problem soon. Here are the locations in the program for the Google > Earth feature: > > Main Menu under View / Google Earth > Event Report Dialog Box has a new button called "Google Earth" > Location Map Window - Place mouse cursor on location, right click select > Google Earth > > From geoff, > > >Howdy you Winquake Experts; > > >how in heck does one get winquake to recognize > >the exact time for the very first sample ? > > >I will put in like 20:45:37.123 > >for the start time but winquake will show at > >the higest resolution only 20:45:38 > >if I put in 20:45:37 it will then report 20:45:37 > >but thats not the right time, > >there seems nothing I can do get the exact right time > >I want the first sample to represent ?? > > Geoff, > > WinQuake starts to display data samples at the top of the second. If the > nanosecond field in the event header is zero all samples will be > displayed. If the nanosecond field is more then the period of one sample, > WinQuake will skip to the next top of the second by skipping the first few > samples in the data set. > > Regards, > Larry Cochrane > Redwood City, PSN > > tchannel wrote: >> Hi Folks, For some reason I can no longer use Google with Winquake to >> AUTOMATICALLY view my Station or Events........It worked fine before. I >> tried opening different .psn in Winquake, different days or months, and >> none will show in Google Earth, and they all did before. I get an >> error message. "Could not open file C:\Program >> Files\WinQuake\GoogleEarth.kml for reading" >> > __________________________________________________________ > > 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: Winquake GoogleEarth and Time Display From: Bob Hancock icarus@......... Date: Mon, 16 Feb 2009 20:45:50 -0700 Larry - VERY NICE - THANKS !!! Bob Hancock On Feb 16, 2009, at 6:45 PM, Larry Cochrane wrote: __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Winquake GoogleEarth and Time Display From: "tchannel" tchannel@............ Date: Mon, 16 Feb 2009 21:12:39 -0700 Hi Larry and All, I fixed my problem with GoogleEarth...........I simply reinstalled GoogleEarth and Winquake now works with Google as it should and as it did before. Thanks again I sure do like this feature in Winquake. Ted ----- Original Message ----- From: "Larry Cochrane" To: Sent: Monday, February 16, 2009 6:45 PM Subject: Winquake GoogleEarth and Time Display > Hi Everyone, > > Sorry for the delay. I have been a little busy with my "day job"... > > Ted, did you resolve your problem? > > Regarding Pete Rowe's question on WinQuake and Google Earth. Last year as > a fun little project I added to WinQuake the ability to view the event > and/or station location in Google Earth. Today I created a new WinQuake > setup program that contains this new feature. WinQuake version 3.1.2 can > be downloaded from here http://www.seismicnet.com/software.html#WinQuake. > The documentation for WinQuake is a little out dated. I'll try and correct > that problem soon. Here are the locations in the program for the Google > Earth feature: > > Main Menu under View / Google Earth > Event Report Dialog Box has a new button called "Google Earth" > Location Map Window - Place mouse cursor on location, right click select > Google Earth > > From geoff, > > >Howdy you Winquake Experts; > > >how in heck does one get winquake to recognize > >the exact time for the very first sample ? > > >I will put in like 20:45:37.123 > >for the start time but winquake will show at > >the higest resolution only 20:45:38 > >if I put in 20:45:37 it will then report 20:45:37 > >but thats not the right time, > >there seems nothing I can do get the exact right time > >I want the first sample to represent ?? > > Geoff, > > WinQuake starts to display data samples at the top of the second. If the > nanosecond field in the event header is zero all samples will be > displayed. If the nanosecond field is more then the period of one sample, > WinQuake will skip to the next top of the second by skipping the first few > samples in the data set. > > Regards, > Larry Cochrane > Redwood City, PSN > > tchannel wrote: >> Hi Folks, For some reason I can no longer use Google with Winquake to >> AUTOMATICALLY view my Station or Events........It worked fine before. I >> tried opening different .psn in Winquake, different days or months, and >> none will show in Google Earth, and they all did before. I get an >> error message. "Could not open file C:\Program >> Files\WinQuake\GoogleEarth.kml for reading" >> > __________________________________________________________ > > 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: Winquake GoogleEarth and Time Display From: Pete Rowe ptrowe@......... Date: Mon, 16 Feb 2009 20:28:43 -0800 (PST) Very cool, Larry. Thanks for your good work. Pete --- On Mon, 2/16/09, Larry Cochrane wrote: From: Larry Cochrane Subject: Winquake GoogleEarth and Time Display To: psn-l@.............. Date: Monday, February 16, 2009, 5:45 PM Hi Everyone, Sorry for the delay. I have been a little busy with my "day job"... Ted, did you resolve your problem? Regarding Pete Rowe's question on WinQuake and Google Earth. Last year as a= fun little project I added to WinQuake the ability to view the event and/o= r station location in Google Earth. Today I created a new WinQuake setup pr= ogram that contains this new feature. WinQuake version 3.1.2 can be downloa= ded from here http://www.seismicnet.com/software.html#WinQuake. The documen= tation for WinQuake is a little out dated. I'll try and correct that proble= m soon. Here are the locations in the program for the Google Earth feature: Main Menu under View / Google Earth Event Report Dialog Box has a new button called "Google Earth" Location Map Window - Place mouse cursor on location, right click select Go= ogle Earth From geoff, >Howdy you Winquake Experts; >how in heck does one get winquake to recognize >the exact time for the very first sample ? >I will put in like 20:45:37.123 >for the start time but winquake will show at >the higest resolution only 20:45:38 >if I put in 20:45:37 it will then report 20:45:37 >but thats not the right time, >there seems nothing I can do get the exact right time >I want the first sample to represent ?? Geoff, WinQuake starts to display data samples at the top of the second. If the na= nosecond field in the event header is zero all samples will be displayed. I= f the nanosecond field is more then the period of one sample, WinQuake will= skip to the next top of the second by skipping the first few samples in th= e data set. Regards, Larry Cochrane Redwood City, PSN tchannel wrote: > Hi Folks, For some reason I can no longer use Google with Winquake to AUT= OMATICALLY view my Station or Events........It worked fine before.=A0=A0=A0= I tried opening different .psn in Winquake, different days or months, and n= one will show in Google Earth, and they all did before.=A0 =A0=A0=A0I get a= n error message.=A0=A0=A0"Could not open file C:\Program Files\WinQuake\Goo= gleEarth.kml for reading" >=A0=20 __________________________________________________________ Public Seismic Network Mailing List (PSN-L) =0A=0A=0A
=0A=0A=0A=0A Subject: Re: Winquake GoogleEarth and Time Display From: "GMV" gmvoeth@........... Date: Tue, 17 Feb 2009 02:04:42 -0700 wUNDERBARRRR !! THANKS TO THE GOOGLEPLEX POWER i THOUGHT i WAS GOING CRAZY IN TRYING TO DEAL WITH WINQUAKE. I should have asked you in the first place. Thanks. Your registration for the new winquake says nothing about paypal... I assume I simply go to paypal and have paypal itself send money into your account which will be your email address ??? after which you will email me the reg code ? Best regards; geoff ----- Original Message ----- From: "Larry Cochrane" To: Sent: Monday, February 16, 2009 6:45 PM Subject: Winquake GoogleEarth and Time Display > Hi Everyone, > > Sorry for the delay. I have been a little busy with my "day job"... > > Ted, did you resolve your problem? > > Regarding Pete Rowe's question on WinQuake and Google Earth. Last year as a fun > little project I added to WinQuake the ability to view the event and/or station > location in Google Earth. Today I created a new WinQuake setup program that contains > this new feature. WinQuake version 3.1.2 can be downloaded from here > http://www.seismicnet.com/software.html#WinQuake. The documentation for WinQuake is a > little out dated. I'll try and correct that problem soon. Here are the locations in > the program for the Google Earth feature: > > Main Menu under View / Google Earth > Event Report Dialog Box has a new button called "Google Earth" > Location Map Window - Place mouse cursor on location, right click select Google Earth > > From geoff, > > >Howdy you Winquake Experts; > > >how in heck does one get winquake to recognize > >the exact time for the very first sample ? > > >I will put in like 20:45:37.123 > >for the start time but winquake will show at > >the higest resolution only 20:45:38 > >if I put in 20:45:37 it will then report 20:45:37 > >but thats not the right time, > >there seems nothing I can do get the exact right time > >I want the first sample to represent ?? > > Geoff, > > WinQuake starts to display data samples at the top of the second. If the nanosecond > field in the event header is zero all samples will be displayed. If the nanosecond > field is more then the period of one sample, WinQuake will skip to the next top of > the second by skipping the first few samples in the data set. > > Regards, > Larry Cochrane > Redwood City, PSN > > tchannel wrote: >> Hi Folks, For some reason I can no longer use Google with Winquake to >> AUTOMATICALLY view my Station or Events........It worked fine before. >> I tried opening different .psn in Winquake, different days or months, >> and none will show in Google Earth, and they all did before. I get >> an error message. "Could not open file C:\Program >> Files\WinQuake\GoogleEarth.kml for reading" >> > __________________________________________________________ > > 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: Google Earth feature From: "Bruce Cartwright" bruce@....... Date: Tue, 17 Feb 2009 08:52:24 -0500 Hi Larry, I have a similar problem to Ted's. If I launch Google Earth from the menu = (Display/Modify, Google Earth, Event or Station) everything works fine but = if I try to launch it by right clicking on the event on the "Location Map" = I receive the "Could not open file Files\WinQuake\GoogleEarth.kml for = reading." error message. I tried reinstalling Google earth as Ted had = done but that didn't resolve the problem. I then uninstalled and = reinstalled WinQuake w/o any change. Not a "biggie" as I can get there = the other way, just thought you'd like to know that it isn't always = working as you designed it. (Think we call that an anomaly, there are no = such things as "Bugs" ). Bruce

Very cool, Larry.
Thanks for your good= work.
Pete
--- On Mon, 2/16/09, Larry Cochrane <lcochrane@w= ebtronics.com> wrote:

From: Larr= y Cochrane <lcochrane@..............>
Subject: Winquake GoogleEart= h and Time Display
To: psn-l@..............
Date: Monday, February 16= , 2009, 5:45 PM

Hi Everyone,

Sorry f= or the delay. I have been a little busy with my "day job"...

Ted, di= d you resolve your problem?

Regarding Pete Rowe's question on WinQua= ke and Google Earth. Last year as a fun little project I added to WinQuake = the ability to view the event and/or station location in Google Earth. Toda= y I created a new WinQuake setup program that contains this new feature. Wi= nQuake version 3.1.2 can be downloaded from here http://www.seismicnet.com/so= ftware.html#WinQuake. The documentation for WinQuake is a little out da= ted. I'll try and correct that problem soon. Here are the locations in the = program for the Google Earth feature:

Main Menu under View / Google = Earth
Event Report Dialog Box has a new button called "Google Earth"
= Location Map Window - Place mouse cursor on location, right click select Go= ogle Earth

From geoff,

>Howdy you Winquake Experts;
>how in heck does one get winquake to recognize
>the exact time f= or the very first sample ?

>I will put in like 20:45:37.123
&g= t;for the start time but winquake will show at
>the higest resolution= only 20:45:38
>if I put in 20:45:37 it will then report 20:45:37
= >but thats not the right time,
>there seems nothing I can do get the exact right time
>I want the first sample to represent ??
Geoff,

WinQuake starts to display data samples at the top of th= e second. If the nanosecond field in the event header is zero all samples w= ill be displayed. If the nanosecond field is more then the period of one sa= mple, WinQuake will skip to the next top of the second by skipping the firs= t few samples in the data set.

Regards,
Larry Cochrane
Redwood= City, PSN

tchannel wrote:
> Hi Folks, For some reason I can n= o longer use Google with Winquake to AUTOMATICALLY view my Station or Event= s........It worked fine before.   I tried opening different = ..psn in Winquake, different days or months, and none will show in Google Ea= rth, and they all did before.     I get an error messag= e.   "Could not open file C:\Program Files\WinQuake\GoogleEa= rth.kml for reading"

__________________________________________________________

Publ= ic 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/m= aillist.html for more information.
Subject: Magnets and coil vs. LED and Photo Transistor From: "tchannel" tchannel@............ Date: Tue, 17 Feb 2009 12:27:54 -0700 I asked this question earlier but got no response. Just wondering if = the coil and magnet, widely used, is better than an LED, and why? Another question about this site........he uses a LED and Photo = Transistor in place of the coil and magnet. I have never used this. = Is one better than the other? This approach would be smaller and = lighter. =20 http://tinkeringcaveman.googlepages.com/home Thanks, Ted
I asked this question earlier but got = no=20 response.  Just wondering if the coil and magnet, widely used, is = better=20 than an LED, and why?
 
Another question about this = site........he uses a=20 LED and Photo Transistor in place of the coil and magnet.   I = have=20 never used this.  Is one better than the other?   This = approach=20 would be smaller and lighter. 
 
 
http://tinkeringcaveman.go= oglepages.com/home
 
Thanks, = Ted
Subject: Re: Shaking house From: "GMV" gmvoeth@........... Date: Tue, 17 Feb 2009 16:03:51 -0700 Just A thought; I think I heard reference to bedrock and on bedrock is exactly where you want to be. just a thought; Id consider hacking/blasting/jack hammering a little nook or cranny into the side of bedrock if it is really bedrock. I understand its better than underground for seismic quiet. its like 800 feet straight down to bedrock where I live. geoff ----- Original Message ----- From: To: Sent: Monday, February 16, 2009 5:41 PM Subject: Re: Shaking house > In a message dated 16/02/2009, rog@.......... writes: > > I am a novice and building up a vertical-type seismometer, but live in a > wood frame house with a crawl space that shakes considerably with doors > closing and the washing machine going, etc. > Hi Robert, > > Can you describe your house and the setup in more detail, please? What > are the dimensions of the crawl space, the location of the seismometer, the > composition of the ground, the ground slope around the house and the depth of > the water table? > > You will not be able to get a low noise seismic signal if the > seismometer is supported by a wooden building. Mounting the seismometer on the ground > well away from the outer walls usually reduces any noise from the building. > It is usual to provide a concrete block on which to mount the > seismometer and a suitable draftproof + insulation cover, which may be made from 2" > Celotex. You can dig a shallow pit and cast a 50:50 sand and cement plinth. > Don't use any gravel. First lay 1" sand and two sheets of damp proof polythene in > the bottom of the pit and fold up the corners to above ground level. Staple > / tape the top of the folds. Then use a wood surround mould. If you need more > height, dig a deeper pit with sloping sides and surround the plinth with > cast concrete walls. You leave the plinth covered and wet for up to 4 weeks to > allow the cement to cure fully. Then you can dry it out. I stick SS mounting > disks to dry concrete with two component acrylic cement. > The house wiring and Earth connection should provide significant > shielding and protection from lightning. > > Is it possible to locate the seismometer outside? > Certainly, but you need to build a watertight housing for it. Have a > look at _http://www.guralp.com/articles/20040400-casestudy-eskdalemuir/support_ > (http://www.guralp.com/articles/20040400-casestudy-eskdalemuir/support) You > will get lower noise if you make the top nearly flush with the ground / put a > vertical bar fence around the site. Maybe wood + wire paling? You may need to > consider possible problems with high rainfall and flooding. > > What is the easiest way to run a long cable? I do have massive bedrock > on the property about 300 ft from the house. > > > A 300 ft cable run will very likely require you to provide lightning > protection, but this depends on the location. A lot of the US has poor ground > conduction and / or a deep water table. Check on the local advice? You can buy > power cable with spiral steel wire reinforcing and extra insulation so that it > can be laid directly in a trench. This protects it from ground movements, but > it won't be cheap. Otherwise you can lay ordinary cable in polythene water > pipe. > The difficulty is in threading the cable through the pipe. It has a very > high total friction. If you have a suitable quarry, cliff, bridge, > stairwell, or tower, you can hang the pipe vertically and feed the cable in from the > top. Otherwise you need a smooth iron rod and a strong magnet. You use this to > pull a cotton or similar strong string through the pipe, then a strong cord > and then the cable. You can put talc powder in the pipe to lubricate it. Suck > the powder through first with a vacuum cleaner? You can also use Molybdenum > Disulphide or Graphite powder, but they are both messy. > > Hope that this helps, > > Chris Chapman > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Magnets and coil vs. LED and Photo Transistor From: ChrisAtUpw@....... Date: Wed, 18 Feb 2009 00:13:04 EST In a message dated 17/02/2009, tchannel@............ writes: I asked this question earlier but got no response. Just wondering if the coil and magnet, widely used, is better than an LED, and why? Another question about this site..... he uses a LED and Photo Transistor in place of the coil and magnet. I have never used this. Is one better than the other? This approach would be smaller and lighter. _http://tinkeringcaveman.googlepages.com/home_ (mhtml:{6B067749-3EC5-4114-A01F-ABF5F9C52356}mid://00000007/!x-usc:http://tinkeringcaveman.googlepages.com/ho me) Hi Ted, You are talking about two different types of sensor system. Photo detection systems detect position. Coil + magnet systems detect velocity and are likely to suffer noise problems at very long periods. They can be made comparable or better than photo detection at the short periods discussed here. For very low noise position sensors, variable capacitor detection systems are used. Kevin will get a poor performance out of his proposed LED + Phototransistor seismic system. It will be very noisy and it will show temperature drifts due to the components he has chosen. He has used a bundle of fibres as the suspension. This will not give a constant torque with time. The area of the copper in the damping magnet changes as it rotates, so the damping will not be constant with changes in position. You CAN make photo detection systems with resolutions of maybe 10 nano metres, if you design them correctly. Quad magnet damping systems can give constant damping with changes in angle. Single wires and foil strips can give a constant torque / angle relationship. The manufacturers of LEDs don't often tell you that the light output at a constant current varies by >x10 for LED substrate temperature changes between 0 and 100 C. Can't think why! The unstabilised thermal drifts are huge and the photo noise is considerable. You can stabilise the output fairly well with a large area Si photocell + a driver amplifier. Phototransistors have very high noise levels compared to large area photodiodes. They also have metal mask contacts which may make the output both position and rotation dependant. You need large area differential photocells and an intense stable light source to give the high photo currents required (50 to 100 micro A) to get the photo noise and drift down. The current is proportional to the number of electrons in a sample. The photo noise is the square root of this number. You can do it OK with differential Si photocells BPW34 or larger and an under run tungsten filament bulb. They are 'quiet', but do choose straight / tensioned filaments and use a voltage regulated supply. Use about 3/4 the rated voltage to give ~infinite filament life. Maybe put the bulb outside the glass jar to keep down the heating / air convection? There is a differential photo amplifier on John Lahr's website. Remember that this is a position detector, NOT a velocity detector. If you use a coil + magnet block sensor, you have to get the output current away from the armature. Maybe you can use the two suspension wires? You need very small diameter suspension wires to get the longer periods. The Wood-Anderson seismometers used about 0.8 thou OD Tungsten wire. The smallest that I can get off the shelf is 2.4 thou OD. It is used in laser printers. Check used cartridges? _www.wires.co.uk_ (http://www.wires.co.uk) You might also be able to use small diameter NiChrome wire. I have some 2 thou OD. What do _www.smallparts.com_ (http://www.smallparts.com/) keep? The smallest steel music wire is about 7 thou diameter - much too large. Smaller diameters are produced, but I don't know of a source. Glass filaments tend to be brittle and don't conduct electric current. S glass is often used for fibreglass construction instead of O glass. Suspensions are often made from fused silica, but pyrex is also used. Regards, Chris Chapman
In a message dated 17/02/2009, tchannel@............ writes:
<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size= =3D2>
I asked this question earlier but got no=20 response. Just wondering if the coil and magnet, widely used, is bett= er=20 than an LED, and why?
Another question about this site..... he=20= uses a=20 LED and Photo Transistor in place of the coil and magnet. I have never use= d=20 this. Is one better than the other? This approach would be smaller an= d=20 lighter. 
 
http://tinkeringcaveman.google= pages.com/home
 Hi Ted,
 
    You are talking about two different types of se= nsor=20 system. Photo detection systems detect position. Coil + magnet systems detec= t=20 velocity and are likely to suffer noise problems at very long periods. They=20= can=20 be made comparable or better than photo detection at the short periods discu= ssed=20 here.
    For very low noise position sensors, variable=20 capacitor detection systems are used.
 
    Kevin will get a poor performance out of his=20 proposed LED + Phototransistor seismic system. It will be very noisy and it=20= will=20 show temperature drifts due to the components he has chosen. He has used a=20 bundle of fibres as the suspension. This will not give a constant torque wit= h=20 time. The area of the copper in the damping magnet changes as it rotates, so= the=20 damping will not be constant with changes in position.
 
    You CAN make photo detection systems with=20 resolutions of maybe 10 nano metres, if you design them correctly. Quad magn= et=20 damping systems can give constant damping with changes in angle. Single= =20 wires and foil strips can give a constant torque / angle=20 relationship. 
 
    The manufacturers of LEDs don't often tell you=20= that=20 the light output at a constant current varies by >x10 for LED substrate=20 temperature changes between 0 and 100 C. Can't think why! The unstabili= sed=20 thermal drifts are huge and the photo noise is considerable. You can stabili= se=20 the output fairly well with a large area Si photocell + a driver amplif= ier.=20 Phototransistors have very high noise levels compared to large area photodio= des.=20 They also have metal mask contacts which may make the output both posit= ion=20 and rotation dependant. 
 
    You need large area differential photocells and= an=20 intense stable light source to give the high photo currents required (50 to=20 100 micro A) to get the photo noise and drift down. The current is= =20 proportional to the number of electrons in a sample. The photo noise is the=20 square root of this number. You can do it OK with differential Si photocells= =20 BPW34 or larger and an under run tungsten filament bulb. They are 'quie= t',=20 but do choose straight / tensioned filaments and use a voltage regulated sup= ply.=20 Use about 3/4 the rated voltage to give ~infinite filament life. Maybe put t= he=20 bulb outside the glass jar to keep down the heating / air convection? There=20= is a=20 differential photo amplifier on John Lahr's website.
 
    Remember that this is a position detector, NOT=20= a=20 velocity detector.
 
    If you use a coil + magnet block sensor, you ha= ve=20 to get the output current away from the armature. Maybe you can use the two=20 suspension wires?
 
    You need very small diameter suspension wires t= o=20 get the longer periods. The Wood-Anderson seismometers used about 0.8 thou O= D=20 Tungsten wire. The smallest that I can get off the shelf is 2.4 thou OD= .. It=20 is used in laser printers. Check used cartridges? www.wires.co.uk You might also be able t= o use=20 small diameter NiChrome wire. I have some 2 thou OD. What do www.smallparts.com keep?
    The smallest steel music wire is about 7 thou=20 diameter - much too large. Smaller diameters are produced, but I don't know=20= of a=20 source. Glass filaments tend to be brittle and don't conduct electric curren= t. S=20 glass is often used for fibreglass construction instead of O glass. Suspensi= ons=20 are often made from fused silica, but pyrex is also used.
 
    Regards,
 
    Chris Chapman
Subject: Coil + magnet sensors = long period noise? From: Larry Conklin lconklin@............ Date: Wed, 18 Feb 2009 10:08:48 -0500 In a recent post, Chris Chapman commented "Coil + magnet systems detect velocity and are likely to suffer noise problems at very long periods". Could you elaborate a little on this? What is the source of the noise, and what sort of periods are we talking about? Larry Conklin lconklin@............ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Winquake GoogleEarth and Time Display From: Pete Rowe ptrowe@......... Date: Wed, 18 Feb 2009 08:37:37 -0800 (PST) Oh Oh, now I get the "Could not open file C:\Program Files\WinQuake\GoogleE= arth.kml for reading" error when I try to look at my events. When I made it= work earlier this week I played with some sample files built into WinQuake= .. Now I'm trying to view my events. I assume I need to set up some path for= the Google Earth to find??? Pete --- On Mon, 2/16/09, Larry Cochrane wrote: From: Larry Cochrane Subject: Winquake GoogleEarth and Time Display To: psn-l@.............. Date: Monday, February 16, 2009, 5:45 PM Hi Everyone, Sorry for the delay. I have been a little busy with my "day job"... Ted, did you resolve your problem? Regarding Pete Rowe's question on WinQuake and Google Earth. Last year as a= fun little project I added to WinQuake the ability to view the event and/o= r station location in Google Earth. Today I created a new WinQuake setup pr= ogram that contains this new feature. WinQuake version 3.1.2 can be downloa= ded from here http://www.seismicnet.com/software.html#WinQuake. The documen= tation for WinQuake is a little out dated. I'll try and correct that proble= m soon. Here are the locations in the program for the Google Earth feature: Main Menu under View / Google Earth Event Report Dialog Box has a new button called "Google Earth" Location Map Window - Place mouse cursor on location, right click select Go= ogle Earth From geoff, >Howdy you Winquake Experts; >how in heck does one get winquake to recognize >the exact time for the very first sample ? >I will put in like 20:45:37.123 >for the start time but winquake will show at >the higest resolution only 20:45:38 >if I put in 20:45:37 it will then report 20:45:37 >but thats not the right time, >there seems nothing I can do get the exact right time >I want the first sample to represent ?? Geoff, WinQuake starts to display data samples at the top of the second. If the na= nosecond field in the event header is zero all samples will be displayed. I= f the nanosecond field is more then the period of one sample, WinQuake will= skip to the next top of the second by skipping the first few samples in th= e data set. Regards, Larry Cochrane Redwood City, PSN tchannel wrote: > Hi Folks, For some reason I can no longer use Google with Winquake to AUT= OMATICALLY view my Station or Events........It worked fine before.=A0=A0=A0= I tried opening different .psn in Winquake, different days or months, and n= one will show in Google Earth, and they all did before.=A0 =A0=A0=A0I get a= n error message.=A0=A0=A0"Could not open file C:\Program Files\WinQuake\Goo= gleEarth.kml for reading" >=A0=20 __________________________________________________________ Public Seismic Network Mailing List (PSN-L) =0A=0A=0A
Hi Larry,
 
I have a similar problem to Ted's.  If I launch Google = Earth=20 from the menu (Display/Modify, Google Earth, Event or Station) = everything=20 works fine but if I try to launch it by right clicking on the=20 event on the "Location Map"  I receive the "Could not open = file=20 Files\WinQuake\GoogleEarth.kml for reading." = error=20 message.  I tried reinstalling Google earth as Ted had done but = that=20 didn't resolve the problem.  I then uninstalled and = reinstalled=20 WinQuake w/o any change.  Not a "biggie" as I can get there the = other=20 way, just thought you'd like to know that it isn't always working as = you=20 designed it.  (Think we call that an anomaly, there are no = such=20 things as "Bugs" <grin>).
 
Bruce
 
 

 

Oh Oh, now I get the "Could not open file C:\= Program Files\WinQuake\GoogleEarth.kml for reading" error when I try to loo= k at my events. When I made it work earlier this week I played with some sa= mple files built into WinQuake. Now I'm trying to view my events. I assume = I need to set up some path for the Google Earth to find???

Pete
<= br>--- On Mon, 2/16/09, Larry Cochrane <lcochrane@..............&g= t; wrote:

From: Larry Cochrane <= lcochrane@..............>
Subject: Winquake GoogleEarth and Time Disp= lay
To: psn-l@..............
Date: Monday, February 16, 2009, 5:45 PM=

Hi Everyone,

Sorry for the delay. I= have been a little busy with my "day job"...

Ted, did you resolve y= our problem?

Regarding Pete Rowe's question on WinQuake and Google Eart= h. Last year as a fun little project I added to WinQuake the ability to vie= w the event and/or station location in Google Earth. Today I created a new = WinQuake setup program that contains this new feature. WinQuake version 3.1= ..2 can be downloaded from here http://www.seismicnet.com/software.html#= WinQuake. The documentation for WinQuake is a little out dated. I'll tr= y and correct that problem soon. Here are the locations in the program for = the Google Earth feature:

Main Menu under View / Google Earth
Eve= nt Report Dialog Box has a new button called "Google Earth"
Location Map= Window - Place mouse cursor on location, right click select Google Earth
From geoff,

>Howdy you Winquake Experts;

>how in = heck does one get winquake to recognize
>the exact time for the very first sample ?

>I will put in like 20:45:37.123
>for = the start time but winquake will show at
>the higest resolution only = 20:45:38
>if I put in 20:45:37 it will then report 20:45:37
>bu= t thats not the right time,
>there seems nothing I can do get the exa= ct right time
>I want the first sample to represent ??

Geoff,<= br>
WinQuake starts to display data samples at the top of the second. If= the nanosecond field in the event header is zero all samples will be displ= ayed. If the nanosecond field is more then the period of one sample, WinQua= ke will skip to the next top of the second by skipping the first few sample= s in the data set.

Regards,
Larry Cochrane
Redwood City, PSN
tchannel wrote:
> Hi Folks, For some reason I can no longer use= Google with Winquake to AUTOMATICALLY view my Station or Events........It = worked fine before.   I tried opening different .psn in Winquake, different days or months, and none will show in Google Earth,= and they all did before.     I get an error message.&n= bsp;  "Could not open file C:\Program Files\WinQuake\GoogleEarth.= kml for reading"

________________________________________= __________________

Public Seismic Network Mailing List (PSN-L)
To leave this list email PSN-L-REQUEST@SEI= SMICNET.COM with the body of the message (first line only): unsubscribe=
See http://www.seismicnet.com/maillist.html for more information.

=0A=0A Subject: Re: Winquake GoogleEarth and Time Display From: "tchannel" tchannel@............ Date: Wed, 18 Feb 2009 09:58:49 -0700 Hi Pete, As I said, I tried many different things, when mine stopped = working, even reinstalling Winquake.............nothing worked for me = EXCEPT when I uninstalled and reinstalled GoogleEarth. Don't know why = but after doing it, mine works perfectly as it did before. Ted ----- Original Message -----=20 From: Pete Rowe=20 To: psn-l@................. Sent: Wednesday, February 18, 2009 9:37 AM Subject: Re: Winquake GoogleEarth and Time Display Oh Oh, now I get the "Could not open file C:\Program = Files\WinQuake\GoogleEarth.kml for reading" error when I try to look at = my events. When I made it work earlier this week I played with some = sample files built into WinQuake. Now I'm trying to view my events. I = assume I need to set up some path for the Google Earth to find??? Pete --- On Mon, 2/16/09, Larry Cochrane = wrote: From: Larry Cochrane Subject: Winquake GoogleEarth and Time Display To: psn-l@.............. Date: Monday, February 16, 2009, 5:45 PM Hi Everyone, Sorry for the delay. I have been a little busy with my "day = job"... Ted, did you resolve your problem? Regarding Pete Rowe's question on WinQuake and Google Earth. = Last year as a fun little project I added to WinQuake the ability to = view the event and/or station location in Google Earth. Today I created = a new WinQuake setup program that contains this new feature. WinQuake = version 3.1.2 can be downloaded from here = http://www.seismicnet.com/software.html#WinQuake. The documentation for = WinQuake is a little out dated. I'll try and correct that problem soon. = Here are the locations in the program for the Google Earth feature: Main Menu under View / Google Earth Event Report Dialog Box has a new button called "Google Earth" Location Map Window - Place mouse cursor on location, right = click select Google Earth From geoff, >Howdy you Winquake Experts; >how in heck does one get winquake to recognize >the exact time for the very first sample ? >I will put in like 20:45:37.123 >for the start time but winquake will show at >the higest resolution only 20:45:38 >if I put in 20:45:37 it will then report 20:45:37 >but thats not the right time, >there seems nothing I can do get the exact right time >I want the first sample to represent ?? Geoff, WinQuake starts to display data samples at the top of the = second. If the nanosecond field in the event header is zero all samples = will be displayed. If the nanosecond field is more then the period of = one sample, WinQuake will skip to the next top of the second by skipping = the first few samples in the data set. Regards, Larry Cochrane Redwood City, PSN tchannel wrote: > Hi Folks, For some reason I can no longer use Google with = Winquake to AUTOMATICALLY view my Station or Events........It worked = fine before. I tried opening different .psn in Winquake, different = days or months, and none will show in Google Earth, and they all did = before. I get an error message. "Could not open file C:\Program = Files\WinQuake\GoogleEarth.kml for reading" > =20 __________________________________________________________ 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. =20
Hi Pete,  As I said,  I tried = many=20 different things, when mine stopped working, even reinstalling=20 Winquake.............nothing worked for me EXCEPT when I uninstalled and = reinstalled GoogleEarth.   Don't know why but after doing it, = mine=20 works perfectly as it did before.
Ted
----- Original Message -----
From:=20 Pete = Rowe
To: psn-l@..............
Sent: Wednesday, February 18, = 2009 9:37=20 AM
Subject: Re: Winquake = GoogleEarth and=20 Time Display

Oh Oh, now I get the "Could not open file = C:\Program=20 Files\WinQuake\GoogleEarth.kml for reading" error when I try to = look at=20 my events. When I made it work earlier this week I played with = some=20 sample files built into WinQuake. Now I'm trying to view my = events. I=20 assume I need to set up some path for the Google Earth to=20 find???

Pete

--- On Mon, 2/16/09, Larry = Cochrane=20 <lcochrane@..............> wrote:

From:=20 Larry Cochrane <lcochrane@..............>
Subject: = Winquake=20 GoogleEarth and Time Display
To: = psn-l@..............
Date:=20 Monday, February 16, 2009, 5:45 PM

Hi Everyone,

Sorry for the = delay. I have=20 been a little busy with my "day job"...

Ted, did you = resolve=20 your problem?

Regarding Pete Rowe's question on = WinQuake and=20 Google Earth. Last year as a fun little project I added to = WinQuake=20 the ability to view the event and/or station location in = Google Earth.=20 Today I created a new WinQuake setup program that contains = this new=20 feature. WinQuake version 3.1.2 can be downloaded from here http://www.seismicnet.com/software.html#WinQuake.=20 The documentation for WinQuake is a little out dated. I'll try = and=20 correct that problem soon. Here are the locations in the = program for=20 the Google Earth feature:

Main Menu under View / Google = Earth
Event Report Dialog Box has a new button called = "Google=20 Earth"
Location Map Window - Place mouse cursor on = location, right=20 click select Google Earth

From geoff,

>Howdy = you=20 Winquake Experts;

>how in heck does one get winquake = to=20 recognize
>the exact time for the very first sample=20 ?

>I will put in like 20:45:37.123
>for the = start time=20 but winquake will show at
>the higest resolution only=20 20:45:38
>if I put in 20:45:37 it will then report=20 20:45:37
>but thats not the right time,
>there = seems=20 nothing I can do get the exact right time
>I want the = first=20 sample to represent ??

Geoff,

WinQuake starts to = display=20 data samples at the top of the second. If the nanosecond field = in the=20 event header is zero all samples will be displayed. If the = nanosecond=20 field is more then the period of one sample, WinQuake will = skip to the=20 next top of the second by skipping the first few samples in = the data=20 set.

Regards,
Larry Cochrane
Redwood City,=20 PSN

tchannel wrote:
> Hi Folks, For some reason I = can no=20 longer use Google with Winquake to AUTOMATICALLY view my = Station or=20 Events........It worked fine before.   I tried = opening=20 different .psn in Winquake, different days or months, and none = will=20 show in Google Earth, and they all did before. =20    I get an error = message.   "Could not=20 open file C:\Program Files\WinQuake\GoogleEarth.kml for=20 reading"
> =20 =
__________________________________________________________

Pub= lic=20 Seismic Network Mailing List (PSN-L)

To leave this list = email=20 PSN-L-REQUEST@............ COM=20 with the body of the message (first line only): = unsubscribe
See http://www.seismicnet.com/maillist.html = for more=20 = information.

Subject: Re: Winquake GoogleEarth and Time Display From: Thomas Dick dickthomas01@............. Date: Wed, 18 Feb 2009 11:05:49 -0600 I'm having trouble too. I upgraded to the latest Winquake. Now the shift key doesn't work (to bring up more than one file at a time). The add file command does work. Also, all files are displayed with the latest at the bottom of the list for the month rather than the top. Running XP __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Winquake GoogleEarth and Time Display From: Thomas Dick dickthomas01@............. Date: Wed, 18 Feb 2009 11:24:19 -0600 > > > Main Menu under View / Google Earth > Event Report Dialog Box has a new button called "Google Earth" > Location Map Window - Place mouse cursor on location, right click > select Google Earth Larry, in my download of WinQuake, Google Earth works from the Display/Modify pull down menu. Very fine ad to a very good program __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Coil + magnet sensors = long period noise? From: ChrisAtUpw@....... Date: Wed, 18 Feb 2009 19:29:37 EST In a message dated 18/02/2009, lconklin@............ writes: In a recent post, Chris Chapman commented "Coil + magnet systems detect velocity and are likely to suffer noise problems at very long periods". Could you elaborate a little on this? What is the source of the noise, and what sort of periods are we talking about? Larry Conklin lconklin@............ Hi Larry, Apart from the background seismic noise, you have to consider the input voltage and current noise of the amplifier, the intrinsic noise of the input resistances on both inputs and the 1/f (flicker) noise of the system. Note that a coil has noise determined by it's resistance. The 1/f noise is likely to be a limiting factor below about a few Hz. It can be avoided by using a chopper or a CAZ amplifier. Note that CAZ amplifiers like the MAX420, MAX430, LTC1150 etc., still have much more noise than true chopper amplifiers, although their drift and VLF noise is reduced when compared to ordinary amplifiers. See AN-45 from _www.linear.com_ (http://www.linear.com) The RMS voltage noise of a resistor = SQRT(4.k.T.R.B) where k = 1.38x10^-23 in J/K, T is the absolute temperature in Deg Kelvin (Deg C + 273.14), R is the resistance on Ohms and B is the bandwidth in Hz. Professional seismometers usually use variable capacitor sensors and chopper amplifiers measuring position. See AN-87, p87 at _www.linear.com_ (http://www.linear.com) There is usually no significant intrinsic noise associated with a capacitor, as there is with a resistor or an inductor. These give the same output per mm of movement whether this occurs over 1 or 1000 seconds. However, a coil + magnet velocity detection system would only give 1/1000 the voltage output for the 1000 second signal as compared to a 1 second signal, so you quickly reach the amplifier noise limits as the period increases. The seismic background noise is likely to be greater than the 'ordinary' amplifier noise for periods up to ~ 30 seconds, maybe quite a bit more. The complicating factor is the variation in the minimum background seismic noise seen at different periods. See _http://www.geophys.uni-stuttgart.de/oldwww/seismometry/man_html/node28.html_ (http://www.geophys.uni-stuttgart.de/oldwww/seismometry/man_html/node28.html) I hope that this helps. Regards, Chris Chapman
In a message dated 18/02/2009, lconklin@............ writes:
<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size= =3D2>In a=20 recent post, Chris Chapman commented "Coil + magnet systems detect=20
velocity and are likely to suffer noise problems at very long=20 periods".
Could you elaborate a little on this?  What is the sourc= e of=20 the noise,
and what sort of periods are we talking about?
Larry=20 Conklin
lconklin@............
Hi Larry,
 
    Apart from the background seismic noise, you ha= ve=20 to consider the input voltage and current noise of the amplifier, the intrin= sic=20 noise of the input resistances on both inputs and the 1/f (flicker) noise of= the=20 system. Note that a coil has noise determined by it's resistance. The 1/f no= ise=20 is likely to be a limiting factor below about a few Hz. It can be avoided by= =20 using a chopper or a CAZ amplifier. Note that CAZ amplifiers like the=20 MAX420, MAX430, LTC1150 etc., still have much more noise than true chopper=20 amplifiers, although their drift and VLF noise is reduced when compared to=20 ordinary amplifiers. See AN-45 from www.linear.com 
 
    The RMS voltage noise of a resistor =3D=20 SQRT(4.k.T.R.B) where k =3D 1.38x10^-23 in J/K, T is the absolute temperatur= e in=20 Deg Kelvin (Deg C + 273.14), R is the resistance on Ohms and B is the bandwi= dth=20 in Hz.
 
    Professional seismometers usually use variable=20 capacitor sensors and chopper amplifiers measuring position. See AN-87, p87=20= at=20 www.linear.com There is usually no=20 significant intrinsic noise associated with a capacitor, as there is with a=20 resistor or an inductor. These give the same output per mm of movement wheth= er=20 this occurs over 1 or 1000 seconds.  However, a coil + magnet velocity=20 detection system would only give 1/1000 the voltage output for the 1000 seco= nd=20 signal as compared to a 1 second signal, so you quickly reach the ampli= fier=20 noise limits as the period increases.
 
    The seismic background noise is likely to be=20 greater than the 'ordinary' amplifier noise for periods up to ~ 30 seco= nds,=20 maybe quite a bit more. The complicating factor is the variation in the mini= mum=20 background seismic noise seen at different periods.
    See http://www.geophys.uni-stuttgart.de/oldwww/seismometry/man_html/nod= e28.html
 
    I hope that this helps.
 
    Regards,
 
    Chris Chapman
Subject: Re: Coil + magnet sensors = long period noise? From: "tchannel" tchannel@............ Date: Wed, 18 Feb 2009 17:47:57 -0700 Hi Chris, Earlier I posted this question about this "Jar Project" = http://tinkeringcaveman.googlepages.com/home On his posting he used an = LED and phototransistor, instead of a coil and magnet. Could you or = anyone explain the benefits of each? The coil and magnet are more = common, is it better? Thanks, Ted ----- Original Message -----=20 From: ChrisAtUpw@.......... To: psn-l@................. Sent: Wednesday, February 18, 2009 5:29 PM Subject: Re: Coil + magnet sensors =3D long period noise? In a message dated 18/02/2009, lconklin@............ writes: In a recent post, Chris Chapman commented "Coil + magnet systems = detect=20 velocity and are likely to suffer noise problems at very long = periods". Could you elaborate a little on this? What is the source of the = noise,=20 and what sort of periods are we talking about? Larry Conklin lconklin@............ Hi Larry, Apart from the background seismic noise, you have to consider the = input voltage and current noise of the amplifier, the intrinsic noise of = the input resistances on both inputs and the 1/f (flicker) noise of the = system. Note that a coil has noise determined by it's resistance. The = 1/f noise is likely to be a limiting factor below about a few Hz. It can = be avoided by using a chopper or a CAZ amplifier. Note that CAZ = amplifiers like the MAX420, MAX430, LTC1150 etc., still have much more = noise than true chopper amplifiers, although their drift and VLF noise = is reduced when compared to ordinary amplifiers. See AN-45 from = www.linear.com=20 The RMS voltage noise of a resistor =3D SQRT(4.k.T.R.B) where k = =3D 1.38x10^-23 in J/K, T is the absolute temperature in Deg Kelvin (Deg = C + 273.14), R is the resistance on Ohms and B is the bandwidth in Hz. Professional seismometers usually use variable capacitor sensors = and chopper amplifiers measuring position. See AN-87, p87 at = www.linear.com There is usually no significant intrinsic noise = associated with a capacitor, as there is with a resistor or an inductor. = These give the same output per mm of movement whether this occurs over 1 = or 1000 seconds. However, a coil + magnet velocity detection system = would only give 1/1000 the voltage output for the 1000 second signal as = compared to a 1 second signal, so you quickly reach the amplifier noise = limits as the period increases.=20 The seismic background noise is likely to be greater than the = 'ordinary' amplifier noise for periods up to ~ 30 seconds, maybe quite a = bit more. The complicating factor is the variation in the minimum = background seismic noise seen at different periods.=20 See = http://www.geophys.uni-stuttgart.de/oldwww/seismometry/man_html/node28.ht= ml I hope that this helps. Regards, Chris Chapman
Hi Chris,  Earlier I posted this question about this "Jar=20 Project"  http://tinkeringcav= eman.googlepages.com/home =20 On his posting he used an LED and phototransistor, instead of a coil and = magnet.   Could you or anyone explain the benefits of=20 each?   The coil and magnet are more common, is it = better?
 
Thanks, Ted
 
 
 
 
 
 
 
----- Original Message -----
From:=20 ChrisAtUpw@.......
To: psn-l@..............
Sent: Wednesday, February 18, = 2009 5:29=20 PM
Subject: Re: Coil + magnet = sensors =3D long=20 period noise?

In a message dated 18/02/2009, lconklin@............ = writes:
In a=20 recent post, Chris Chapman commented "Coil + magnet systems detect=20
velocity and are likely to suffer noise problems at very long=20 periods".
Could you elaborate a little on this?  What is the = source=20 of the noise,
and what sort of periods are we talking = about?
Larry=20 Conklin
lconklin@............
Hi Larry,
 
    Apart from the background seismic noise, = you have=20 to consider the input voltage and current noise of the amplifier, the=20 intrinsic noise of the input resistances on both inputs and the 1/f = (flicker)=20 noise of the system. Note that a coil has noise determined by it's = resistance.=20 The 1/f noise is likely to be a limiting factor below about a few Hz. = It can=20 be avoided by using a chopper or a CAZ amplifier. Note that CAZ=20 amplifiers like the MAX420, MAX430, LTC1150 etc., still have much more = noise=20 than true chopper amplifiers, although their drift and VLF noise is = reduced=20 when compared to ordinary amplifiers. See AN-45 from www.linear.com 
 
    The RMS voltage noise of a resistor =3D=20 SQRT(4.k.T.R.B) where k =3D 1.38x10^-23 in J/K, T is the absolute = temperature in=20 Deg Kelvin (Deg C + 273.14), R is the resistance on Ohms and B is the=20 bandwidth in Hz.
 
    Professional seismometers usually use = variable=20 capacitor sensors and chopper amplifiers measuring position. See = AN-87, p87 at=20 www.linear.com There is usually = no=20 significant intrinsic noise associated with a capacitor, as there is = with a=20 resistor or an inductor. These give the same output per mm of movement = whether=20 this occurs over 1 or 1000 seconds.  However, a coil + magnet = velocity=20 detection system would only give 1/1000 the voltage output for the = 1000 second=20 signal as compared to a 1 second signal, so you quickly reach the = amplifier noise limits as the period increases.
 
    The seismic background noise is likely to = be=20 greater than the 'ordinary' amplifier noise for periods up to ~ = 30=20 seconds, maybe quite a bit more. The complicating factor is the = variation in=20 the minimum background seismic noise seen at different periods.
    See http://www.geophys.uni-stuttgart.de/oldwww/seismometry/man_ht= ml/node28.html
 
    I hope that this helps.
 
    Regards,
 
    Chris=20 Chapman
Subject: Re: Winquake GoogleEarth and Time Display From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@......... Date: Thu, 19 Feb 2009 00:59:51 +0000 Hi I am having the same issue with the list. It is a problem when you have a large list of files to work with, like do most of the time. I guess for the time being that I need to downgrade. Regards. J=F3n Fr=EDmann. On mi=F0, 2009-02-18 at 11:05 -0600, Thomas Dick wrote: > I'm having trouble too. I upgraded to the latest Winquake. Now the shift=20 > key doesn't work (to bring up more than one file at a time). The add =20 > file command does work. Also, all files are displayed with the=20 > latest at the bottom of the list for the month rather than the top.=20 > Running XP > __________________________________________________________ >=20 > Public Seismic Network Mailing List (PSN-L) >=20 > To leave this list email PSN-L-REQUEST@.............. with=20 > 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: Winquake GoogleEarth and Time Display From: Larry Conklin lconklin@............ Date: Wed, 18 Feb 2009 20:44:07 -0500 I don't understand the concern regarding using the key when to open more than one file. It has always been possible to highlight more than one file in the file list dialog. The "Open File" button will then open all of the highlighted files for display. As for the order that the files are displayed in the file list dialog, it looks like Larry has adopted a standard Windows convention. If you click on any of the column headings in the file list dialog, the list will be sorted on that column. A second click on the same column reverses the sort order. Larry Conklin Jón Frímann wrote: > Hi > > I am having the same issue with the list. It is a problem when you have > a large list of files to work with, like do most of the time. > > I guess for the time being that I need to downgrade. > > Regards. > Jón Frímann. > > On mið, 2009-02-18 at 11:05 -0600, Thomas Dick wrote: >> I'm having trouble too. I upgraded to the latest Winquake. Now the shift >> key doesn't work (to bring up more than one file at a time). The add >> file command does work. Also, all files are displayed with the >> latest at the bottom of the list for the month rather than the top. >> Running XP >> __________________________________________________________ >> >> 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: Coil + magnet sensors = long period noise? From: Larry Conklin lconklin@............ Date: Wed, 18 Feb 2009 20:54:21 -0500 Chris, Thanks for the reply. The phrase that caught my eye was "very long periods". I have an SG sensor that is based on Larry's electronics board, which doesn't use a coil/magnet sensor. But I have always had a substantial amount of "wandering" with a period of 60 seconds or more. I always have attributed it to incompletely controlled air currents inside the enclosure. But after several different enclosures, internal baffles, warming the box from the top with a couple of power resistors, etc, I have never made much of an impact on the noise. I wound up by usin a 30 second hi-pass filter to knock down my "very long period" noise. Larry ChrisAtUpw@....... wrote: > In a message dated 18/02/2009, lconklin@............ writes: > > In a recent post, Chris Chapman commented "Coil + magnet systems detect > velocity and are likely to suffer noise problems at very long periods". > Could you elaborate a little on this? What is the source of the noise, > and what sort of periods are we talking about? > Larry Conklin > lconklin@............ > > Hi Larry, > > Apart from the background seismic noise, you have to consider the > input voltage and current noise of the amplifier, the intrinsic noise of > the input resistances on both inputs and the 1/f (flicker) noise of the > system. Note that a coil has noise determined by it's resistance. The > 1/f noise is likely to be a limiting factor below about a few Hz. It can > be avoided by using a chopper or a CAZ amplifier. Note that CAZ > amplifiers like the MAX420, MAX430, LTC1150 etc., still have much more > noise than true chopper amplifiers, although their drift and VLF noise > is reduced when compared to ordinary amplifiers. See AN-45 from > www.linear.com > > The RMS voltage noise of a resistor = SQRT(4.k.T.R.B) where k = > 1.38x10^-23 in J/K, T is the absolute temperature in Deg Kelvin (Deg C + > 273.14), R is the resistance on Ohms and B is the bandwidth in Hz. > > Professional seismometers usually use variable capacitor sensors and > chopper amplifiers measuring position. See AN-87, p87 at www.linear.com > There is usually no significant intrinsic noise > associated with a capacitor, as there is with a resistor or an inductor. > These give the same output per mm of movement whether this occurs over 1 > or 1000 seconds. However, a coil + magnet velocity detection system > would only give 1/1000 the voltage output for the 1000 second signal as > compared to a 1 second signal, so you quickly reach the amplifier noise > limits as the period increases. > > The seismic background noise is likely to be greater than the > 'ordinary' amplifier noise for periods up to ~ 30 seconds, maybe quite a > bit more. The complicating factor is the variation in the minimum > background seismic noise seen at different periods. > See > http://www.geophys.uni-stuttgart.de/oldwww/seismometry/man_html/node28.html > > I hope that this helps. > > Regards, > > Chris Chapman __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Winquake GoogleEarth and Time Display From: Larry Cochrane lcochrane@.............. Date: Wed, 18 Feb 2009 22:36:46 -0800 Let me add that you can use the Ctrl key and the mouse to select more then one event file in the Open File dialog box. Larry Cochrane Redwood City, PSN Larry Conklin wrote: > I don't understand the concern regarding using the key when to > open more than one file. It has always been possible to highlight more > than one file in the file list dialog. The "Open File" button will then > open all of the highlighted files for display. > > As for the order that the files are displayed in the file list dialog, > it looks like Larry has adopted a standard Windows convention. If you > click on any of the column headings in the file list dialog, the list > will be sorted on that column. A second click on the same column > reverses the sort order. > > Larry Conklin > > > Jón Frímann wrote: >> Hi >> >> I am having the same issue with the list. It is a problem when you have >> a large list of files to work with, like do most of the time. >> >> I guess for the time being that I need to downgrade. >> >> Regards. >> Jón Frímann. >> >> On mið, 2009-02-18 at 11:05 -0600, Thomas Dick wrote: >>> I'm having trouble too. I upgraded to the latest Winquake. Now the shift >>> key doesn't work (to bring up more than one file at a time). The add >>> file command does work. Also, all files are displayed with the >>> latest at the bottom of the list for the month rather than the top. >>> Running XP >>> __________________________________________________________ >>> >>> 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: Re: Coil + magnet sensors = long period noise? From: "GMV" gmvoeth@........... Date: Thu, 19 Feb 2009 00:15:09 -0700 That publication seems to be referencing db to one meter per second squared ( acceleration) and I was just wondering if it would be calculated 10(log(n/(1m/s^2))) or 20(log(n/(1m/s^2))) n being what you want to measure against the chart ? anybody know what they are using here ? thanx geoff ----- Original Message ----- From: To: Sent: Wednesday, February 18, 2009 5:29 PM Subject: Re: Coil + magnet sensors = long period noise? > > In a message dated 18/02/2009, lconklin@............ writes: > > In a recent post, Chris Chapman commented "Coil + magnet systems detect > velocity and are likely to suffer noise problems at very long periods". > Could you elaborate a little on this? What is the source of the noise, > and what sort of periods are we talking about? > Larry Conklin > lconklin@............ > > > > Hi Larry, > > Apart from the background seismic noise, you have to consider the input > voltage and current noise of the amplifier, the intrinsic noise of the input > resistances on both inputs and the 1/f (flicker) noise of the system. Note > that a coil has noise determined by it's resistance. The 1/f noise is likely to > be a limiting factor below about a few Hz. It can be avoided by using a > chopper or a CAZ amplifier. Note that CAZ amplifiers like the MAX420, MAX430, > LTC1150 etc., still have much more noise than true chopper amplifiers, although > their drift and VLF noise is reduced when compared to ordinary amplifiers. > See AN-45 from _www.linear.com_ (http://www.linear.com) > > The RMS voltage noise of a resistor = SQRT(4.k.T.R.B) where k = > 1.38x10^-23 in J/K, T is the absolute temperature in Deg Kelvin (Deg C + 273.14), R > is the resistance on Ohms and B is the bandwidth in Hz. > > Professional seismometers usually use variable capacitor sensors and > chopper amplifiers measuring position. See AN-87, p87 at _www.linear.com_ > (http://www.linear.com) There is usually no significant intrinsic noise associated > with a capacitor, as there is with a resistor or an inductor. These give the > same output per mm of movement whether this occurs over 1 or 1000 seconds. > However, a coil + magnet velocity detection system would only give 1/1000 the > voltage output for the 1000 second signal as compared to a 1 second signal, > so you quickly reach the amplifier noise limits as the period increases. > > The seismic background noise is likely to be greater than the 'ordinary' > amplifier noise for periods up to ~ 30 seconds, maybe quite a bit more. The > complicating factor is the variation in the minimum background seismic noise > seen at different periods. > See > _http://www.geophys.uni-stuttgart.de/oldwww/seismometry/man_html/node28.html_ > (http://www.geophys.uni-stuttgart.de/oldwww/seismometry/man_html/node28.html) > > I hope that this helps. > > Regards, > > Chris Chapman > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Winquake and Google Earth From: Larry Cochrane lcochrane@.............. Date: Wed, 18 Feb 2009 23:48:30 -0800 Hi Pete, There's no path to setup. Here are some things to try if you are having a problem with this feature: If you use Vista try disabling the UAC (User Account Control) "feature". Do a Google search on "disable vista uac" for more information. Try installing WinQuake in an other directory other then "Program Files" like c:\winquake or d:\winquake. Try logging in as Administrator, if your system is setup with different user accounts. To work properly, the system must associate the file type of .kml to Google Earth. This should happen automatically when you install Google Earth. Regards, Larry Cochrane Redwood City, PSN Pete Rowe wrote: > Oh Oh, now I get the "Could not open file C:\Program > Files\WinQuake\GoogleEarth.kml for reading" error when I try to look at > my events. When I made it work earlier this week I played with some > sample files built into WinQuake. Now I'm trying to view my events. I > assume I need to set up some path for the Google Earth to find??? > > Pete > > --- On *Mon, 2/16/09, Larry Cochrane //* wrote: > > > From: Larry Cochrane > Subject: Winquake GoogleEarth and Time Display > To: psn-l@.............. > Date: Monday, February 16, 2009, 5:45 PM > > Hi Everyone, > > Sorry for the delay. I have been a little busy with my "day job"... > > Ted, did you resolve your problem? > > Regarding Pete Rowe's question on WinQuake and Google Earth. Last > year as a fun little project I added to WinQuake the ability to view > the event and/or station location in Google Earth. Today I created a > new WinQuake setup program that contains this new feature. WinQuake > version 3.1.2 can be downloaded from here > http://www.seismicnet.com/software.html#WinQuake. The documentation > for WinQuake is a little out dated. I'll try and correct that > problem soon. Here are the locations in the program for the Google > Earth feature: > > Main Menu under View / Google Earth > Event Report Dialog Box has a new button called "Google Earth" > Location Map Window - Place mouse cursor on location, right click > select Google Earth > > From geoff, > > >Howdy you Winquake Experts; > > >how in heck does one get winquake to recognize > >the exact time for the very first sample ? > > >I will put in like 20:45:37.123 > >for the start time but winquake will show at > >the higest resolution only 20:45:38 > >if I put in 20:45:37 it will then report 20:45:37 > >but thats not the right time, > >there seems nothing I can do get the exact right time > >I want the first sample to represent ?? > > Geoff, > > WinQuake starts to display data samples at the top of the second. If > the nanosecond field in the event header is zero all samples will be > displayed. If the nanosecond field is more then the period of one > sample, WinQuake will skip to the next top of the second by skipping > the first few samples in the data set. > > Regards, > Larry Cochrane > Redwood City, PSN > > tchannel wrote: > > Hi Folks, For some reason I can no longer use Google with > Winquake to AUTOMATICALLY view my Station or Events........It worked > fine before. I tried opening different .psn in Winquake, different > days or months, and none will show in Google Earth, and they all did > before. I get an error message. "Could not open file > C:\Program Files\WinQuake\GoogleEarth.kml for reading" > > > __________________________________________________________ > > 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: coil/magnet sensors From: Randall Peters PETERS_RD@.......... Date: Thu, 19 Feb 2009 19:42:07 -0500 Larry, The primary reason for poor signal to noise ratio at long periods wit= h a coil/magnet system involves the physics employed. Such a sensor functi= ons on the basis of Faraday's law, which says that a time changing magnetic= flux gives rise to a voltage. The key word in this process is 'changing';= the output depends on the flux rate. If the boom of the seismometer is sw= inging sinusoidally at a frequency f, then the amplitude of the output volt= age of the sensor is proportional to f-which is the very nature of the time= derivative of the sine function, involving the chain rule. Because the si= gnal is proportional to f, the signal level decreases by the same amount as= f decreases. Regardless of the nature of the noise, this means there is a= significant reduction in the signal to noise ratio for accelerations havin= g a frequency below the natural frequency of the instrument. When operatin= g without the high-pass filter with your S-G instrument, your output is not= rate sensitive; therefore it isn't afflicted with this low frequency loss.= The 'wandering' you experience is actually representative of the various = changes occurring. Although some of those changes are oftentimes the undes= irables of instrument thermal coefficient or whatever, there are also signi= ficant variations associated with the Earth itself. When you high pass the= output, any earth motions having frequencies lower than the cutoff are su= ppressed. I operate the VolksMeter with a high pass and also low pass filt= er of recursive type in WinSDR. The primary reason is so that the helicord= record is well behaved for purpose of seeing earthquakes. But for viewing= tides, or magnetoelastic phenomena, or earth hum, or .... It is necessary = to look at the unfiltered output, which is what I save. The obsession with 'velocity' sensing is almost universal. Even forc= e balance instruments of the highest dollar type use a network that causes = the seismograph to behave just like a magnet/coil system with a low corner = frequency, usually about 30 s. Thus the greatest advantage of the capaciti= ve sensor is actually lost, for signals having frequencies lower than the d= esign corner. For signal variations having a frequency below the corner, t= he output from such an instrument is not 'velocity'; it is instead the deri= vative of acceleration, called the 'jerk'. Only for drive frequencies abov= e the corner can one use the term 'velocity' appropriately. Randall

Larry,

      The primary reason for = poor signal to noise ratio at long periods with a coil/magnet system involves th= e physics employed.  Such a sensor functions on the basis of FaradayR= 17;s law, which says that a time changing magnetic flux gives rise to a voltage.=   The key word in this process is ‘changing’; the output depends = on the flux rate.  If the boom of the seismometer is swinging sinusoidall= y at a frequency f, then the amplitude of the output voltage of the sensor is proportional to f—which is the very nature of the time derivative of = the sine function, involving the chain rule.  Because the signal is propor= tional to f, the signal level decreases by the same amount as f decreases.  Regardless of the nature of the noise, this means there is a significant reduction in the signal to noise ratio for accelerations having a frequency below the natural frequency of the instrument.  When operating without= the high-pass filter with your S-G instrument, your output is not rate sensitiv= e; therefore it isn’t afflicted with this low frequency loss.  The = ‘wandering’ you experience is actually representative of the various changes occurring.  Although some of those changes are oftentimes the undesira= bles of instrument thermal coefficient or whatever, there are also significant v= ariations associated with the Earth itself.  When you high pass the output, any earth motions having frequencies lower than the cutoff  are suppressed= ..  I operate the VolksMeter with a high pass and also low pass filter of recur= sive type in WinSDR.  The primary reason is so that the helicord record is = well behaved for purpose of seeing earthquakes.  But for viewing tides, or magnetoelastic phenomena, or earth hum, or …. It is necessary to look= at the unfiltered output, which is what I save. 

      The obsession with R= 16;velocity’ sensing is almost universal.  Even force balance instruments of the highest dollar type use a network that causes the seismograph to behave jus= t like a magnet/coil system with a low corner frequency, usually about 30 s.  Thus the greatest advantage of the capacitive sensor is actually l= ost, for signals having frequencies lower than the design corner.  For sign= al variations having a frequency below the corner, the output from such an instrument is = not ‘velocity’; it is instead the derivative of acceleration, called the ‘jerk’= ..  Only for drive frequencies above the corner can one use the term ‘vel= ocity’ appropriately.

    Randall

Subject: Re: coil/magnet sensors From: Pete Rowe ptrowe@......... Date: Thu, 19 Feb 2009 17:20:31 -0800 (PST) Hi Randall Thanks for your lucid thoughts. What are your high pass and low pass freque= ncies? The high pass function in my system is just the coupling caps in the= amplifier chain and I'm not sure where it rolls off on the bottom end. It = seems that I should try a real high pass and I'd like some advice on settin= g the corner frequency. Thanks, Pete --- On Thu, 2/19/09, Randall Peters wrote: From: Randall Peters Subject: coil/magnet sensors To: "psn-l@.............." Date: Thursday, February 19, 2009, 4:42 PM =20 =20 Larry,=20 =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 The primary reason for poor signal to noise ratio at long periods with a coil/magnet system involves th= e physics employed.=C2=A0 Such a sensor functions on the basis of Faraday=E2= =80=99s law, which says that a time changing magnetic flux gives rise to a voltage.= =C2=A0 The key word in this process is =E2=80=98changing=E2=80=99; the output depe= nds on the flux rate.=C2=A0 If the boom of the seismometer is swinging sinusoidall= y at a frequency f, then the amplitude of the output voltage of the sensor is proportional to f=E2=80=94which is the very nature of the time derivative o= f the sine function, involving the chain rule. =C2=A0Because the signal is propor= tional to f, the signal level decreases by the same amount as f decreases.=C2=A0 Regardless of the nature of the noise, this means there is a significant reduction in the signal to noise ratio for accelerations having a frequency below the natural frequency of the instrument.=C2=A0 When operating without= the high-pass filter with your S-G instrument, your output is not rate sensitiv= e; therefore it isn=E2=80=99t afflicted with this low frequency loss.=C2=A0 Th= e =E2=80=98wandering=E2=80=99 you experience is actually representative of the various changes occurring.=C2=A0 Although some of those changes are oftentimes the undesira= bles of instrument thermal coefficient or whatever, there are also significant v= ariations associated with the Earth itself.=C2=A0 When you high pass the output, any earth motions having frequencies lower than the cutoff =C2=A0are suppressed= ..=C2=A0 I operate the VolksMeter with a high pass and also low pass filter of recur= sive type in WinSDR.=C2=A0 The primary reason is so that the helicord record is = well behaved for purpose of seeing earthquakes.=C2=A0 But for viewing tides, or magnetoelastic phenomena, or earth hum, or =E2=80=A6. It is necessary to lo= ok at the unfiltered output, which is what I save.=C2=A0 =20 =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 The obsession with =E2=80=98velocity=E2=80= =99 sensing is almost universal.=C2=A0 Even force balance instruments of the highest dollar type use a network that causes the seismograph to behave jus= t like a magnet/coil system with a low corner frequency, usually about 30 s.=C2=A0 Thus the greatest advantage of the capacitive sensor is actually l= ost, for signals having frequencies lower than the design corner.=C2=A0 For sign= al variations having a frequency below the corner, the output from such an instrument is = not =E2=80=98velocity=E2=80=99; it is instead the derivative of acceleration, called the =E2=80=98jerk=E2= =80=99.=C2=A0 Only for drive frequencies above the corner can one use the term =E2=80=98v= elocity=E2=80=99 appropriately.=20 =C2=A0=C2=A0=C2=A0 Randall=20 =20 =0A=0A=0A
Hi Randall
Thanks for your lucid thoughts.= What are your high pass and low pass frequencies? The high pass function i= n my system is just the coupling caps in the amplifier chain and I'm not su= re where it rolls off on the bottom end. It seems that I should try a real = high pass and I'd like some advice on setting the corner frequency.
Than= ks,
Pete

--- On Thu, 2/19/09, Randall Peters <PETERS_RD@= mercer.edu> wrote:
From: Randall Pet= ers <PETERS_RD@..........>
Subject: coil/magnet sensors
To: "ps= n-l@.............." <psn-l@..............>
Date: Thursday, Februar= y 19, 2009, 4:42 PM

=20 =20

Larry,

=20

      The primary reason fo= r poor signal to noise ratio at long periods with a coil/magnet system involves th= e physics employed.  Such a sensor functions on the basis of Faraday=E2= =80=99s law, which says that a time changing magnetic flux gives rise to a voltage.=   The key word in this process is =E2=80=98changing=E2=80=99; the output depe= nds on the flux rate.  If the boom of the seismometer is swinging sinusoidall= y at a frequency f, then the amplitude of the output voltage of the sensor is proportional to f=E2=80=94which is the very nature of the time derivative o= f the sine function, involving the chain rule.  Because the signal is propor= tional to f, the signal level decreases by the same amount as f decreases.  Regardless of the nature of the noise, this means there is a significant reduction in the signal to noise ratio for accelerations having a frequency below the natural frequency of the instrument.  When operating without= the high-pass filter with your S-G instrument, your output is not rate sensitiv= e; therefore it isn=E2=80=99t afflicted with this low frequency loss.  Th= e =E2=80=98wandering=E2=80=99 you experience is actually representative of the various changes occurring.  Although some of those changes are oftentimes the undesira= bles of instrument thermal coefficient or whatever, there are also significant v= ariations associated with the Earth itself.  When you high pass the output, any earth motions having frequencies lower than the cutoff  are suppressed= ..  I operate the VolksMeter with a high pass and also low pass filter of recur= sive type in WinSDR.  The primary reason is so that the helicord record is = well behaved for purpose of seeing earthquakes.  But for viewing tides, or magnetoelastic phenomena, or earth hum, or =E2=80=A6. It is necessary to lo= ok at the unfiltered output, which is what I save. 

=20

      The obsession with = =E2=80=98velocity=E2=80=99 sensing is almost universal.  Even force balance instruments of the highest dollar type use a network that causes the seismograph to behave jus= t like a magnet/coil system with a low corner frequency, usually about 30 s.  Thus the greatest advantage of the capacitive sensor is actually l= ost, for signals having frequencies lower than the design corner.  For sign= al variations having a frequency below the corner, the output from such an instrument is = not =E2=80=98velocity=E2=80=99; it is instead the derivative of acceleration, called the =E2=80=98jerk=E2= =80=99.  Only for drive frequencies above the corner can one use the term =E2=80=98v= elocity=E2=80=99 appropriately.

=20

    Randall

=20
=20

=0A=0A Subject: my filters From: Randall Peters PETERS_RD@.......... Date: Fri, 20 Feb 2009 06:57:30 -0500 Pete, What I do effectively is to 'bandpass' my helicord records for purpose = of seeing mostly teleseismic earthquakes. For example, in the 'integrated'= (true velocity) output from the VolksMeter, I operate with a 1-pole-each-p= air of high-pass and low-pass filters. The WinSDR high-pass cutoff is 0.05= Hz (20 s period, sitting "on top of " the typical Rayleighh wave) and a lo= w pass cutoff at 0.5 Hz (2 s period). This way I have a good chance of se= eing teleseismic events whose signals are above my SNR threshold. To see l= ocal , usually small earthquakes (which I'm not interested in, since I don'= t live in a place like California, where you could see them almost daily, I= would want to operate with the 'raw' signal (displacement proportional to = acceleration) output from the VM. I would set the low pass for that case a= t probably 10 Hz, since the 'signature' of seismic waves received from suc= h are much higher frequency than what is left after the waves travel large = distances through the Earth. I don't save anything from my instrument for later analysis using sample = rates greater than one per second, since I don't care about looking at loca= lly generated 'noises'. If you look at Larry Cochrane's VM output you can= see (for reason of his filter settings) when San Francisco is awake as opp= osed to asleep. My buddy at another place in CA, who's also using a VolksMeter (on Cobb= Mtn, I leave it to you readers to see if you can figure out his name from= his extensive webpages) has been doing something that list-serve readers m= ight find interesting. The data that is presented in his animations at htt= p://flyingsnail.com/AmateurRadio/Indonesia7-2-fft-csp.html Involves records for which the high-pass cutoff frequency was 0.0005 Hz. I am working with an internationally distributed group to look at something= at even lower frequencies, that is really exciting. It appears that Volks= Meter tilt data is highly correlated with magnetic field variations of the = Earth derived from flux-gate magnetometers. One cannot for such studies ha= ve any high-pass filter whatsoever. The VolksMeter is ideally suited to th= ese investigations, since it responds all the way down to d.c. Probably th= e reason what we're seeing has not been observed many times in the past, is= because seismologists have operated mostly with instruments that don't go = that low in frequency. Randall

Pete,

    What I do effectively is to ‘= bandpass’ my helicord records for purpose of seeing mostly teleseismic earthquakes.&n= bsp; For example, in the ‘integrated’ (true velocity) output from th= e VolksMeter, I operate with a 1-pole-each-pair of high-pass and low-pass fil= ters.  The WinSDR high-pass cutoff is 0.05 Hz (20 s period, sitting “on top = of “ the typical Rayleighh wave) and a low pass cutoff at 0.5 Hz (2 s period).   This way I have a good chance of seeing teleseismic ev= ents whose signals are above my SNR threshold.  To see local , usually smal= l earthquakes (which I’m not interested in, since I don’t live in a place lik= e California, where you could see them almost daily, I would want to operate = with the ‘raw’ signal (displacement proportional to acceleration) ou= tput from the VM.  I would set the low pass for that case at probably 10 Hz= , since the ‘signature’ of seismic  waves received from such= are much higher frequency than what is left after the waves travel large distan= ces through the Earth.

  I don’t save anything from my instrument = for later analysis using sample rates greater than one per second, since I don&= #8217;t care about looking at locally generated ‘noises’.   I= f you look at Larry Cochrane’s VM output you can see (for reason of his filter settings) when San Francisco is awake as opposed to asleep.

    My buddy at another place in CA, wh= o’s also using a VolksMeter (on Cobb Mtn,  I leave it to you readers to se= e if you can figure out his name from his extensive webpages) has been doing something that list-serve readers might find interesting.  The data th= at is presented in his animations at http= ://flyingsnail.com/AmateurRadio/Indonesia7-2-fft-csp.html

  Involves records for which the high-pass cutoff frequency was 0.0005 Hz. 

I am working with an internationally distributed group= to look at something at even lower frequencies, that is really exciting.  = ;It appears that VolksMeter tilt data is highly correlated with magnetic field = variations of the Earth derived from flux-gate magnetometers.  One cannot for suc= h studies have any high-pass filter whatsoever.  The VolksMeter is ideal= ly suited to these investigations, since it responds all the way down to d.c.&= nbsp; Probably the reason what we’re seeing has not been observed many time= s in the past, is because seismologists have operated mostly with instruments th= at don’t go that low in frequency.

 

  Randall

Subject: Re: coil/magnet sensors From: "GMV" gmvoeth@........... Date: Sat, 21 Feb 2009 08:20:30 -0700 not too butt in but I believe it to be important that you include either a digital or analog low pass filter of like n8 or n6 that is maybe ((0.1 to 0.27)* Samp/sec)in Hz of your sample rate before the analog signal hits the a/d converter or you will get artifacts that fold back into the same frequency range in which you are looking as a matter of frequency translation which is like a superhetrodyn receiver. I know this both from military technical training as well as personal experiences. unrelated note of interest: Also I have noted that in order to like integrate the data in Winquake you must first bandpass filter equalize the data so it stays at zero and not a diagonal line across the screen. after integrating you will still see noise if only there is noise but if like there is human activity in the neighborhood the signals will appear as low frequency artifacts. When you equalize the data you can have differing N factors for high and low pass sides of your filter. whatever takes the noise and creates a straight line data set at zero baseline. I have never seen anyone recommend this before. also, I have seen the integrate function totally eliminate a valid signal and appear only as noise. ----- Original Message ----- From: "Randall Peters" To: Sent: Thursday, February 19, 2009 5:42 PM Subject: coil/magnet sensors Larry, The primary reason for poor signal to noise ratio at long periods with a coil/magnet system involves the physics employed. Such a sensor functions on the basis of Faraday's law, which says that a time changing magnetic flux gives rise to a voltage. The key word in this process is 'changing'; the output depends on the flux rate. If the boom of the seismometer is swinging sinusoidally at a frequency f, then the amplitude of the output voltage of the sensor is proportional to f-which is the very nature of the time derivative of the sine function, involving the chain rule. Because the signal is proportional to f, the signal level decreases by the same amount as f decreases. Regardless of the nature of the noise, this means there is a significant reduction in the signal to noise ratio for accelerations having a frequency below the natural frequency of the instrument. When operating without the high-pass filter with your S-G instrument, your output is not rate sensitive; therefore it isn't afflicted with this low frequency loss. The 'wandering' you experience is actually representative of the various changes occurring. Although some of those changes are oftentimes the undesirables of instrument thermal coefficient or whatever, there are also significant variations associated with the Earth itself. When you high pass the output, any earth motions having frequencies lower than the cutoff are suppressed. I operate the VolksMeter with a high pass and also low pass filter of recursive type in WinSDR. The primary reason is so that the helicord record is well behaved for purpose of seeing earthquakes. But for viewing tides, or magnetoelastic phenomena, or earth hum, or .... It is necessary to look at the unfiltered output, which is what I save. The obsession with 'velocity' sensing is almost universal. Even force balance instruments of the highest dollar type use a network that causes the seismograph to behave just like a magnet/coil system with a low corner frequency, usually about 30 s. Thus the greatest advantage of the capacitive sensor is actually lost, for signals having frequencies lower than the design corner. For signal variations having a frequency below the corner, the output from such an instrument is not 'velocity'; it is instead the derivative of acceleration, called the 'jerk'. Only for drive frequencies above the corner can one use the term 'velocity' appropriately. Randall __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: aliasing From: Randall Peters PETERS_RD@.......... Date: Sat, 21 Feb 2009 12:45:06 -0500 No 'butt-in' offense to me by your email, GM. (I hope it is acceptable to= address you in this manner.) We in physics also 'speak our peace' on subj= ects important to us. You are absolutely correct that periodic signals with a frequency hig= her than the Nyquist frequency (1/2 the sampling rate of an ADC) will show = up as an alias. The key element to whether or not you get such a high freq= uency signal masquerading as one of lower frequency-depends on the coherenc= e time of the offending signal. It must exist through a large enough numbe= r of cycles that what is admitted to the record saved is coherent enough to= show up as a spectral line. In the case of the VolksMeter, there is no analog signal to begin with.= Stated differently, there is no ADC; rather the device is a 'direct' capa= citance to digital converter (CDC). Because of the award winning AD7745 ch= ip of Analog Devices, that is the heart of the instrument, the VM is more t= han just a "State of the art digital seismometer", as described in the link= on Larry's page. http://seismicnet.com/volksmeter/State-of-the-art_Digital_Seismograph.pdf It is also the worlds' first fully digital seismograph'. It is true that = some detractors from this claim would say that there is no such thing as a = fully-digital anything that interacts with our world which is itself analog= .. But my point is the following. Unlike other commericial instruments tha= t use analog electronics to monitor a capacitive sensor (and then finally d= igitize the analog signal), the VolksMeter has no analog components whatsoe= ver, except for internal 'workings' of the chip-for which one would have gr= eat debate as to whether the 'pieces' are digital or analog. There is one other significant 'fully'-part to the instrument. The capacit= ive sensor used by the VolksMeter is "fully differential". There are a host of advantages associated with an architecture that = is fully digital in the electronics with a fully symmetric (differential) s= ensor; I don't have time now to go into detail. Incidently, some of you amateurs might want to 'tackle' the home-brew c= onstruction of such an instrument yourself; maybe even extend what I've don= e to the world of vertical seismographs. As Chris Chapman has indicated, t= hey're much tougher because of material problems (not my expertise). If y= ou want to build something that could make even the seismology pro's saliva= te over, then talk with Larry about the electronics package. He will proba= bly sell you the all the necessary things 'for a song', compared to what th= e big companies want for anything. Randall

No ‘butt-in’ offense to me by your email, GM.   (I hope it is acceptable to address you in this manner.)&nb= sp; We in physics also ‘speak our peace’ on subjects important to us.<= o:p>

      You are absolutely corr= ect that periodic signals with a frequency higher than the Nyquist frequency (1= /2 the sampling rate of an ADC) will show up as an alias.  The key elemen= t to whether or not you get such a high frequency signal masquerading as one of lower frequency—depends on the coherence time of the offending signal.  It must exist through a large enough number of cycles that wh= at is admitted to the record saved is coherent enough to show up as a spectral line.   

    In the case of the VolksMeter, ther= e is no analog signal to begin with.  Stated differently, there is no ADC; rather the device is a ‘direct’ capacitance to digital converte= r (CDC).  Because of the award winning AD7745 chip of Analog Devices, th= at is the heart of the instrument, the VM is more than just a “State of = the art digital seismometer”, as described in the link on Larry’s p= age. 

http://seismicnet.com/volksmeter/State-of-the-art_Digital_Seismogra= ph.pdf

 

It  is also the worlds’ first fully digital seismograph’.  It is true that some detractors from this claim w= ould say that there is no such thing as a fully-digital anything that interacts = with our world which is itself analog.  But my point is the following. = ; Unlike other commericial instruments that use analog electronics to monitor= a capacitive sensor (and then finally digitize the analog signal), the VolksM= eter has no analog components whatsoever, except for internal ‘workings= 217; of the chip—for which one would have great debate as to whether the &= #8216;pieces’ are digital or analog.

There is one other significant ‘fully’-par= t to the instrument.  The capacitive sensor used by the VolksMeter is “fu= lly differential”.

       There are a host = of advantages associated with an architecture that is fully digital in the electronics with a fully symmetric (differential) sensor; I don’t hav= e time now to go into detail.

    Incidently, some of you amateurs mi= ght want to ‘tackle’ the home-brew construction of such an instrume= nt yourself; maybe even extend what I’ve done to the world of vertical seismographs.  As Chris Chapman has indicated, they’re much toug= her because  of material problems (not my expertise).  If you want to build somethi= ng that could make even the seismology pro’s salivate over, then talk with La= rry about the electronics package.  He will probably sell you the all the necessary things ‘for a song’, compared to what the big compani= es want for anything. 

 

   Randall

Subject: Soft Force Feedback From: Chuck/Judy Burch cjburch@........... Date: Sat, 21 Feb 2009 13:46:23 -0700 Randall Peters, You have advocated a "soft" feedback scheme for seismometers owing to improved sensitivity at long periods. Conventional PID force feedback schemes, such as that used in the STS-1, are well described in numerous publications. I assume you are suggesting an "I only" scheme (no P or D). Is the feedback current deliberately weak so as to allow some movement of the reference mass, yet strong enough to keep it from hitting the pins? Is the idea to integrate over one frequency range and observe events in another frequency range? Or do you suggest allowing the integrator to see the entire frequency range of interest? Thanks for any details you can provide. Charles Burch __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: aliasing From: "GMV" gmvoeth@........... Date: Sat, 21 Feb 2009 14:32:50 -0700 It does not matter the sensor feeding the data into an A/D converter unless there is something I have never heard of before. it is simply a fact of science that sampled data will be troubled by alizing if signals are present above 1/2 the samplke rate. regards; geoff Im not knocking anyones creation simply making people sensitive to a fact of science. we are amateures here in this field of seismology and there may be people who have never heard or thought of alizing before. Anyone with a university degree in the sciences should already be aware of alizing. What kind of college is mercer ?? Arts or Sciences ? I think I have seen the volksmeter and like it. If I were rich Id have a copy of everyones creations. to compare and contrast. But I am no University graduate myself. Just ex SONAR tech with avid intertest in all physical sciences. I also believe there should be no such thing as intellectual rights. It impedes the placement of truth/science over religion/arts. ----- Original Message ----- From: "Randall Peters" To: Sent: Saturday, February 21, 2009 10:45 AM Subject: aliasing No 'butt-in' offense to me by your email, GM. (I hope it is acceptable to address you in this manner.) We in physics also 'speak our peace' on subjects important to us. You are absolutely correct that periodic signals with a frequency higher than the Nyquist frequency (1/2 the sampling rate of an ADC) will show up as an alias. The key element to whether or not you get such a high frequency signal masquerading as one of lower frequency-depends on the coherence time of the offending signal. It must exist through a large enough number of cycles that what is admitted to the record saved is coherent enough to show up as a spectral line. In the case of the VolksMeter, there is no analog signal to begin with. Stated differently, there is no ADC; rather the device is a 'direct' capacitance to digital converter (CDC). Because of the award winning AD7745 chip of Analog Devices, that is the heart of the instrument, the VM is more than just a "State of the art digital seismometer", as described in the link on Larry's page. http://seismicnet.com/volksmeter/State-of-the-art_Digital_Seismograph.pdf It is also the worlds' first fully digital seismograph'. It is true that some detractors from this claim would say that there is no such thing as a fully-digital anything that interacts with our world which is itself analog. But my point is the following. Unlike other commericial instruments that use analog electronics to monitor a capacitive sensor (and then finally digitize the analog signal), the VolksMeter has no analog components whatsoever, except for internal 'workings' of the chip-for which one would have great debate as to whether the 'pieces' are digital or analog. There is one other significant 'fully'-part to the instrument. The capacitive sensor used by the VolksMeter is "fully differential". There are a host of advantages associated with an architecture that is fully digital in the electronics with a fully symmetric (differential) sensor; I don't have time now to go into detail. Incidently, some of you amateurs might want to 'tackle' the home-brew construction of such an instrument yourself; maybe even extend what I've done to the world of vertical seismographs. As Chris Chapman has indicated, they're much tougher because of material problems (not my expertise). If you want to build something that could make even the seismology pro's salivate over, then talk with Larry about the electronics package. He will probably sell you the all the necessary things 'for a song', compared to what the big companies want for anything. Randall __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Setting magnetic damping level From: "Robert O. Green" rog@.......... Date: Sat, 21 Feb 2009 17:12:25 -0800 I am a novice and working on a small vertical seismometer. I have Larry's amplifier and A/D. My current approach to assessing the damping is to move the coil some distance from the magnet and watch the wave form following a 1 mm drop of the arm. Are there other approaches? How should the properly damped waveform look? I have moved the VS under the house into the crawl space for now. This is far better than my shaking house. Robert __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Setting magnetic damping level From: "GMV" gmvoeth@........... Date: Sun, 22 Feb 2009 06:53:33 -0700 Larry is certainly the one to talk to. he builds these things. All I know is what a Geophysicist named Willis Jacobs from the usgs ( retired ) told me and that is you want significant damping like if you drop the mass the signal on the opposite side of zero will be only 1/10 the amplitude of the the initial signal on the positive side. I have heard you can pulse the geophone with a tiny voltage and watch its response. When you apply the voltage ( microvolts?) it will raise the mass ever so slightly it is when you remove the voltage that gives you the impulse to watch. regards; geoff In my personal opinion you want the damping at 1.414 and the Q at 1/1.414 if the electronics support that or you want very heavy damping that straightens the slope to like 2 HZ then use a straight forward amplifier to both equalize and make up the losses. If your Q is greater than 0.7071 area it seems the mass will not stop oscillating fast enough to satisfy the geophysics peoples who are really the ones who know how to read the graphs. Matching the geophone to the electronics is kind of the secret to decent pictures and its not as easy or cheap as it seems it should be. geoff ----- Original Message ----- From: "Robert O. Green" To: Sent: Saturday, February 21, 2009 6:12 PM Subject: Setting magnetic damping level >I am a novice and working on a small vertical seismometer. I have > Larry's amplifier and A/D. My current approach to assessing the damping > is to move the coil some distance from the magnet and watch the wave > form following a 1 mm drop of the arm. > > Are there other approaches? > > How should the properly damped waveform look? > > I have moved the VS under the house into the crawl space for now. This > is far better than my shaking house. > > Robert > > __________________________________________________________ > > 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: 'soft force feedback' From: Randall Peters PETERS_RD@.......... Date: Sun, 22 Feb 2009 09:15:05 -0500 Charles, What you have indicated is indeed what I have used with a fully differen= tial capacitive sensor monitoring the displacement of my modified Sprengnet= her (zero-length, Lacoste) vertical seismometer. The output from the senso= r goes to an opamp integrator, whose output is a very weak correction signa= l (fed in turn to the original coil/magnet sensor, now acting as an actuat= or) to keep the system from 'going to the rails' of my capacitive sensor. As I have noted previously, to operate with a PID feedback and then us= e the (so called 'velocity' (really 'jerk' below the corner frequency) outp= ut only-destroys low frequency response. This 'pulls out the frequency mul= tiplier term' by the chain rule of differentiation, causing the response to= go to zero as the frequency goes to zero. I teach my students to recogniz= e the important differences between differentiation and integration when it= comes to electronic signals containing noise. The former is a 'noise enh= ancer' and the latter a 'noise reducer', as is well known to anybody who ha= s looked at their differences using an oscilloscope. About the differences between 'force balance' and 'soft feedback'. Forc= e balance is 'hard' in the sense that ideally there is no motion of the sei= smic mass whatsoever. The feedback signal is so strong that it allows one = to monitor the 'error' value required to eliminate motion-as representative= of what the mass would do if allowed to move in an ideal Hooke's law oscil= lator. Unfortunately, there are no Hooke's law oscillators. It has taken me a = long time for the scientific community to begin finally accepting my claims= concerning mesoanelastic complexity. There are two types of anharmonicity= , (i) elastic and (ii) damping. Many of you know about (i) since a big, cl= ose earthquake will cause anomalous response from any seismometer, because = it is afflicted (large motions) with a restoring feature that is not perfec= tly harmonic. When seismic disturbances are 'low and slow', meaning low f= requency as well as small amplitude, the 'corrugation-like' features of the= restoration potential come into play. Engineers know about 'dithering' as= a means to combat friction effects. In effect, that is what I recommend. = It is advantageous to let the system 'skate' over the metastabilties of in= ternal friction type, some of which can cause the system to be effectively = 'latched' against being able to see the low/slow signals. For my Sprengnether, the time constant of the ompamp integrator was set= at several hundred seconds, so as you say, to integrate in a lower range t= han the one of interest. My approach to this is not the first. Erhard Wie= landt mentioned at the IRIS Broadband Conference that a German seismology t= eam did effectively the same thing about a hundred years ago. They used wa= ter (probably hundreds of gallons) in a feedback scheme to alter the tilt o= f their seismic platform to keep the instrument from going to the rail beca= use of the adversities of (i) buoyancy of air pressure changes associated w= ith moving fronts, and (ii) temperature changes altering the modulus of the= spring. Randall

Charles,

   What you have indicated is indeed what I = have used with a fully differential capacitive sensor monitoring the displacemen= t of my modified Sprengnether (zero-length, Lacoste) vertical seismometer. = The output from the sensor goes to an opamp integrator, whose output is a very = weak correction signal  (fed in turn to the original coil/magnet sensor, no= w acting as an actuator) to keep the system from ‘going to the rails= 217; of my capacitive sensor.

     As I have noted previously, t= o operate with a PID feedback and then use the (so called ‘velocityR= 17; (really ‘jerk’ below the corner frequency) output only—de= stroys low frequency response.  This ‘pulls out the frequency multiplie= r term’ by the chain rule of differentiation, causing the response to g= o to zero as the frequency goes to zero.  I teach my students to recognize = the important differences between differentiation and integration when it comes= to electronic signals containing noise.   The former is a ‘noise enhancer= ’ and the latter a ‘noise reducer’, as is well known to anybody w= ho has looked at their differences using an oscilloscope.

   About the differences between ‘forc= e balance’ and ‘soft feedback’.  Force balance is R= 16;hard’ in the sense that ideally there is no motion of the seismic mass whatsoever.  The feedback signal is so strong that it allows one to monitor the ‘error’ value required to eliminate motion—as= representative of what the mass would do if allowed to move in an ideal Hooke’s law oscillator. 

   Unfortunately, there are no Hooke’s= law oscillators.  It has taken me a long time for the scientific community= to begin finally accepting my claims concerning mesoanelastic complexity.  Ther= e are two types of anharmonicity, (i) elastic and (ii) damping.  Many of= you know about (i) since a big, close earthquake will cause anomalous response = from any seismometer, because it is afflicted (large motions) with a restoring f= eature that is not perfectly harmonic.   When seismic disturbances are &= #8216;low and slow’, meaning low frequency as well as small amplitude, the R= 16;corrugation-like’ features of the restoration potential come into play.  Engineers know about ‘dithering’ as a means to combat friction effects.  = In effect, that is what I recommend.  It is advantageous to let the syste= m ‘skate’ over the metastabilties of internal friction type, some of which can cause = the system to be effectively ‘latched’ against being able to see th= e low/slow signals.

    For my Sprengnether, the time const= ant of the ompamp integrator was set at several hundred seconds, so as you say, to= integrate in a lower range than the one of interest.  My approach to this is not= the first.  Erhard Wielandt mentioned at the IRIS Broadband Conference tha= t a German seismology team did effectively the same thing about a hundred years= ago.  They used water (probably hundreds of gallons) in a feedback scheme to alte= r the tilt of their seismic platform to keep the instrument from going to the rail because of the adversities of (i) buoyancy of air pressure changes associated with moving fronts, and (ii) temperature changes altering the modulus of the spring. 

   Randall

 

  

Subject: Re: 'soft force feedback' From: "GMV" gmvoeth@........... Date: Sun, 22 Feb 2009 07:38:24 -0700 Hello Randall Peters; Have you ever used an industrial control PID loop kind of thing with a Hall Effect sensor ? I would imagine it may work quite well to keep a mass locked in one position then look at the energy expended to keep the mass locked when anything tries to move it. You talk capacitive sensor but that is an active device purring out all kinds of RFI in an already saturated RFI world. I am interested in all forms of passive or baseband devices that do not need artificially applied AC to make them work. PID meaning proportional-integral-derivative. Amplifier/integrator combination. Possibly more complex. I have seen PID loops in auto cruise controls and in food service industry to control flow rates and temps. I imagine PID loops along with 20ma circuits can do about any kind of control. regards; geoff ----- Original Message ----- From: "Randall Peters" To: Sent: Sunday, February 22, 2009 7:15 AM Subject: 'soft force feedback' Charles, What you have indicated is indeed what I have used with a fully differential capacitive sensor monitoring the displacement of my modified Sprengnether (zero-length, Lacoste) vertical seismometer. The output from the sensor goes to an opamp integrator, whose output is a very weak correction signal (fed in turn to the original coil/magnet sensor, now acting as an actuator) to keep the system from 'going to the rails' of my capacitive sensor. As I have noted previously, to operate with a PID feedback and then use the (so called 'velocity' (really 'jerk' below the corner frequency) output only-destroys low frequency response. This 'pulls out the frequency multiplier term' by the chain rule of differentiation, causing the response to go to zero as the frequency goes to zero. I teach my students to recognize the important differences between differentiation and integration when it comes to electronic signals containing noise. The former is a 'noise enhancer' and the latter a 'noise reducer', as is well known to anybody who has looked at their differences using an oscilloscope. About the differences between 'force balance' and 'soft feedback'. Force balance is 'hard' in the sense that ideally there is no motion of the seismic mass whatsoever. The feedback signal is so strong that it allows one to monitor the 'error' value required to eliminate motion-as representative of what the mass would do if allowed to move in an ideal Hooke's law oscillator. Unfortunately, there are no Hooke's law oscillators. It has taken me a long time for the scientific community to begin finally accepting my claims concerning mesoanelastic complexity. There are two types of anharmonicity, (i) elastic and (ii) damping. Many of you know about (i) since a big, close earthquake will cause anomalous response from any seismometer, because it is afflicted (large motions) with a restoring feature that is not perfectly harmonic. When seismic disturbances are 'low and slow', meaning low frequency as well as small amplitude, the 'corrugation-like' features of the restoration potential come into play. Engineers know about 'dithering' as a means to combat friction effects. In effect, that is what I recommend. It is advantageous to let the system 'skate' over the metastabilties of internal friction type, some of which can cause the system to be effectively 'latched' against being able to see the low/slow signals. For my Sprengnether, the time constant of the ompamp integrator was set at several hundred seconds, so as you say, to integrate in a lower range than the one of interest. My approach to this is not the first. Erhard Wielandt mentioned at the IRIS Broadband Conference that a German seismology team did effectively the same thing about a hundred years ago. They used water (probably hundreds of gallons) in a feedback scheme to alter the tilt of their seismic platform to keep the instrument from going to the rail because of the adversities of (i) buoyancy of air pressure changes associated with moving fronts, and (ii) temperature changes altering the modulus of the spring. Randall __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: arrogant university types, part 1 From: Randall Peters PETERS_RD@.......... Date: Sun, 22 Feb 2009 09:53:20 -0500 Geoff, I'm sorry that my comments concerning your list-serve statements were a= pparently misinterpreted. I wasn't disagreeing with you-- only attempting = to provide additional information about aliasing, based in my personal expe= rience. Perhaps what you and I have learned collectively, if we can expre= ss our thoughts without offense to one another, will be of considerable ben= efit to the amateur community. I greatly appreciate amateur seismology, si= nce I have received many blessings from my association with this community.= It helped me, for example, to meet and learn from another PhD profession= al (John Lahr) who is much better skilled at interacting with you guys than= myself. Willie Lee, a USGS (PhD) scientist at Menlo Park, is putting toge= ther IRIS-based materials to honor John and asked me to oversee a section c= oncerned with a part of John's contributions to seismology. Willie and I = didn't want to diminish the scope of those contributions by labeling them a= s being directed toward 'amateurs'-because of the word's conotations in th= e minds of some. I believe (and suggested to Willie) that what John has pr= ovided fits better in the category of "Science in the public interest". Your inference, Geoff, concerning too-many university types, I view a= s 'right on target'. I hope that with this (too-long-for-comfort-on-my-pa= rt) response will help you not to view me in the same context. Mercer phys= ics is part of a College of Liberal Arts; I would rather that it be part of= a college like other places, known as Arts and Sciences. Then the 'frict= ional' nature of various colleagues on my career would have been less influ= ential in causing me to lack diplomacy. This failure is bound to have be= en made worse through my efforts to try and interact meaningfully with prof= essional seismologists on things like 'soft-force feedback' (a question dir= ected to me in the last 24-h, that I will respond to shortly), and 'power = spectral densities'. Because of my insistence concerning the importance of= these issues, and because of the indifference I sensed (whether rightly or= wrongly) concerning the pro's response (really lack thereof)-I began, no d= oubt, to become caustic. The famous astronomer, Fritz Zwicki was known for= his term, "spherical bastard"-individuals who 'look the same from any view= '. I wouldn't be surprised if I have been labeled with this term, for reas= on of my directness. I hope that you don't believe the term fits me. Physicists will, in my experience, engage in whole-hearted dialogue with su= ch fervor that the un-initiated may think a 'knock down drag out fight is a= bout to erupt'. But when the dust settles, everybody remains civil. Our s= tyle of 'doing business' appears not to set well with the geo-science commu= nity. Now another few comments about aliasing and artifacts. You are correc= t, that aliasing is a consequence of periodic sampling, no matter how it is= done. It can be present in any system for which a high-frequency pickup s= ignal 'bleeds through' to the 'sampler'. But the advantage of fully-digita= l operation with the AD7745/6 chip is that it is a very small chip, and the= refore much less vulnerable to the electromagnetic radiation associated wit= h lines that are the most common cause for stray signal pickup responsible = for the alias. Many if not most of you will have experienced first-hand th= e advantage of the standard procedure of working with twisted pair wires to= minimize 60-Hz pickup and/or ground loops. If there are no long wires to= begin with (as with the chip mentioned) do you see thus its benefits? (to be followed with part 2)

Geoff,

    I’m sorry that my comments concerning your list-serve statements were apparently misinterpreted. = I wasn’t disagreeing with you-- only attempting to provide additional information about aliasing, based in my personal experience.   Perhaps what you and I have learned collectively, if we can express o= ur thoughts without offense to one another, will be of considerable benefit to= the amateur community.  I greatly appreciate amateur seismology, since I h= ave received many blessings from my association with this community.  &nbs= p;It helped me, for example, to meet and learn from another PhD professional (Jo= hn Lahr) who is much better skilled at interacting with you guys than myself.  Willie Lee, a USGS (PhD) scientist at Menlo Park, is putting together IRIS-based materials to honor John and asked me to oversee a secti= on concerned with a part of John’s contributions to seismology.  Wi= llie and I  didn’t want to diminish the scope of those contributions = by labeling them as being directed toward  ‘amateurs’—because of the word’s conotations = in the minds of some.  I believe (and suggested to Willie) that what John= has provided fits better in the category of “Science in the public interest”. 

     Your inference, Geoff,  concerning too-many university types, I view as ‘right on target’.   I hope that with this (too-long-for-comfort-on-my-part) response will help you not to view me in = the same context.  Mercer physics is part of a College of Liberal Arts; I would rather that it be part of a college like other places, known as Arts = and Sciences.   Then the ‘frictional’ nature of various colleagues on my career would have been less influential in causing me to l= ack diplomacy.    This failure is bound to have been made worse through my efforts to try and interact meaningfully with professional seismologists on things like ‘soft-force feedback’ (a question = directed to me in the last 24-h, that I will respond to shortly),  and ‘p= ower spectral densities’.  Because of my insistence concerning the importance of these issues, and because of the indifference I sensed (wheth= er rightly or wrongly) concerning the pro’s response (really lack thereo= f)—I began, no doubt, to become caustic.  The famous astronomer, Fritz Zwic= ki was known for his term, “spherical bastard”—individuals w= ho ‘look the same from any view’.  I wouldn’t be surpri= sed if I have been labeled with this term, for reason of my directness.  I hope that you don’t believe the term fits me.

Physicists will, in my experience, engage in whole-hea= rted dialogue with such fervor that the un-initiated may think a ‘knock do= wn drag out fight is about to erupt’.  But when the dust settles, everybody remains civil.  Our style of ‘doing business’ appears not to set well with the geo-science community.

     Now another few comments abou= t aliasing and artifacts.  You are correct, that aliasing is a consequen= ce of periodic sampling, no matter how it is done.  It can be present in = any system for which a high-frequency pickup signal ‘bleeds through’= ; to the ‘sampler’.  But the advantage of fully-digital operati= on with the AD7745/6 chip is that it is a very small chip, and therefore much = less vulnerable to the electromagnetic radiation associated with lines that are = the most common cause for stray signal pickup responsible for the alias.  = Many if not most of you will have experienced first-hand the advantage of the standard procedure of working with twisted pair wires to minimize 60-Hz pic= kup and/or ground loops.   If there are no long wires to begin with (= as with the chip mentioned) do you see thus its benefits?

   (to be followed with part 2)

Subject: arrogant university types, part 2 From: Randall Peters PETERS_RD@.......... Date: Sun, 22 Feb 2009 09:55:47 -0500 (for reason of size, broken into two parts) About spurious signals other than aliases-I believe, Geoff, you have= also alluded to signals that can occur because of a 'heterodyne' effect. = Please permit me to speak to this issue in some detail without (hopefully) = appearing to be an arrogant ass. I believe the salient features of this ty= pe of artifact are something I understand pretty well. When the electronic= s has nonlinear characteristics (fundamental requirement for a mixer), then= two signals interacting via this nonlinearity will generate sum and differ= ence frequencies. On a related issue, a single pure (monochromatic) signal= will, when passing through the system that is nonlinear, produce harmonics= .. (My PhD research was concerned with ultrasonic harmonic generation-simil= ar to frequency doubling used to convert an invisible infrared laser (YAG) = beam into a visible beam after passing through a KDP crystal). The amount= of harmonic(s) that are generated depends on the power. For a single sign= al, the amount of harmonic content produced depends on the square of the po= wer in that signal. For two signals that mix, the sum/difference signals a= re proportional to the product of their individual powers. The 'verbosity' of the previous paragraph is to try and convince you t= hat artifacts of the type that would be part of nonlinearity are not nearly= so important for the list-serve readers as is the artifact of aliasing typ= e. And yes, you are absolutely correct-the standard procedure for eliminat= ing an alias is to hardware filter out the offending signal before it can c= ause problems. Again, however, I want to try and make the point (which I b= elieve to be correct)-that the smaller the electronics package, the less li= kely is the probability of offending pickup signals to cause an alias. I want to also elaborate on the matter of what is required of the off= ending signal. It must, as I mentioned before, be a persistent signal, suc= h as 60-Hz pickup. The coherence time (number of cycles through which the = offending signal exists) is a very important issue, depending on its freque= ncy compared to the frequency one studies. These two must be related to on= e another as a ratio of commensurate integers for the alias to exist. Another of my comments that needs clarification. You mention, Geoff, t= he possible ridiculous consequence of software 'integration' (a discrete nu= merical approximation using software, operating by an iterative process). = You are correct that what comes out of the 'integral' may be useless. The= 'integrated' signal from the VolksMeter is used by me only as a 'cue'. I= am interested in studying the 'pure' (raw) signals before, during, and aft= er an earthquake, particularly teleseismic ones. The helicord display of t= he integrated signal is a convenient way to improve the SNR for teleseismic= viewing. When I see something interesting in the integrated signal, I wil= l then download only the non-integrated record. I have never saved the int= egrated signals because so much information has been lost from them. More about the VolksMeter-my encouragement for some of you list-serve r= eaders try and build something (especially a vertical instrument) using its= operational principles-this was with the sure knowledge that many of you a= re much better skilled than myself (and probably every other 'professional'= that I've met) when it comes to building both mechanical devices and also = electronics. Larry Cochrane put together the first working prototype a cou= ple of years ago. Hearing what was needed (both mechanical and electronic)= on a Saturday, he proceeded to have one both built and operational on the = web the following Monday! I wrote and asked, "do you routinely 'walk on wa= ter'; if so I want to come out and watch sometime". You could build such an instrument 'on a shoestring'. The mechanical p= arts would be 'a breeze' for many of you and I'll bet that you will be surp= rised at how low the cost is for the electronics. I want to see what migh= t develop, because my efforts have 'only scratched the surface' of possibil= ities. Randall

(for reason of size, broken into two parts)=

 

      About spurious signals = other than aliases—I believe, Geoff,  you have also alluded to signals= that can occur because of a ‘heterodyne’ effect.  Please permit me = to speak to this issue in some detail without (hopefully) appearing to be an arrogant ass.  I believe the salient features of this type of artifact= are something I understand pretty well.  When the electronics has nonlinea= r characteristics (fundamental requirement for a mixer), then two signals interacting via this nonlinearity will generate sum and difference frequencies.  On a related issue, a single pure (monochromatic) signal will, when passing through the system that is nonlinear, produce harmonics.  (My PhD research was concerned with ultrasonic harmonic generation—similar to frequency doubling used to convert an invisible infrared laser (YAG) beam into a visible beam after passing through a KDP crystal).   The amount of harmonic(s) that are generated depends = on the power.  For a single signal, the amount of harmonic content produc= ed depends on the square of the power in that signal.  For two signals th= at mix, the sum/difference signals are proportional to the product of their individual powers. 

     The ‘verbosity’ o= f the previous paragraph is to try and convince you that artifacts of the type th= at would be part of nonlinearity are not nearly so important for the list-serv= e readers as is the artifact of aliasing type.  And yes, you are absolut= ely correct—the standard procedure for eliminating an alias is to hardwar= e filter out the offending signal before it can cause problems.  Again, however, I want to try and make the point (which I believe to be correct)—that the smaller the electronics package, the less likely is= the probability of offending pickup signals to cause an alias.

      I want to also elaborat= e on the matter of what is required of the offending signal.  It must, as I= mentioned before, be a persistent signal, such as 60-Hz pickup.  The coherence t= ime (number of cycles through which the offending signal exists) is a very important issue, depending on its frequency compared to the frequency one studies.  These two must be related to one another as a ratio of commensurate integers for the alias to exist.

    Another of my comments that needs clarification.  You mention, Geoff, the possible ridiculous consequenc= e of software ‘integration’ (a discrete numerical approximation usin= g software, operating by an iterative process).  You are correct that wh= at comes out of the ‘integral’ may be useless.   The ‘integrated’ signal from the VolksMeter is used by me only as  a ‘cue’.  I am interested in studying the ‘pure’ (raw) signals before, during, and after an earthquake, particularly teleseismic ones.  The helicord display of the integrated signal is a convenient way to improve the SNR for teleseismic viewing. = ; When I see something interesting in the integrated signal, I will then down= load only the non-integrated record.  I have never saved the integrated sig= nals because so much information has been lost from them.

    More about the VolksMeter—my encouragement for some of you list-serve readers try and build something (especially a vertical instrument) using its operational principles—t= his was with the sure knowledge that many of you are much better skilled than myself (and probably every other ‘professional’ that I’ve met) when it comes to building both mechanical devices and also electronics= ..  Larry Cochrane put together the first working prototype a couple of years ago.  Hearing what was needed (both mechanical and electronic) on a Saturday, he proceeded to have one both built and operational on the web th= e following Monday!  I wrote and asked, “do you routinely ‘w= alk on water’; if so I want to come out and watch sometime”. <= /o:p>

    You could build such an instrument ‘on a shoestring’.  The mechanical parts would be ‘a breeze’ for many of you and I’ll bet that you will be surprised= at how low the cost is for the electronics.   I want to see what mig= ht develop, because my efforts have ‘only scratched the surface’ o= f possibilities. 

    Randall

 

Subject: PID controllers From: Randall Peters PETERS_RD@.......... Date: Sun, 22 Feb 2009 10:56:00 -0500 In ways similar to your own experiences, Geoff, I am familiar with PID cont= rollers. I even published a paper in one of the first journal issues conce= rned with micro-electro-mechanical systems (MEMS) about a feedback system i= nvolving integration and differentiation that was not 'proportional'. I = greatly admire the many places where PID controllers outperform anything el= se. But at the same time I am confident of one thing, learned like yoursel= f through experiences in the 'school of hard knocks', by methods never taug= ht in an institution like Mercer University-there is no single method or si= ngle system that will ever be perfect for every application. The reason IR= IS held a "Broadband Conference" several years ago, concerned with improvem= ent to seismic instrumentation-is because the best and most expensive of PI= D-like instruments-still can't do it all. I predict that this will always= remain the case; that there will never be a single-package-do-everything s= eismograph, no matter the cost. You suggest that capacitive sensors are 'flawed', as compared to some ot= her possibilities, for reason of their need for AC excitation. I don't thi= nk the frequencies normally used with them is going to contaminate the worl= d very much, compared to the host of truly-radiative devices like cell-phon= es. Only time will tell if something else could come along and do a better= job. Practicing seismologists have settled on the capacitive sensor, beli= eving it to be the best type presently available, based on compromise betwe= en cost and performance, relative to their need. Much in the way of experi= mental comparisons of a variety of different sensors were considered, befor= e they settled on their standard. So I don't believe Erhard Wielandt, who= is one of the world's most knowledgeable professional seismologists, would= agree with the position you seems to have taken. Randall

In ways similar to your own experiences, Geoff, I am familiar with PID controllers.  I even published a paper in one of the first journal issues concerned with micro-electro-mechanical systems (MEMS) about a feedback system involving integration and differentiation that was = not ‘proportional’.   I  greatly admire the many pla= ces where PID controllers outperform anything else.  But at the same time = I am confident of one thing, learned like yourself through experiences in the ‘school of hard knocks’, by methods never taught in an institut= ion like Mercer University—there is no single method or single system tha= t will ever be perfect for every application.  The reason IRIS held a “Broadband Conference” several years ago, concerned with improvement to seismic instrumentation—is because the best and most expensive of PID-like instruments—still can’t do it all. &= nbsp; I predict that this will always remain the case; that there will never be a single-package-do-everything seismograph, no matter the cost.

   You suggest that capacitive sensors are ‘flawed’, as compared to some other possibilities, for reason o= f their need for AC excitation.  I don’t think the frequencies normally used with them is going to contaminate the world very much, compar= ed to the host of truly-radiative devices like cell-phones.  Only time wi= ll tell if something else could come along and do a better job.  Practici= ng seismologists have settled on the capacitive sensor, believing it to be the best type presently available, based on compromise between cost and performance, relative to their need.  Much in the way of experimental comparisons of a variety of different sensors were considered, before they settled on their standard.   So I don’t believe Erhard Wielandt, who is one of the world’s most knowledgeable professional seismologists, would agree with the position you seems to have taken. =

    Randall

Subject: Optimal damping From: "Robert O. Green" rog@.......... Date: Sun, 22 Feb 2009 08:31:54 -0800 Is the graphic at this PSN website a good representation of an optimally damped seismometer? http://psn.quake.net/onlinedocs/sgdamp.html Robert __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Optimal damping From: "GMV" gmvoeth@........... Date: Sun, 22 Feb 2009 10:13:55 -0700 Hello Robert O. Green; yes siree bob; <== just a friendly expression that's the kind of thing I understand they want. But what I do not understand is how to tell what the damping is by measuring the results. If the damping is 1:10 or 1:100 or 1:1000 what is the associated Q or 1/Q which is called Damping ? I can turn Q into a circuit but I do not understand ( since I have little formal education ) what the heck 1:100 means, in other words what would a Q of 1/sqr(2) translate to in actual picture of (1:whatever). I use an 8 bit system so I need a lot of amplification and my resolution is only 127:1 at best. I suffer from my average IQ but I ask no forgiveness since I had no say in what this IQ thing really is. Thanks for all your responses even if I do not agree with whatever. Best regards; <== I learned this from Britishers but I'm USA. I prefer to say sincerely but people do not seem to like that. geoff ----- Original Message ----- From: "Robert O. Green" To: Sent: Sunday, February 22, 2009 9:31 AM Subject: Optimal damping > Is the graphic at this PSN website a good representation of an optimally > damped seismometer? > > http://psn.quake.net/onlinedocs/sgdamp.html > > Robert > > __________________________________________________________ > > 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: Optimal damping From: ChrisAtUpw@....... Date: Sun, 22 Feb 2009 12:14:29 EST In a message dated 22/02/2009, rog@.......... writes: Is the graphic at this PSN website a good representation of an optimally damped seismometer? _http://psn.quake.net/onlinedocs/sgdamp.html_ (http://psn.quake.net/onlinedocs/sgdamp.html) Hi Robert, 0.7 Critical Damping gives a 20:1 reduction the two deflections. Regards, Chris Chapman
In a message dated 22/02/2009, rog@.......... writes:
<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size= =3D2>Is the=20 graphic at this PSN website a good representation of an optimally
damp= ed=20 seismometer?
http://psn.quake.net/= onlinedocs/sgdamp.html
Hi Robert,
 
    0.7 Critical Damping gives a 20:1 reduction=20 the two deflections. 
 
    Regards,
 
    Chris Chapman
Subject: Re: arrogant university types, part 2 From: "GMV" gmvoeth@........... Date: Sun, 22 Feb 2009 10:32:23 -0700 Thankyou Mr. Peters; Wonderful response. I do not normally deal with people on a personal level I have lived in relative isolation for a very long time now by personal choice and I know my communication abilities are suffering due to this. Technical people at the upper levels are very hard to even see since they seem to be shrouded in national security screens they themselves are not aware of. You can be damned simply by studying them (national security) so beware. I have heard of Mercer before but not as a technical college like MIT or CALTECH or BERKLEY. I understand our entire university system is based on a GERMAN model, yet, each college or university has a personality all its own. Mercer is one of many I simply do not know. Your verbosity is welcome by me since the English Language is so terrible at describing things and requires much verbosity to put a triangle exactly from one head into another. Each and every academic discipline has its own vocabulary which in my mind tends to isolate these various areas from one another and make them all appear as being snobbish. I KNOW that in this country somewhere is a vertical seismometer built by military or corporation or nasa that would be a perfect standard for amateurs to have but no one is sharing this knowledge of it. I will continue to pick peoples brains simply because they have filtered out most of the garbage floating around and can get directly to what I need to know. Wading through mountainous garbage of information is stealing my life since I have not the life to learn everything. Thanks for your response. Best Regards; geoff ----- Original Message ----- From: "Randall Peters" To: Sent: Sunday, February 22, 2009 7:55 AM Subject: arrogant university types, part 2 (for reason of size, broken into two parts) About spurious signals other than aliases-I believe, Geoff, you have also alluded to signals that can occur because of a 'heterodyne' effect. Please permit me to speak to this issue in some detail without (hopefully) appearing to be an arrogant ass. I believe the salient features of this type of artifact are something I understand pretty well. When the electronics has nonlinear characteristics (fundamental requirement for a mixer), then two signals interacting via this nonlinearity will generate sum and difference frequencies. On a related issue, a single pure (monochromatic) signal will, when passing through the system that is nonlinear, produce harmonics. (My PhD research was concerned with ultrasonic harmonic generation-similar to frequency doubling used to convert an invisible infrared laser (YAG) beam into a visible beam after passing through a KDP crystal). The amount of harmonic(s) that are generated depends on the power. For a single signal, the amount of harmonic content produced depends on the square of the power in that signal. For two signals that mix, the sum/difference signals are proportional to the product of their individual powers. The 'verbosity' of the previous paragraph is to try and convince you that artifacts of the type that would be part of nonlinearity are not nearly so important for the list-serve readers as is the artifact of aliasing type. And yes, you are absolutely correct-the standard procedure for eliminating an alias is to hardware filter out the offending signal before it can cause problems. Again, however, I want to try and make the point (which I believe to be correct)-that the smaller the electronics package, the less likely is the probability of offending pickup signals to cause an alias. I want to also elaborate on the matter of what is required of the offending signal. It must, as I mentioned before, be a persistent signal, such as 60-Hz pickup. The coherence time (number of cycles through which the offending signal exists) is a very important issue, depending on its frequency compared to the frequency one studies. These two must be related to one another as a ratio of commensurate integers for the alias to exist. Another of my comments that needs clarification. You mention, Geoff, the possible ridiculous consequence of software 'integration' (a discrete numerical approximation using software, operating by an iterative process). You are correct that what comes out of the 'integral' may be useless. The 'integrated' signal from the VolksMeter is used by me only as a 'cue'. I am interested in studying the 'pure' (raw) signals before, during, and after an earthquake, particularly teleseismic ones. The helicord display of the integrated signal is a convenient way to improve the SNR for teleseismic viewing. When I see something interesting in the integrated signal, I will then download only the non-integrated record. I have never saved the integrated signals because so much information has been lost from them. More about the VolksMeter-my encouragement for some of you list-serve readers try and build something (especially a vertical instrument) using its operational principles-this was with the sure knowledge that many of you are much better skilled than myself (and probably every other 'professional' that I've met) when it comes to building both mechanical devices and also electronics. Larry Cochrane put together the first working prototype a couple of years ago. Hearing what was needed (both mechanical and electronic) on a Saturday, he proceeded to have one both built and operational on the web the following Monday! I wrote and asked, "do you routinely 'walk on water'; if so I want to come out and watch sometime". You could build such an instrument 'on a shoestring'. The mechanical parts would be 'a breeze' for many of you and I'll bet that you will be surprised at how low the cost is for the electronics. I want to see what might develop, because my efforts have 'only scratched the surface' of possibilities. Randall __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: 'soft force feedback' From: "James L. Gundersen" jgundie@....... Date: Sun, 22 Feb 2009 11:24:39 -0800 Hi Geoff, I'll put my two cents worth in. I'm prejudice to using capacitive pickup as you may know. Back in "75" when Barry and I built my first seismograph I choose to use a capacitive pickup because the coil and magnet combination signal amplitude drops off as the frequency goes down for a given amount of earth movement. Today I believe I can build a seismograph where the noise level of the electronics will be below the earth's seismic noise levels at all frequencies down to and including DC. I say "I believe" because I have not "had time" to build one yet but my analysis indicates so. One thing that just occurred to me that's probably not been said about a capacitive sensor is it that it can be considered a "parametric amplifier" of the earth movement one is sensing. This a very important advantage over the coil and magnet approach. The coil basically creates a weak output signal from "weak movement" that gets 10,000 times (power wise) weaker when the frequency drops a 100 times. (Power is the key factor for minimum electrical signal detection in a given bandwidth not voltage per se.) The output level of the parametric (capacitive) sensor can be increased by simply increasing the drive level into the sensor (current into the capacitors) to improve the signal-to-noise ratio if needed. In the case of capacitive sensors the effective current is the product of the p-p drive voltage level, the frequency of the drive level and the amount of capacitance of the sensor. (There is more naturally like the capacitor plate seperation that's very important.) So with a capacitive sensor if my memory serves me right you can detect changes in position of much less than a wavelength of light and I believe down to atomic dimensions. I won't take time to find the numbers but I believe these dimensions (sensitivities) can be made much less the seismic noise level at all frequencies. The key advantage is the "pumping" power level of the parametric can be increased to the power level of the detected signal to a far greater the power level than the magnetic sensor's corresponding signal level. The reference noise level for the electronic is basically the thermal noise power level corresponding to the signals bandwidth hence the importance of power per se. What prompted to write was your concern for RFI which I share. With the capacitive sensor and associated electronic can certainly be susceptible to RFI or be a source of RFI. My experience has been this can be controlled or eliminated by design and construction. There is a lot to EMC (electro-magnetic compatibility, the other acronym) design in general but the key to not contaminating the rest of the world is to enclose the capacitive sensor and its electronics in shielding. That is put the electronics in a metal box (it can be small now days with the size of ICs) and us shielded wiring (coax shielded cable) to and from the sensor. Then you can add some shielding to the sensor its self ( I've not done that but its a good idea). This takes care of the emissions and the nice thing about EMC is that it by reciprocity it also eliminates the susceptibility concerns (or a least minimizes them). An interesting note along this line is to assume for instance the oscillator is "too" near the sensor electronics and not shielded well enough (isolated) from the sensor electronics. The coupling tends to create a DC error only which should be very stable and small. This DC gets subtracted with all the other DC offsets when the signals are detected. The thing I would like to do when I get done with the project I'm on for past year is build a seismograph using my favorite ADC. It has a linearity of 0.0005% and a noise level at a 1 KHz sample rate of 1 uv (more than 120 db below its full scale signal). The big advantage of course of using digital electronics is I can integrate the signal for a minute or an hour or 24 hours without the drift problems of an analog design. (Yes I can build an analog integrator than works beyond an hour but its difficult, expensive and easily compromised.) Such integration can greatly reduce the electronic noise to get long period detection sensitivity. I should mention also building the capacitor sensor electronic can be somewhat of a pain but it much easier today than in the past. I also must say the capacitive sensor tends to be good for small movements but has limits for the large displacements one can get with the long period seismographs. Hence in the past I've ended up detecting the acceleration at low frequencies and integrating to recover velocity and displacement information. This puts a real significant limitation on the minimum on my minimum detectable earth movement argument but I think the numbers still work out. Another comment on this type design without feedback is it will saturate on large signals (local earth quakes) and therefore rather than try to perfect the feedback approach I think I may simply build a second seismograph for strong signals probably based on acceleration and not displacement to avoid saturation. In a strong earth the acceleration can exceed 1 g. I'm expecting the big one some day here in Southern California; we're over due I suscept in someways? Another thought on why one design can't do it all. The dynamic range of electrical signal is limited by thermal noise level on the hand and maximum voltage or power level on the other. Once electrical signal ranges approach levels like 120 db (a million-to-one) or 140 db the electronics can become a limit. I believe if one studies the dynamic range of seimic signals they can exceed 140 db particularily if start including strong local activity versus the weakest long period signals and want narrow band (low frequency) minimum noise but also what the broad band (high frequency) local strong earth quakes. I'll have to revisit this area sometimes because the digital processing can circumvent some of the some dynamic range problem along with active force feed back. Jim PS I have no idea what your background is. So excuse me if some things are too simple or esoteric. Mine is electrical engineering. ----- Original Message ----- From: "GMV" To: Sent: Sunday, February 22, 2009 6:38 AM Subject: Re: 'soft force feedback' > Hello Randall Peters; > > Have you ever used an industrial control PID loop > kind of thing with a Hall Effect sensor ? > > I would imagine it may work quite well to keep a mass > locked in one position then look at the energy expended > to keep the mass locked when anything tries to move it. > > You talk capacitive sensor but that is an active device > purring out all kinds of RFI in an already saturated RFI world. > > I am interested in all forms of passive or baseband > devices that do not need artificially applied AC to make them work. > > PID meaning proportional-integral-derivative. > Amplifier/integrator combination. > Possibly more complex. > > I have seen PID loops in auto cruise controls and > in food service industry to control flow rates > and temps. I imagine PID loops along with 20ma > circuits can do about any kind of control. > > regards; > geoff > > > > ----- Original Message ----- > From: "Randall Peters" > To: > Sent: Sunday, February 22, 2009 7:15 AM > Subject: 'soft force feedback' > > > Charles, > What you have indicated is indeed what I have used with a fully > differential capacitive sensor monitoring the displacement of my modified > Sprengnether (zero-length, Lacoste) vertical seismometer. The output from > the sensor goes to an opamp integrator, whose output is a very weak > correction signal (fed in turn to the original coil/magnet sensor, now > acting as an actuator) to keep the system from 'going to the rails' of my > capacitive sensor. > As I have noted previously, to operate with a PID feedback and then > use the (so called 'velocity' (really 'jerk' below the corner frequency) > output only-destroys low frequency response. This 'pulls out the > frequency multiplier term' by the chain rule of differentiation, causing > the response to go to zero as the frequency goes to zero. I teach my > students to recognize the important differences between differentiation > and integration when it comes to electronic signals containing noise. > The former is a 'noise enhancer' and the latter a 'noise reducer', as is > well known to anybody who has looked at their differences using an > oscilloscope. > About the differences between 'force balance' and 'soft feedback'. > Force balance is 'hard' in the sense that ideally there is no motion of > the seismic mass whatsoever. The feedback signal is so strong that it > allows one to monitor the 'error' value required to eliminate motion-as > representative of what the mass would do if allowed to move in an ideal > Hooke's law oscillator. > Unfortunately, there are no Hooke's law oscillators. It has taken me a > long time for the scientific community to begin finally accepting my > claims concerning mesoanelastic complexity. There are two types of > anharmonicity, (i) elastic and (ii) damping. Many of you know about (i) > since a big, close earthquake will cause anomalous response from any > seismometer, because it is afflicted (large motions) with a restoring > feature that is not perfectly harmonic. When seismic disturbances are > 'low and slow', meaning low frequency as well as small amplitude, the > 'corrugation-like' features of the restoration potential come into play. > Engineers know about 'dithering' as a means to combat friction effects. > In effect, that is what I recommend. It is advantageous to let the system > 'skate' over the metastabilties of internal friction type, some of which > can cause the system to be effectively 'latched' against being able to see > the low/slow signals. > For my Sprengnether, the time constant of the ompamp integrator was set > at several hundred seconds, so as you say, to integrate in a lower range > than the one of interest. My approach to this is not the first. Erhard > Wielandt mentioned at the IRIS Broadband Conference that a German > seismology team did effectively the same thing about a hundred years ago. > They used water (probably hundreds of gallons) in a feedback scheme to > alter the tilt of their seismic platform to keep the instrument from going > to the rail because of the adversities of (i) buoyancy of air pressure > changes associated with moving fronts, and (ii) temperature changes > altering the modulus of the spring. > Randall > > > > __________________________________________________________ > > 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: Optimal damping From: "Dale Hardy" photon1@........... Date: Mon, 23 Feb 2009 08:22:58 +1100 There is a good explanation and calculator on John Lahr's site regards Dale http://www.jclahr.com/science/psn/damping/ ----- Original Message ----- From: "Robert O. Green" To: Sent: Monday, February 23, 2009 3:31 AM Subject: Optimal damping > Is the graphic at this PSN website a good representation of an optimally > damped seismometer? > > http://psn.quake.net/onlinedocs/sgdamp.html > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Optimal damping From: "Robert O. Green" rog@.......... Date: Sun, 22 Feb 2009 18:32:15 -0800 Dale, Thank you. Robert Dale Hardy wrote: > There is a good explanation and calculator on John Lahr's site > regards > Dale > http://www.jclahr.com/science/psn/damping/ > > > ----- Original Message ----- From: "Robert O. Green" > To: > Sent: Monday, February 23, 2009 3:31 AM > Subject: Optimal damping > > >> Is the graphic at this PSN website a good representation of an >> optimally damped seismometer? >> >> http://psn.quake.net/onlinedocs/sgdamp.html >> > > > __________________________________________________________ > > 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 - http://www.avg.com > Version: 8.0.176 / Virus Database: 270.11.2/1965 - Release Date: 2/21/2009 3:36 PM > > Dale,

Thank you.

Robert

Dale Hardy wrote:
There is a good explanation and calculator on John Lahr's site
regards
Dale
http://www.jclahr.com/science/psn/damping/


----- Original Message ----- From: "Robert O. Green" <rog@..........>
To: <PSN-L@..............>
Sent: Monday, February 23, 2009 3:31 AM
Subject: Optimal damping


Is the graphic at this PSN website a good representation of an optimally damped seismometer?

http://psn.quake.net/onlinedocs/sgdamp.html



__________________________________________________________

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
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No virus found in this incoming message. Checked by AVG - http://www.avg.com Version: 8.0.176 / Virus Database: 270.11.2/1965 - Release Date: 2/21/2009 3:36 PM

Subject: test From: "GMV" gmvoeth@........... Date: Mon, 23 Feb 2009 04:34:41 -0700 my last post was never posted. this is only a test. :-) geoff __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Entire File Set from Station GVA From: "GMV" gmvoeth@........... Date: Mon, 23 Feb 2009 04:45:37 -0700 Hello PSN folks; here is a link to all the files I use to record and analyze my data. The only thing missing is Winquake which you must get only from Larry. http://gmvoeth.home.mchsi.com/gva60312.ZIP The recording program is useless for most all of you. It requires a special A/D converter connected to comm 1 it runs only under DOS with EMS enabled in the config.sys file. Practically no one but me wants to use DOS anymore. But is both source and executable code as well as one of my data files (text header + raw data) it will convert my data to various image files as well as a PSN text file to see in Winquake. I found this site I am posting to will not let you securely sign anything and post too. Cheers; geoff at Station GVA __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Seismology & Nuclear Weapons Testing From: Bob Hancock icarus@......... Date: Mon, 2 Mar 2009 16:26:44 -0700 Interesting article from Scientific American on the use of seismology to detect underground nuclear explosions. http://www.sciam.com/article.cfm?id=advances-in-monitoring-nuclear&sc=CAT_SP_20090302 __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Seismology & Nuclear Weapons Testing From: "Geoffrey" gmvoeth@........... Date: Tue, 3 Mar 2009 06:46:19 -0700 Wow that is neat you can see the dilatation (ratifaction) of the shock wave in the form of a spreading cloud since the low pressure & temperature condenses the moisture into a cloud front. The intense pressure wave ( higher in temp ) must be invisible just ahead this spreading cloud front. You see the same kind of things around jet fighter wings and jet engine intakes when the relative humidity is high. I wonder if stress and strain in the earth can reveal itself in some indirect way since no one can see it directly. ----- Original Message ----- From: "Bob Hancock" To: "PSN" Sent: Monday, March 02, 2009 4:26 PM Subject: Seismology & Nuclear Weapons Testing > Interesting article from Scientific American on the use of seismology > to detect underground nuclear explosions. > > http://www.sciam.com/article.cfm?id=advances-in-monitoring-nuclear&sc=CAT_SP_20090302 > __________________________________________________________ > > 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: Near and Far Field of an EQ From: "Geoffrey" gmvoeth@........... Date: Tue, 3 Mar 2009 07:37:01 -0700 Hello folks at PSN; can any of you gurus tell me if eqs have a near and far field like a transmitting antenna might. With an antenna most of the energy collapses back into the antenna itself. Only a fraction actually escapes into the universe as radio waves. You must be like 10 wavelengths from the antenna to measure the radiated energy. I think possibly this true of earthquakes too. Like one must be 40 or more miles from the event to really measure its radiated energy output ? Any thoughts ? __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Strong Damping Magnets and pick up coil From: "Robert O. Green" rog@.......... Date: Wed, 04 Mar 2009 06:45:14 -0800 I am working on a VS system with Larry's coil, magnet and signal-chain. Is there any impact to the pick up coil signal from the strong magnets mounted nearby? Rob __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Strong Damping Magnets and pick up coil From: ChrisAtUpw@....... Date: Wed, 4 Mar 2009 10:31:02 EST In a message dated 04/03/2009, rog@.......... writes: I am working on a VS system with Larry's coil, magnet and signal-chain. Is there any impact to the pick up coil signal from the strong magnets mounted nearby? Rob Hi Rob, It depends whether the magnets can move with respect to the coil. Interactions between moving and stationary magnets may give problems. The U Alnico magnets do not give a very strong output voltage. I get over 20x the voltage output using a quad NdFeB magnet block. Have a look at _http://jclahr.com/science/psn/chapman/as1%20damping/index.html_ (http://jclahr.com/science/psn/chapman/as1%20damping/index.html) and at _http://jclahr.com/science/psn/chapman/lehman/index.html_ (http://jclahr.com/science/psn/chapman/lehman/index.html) What period are you trying to get? Regards, Chris Chapman
In a message dated 04/03/2009, rog@.......... writes:
<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size= =3D2>I am=20 working on a VS system with Larry's coil, magnet and signal-chain.
Is t= here=20 any impact to the pick up coil signal from the strong magnets
mounted=20 nearby?
Rob
Hi Rob,
 
    It depends whether the magnets can move with=20 respect to the coil. Interactions between moving and stationary magnets= may=20 give problems.
 
    The U Alnico magnets do not give a very st= rong=20 output voltage. I get over 20x the voltage output using a quad NdFeB ma= gnet=20 block. Have a look at http= ://jclahr.com/science/psn/chapman/as1%20damping/index.html and=20 at  http://jcla= hr.com/science/psn/chapman/lehman/index.html
 
    What period are you trying to get?
 
    Regards,
 
    Chris Chapman
Subject: Re: Strong Damping Magnets and pick up coil From: "Geoffrey" gmvoeth@........... Date: Wed, 4 Mar 2009 11:13:25 -0700 Hello Mr. Green; I assume VS stands for vertical Short Period. Id like to put in my 2 cents for your thoughts. No one as of yet seems to have built what I consider to be a correct sensor. You really need a two sensor device that is grounded in the middle to be a single three wire device. This allows to double the signal level as well as provide a proper balanced input into a differential amplifier. Both sensors need to be identically matched so it might be difficult to build. You cant just make a centered tapped coil. It needs to be two identical coils arranged in a series additive fashion feeding the common center point and the plus minus signals on a 100% Shielded Underground cable. The magnets need to be matched as well in strength. Just thought Id like to say this since everyone is going for only a half kinda sensor and not what the input amplifier design sheets seem to require. ( two identical symmetrical inputs grounded in the center ). This makes construction more difficult if it is one of a kind. Cheers :-) geoff ----- Original Message ----- From: "Robert O. Green" To: Sent: Wednesday, March 04, 2009 7:45 AM Subject: Strong Damping Magnets and pick up coil >I am working on a VS system with Larry's coil, magnet and signal-chain. > > Is there any impact to the pick up coil signal from the strong magnets > mounted nearby? > > Rob > __________________________________________________________ > > 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: Strong Damping Magnets and pick up coil From: ChrisAtUpw@....... Date: Wed, 4 Mar 2009 16:29:41 EST In a message dated 04/03/2009, gmvoeth@........... writes: It needs to be two identical coils arranged in a series additive fashion feeding the common center point and the plus minus signals on a 100% Shielded Underground cable. Hi Geoff and others, I see what you are saying, but it is much easier to invert the problem, use differential quad NdFeB magnets on common mild steel baseplates and a single rectangular pickup coil. This gives me over 20x the voltage output that an Alnico U magnet and a relay coil can provide and it is linear with deflection / drift. See the sensor magnet block and coils at _http://jclahr.com/science/psn/chapman/lehman/index.html_ (http://jclahr.com/science/psn/chapman/lehman/index.html) You can also buy lower noise single ended opamps than differential ones. Regards, Chris Chapman
In a message dated 04/03/2009, gmvoeth@........... writes:
<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size= =3D2>It needs=20 to be two identical coils arranged in a series additive fashion feeding th= e=20 common center
point and the plus minus signals on a 100% Shielded=20 Underground cable.
Hi Geoff and others,
 
    I see what you are saying, but it is much easie= r to=20 invert the problem, use differential quad NdFeB magnets on common mild steel= =20 baseplates and a single rectangular pickup coil. This gives me over 20x= the=20 voltage output that an Alnico U magnet and a relay coil can provide and it i= s=20 linear with deflection / drift. See the sensor magnet block and coils a= t http://jcla= hr.com/science/psn/chapman/lehman/index.html You=20 can also buy lower noise single ended opamps than differential ones.
 
    Regards,
 
    Chris Chapman
Subject: Svalbard earthquake From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@......... Date: Fri, 06 Mar 2009 15:30:38 +0000 Hello Here are two news about the Svalbard earthquake this morning. According to news from Norway, this was the biggest earthquake in the country history. But last year they did have earthquake of the size Mb6.2. http://www.nrk.no/nyheter/distrikt/troms_og_finnmark/1.6512339 http://www.aftenposten.no/nyheter/iriks/article2964253.ece Regards. --=20 J=F3n Fr=EDmann http://www.jonfr.com __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Svalbard earthquake From: Steinar Midtskogen steinar@............. Date: Fri, 06 Mar 2009 16:57:08 +0100 Jón Frímann writes: > Hello > > Here are two news about the Svalbard earthquake this morning. According > to news from Norway, this was the biggest earthquake in the country > history. Formally it was a little outside Norway's territory. > But last year they did have earthquake of the size Mb6.2. > > http://www.nrk.no/nyheter/distrikt/troms_og_finnmark/1.6512339 > http://www.aftenposten.no/nyheter/iriks/article2964253.ece And here's the story in the local paper with a plot from a station 400 km away from the center (80N 2E): http://www.svalbardposten.no/nyheter/jordskjelv-utenfor-svalbard They write that noone has felt the quake, unlike the recent 6.2 quake. The nearest settlement, Ny-Ålesund, is located about 300 km away. I got a huge signal on my seismometer in Oslo 2300 km away: http://voksenlia.net/nytt/2009/jordskjelv-20090306-n.png The P wave looked like this on my geophone: http://voksenlia.net/nytt/2009/jordskjelv-20090306-gz.png -- Steinar Midtskogen http://voksenlia.net/met/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Svalbard earthquake From: "tchannel" tchannel@............ Date: Fri, 6 Mar 2009 09:20:03 -0700 Hi Folks, This morning's monitor indicated a large signature. At first glance it looked like one event followed by two more. I saw a report of the 4.2M Western Montana, but when I processed it, the time indicated matched only the last part of the trace. See image one showing all three sensors. It's very clear on the bottom trace, a Slinky II machine CH3, which is a vertical spring sensor. The P and S show the MONTANA earthquake. For more details, see 09306.105022.tcidch3.gif. Later I found the other parts of the trace were from a 6.4M NORTH OF SVALBARD near Greenland. (See 090306.105022.tcidch1.gif). Makes me wonder if the Svalbard earthquake , encouraged the Montana earthquake as it shook things up, as it passed through? Ted ----- Original Message ----- From: "Steinar Midtskogen" To: Sent: Friday, March 06, 2009 8:57 AM Subject: Re: Svalbard earthquake > Jón Frímann writes: > >> Hello >> >> Here are two news about the Svalbard earthquake this morning. According >> to news from Norway, this was the biggest earthquake in the country >> history. > > Formally it was a little outside Norway's territory. > >> But last year they did have earthquake of the size Mb6.2. >> >> http://www.nrk.no/nyheter/distrikt/troms_og_finnmark/1.6512339 >> http://www.aftenposten.no/nyheter/iriks/article2964253.ece > > And here's the story in the local paper with a plot from a station 400 > km away from the center (80N 2E): > > http://www.svalbardposten.no/nyheter/jordskjelv-utenfor-svalbard > > They write that noone has felt the quake, unlike the recent 6.2 quake. > The nearest settlement, Ny-Ålesund, is located about 300 km away. > > I got a huge signal on my seismometer in Oslo 2300 km away: > > http://voksenlia.net/nytt/2009/jordskjelv-20090306-n.png > > The P wave looked like this on my geophone: > > http://voksenlia.net/nytt/2009/jordskjelv-20090306-gz.png > > -- > Steinar Midtskogen > http://voksenlia.net/met/ > __________________________________________________________ > > 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: Svalbard earthquake From: Dave Nelson dave.nelson@............... Date: Sat, 07 Mar 2009 08:56:40 +1100 Hi Jon and all this was well and truely a Mid Atlantic Ridge event ... epicentre placing= =20 it half way between Svalbard and Greenland, quite some distance from either coast. not too many of that size along the ridge :) cheers Dave N www.sydneystormcity.com At 03:30 PM 3/6/2009 +0000, you wrote: >Hello >Here are two news about the Svalbard earthquake this morning. According >to news from Norway, this was the biggest earthquake in the country >history. But last year they did have earthquake of the size Mb6.2. >http://www.nrk.no/nyheter/distrikt/troms_og_finnmark/1.6512339 >http://www.aftenposten.no/nyheter/iriks/article2964253.ece >Regards. >J=F3n Fr=EDmann __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Svalbard earthquake From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@......... Date: Fri, 06 Mar 2009 22:04:38 +0000 Hi I don't think that the Svalbard earthquake was the trigger in the Montana earthquake case. Just a chance on how that did happen. Regards. J=F3n Fr=EDmann. On f=F6s, 2009-03-06 at 09:20 -0700, tchannel wrote: > Hi Folks, This morning's monitor indicated a large signature. At first=20 > glance it looked like one event followed by two more. >=20 > I saw a report of the 4.2M Western Montana, but when I processed it, the=20 > time indicated matched only the last part of the trace. See image one=20 > showing all three sensors. > It's very clear on the bottom trace, a Slinky II machine CH3, which is a= =20 > vertical spring sensor. >=20 > The P and S show the MONTANA earthquake. For more details, see=20 > 09306.105022.tcidch3.gif. >=20 > Later I found the other parts of the trace were from a 6.4M NORTH OF=20 > SVALBARD near Greenland. (See 090306.105022.tcidch1.gif). >=20 > Makes me wonder if the Svalbard earthquake , encouraged the Montana=20 > earthquake as it shook things up, as it passed through? >=20 > Ted >=20 >=20 >=20 >=20 > ----- Original Message -----=20 > From: "Steinar Midtskogen" > To: > Sent: Friday, March 06, 2009 8:57 AM > Subject: Re: Svalbard earthquake >=20 >=20 > > J=F3n Fr=EDmann writes: > > > >> Hello > >> > >> Here are two news about the Svalbard earthquake this morning. Accordin= g > >> to news from Norway, this was the biggest earthquake in the country > >> history. > > > > Formally it was a little outside Norway's territory. > > > >> But last year they did have earthquake of the size Mb6.2. > >> > >> http://www.nrk.no/nyheter/distrikt/troms_og_finnmark/1.6512339 > >> http://www.aftenposten.no/nyheter/iriks/article2964253.ece > > > > And here's the story in the local paper with a plot from a station 400 > > km away from the center (80N 2E): > > > > http://www.svalbardposten.no/nyheter/jordskjelv-utenfor-svalbard > > > > They write that noone has felt the quake, unlike the recent 6.2 quake. > > The nearest settlement, Ny-=C5lesund, is located about 300 km away. > > > > I got a huge signal on my seismometer in Oslo 2300 km away: > > > > http://voksenlia.net/nytt/2009/jordskjelv-20090306-n.png > > > > The P wave looked like this on my geophone: > > > > http://voksenlia.net/nytt/2009/jordskjelv-20090306-gz.png > > > > --=20 > > Steinar Midtskogen > > http://voksenlia.net/met/ > > __________________________________________________________ > > > > 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.=20 >=20 > __________________________________________________________ >=20 > Public Seismic Network Mailing List (PSN-L) >=20 > To leave this list email PSN-L-REQUEST@.............. with=20 > 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: Svalbard earthquake From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@......... Date: Fri, 06 Mar 2009 22:36:34 +0000 Hi I don't know the exact seismic zone buildup near Svalbard. But to me this looks like a slip-fault event. There is also intersting data on Norsar web page. http://www.norsardata.no/NDC/recenteq/lastweek.html Regards. J=F3n Fr=EDmann. On lau, 2009-03-07 at 08:56 +1100, Dave Nelson wrote: > Hi Jon and all >=20 > this was well and truely a Mid Atlantic Ridge event ... epicentre placin= g=20 > it half > way between Svalbard and Greenland, quite some distance from either coast= . >=20 > not too many of that size along the ridge :) >=20 > cheers > Dave N > www.sydneystormcity.com >=20 >=20 >=20 >=20 >=20 > At 03:30 PM 3/6/2009 +0000, you wrote: > >Hello > >Here are two news about the Svalbard earthquake this morning. According > >to news from Norway, this was the biggest earthquake in the country > >history. But last year they did have earthquake of the size Mb6.2. > >http://www.nrk.no/nyheter/distrikt/troms_og_finnmark/1.6512339 > >http://www.aftenposten.no/nyheter/iriks/article2964253.ece > >Regards. > >J=F3n Fr=EDmann >=20 > __________________________________________________________ >=20 > Public Seismic Network Mailing List (PSN-L) >=20 > To leave this list email PSN-L-REQUEST@.............. with=20 > 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: WinQuake From: "Geoffrey" gmvoeth@........... Date: Mon, 9 Mar 2009 18:01:23 -0700 FYI: There Is Only One Way I can Get Winquake to see right times for my data. It is necessary to crop the data to the nearest second before giving it to Winquake. No matter what I do WQ will not see fractions of seconds for the start time. No matter what the precision is of the numbers WQ only will show the first sample to a whole second. Like if I tell it 23:49: 20.4 for the first second it will show only 23:49:20 for the first sample SO you must run your data until it gets to 23:49:21 then crop it from there to the end before giving it to wq and tell wq it is 23:49:21.0 and you can forget the fractions your start time may be a couple milliseconds off but WTHeck. Otherwise if you do not do this things just aint right. Also, the various filters in the WQ3 FFT used to work fine but since installing the new WQ3 those filters dont work (all grayed out) ?? What am I doing wrong ? cheers geoff __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: WinQuake From: Thomas Dick dickthomas01@............. Date: Tue, 10 Mar 2009 07:01:48 -0500 Geoffrey wrote: > FYI: > > There Is Only One Way I can Get Winquake to > see right times for my data. > > It is necessary to crop the data to the nearest > second before giving it to Winquake. > > No matter what I do WQ will not see fractions of seconds > for the start time. > > No matter what the precision is of the numbers > WQ only will show the first sample to a whole second. > > Like if I tell it 23:49: 20.4 for the first second > it will show only 23:49:20 for the first sample > > SO you must run your data until it gets to > 23:49:21 then crop it from there to the end > before giving it to wq and tell wq > it is 23:49:21.0 and you can forget the fractions > your start time may be a couple milliseconds off > but WTHeck. > > Otherwise if you do not do this things just aint right. > > Also, the various filters in the WQ3 FFT used to work fine > but since installing the new WQ3 those filters dont work (all grayed > out) ?? > What am I doing wrong ? > > cheers > geoff > > Geoff and all .... I know I don't belong in the same theater as most of you -- let along the same stage. This is going to show my ignorance. I am confused about the value of your pursuit into "It is necessary to crop the data to the nearest second before giving it to Winquake". Here is where I am coming from; 1. when you try to get that close with the timing issue on P, aren't you ignoring the timing errors caused by internal computer timing inaccuracies and delays caused by getting the timing signal from the satellite or whatever your source is 2. the time of arrival tables for earthquake waves that are used are not set in stone ---- they are averages ..... are you taking this into consideration ... 3. are you also pursuing the reaction time delays within the seismic unit as well ... just how long does it take for you units to show the first arrival of P 4. and finally, what about the inaccuracies within the graphics display of the computer .... what degree of definition are you using and will this effect timing I am NOT attacking your efforts but trying to appreciate where you are headed with your efforts. Yours, TomD __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: WinQuake From: "Geoffrey" gmvoeth@........... Date: Tue, 10 Mar 2009 13:38:10 -0700 Howdy Mr. Thomas Dick; Answers inline below. ----- Original Message ----- From: "Thomas Dick" To: Sent: Tuesday, March 10, 2009 5:01 AM Subject: Re: WinQuake > Geoffrey wrote: >> FYI: >> >> There Is Only One Way I can Get Winquake to >> see right times for my data. >> >> It is necessary to crop the data to the nearest >> second before giving it to Winquake. >> >> No matter what I do WQ will not see fractions of seconds >> for the start time. >> >> No matter what the precision is of the numbers >> WQ only will show the first sample to a whole second. >> >> Like if I tell it 23:49: 20.4 for the first second >> it will show only 23:49:20 for the first sample >> >> SO you must run your data until it gets to >> 23:49:21 then crop it from there to the end >> before giving it to wq and tell wq >> it is 23:49:21.0 and you can forget the fractions >> your start time may be a couple milliseconds off >> but WTHeck. >> >> Otherwise if you do not do this things just aint right. >> >> Also, the various filters in the WQ3 FFT used to work fine >> but since installing the new WQ3 those filters dont work (all grayed >> out) ?? >> What am I doing wrong ? >> >> cheers >> geoff >> >> > Geoff and all .... > > I know I don't belong in the same theater as most of you -- let along > the same stage. This is going to show my ignorance. I am confused about > the value of your pursuit into "It is necessary to crop the data to the > nearest second before giving it to Winquake". Hey...thats why the academia split up the knowledge into celluraized groups cause there is not enough human life for one to know everything. > > Here is where I am coming from; > 1. when you try to get that close with the timing issue on P, aren't you > ignoring the timing errors caused by internal computer timing > inaccuracies and delays caused by getting the timing signal from the > satellite or whatever your source is My system is entirely slaved to a ring counter syncronized via WWV at whatever freq works when tuned in via SW radio. When the ring counter tells my computer it is exactly HH:MM.00 then thats what the time is in the record. The errors up to the ring counter are being entirely ignored since I do not have the capability of dealing with millisecond errors. The computer clock only gets me to the correct minute. The ring counter to tens of milliseconds and math does the rest. I am totally unable to tell what the real time is except my robot clocks (WWVB) all agree Im in the very same second. But Winquake should simply do what i tell it to since it is no master of time. If I tell it the first sample is whatever date and time it should by all rights reflect this fact. It really should not guestimate amy time between the samples unless it does so between the first and the last as relating to the sample rate. The most impoirtant thing is that you give it the right time in the first place as well as the proper sample rate. not as easy to do as youd like to imagine. > 2. the time of arrival tables for earthquake waves that are used are not > set in stone ---- they are averages ..... are you taking this into > consideration ... Trust the masters since the regular person does not have the ability to generate such tables. For ametures this is fun and not life and death. > 3. are you also pursuing the reaction time delays within the seismic > unit as well ... just how long does it take for you units to show the > first arrival of P Are you talking about delays through the Electronics ?? I have a hard time seeing any delays with the test equipment at my fingertips. I only know there is a phase delay meaning you put a signal in at 0 degrees but get one shifted in phase by 45 or 180 or 270 or whatever. If I DROP something on the ground it is like the ground first goes downward so if my trace is upward I simply swap the leads intp the amplifier to reflect the initial ground motion. But for all testing I see no actual delays only phase shifting. Even 50% the speed of light is nothing to 5 HZ or less. > 4. and finally, what about the inaccuracies within the graphics display > of the computer .... what degree of definition are you using and will > this effect timing I use no graphics for recording. You simply make sure that what you are looking at is good enough to show each and every sample per line so if you look at 1000 samples you want like 1000 to 1024 pix on the horizontal. Any other times than pixel times are simply an educated guess. But what I have found is that sometimes my recorder may either miss or add an extra sample you do not expect and its practically impossible for me to tell what samples where are not right in the middle of everything. If you cant find the errors you simply assume the thing works. BUT you want your software to behave exactly as you expect it to work. Computers are not human and they should never have a mind of their own. They should only do whatever you tell them to do or something else is wrong too. Possibly the programmer has made mistakes in the philosophy that built the program in the first place. (for time that is) Amplitude is yet another story to examine. > > I am NOT attacking your efforts but trying to appreciate where you are > headed with your efforts. Simply put, my times are all slaved to the ring counter which is synchronized to the minute mark in WWV and the computer RTC gets me into the neighborhood ( DARE + nearest minute after midnight ) rest to mathematically work everything else out to the millisecond ( do not round numbers till the last result is desired ). Ta DAAAA :-) Cheers geoff > > Yours, TomD > __________________________________________________________ > > 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: WinQuake From: Thomas Dick dickthomas01@............. Date: Tue, 10 Mar 2009 16:09:39 -0500 OK Georff; I think I see where you are going with this. I had access to your email before I left. I was mauling your email over in my mind the whole time I was gone. Even using WWV would create an error of some milliseconds and I thought you were talking nanoseconds. Gee, back to the good old days when my amateur radio log had to be accurate to the nearest minute! Thanks for the mental stimulation! TomD > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: WinQuake From: Kevin Brunt k.brunt@......... Date: Tue, 10 Mar 2009 21:41:48 +0000 (GMT Standard Time) On Mon, 9 Mar 2009 18:01:23 -0700 Geoffrey wrote: > FYI: > > There Is Only One Way I can Get Winquake to > see right times for my data. > > It is necessary to crop the data to the nearest > second before giving it to Winquake. > > No matter what I do WQ will not see fractions of seconds > for the start time. > > No matter what the precision is of the numbers > WQ only will show the first sample to a whole second. > > Like if I tell it 23:49: 20.4 for the first second > it will show only 23:49:20 for the first sample > > SO you must run your data until it gets to > 23:49:21 then crop it from there to the end > before giving it to wq and tell wq > it is 23:49:21.0 and you can forget the fractions > your start time may be a couple milliseconds off > but WTHeck. > > Otherwise if you do not do this things just aint right. > > Also, the various filters in the WQ3 FFT used to work fine > but since installing the new WQ3 those filters dont work (all grayed out) ?? > What am I doing wrong ? > > cheers > geoff Hi, I'm starting back here, rather than following on from the other posts, because I want to ask you to describe the format of the data that you are putting into WinQuake. By this, I *don't* mean the exact arrangement of bytes in the input file, but rather the "conceptual" format of the data. Why I'm asking is because from what you have written, it almost sounds as if you are supplying a file containing only the samples and are trying to tell WinQuake what the time the data starts separately. If we can get onto the same wavelength on this, it will make things clearer. I don't run WinQuake (nor indeed a seismic sensor at the moment) but it looks to me as if WinQuake wants to display the data starting at a round second. (It makes the divisions on the time axis regular.) I think that if you tell it to start in the middle of a second, it will wind back to the sample that was taken closest to the "start" of the second, and start displaying from there. This is not the same as what you are describing, which is why I'm asking about your data input. Kevin __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: WinQuake From: "Geoffrey" gmvoeth@........... Date: Tue, 10 Mar 2009 15:03:04 -0700 ----- Original Message ----- From: "Kevin Brunt" To: Sent: Tuesday, March 10, 2009 2:41 PM Subject: Re: WinQuake > > On Mon, 9 Mar 2009 18:01:23 -0700 Geoffrey wrote: > >> FYI: >> >> There Is Only One Way I can Get Winquake to >> see right times for my data. >> >> It is necessary to crop the data to the nearest >> second before giving it to Winquake. >> >> No matter what I do WQ will not see fractions of seconds >> for the start time. >> >> No matter what the precision is of the numbers >> WQ only will show the first sample to a whole second. >> >> Like if I tell it 23:49: 20.4 for the first second >> it will show only 23:49:20 for the first sample >> >> SO you must run your data until it gets to >> 23:49:21 then crop it from there to the end >> before giving it to wq and tell wq >> it is 23:49:21.0 and you can forget the fractions >> your start time may be a couple milliseconds off >> but WTHeck. >> >> Otherwise if you do not do this things just aint right. >> >> Also, the various filters in the WQ3 FFT used to work fine >> but since installing the new WQ3 those filters dont work (all grayed out) ?? >> What am I doing wrong ? >> >> cheers >> geoff > > Hi, > > I'm starting back here, rather than following on from the other posts, because > I want to ask you to describe the format of the data that you are putting into > WinQuake. By this, I *don't* mean the exact arrangement of bytes in the input > file, but rather the "conceptual" format of the data. > > Why I'm asking is because from what you have written, it almost sounds as if > you are supplying a file containing only the samples and are trying to tell > WinQuake what the time the data starts separately. If we can get onto the same > wavelength on this, it will make things clearer. > > I don't run WinQuake (nor indeed a seismic sensor at the moment) but it looks > to me as if WinQuake wants to display the data starting at a round second. (It > makes the divisions on the time axis regular.) I think that if you tell it to > start in the middle of a second, it will wind back to the sample that was taken > closest to the "start" of the second, and start displaying from there. This is > not the same as what you are describing, which is why I'm asking about your > data input. > > Kevin Hello Master Kevin; This header is for a PSN TEXT FILE which I preferr to use. THE other called PSN4 which I believe is a binary file mifgr work differently. I have not yet tried the PSN4 format because text is so much easier to deal with. ( Its all relative my dear einstein/watson) Heres the headers of which I speak, One is named work and the other Dont_Work ********************************** CUT HERE******************************************** In this one your data has also been cropped to start at the right second or as close as possible to that second. WORKS.TXT ! PSN ASCII Event File Format 2.0 Start Time: 2009/03/10 19:56:00 Start Time Offset: 26 Number of Samples: 65560 SPS: 18.2058 Time Reference Type: Oth Comment:[GVA] A/D Converter Bits: 8 Data Minimum: -33.8 Data Maximum: 38.2 Data Mean: 0 ! Sensor Information: Sensor Location: GVA Sensor Description: HS10-1 Sensor Latitude: 33.42138 Sensor Longitude: -111.57477 Sensor Elevation: 507.5 Sensor Incident: 0 Sensor Azimuth: 0 Sensor Orientation: Z Sensor Type: Velocity Sensor Sensitivity: 7.100e-008 Sensor ID: HS-10 Magnitude Correction: 0.00235574 Component Name: SPZ Network Affiliation: IRSS Pick Information: Pick Information: Data: ***************************************CUT HERE*************************************** DONT WORK In this one your data starts at the exact time you are trying to tell winquake to use. ! PSN ASCII Event File Format 2.0 Start Time: 2009/03/10 19:56:25.250000000 Start Time Offset: 0.000 Number of Samples: 65560 SPS: 18.2058 Time Reference Type: Oth Comment:[GVA] A/D Converter Bits: 8 Data Minimum: -33.8 Data Maximum: 38.2 Data Mean: 0 ! Sensor Information: Sensor Location: GVA Sensor Description: HS10-1 Sensor Latitude: 33.42138 Sensor Longitude: -111.57477 Sensor Elevation: 507.5 Sensor Incident: 0 Sensor Azimuth: 0 Sensor Orientation: Z Sensor Type: Velocity Sensor Sensitivity: 7.100e-008 Sensor ID: HS-10 Magnitude Correction: 0.00235574 Component Name: SPZ Network Affiliation: IRSS Pick Information: Pick Information: Data: *************************************CUT HERE************************** > > > __________________________________________________________ > > 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: WinQuake From: "Geoffrey" gmvoeth@........... Date: Tue, 10 Mar 2009 15:23:40 -0700 LOL I see you have trouble typing like I do. I used to stand fathometer watches on the bridge going in and out of various ports. No one ever said how accurate my times had to be but I would carry one of those led watches that glowed in the dark. I went through so many batteries that I took three "D" cells with a three pos toggle switch and rewired my watch to use that power source it was bulky but lasted the about the shelf life of the three zinc carbon D cells. I was sitting on the bridge next to one of the very first navigational satellite receivers. You could put on a set of headphones and hear the Doppler of the satellite as it passed over the horizon. That was in the 1970s, Today we are still playing with that kind of technology. We had three chronometers that were spring powered that still had to be wound and compared and error data kept in the logs as to how good they all kept time. The last thing I remember most was this crazy pilot making suicidal runs at our ship. I can still see in my mind the engine crashing through the bridge spilling burning gasoline over all of us and we do nothing but stand there like statues suspended in time watching this crazy fool whose girlfriend had just jilted him. Time had a whole new meaning after this. It was like everyone but me was suspended in time and unlike the other statues I was watching their reaction on the bridge instead of that airplane with the crazy pilot. Time vs. Human Behavior. Now here I am once again playing with time. Just a thought. :-) geoff ----- Original Message ----- From: "Thomas Dick" To: Sent: Tuesday, March 10, 2009 2:09 PM Subject: Re: WinQuake > OK Georff; > I think I see where you are going with this. I had access to your email > before I left. I was mauling your email over in my mind the whole time I > was gone. Even using WWV would create an error of some milliseconds and > I thought you were talking nanoseconds. > > Gee, back to the good old days when my amateur radio log had to be > accurate to the nearest minute! > > Thanks for the mental stimulation! > TomD >> > > __________________________________________________________ > > 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: WinQuake From: Kevin Brunt k.brunt@......... Date: Wed, 11 Mar 2009 00:01:03 +0000 (GMT) ---- Original message ---- >Date: Tue, 10 Mar 2009 15:03:04 -0700 >From: Geoffrey >Subject: Re: WinQuake >To: psn-l > >Hello Master Kevin; > >This header is for a PSN TEXT FILE which I preferr to use. >THE other called PSN4 which I believe is a binary file mifgr work >differently. >I have not yet tried the PSN4 format because text is so much easier to deal with. >( Its all relative my dear einstein/watson) > > >Heres the headers of which I speak, One is named work and the other Dont_Work >********************************** CUT HERE******************************************** >In this one your data has also been cropped to start at the right second >or as close as possible to that second. > >WORKS.TXT >! PSN ASCII Event File Format 2.0 >Start Time: 2009/03/10 19:56:00 >Start Time Offset: 26 >Number of Samples: 65560 >SPS: 18.2058 >Time Reference Type: Oth >Comment:[GVA] >A/D Converter Bits: 8 >Data Minimum: -33.8 >Data Maximum: 38.2 >Data Mean: 0 >! Sensor Information: >Sensor Location: GVA >Sensor Description: HS10-1 >Sensor Latitude: 33.42138 >Sensor Longitude: -111.57477 >Sensor Elevation: 507.5 >Sensor Incident: 0 >Sensor Azimuth: 0 >Sensor Orientation: Z >Sensor Type: Velocity >Sensor Sensitivity: 7.100e-008 >Sensor ID: HS-10 >Magnitude Correction: 0.00235574 >Component Name: SPZ >Network Affiliation: IRSS >Pick Information: >Pick Information: >Data: > >***************************************CUT HERE*************************************** > DONT WORK >In this one your data starts at the exact time you are trying to tell >winquake to use. > >! PSN ASCII Event File Format 2.0 >Start Time: 2009/03/10 19:56:25.250000000 >Start Time Offset: 0.000 >Number of Samples: 65560 >SPS: 18.2058 >Time Reference Type: Oth >Comment:[GVA] >A/D Converter Bits: 8 >Data Minimum: -33.8 >Data Maximum: 38.2 >Data Mean: 0 >! Sensor Information: >Sensor Location: GVA >Sensor Description: HS10-1 >Sensor Latitude: 33.42138 >Sensor Longitude: -111.57477 >Sensor Elevation: 507.5 >Sensor Incident: 0 >Sensor Azimuth: 0 >Sensor Orientation: Z >Sensor Type: Velocity >Sensor Sensitivity: 7.100e-008 >Sensor ID: HS-10 >Magnitude Correction: 0.00235574 >Component Name: SPZ >Network Affiliation: IRSS >Pick Information: >Pick Information: >Data: OK. I think the issue is about what is valid in a "PSN ASCII Event File". None of the (admittedly few) examples a quick Google search has thrown up have got more than 1 decimal place in the "Start time" seconds, so it may well be that you're not allowed more than one. Is there actually a definitive spec for the file format online? Also I can't find any reference to "Start time offset" at all, so there's no indication of what the units are. If you can't get the file to start at a fractional second, can you not add a sufficient number of zero samples at the start? Perhaps what's going on is that the data collection is "locked" to the 1 Hz "tick" of the external time source, so that the first sample is taken on the tick. If the data is collected over a period of a whole number of seconds, there is no need to compute partial seconds. And as long as the sample rate is not subject to a systematic drift, the actual rate can be calculated by dividing the total number of sample by the number of seconds. Kevin __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: RE: WinQuake From: "Gary Lindgren" gel@................. Date: Tue, 10 Mar 2009 17:13:44 -0700 Geoff, Could tell us more about your setup. What equipment do you have, i.e., sensor, A/D converter, system to convert sensor information that goes to WinQuake. You may want to get Larry Cochrane's amplifier/filter and A/D boards. He makes it so simple. You can also get from Larry a Garmin GPS unit to keep your system time very accurate. It is all automatic. You use WinSDR to gather and display the data and when you get something interesting to analyze you save the data and send it to WinQuake. It's a piece of cake. Gary -----Original Message----- From: psn-l-request@.............. [mailto:psn-l-request@............... On Behalf Of Geoffrey Sent: Monday, March 09, 2009 6:01 PM To: PSN-LIST Subject: WinQuake FYI: There Is Only One Way I can Get Winquake to see right times for my data. It is necessary to crop the data to the nearest second before giving it to Winquake. No matter what I do WQ will not see fractions of seconds for the start time. No matter what the precision is of the numbers WQ only will show the first sample to a whole second. Like if I tell it 23:49: 20.4 for the first second it will show only 23:49:20 for the first sample SO you must run your data until it gets to 23:49:21 then crop it from there to the end before giving it to wq and tell wq it is 23:49:21.0 and you can forget the fractions your start time may be a couple milliseconds off but WTHeck. Otherwise if you do not do this things just aint right. Also, the various filters in the WQ3 FFT used to work fine but since installing the new WQ3 those filters dont work (all grayed out) ?? What am I doing wrong ? cheers geoff __________________________________________________________ Public Seismic Network Mailing List (PSN-L) __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: WinQuake From: "Geoffrey" gmvoeth@........... Date: Tue, 10 Mar 2009 19:57:33 -0700 ----- Original Message ----- From: "Kevin Brunt" To: "psn-l" Sent: Tuesday, March 10, 2009 5:01 PM Subject: Re: WinQuake > > > ---- Original message ---- >>Date: Tue, 10 Mar 2009 15:03:04 -0700 >>From: Geoffrey >>Subject: Re: WinQuake >>To: psn-l > >> >>Hello Master Kevin; >> >>This header is for a PSN TEXT FILE which I preferr to use. >>THE other called PSN4 which I believe is a binary file mifgr work >>differently. >>I have not yet tried the PSN4 format because text is so much easier to deal with. >>( Its all relative my dear einstein/watson) >> >> >>Heres the headers of which I speak, One is named work and the other Dont_Work >>********************************** CUT HERE******************************************** >>In this one your data has also been cropped to start at the right second >>or as close as possible to that second. >> >>WORKS.TXT >>! PSN ASCII Event File Format 2.0 >>Start Time: 2009/03/10 19:56:00 >>Start Time Offset: 26 >>Number of Samples: 65560 >>SPS: 18.2058 >>Time Reference Type: Oth >>Comment:[GVA] >>A/D Converter Bits: 8 >>Data Minimum: -33.8 >>Data Maximum: 38.2 >>Data Mean: 0 >>! Sensor Information: >>Sensor Location: GVA >>Sensor Description: HS10-1 >>Sensor Latitude: 33.42138 >>Sensor Longitude: -111.57477 >>Sensor Elevation: 507.5 >>Sensor Incident: 0 >>Sensor Azimuth: 0 >>Sensor Orientation: Z >>Sensor Type: Velocity >>Sensor Sensitivity: 7.100e-008 >>Sensor ID: HS-10 >>Magnitude Correction: 0.00235574 >>Component Name: SPZ >>Network Affiliation: IRSS >>Pick Information: >>Pick Information: >>Data: >> >>***************************************CUT HERE*************************************** >> DONT WORK >>In this one your data starts at the exact time you are trying to tell >>winquake to use. >> >>! PSN ASCII Event File Format 2.0 >>Start Time: 2009/03/10 19:56:25.250000000 >>Start Time Offset: 0.000 >>Number of Samples: 65560 >>SPS: 18.2058 >>Time Reference Type: Oth >>Comment:[GVA] >>A/D Converter Bits: 8 >>Data Minimum: -33.8 >>Data Maximum: 38.2 >>Data Mean: 0 >>! Sensor Information: >>Sensor Location: GVA >>Sensor Description: HS10-1 >>Sensor Latitude: 33.42138 >>Sensor Longitude: -111.57477 >>Sensor Elevation: 507.5 >>Sensor Incident: 0 >>Sensor Azimuth: 0 >>Sensor Orientation: Z >>Sensor Type: Velocity >>Sensor Sensitivity: 7.100e-008 >>Sensor ID: HS-10 >>Magnitude Correction: 0.00235574 >>Component Name: SPZ >>Network Affiliation: IRSS >>Pick Information: >>Pick Information: >>Data: > > OK. I think the issue is about what is valid in a "PSN ASCII Event File". None of the (admittedly few) examples a quick Google > search has thrown up have got more than 1 decimal place in the "Start time" seconds, so it may well be that you're not allowed > more than one. Is there actually a definitive spec for the file format online? > > Also I can't find any reference to "Start time offset" at all, so there's no indication of what the units are. > > If you can't get the file to start at a fractional second, can you not add a sufficient number of zero samples at the start? > > Perhaps what's going on is that the data collection is "locked" to the 1 Hz "tick" of the external time source, so that the first > sample is taken on the tick. If the data is collected over a period of a whole number of seconds, there is no need to compute > partial seconds. And as long as the sample rate is not subject to a systematic drift, the actual rate can be calculated by > dividing the total number of sample by the number of seconds. Hello Kevin; I think this to be the best answer so far. My cal time is taken at synchronization then the start time is estimated mathematically from the tested sample rate. So if I cal at lets say 03:20:00.000 UTC I must then count backwards subtracting time to the very first sample. So my first time then becomes: 03:20:00.000 minus 3277 samples times 3600 seconds divided by 65541 samples per hour the first time should be 03:20:00.000 minus 179.997253628 and nothing is to be rounded until after all other necessary times are derived. You need to establish a reference point then the sample times are decided by the time displacements between them. So if you have 1000 samples the first one is only a place holder and you decide all other times by the spaces of time between them. These are the only measured times and if you estimate between them it is all sheer speculation since you measured nothing in the spaces between the samples themselves. There are N samples and N-1 time increments between them. I do noy like to estimate times between the samples themselves although it does make a prettier picture. You never sure of the error unless you can compare to something you are sure is correct. I like to put a small capacitor across the input to tickle the geophone then look at the results and compare my times with the one I ticled with and if everytthing is correct i get good times or so it seems. So like I will tickle the geophone and compare the recorded time and see that they closely match. But I can not do any better than this without better equipment since I am no scientist or mathmatician. Those guys have ways of testing the impossible for us to test. But i know from experience I can be very close in the civilian sense of close. Like hundredth of a second. givin I have the correct sample rate and my hardware synchronized correctly and no samples were either missed or duplicated during the recording process. My greatest problem is the sample rate. I need the computer program to run 10X faster then the desired sample rate or possibly faster so that the tic counter does not change between loops. I syncronize my sample rate to the computer tic counter which in the old DOS machines is about 65536 samples per 3600 seconds. In this machine it appears fast or about 65541/ hour. Each machine will be a bit different. Nothing seems calibrated any more. They just build them and forget them. It costs them too much to spudge oscillators to the correct frequency. My ring counter depends upon the master oscillator which needs to be exactly 12 MHz which I can only get close to with no decent test equipment to play with. I do not use Larrys' equipment simply because I want to understand the instrumentation and kit building and programming is fun to me. I believe I purchased the HS10 from him but that was because I do not have the ability to build a weather tight one for buriel myself. Larry was my second attempt because an earlier geophone THROUGH (RTL)??? Was faulty and I took maybe a $250+ loss on that one that was usec and AS IS kinda thing. Dangerous buying used goods of a scientific nature. Easy to get ripped since most such equipment is not for the field or is not to be handled normally but with great care. What G force has it been exposed to from here to there. Lucky if it still works right when you get it. Id like to go right to the manufacturer and fetch my own equipment and deliver it to myself then and only then am I sure how it has been handled. Cheers; geoff > > Kevin > __________________________________________________________ > > 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: WinQuake From: "Geoffrey" gmvoeth@........... Date: Tue, 10 Mar 2009 20:14:30 -0700 Hello: Gary Lindgren; I do not use Garys Equipment simply because I wanted to do things myself as a hobby kinda thing. Remember the old HEATHKITS. more fun than a barrel of monkies. I think if you amateurs could get together and build a kit from the ground up you might get a lot of interest from the technical community even if they are not amateurs in seismology. The only thing missing is a proper input into a differential amplifier. You can use one mechanical thinger but you need two identical sensors grounded in the middle. From my viewpoint it is the only way. Then you need a full 16 bit A/d good to the last bit Which nowadays I just don't see. Then you need a proper amplifier filter equalizer to get the proper bandwidth maybe 1/20 to 3Hz. This could be a standard for beginners to be extra pursued later if they are so inclined. Above 2 HZ you can have great problems if there is a lot of human activity in the area. Below 2 hertz human activity is probably intentional if it causes you problems. Someone just simply don't like you. Bounce their low rider every time they drive by. There used to be converters that always show all the bits you just need to strobe them into a solid number to read the results. I do not see such converters anymore. They seem to take time just to convert the numbers. I use a Prairie Digital 12-40 after conversion I look at only the top 8 bits. I am thinking of lowering the gain and looking at all 12 but that is only a pipe dream at the moment ( I do not Smoke) but I do dream like anyone else. None of my ideas are original I had to experiment to see what was best for ME. I have no intention of capitalizing on anything. Cheers; geoff ----- Original Message ----- From: "Gary Lindgren" To: Sent: Tuesday, March 10, 2009 5:13 PM Subject: RE: WinQuake > Geoff, > Could tell us more about your setup. What equipment do you have, i.e., > sensor, A/D converter, system to convert sensor information that goes to > WinQuake. You may want to get Larry Cochrane's amplifier/filter and A/D > boards. He makes it so simple. You can also get from Larry a Garmin GPS unit > to keep your system time very accurate. It is all automatic. You use WinSDR > to gather and display the data and when you get something interesting to > analyze you save the data and send it to WinQuake. It's a piece of cake. > Gary > > > > > -----Original Message----- > From: psn-l-request@.............. [mailto:psn-l-request@............... On > Behalf Of Geoffrey > Sent: Monday, March 09, 2009 6:01 PM > To: PSN-LIST > Subject: WinQuake > > FYI: > > There Is Only One Way I can Get Winquake to > see right times for my data. > > It is necessary to crop the data to the nearest > second before giving it to Winquake. > > No matter what I do WQ will not see fractions of seconds > for the start time. > > No matter what the precision is of the numbers > WQ only will show the first sample to a whole second. > > Like if I tell it 23:49: 20.4 for the first second > it will show only 23:49:20 for the first sample > > SO you must run your data until it gets to > 23:49:21 then crop it from there to the end > before giving it to wq and tell wq > it is 23:49:21.0 and you can forget the fractions > your start time may be a couple milliseconds off > but WTHeck. > > Otherwise if you do not do this things just aint right. > > Also, the various filters in the WQ3 FFT used to work fine > but since installing the new WQ3 those filters dont work (all grayed out) > ?? > What am I doing wrong ? > > cheers > geoff > > > > > __________________________________________________________ > > 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: WinQuake From: "Geoffrey" gmvoeth@........... Date: Wed, 11 Mar 2009 06:06:53 -0700 hello k.brunt; I believe I have answered your questions in other posts yet I wish to add that I am using Winquake I believe not as it was originally intended to be used So I understand the problems here are my own doing and not whoever programmed winquake itself. I am putting in 1 hour raw 8 bit data into a text file with the proper data I expect Winquake to use but obviously from personal experience I realize I did not understand Winquake actually wants data exactly on the second mark or the mouse will not display the correct time of the samples given. This is obviously (now) because it was designed to work within a system geared to the exact second and not an arbitrary calibration mark which I give to my data in the first three minutes of the record. My first sample will only rarely be an exact second mark since it can begin at any time. My program will mark a sample number as a cal mark at the top of every minute until a recording is triggered automatically at which time that cal sample number becomes the reference for the entire record. The record then needs to be cropped to the next top of the second in order for winquake to properly read the times as I wish to see them. I am not using Larry's system but one I built myself but Winquake is much better than anything I could program myself so I have purchased the right to use his program to look at my own data. It is only now I have looked into and discovered why my times were not right within his program...no fault of his only lack of understanding on my own. Cheers; geoff ----- Original Message ----- From: "Kevin Brunt" To: Sent: Tuesday, March 10, 2009 2:41 PM Subject: Re: WinQuake > > On Mon, 9 Mar 2009 18:01:23 -0700 Geoffrey wrote: > >> FYI: >> >> There Is Only One Way I can Get Winquake to >> see right times for my data. >> >> It is necessary to crop the data to the nearest >> second before giving it to Winquake. >> >> No matter what I do WQ will not see fractions of seconds >> for the start time. >> >> No matter what the precision is of the numbers >> WQ only will show the first sample to a whole second. >> >> Like if I tell it 23:49: 20.4 for the first second >> it will show only 23:49:20 for the first sample >> >> SO you must run your data until it gets to >> 23:49:21 then crop it from there to the end >> before giving it to wq and tell wq >> it is 23:49:21.0 and you can forget the fractions >> your start time may be a couple milliseconds off >> but WTHeck. >> >> Otherwise if you do not do this things just aint right. >> >> Also, the various filters in the WQ3 FFT used to work fine >> but since installing the new WQ3 those filters dont work (all grayed out) ?? >> What am I doing wrong ? >> >> cheers >> geoff > > Hi, > > I'm starting back here, rather than following on from the other posts, because > I want to ask you to describe the format of the data that you are putting into > WinQuake. By this, I *don't* mean the exact arrangement of bytes in the input > file, but rather the "conceptual" format of the data. > > Why I'm asking is because from what you have written, it almost sounds as if > you are supplying a file containing only the samples and are trying to tell > WinQuake what the time the data starts separately. If we can get onto the same > wavelength on this, it will make things clearer. > > I don't run WinQuake (nor indeed a seismic sensor at the moment) but it looks > to me as if WinQuake wants to display the data starting at a round second. (It > makes the divisions on the time axis regular.) I think that if you tell it to > start in the middle of a second, it will wind back to the sample that was taken > closest to the "start" of the second, and start displaying from there. This is > not the same as what you are describing, which is why I'm asking about your > data input. > > Kevin > > > __________________________________________________________ > > 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: WinQuake From: Robert McClure bobmcclure90@......... Date: Wed, 11 Mar 2009 20:35:42 -0400 Hi Geoff and all, I disagree with your comments. If you give WinQuake the correct time of the first sample, it will start plotting on the first second after the first sample. It will plot from the first sample if it is on an even second. The plotted data will be correctly timed. The new WinQuake provides an easy way to enter or edit the starting time to millisecond resolution. Select "Display/Modify" on the menu bar and click on "Time information". Edit "UTC Date:", "UTC Time:" and "Milliseconds". Then click on "OK" Cheers, Bob ~~~~~Original Message~~~~~ I believe I have answered your questions in other posts yet I wish to add that I am using Winquake I believe not as it was originally intended to be used So I understand the problems here are my own doing and not whoever programmed winquake itself. I am putting in 1 hour raw 8 bit data into a text file with the proper data I expect Winquake to use but obviously from personal experience I realize I did not understand Winquake actually wants data exactly on the second mark or the mouse will not display the correct time of the samples given. This is obviously (now) because it was designed to work within a system geared to the exact second and not an arbitrary calibration mark which I give to my data in the first three minutes of the record. My first sample will only rarely be an exact second mark since it can begin at any time. My program will mark a sample number as a cal mark at the top of every minute until a recording is triggered automatically at which time that cal sample number becomes the reference for the entire record. The record then needs to be cropped to the next top of the second in order for winquake to properly read the times as I wish to see them. I am not using Larry's system but one I built myself but Winquake is much better than anything I could program myself so I have purchased the right to use his program to look at my own data. It is only now I have looked into and discovered why my times were not right within his program...no fault of his only lack of understanding on my own. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: WinQuake From: Larry Cochrane lcochrane@.............. Date: Thu, 12 Mar 2009 00:48:15 -0700 Geoff, Kevin Brunt wrote: > I don't run WinQuake (nor indeed a seismic sensor at the moment) but it looks > to me as if WinQuake wants to display the data starting at a round second. (It > makes the divisions on the time axis regular.) I think that if you tell it to > start in the middle of a second, it will wind back to the sample that was taken > closest to the "start" of the second, and start displaying from there. This is > not the same as what you are describing, which is why I'm asking about your > data input. Kevin has it right. WinQuake rounds to the next top of the second and starts to display the data from there. When you crop an event file and then save the file the new file will start at the top of the second. Regarding the PSN Text Format Geoff is using. The fields are the same as the binary version (http://www.seismicnet.com/psnformat4.html) just converted to ASCII. So the "Start Time Offset" has the following definition: "Offset in seconds between the Start Time above and the first sample point. Start time = Start Time + Offset" This field normally should be zero but can be used to add or subtract a small amount of time to/from the "Start Time" field. Geoff, the following is not correct in your event file: ! PSN ASCII Event File Format 2.0 Start Time: 2009/03/10 19:56:00 Start Time Offset: 26 .... What you are doing is adding 26 seconds to the start. You should use 2009/03/10 19:56:26 in the Start Time field. From your other event file: ! PSN ASCII Event File Format 2.0 Start Time: 2009/03/10 19:56:25.250000000 Start Time Offset: 0.000 This is correct. Since there is a fraction in the start time WinQuake will display the data starting at 19:56:26. Regards, Larry Cochrane Redwood City, PSN __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: WinQuake Timing of text file From: "Randy Pratt" rpratt@............. Date: Thu, 12 Mar 2009 12:47:41 -0500 Hello All, I did a quick experiment on this and I would agree the timing is = incorrect on the WinQuake display. Here is my procedure: Make text file from the "don't work header" submitted a few days back = with some modification of data and sample rate for 100 sps and 1000 = total samples decreasing linearly with time. This should from the = explanations given earlier begin to display at second number 26 given = the start time of 19:56:25.25 and 75 samples into the data or at value = 925 in theory. In fact the display starts at second 25 which is before = the data start time and at the first sample value giving a .25 second = time offset error. My test header and portion of data are here and the = WinQuake display is posted at http:/mit.midco.net/rpratt. I set the = mean data to 950 to put the beginning portion expanded on the display. = I used WinQuake 2.9.8. =20 Randy ! PSN ASCII Event File Format 2.0 Start Time: 2009/03/10 19:56:25.250000000 Start Time Offset: 0.000 Number of Samples: 1000 SPS: 100 Time Reference Type: Oth Comment:[GVA]=20 A/D Converter Bits: 8 Data Minimum: 1 Data Maximum: 1000 Data Mean: 950 ! Sensor Information: Sensor Location: GVA Sensor Description: HS10-1 Sensor Latitude: 33.42138 Sensor Longitude: -111.57477 Sensor Elevation: 507.5 Sensor Incident: 0 Sensor Azimuth: 0 Sensor Orientation: Z Sensor Type: Velocity Sensor Sensitivity: 7.100e-008 Sensor ID: HS-10 Magnitude Correction: 0.00235574 Component Name: SPZ Network Affiliation: IRSS Pick Information: Pick Information: Data: 1000 999 998 997 996 995 .... 2 1
Hello All,
 
I did a quick experiment on this and I = would agree=20 the timing is incorrect on the WinQuake display.  Here is my=20 procedure:
 
Make text file from the "don't work = header"=20 submitted a few days back with some modification of data and sample rate = for 100=20 sps and 1000 total samples decreasing linearly with time.  This = should from=20 the explanations given earlier begin to display at second number 26=20 given the start time of 19:56:25.25 and 75 samples into the = data or at=20 value 925 in theory.  In fact the display starts at second 25 = which is=20 before the data start time and at the first sample value giving a = ..25=20 second time offset error.  My test header and portion = of data are=20 here and the WinQuake display is posted=20 at http:/mit.midco.net/rpratt.  I set the mean data to 950 to = put=20 the beginning portion expanded on the display.  I used = WinQuake=20 2.9.8. 
 
Randy
 
! PSN ASCII Event File Format = 2.0
Start Time:=20 2009/03/10 19:56:25.250000000
Start Time Offset: 0.000
Number of=20 Samples:  1000
SPS: 100
Time Reference Type: = Oth
Comment:[GVA]=20
A/D Converter Bits: 8
Data Minimum: 1
Data Maximum:  = 1000
Data=20 Mean:  950
! Sensor Information:
Sensor Location: = GVA
Sensor=20 Description: HS10-1
Sensor Latitude: 33.42138
Sensor Longitude:=20 -111.57477
Sensor Elevation: 507.5
Sensor Incident: 0
Sensor = Azimuth:=20 0
Sensor Orientation: Z
Sensor Type: Velocity
Sensor = Sensitivity: =20 7.100e-008
Sensor ID: HS-10
Magnitude Correction: = 0.00235574
Component=20 Name: SPZ
Network Affiliation: IRSS
Pick Information:
Pick=20 Information:
Data:
1000
999
998
997
996
995
...
2
1
 
Subject: Re: WinQuake Timing of text file From: Larry Cochrane lcochrane@.............. Date: Thu, 12 Mar 2009 16:08:40 -0700 All, I found the problem, it has to do with the Start Time field. When WinQuake loads a PSN Text formated event file it treats the number after the decimal point as milliseconds. So a number like 250000000 is not correct, it must be in the range of 000 to 999. Also, there must be one or two leading or trailing zeros after the decimal point to get the correct time in milliseconds. Here's some examples: 2009/03/10 19:56:25.0 - First sample happened at the top of the second. This is OK. 2009/03/10 19:56:25.1 - WQ would treat this as 1 millisecond NOT 100 ms. 2009/03/10 19:56:25.100 - WQ would treat this as 100 millisecond as expected. Since this is confusing, .1 should equal 100ms not 1ms, I released a new version of WQ to fix the problem. The new version can be downloaded from there: http://www.seismicnet.com/software/wq314b_setup.exe Randy, there is a problem with your text file besides the Start Time. The header info has the number of A/D bits set to 8, but you are placing numbers in the data section above 127. An 8 bit number would have the range of +127 to - 128. I'm not sure what WinQuake will do with this discrepancy. Regards, Larry Cochrane Redwood City, PSN Randy Pratt wrote: > Hello All, > > I did a quick experiment on this and I would agree the timing is incorrect on the WinQuake display. Here is my procedure: > > Make text file from the "don't work header" submitted a few days back with some modification of data and sample rate for 100 sps and 1000 total samples decreasing linearly with time. This should from the explanations given earlier begin to display at second number 26 given the start time of 19:56:25.25 and 75 samples into the data or at value 925 in theory. In fact the display starts at second 25 which is before the data start time and at the first sample value giving a .25 second time offset error. My test header and portion of data are here and the WinQuake display is posted at http:/mit.midco.net/rpratt. I set the mean data to 950 to put the beginning portion expanded on the display. I used WinQuake 2.9.8. > > Randy > > ! PSN ASCII Event File Format 2.0 > Start Time: 2009/03/10 19:56:25.250000000 > Start Time Offset: 0.000 > Number of Samples: 1000 > SPS: 100 > Time Reference Type: Oth > Comment:[GVA] > A/D Converter Bits: 8 > Data Minimum: 1 > Data Maximum: 1000 > Data Mean: 950 > ! Sensor Information: > Sensor Location: GVA > Sensor Description: HS10-1 > Sensor Latitude: 33.42138 > Sensor Longitude: -111.57477 > Sensor Elevation: 507.5 > Sensor Incident: 0 > Sensor Azimuth: 0 > Sensor Orientation: Z > Sensor Type: Velocity > Sensor Sensitivity: 7.100e-008 > Sensor ID: HS-10 > Magnitude Correction: 0.00235574 > Component Name: SPZ > Network Affiliation: IRSS > Pick Information: > Pick Information: > Data: > 1000 > 999 > 998 > 997 > 996 > 995 > ... > 2 > 1 > > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Timing Error From: "Randy Pratt" rpratt@............. Date: Fri, 13 Mar 2009 10:14:37 -0500 Larry, Thanks for the explanation. I redid the test with AD set to 12 bits and = used 250 in the decimal portion of seconds. The program works perfect = when given the correct info. Randy
Larry,
 
Thanks for the explanation.  I = redid the test=20 with AD set to 12 bits and used 250 in the decimal portion of = seconds.  The=20 program works perfect when given the correct info.
 
Randy
Subject: Re: Timing Error From: "Geoffrey" gmvoeth@........... Date: Fri, 13 Mar 2009 16:34:07 -0700 Just For Fun: Timing Error Timin Error Timi Error Tim Error Ti Error TError :-) ----- Original Message ----- From: "Randy Pratt" To: Sent: Friday, March 13, 2009 8:14 AM Subject: Timing Error Larry, Thanks for the explanation. I redid the test with AD set to 12 bits and used 250 in the decimal portion of seconds. The program works perfect when given the correct info. Randy __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Looking for Teledyne Geotech BB-13 plug to copy From: mongo@......... Date: Thu, 19 Mar 2009 21:21:38 +0000 Hi all, I have a Teledyne Geotech BB-13 seismometer which came without the plug. = This is the threaded plug that screws into the top of the seismometer (in= place of the locking plug) to seal it during operation. If anyone has one, I'd like to borrow it to have a copy machined. My BB-1= 3 did not come with it. Thanks, Bob Hammond PSN - Alaska Hi all,

I have a Teledyne Geotech= BB-13 seismometer which came without the plug.  This is the threade= d plug that screws into the top of the seismometer (in place of the locki= ng plug) to seal it during operation. 

If anyone has one, I'= d like to borrow it to have a copy machined.  My BB-13 did not come = with it.

Thanks,

Bob Hammond
PSN - Alaska
Subject: Re: Looking for Teledyne Geotech BB-13 plug to copy From: "fgentges@............... fgentges@mindspring.com Date: Thu, 19 Mar 2009 17:49:40 -0400 Bob, I have a BB-13 and it has a large plug in the center and smaller plugs over by the edge. Which are you looking for? Frank Gentges mongo@......... wrote: > Hi all, > > I have a Teledyne Geotech BB-13 seismometer which came without the > plug. This is the threaded plug that screws into the top of the > seismometer (in place of the locking plug) to seal it during operation. > > If anyone has one, I'd like to borrow it to have a copy machined. My > BB-13 did not come with it. > > Thanks, > > Bob Hammond > PSN - Alaska > > > ------------------------------------------------------------------------ > > > No virus found in this incoming message. > Checked by AVG - www.avg.com > Version: 8.0.237 / Virus Database: 270.11.17/2007 - Release Date: 03/17/09 10:18:00 > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Looking for Teledyne Geotech BB-13 plug to copy From: mongo@......... Date: Fri, 20 Mar 2009 14:54:23 +0000 HI Frank, I need the big one in the center. It should be a big knurled knob with an O-ring and maybe a bubble level in it. Thanks, Bob Hammond PSN-Alaska Subject: Re: Looking for Teledyne Geotech BB-13 plug to copy From: "fgentges@.............." Date: Thu, 19 Mar 2009 17:49:40 -0400 Bob, I have a BB-13 and it has a large plug in the center and smaller plugs over by the edge. Which are you looking for? Frank Gentges HI Frank,

I need the big one in t= he center.  It should be a big knurled knob with an O-ring and maybe= a bubble level in it.

Thanks,

Bob Hammond
PSN-Alaska

Subject: Re: Looking for Teledyne Geotech BB-13 plug to copy
= From:    "fgentges@m= indspring.com" <fgentge= s@..............>
Date:    Thu, 19 Mar 2009 17:49:40 -0400

Bob,

I have a BB-13 and it has a large plug in the center and smaller plugs over by the edge.  Which are you looking for?

Frank Gentges
Subject: Re: Looking for Teledyne Geotech BB-13 plug to copy From: George Bush ke6pxp@....... Date: Fri, 20 Mar 2009 08:42:53 -0700 Hi Ted- I have a BB-13 that is complete with manual I and have a plug on mine. It has standard NF 1/2"-20tpi threads and should be avilable from any hardwre or auto supply store. Of course, the one that comes on it is a really nice one with a knurled top, but a commercial bolt with an O-ring on it should seal until you can get something better. You would need to get the shortest bolt you could as the plug is 3/8" long (from face of head to end) and that includes a 1/8" captive groove for the O-ring and 1/4" of threads. I would love to talk to you about your instrument and mine. I have been fiddling with the filtering to detect earthquakes, and have wondered if I could use it to detct earth tides, I understand that the output goes down to DC. I built box of hard foam-core insulation around the istrument and it has really helped with temperature control and has minimized re-adjusting it. Hope this helps- George At 09:21 PM 3/19/2009 +0000, you wrote: >>>> Hi all, I have a Teledyne Geotech BB-13 seismometer which came without the plug. This is the threaded plug that screws into the top of the seismometer (in place of the locking plug) to seal it during operation. If anyone has one, I'd like to borrow it to have a copy machined. My BB-13 did not come with it. Thanks, Bob Hammond PSN - Alaska <<<<<<<< George Subject: Tonga 7.9 From: JAMES RIDOUT jamesridout@.............. Date: Fri, 20 Mar 2009 18:28:56 +0000 (GMT) Heres a link to my recording of this quake. =A0 http://www.youtube.com/watch?v=3DHJ8Oq0nn4LM
Heres a link to my recording of this qua= ke.
 
Subject: Tonga 7.9 From: JAMES RIDOUT jamesridout@.............. Date: Fri, 20 Mar 2009 18:31:16 +0000 (GMT) http://www.youtube.com/watch?v=3DHJ8Oq0nn4LM Subject: Re: Looking for Teledyne Geotech BB-13 plug to copy From: mongo@......... Date: Fri, 20 Mar 2009 21:44:41 +0000 Hi George, T think you got my name mixed up. Anyhow, I need thebig plug in the center. It should be a big knurled knob= with an O-ringand maybe a bubble level in it. This is the one that repla= ces the long shipping plug which locks the mass. I have all the other plu= gs (the two 1/2" ones). As far as using the BB-13 for earth tides, I think it's possible but I al= so think you'd have to have a very high quality seismic vault. My BB-13 i= s inside an aluminum foil covered blue-board insulation box about 4" thic= k all around and it still tends to drift, from either temperature or pres= sure changes. The manual stresses airtight operation and that's why I'm l= ooking for the original center plug with the O-ring.....to try and elimin= ate atmospheric pressure changes. If I cannot find a plug to copy, I may take Chris Chapman's advice and us= e a rubber stopper with vacuum grease or some other air-tight scheme. Thanks, Bob Hammond PSN-Alaska Subject: Re: Looking for Teledyne Geotech BB-13 plug to copy From: George Bush ke6pxp@....... Date: Fri, 20 Mar 2009 08:42:53 -0700 Hi Ted- I have a BB-13 that is complete with manual I and have a plug on mine. It= has standard NF 1/2"-20tpi threads and should be avilable from any hardwre or auto supply store. Of course, the one that comes on it is a really nice one with a knurled top, but a commercial bolt with an O-ring on it should seal until you can get something better. You would need to get the shortest bolt you could as the plug is 3/8" long (from face of head to end) and that includes a 1/8" captive groove for the O-ring and 1/4" of threads. I would love to talk to you about your instrument and mine. I have been fiddling with the filtering to detect earthquakes, and have wondered if I= could use it to detct earth tides, I understand that the output goes down= to DC. I built box of hard foam-core insulation around the istrument and it has really helped with temperature control and has minimized re-adjusting it. Hope this helps- George Hi George,

T think you got my nam= e mixed up. 

Anyhow, I need the big plug in the center.  It should be a big knurled knob with an O-r= ing and maybe a bubble level in it.  This is the one that replaces the l= ong shipping plug which locks the mass.  I have all the other plugs = (the two 1/2" ones).

As far as using the BB-13 for earth tides, I = think it's possible but I also think you'd have to have a very high quali= ty seismic vault.  My BB-13 is inside an aluminum foil covered blue-= board insulation box about 4" thick all around and it still tends to drif= t, from either temperature or pressure changes.  The manual stresses= airtight operation and that's why I'm looking for the original center pl= ug with the O-ring.....to try and eliminate atmospheric pressure changes.=

If I cannot find a plug to copy, I may take Chris Chapman's advic= e and use a rubber stopper with vacuum grease or some other air-tight sch= eme.

Thanks,

Bob Hammond
PSN-Alaska


Subject: Re: Looking for Teledyne Geotech BB-13 plug to copy
From= : George Bush ke6pxp@.......
Date: Fri, 20 Mar 2009 08:42:53 -0700
Hi Ted-


I have a BB-13 that is complete with manual I an= d have a plug on mine. It
has standard NF 1/2"-20tpi threads and shoul= d be avilable from any
hardwre or auto supply store. Of course, the on= e that comes on it is a
really nice one with a knurled top, but a comm= ercial bolt with an O-ring
on it should seal until you can get somethi= ng better. You would need to
get the shortest bolt you could as the pl= ug is 3/8" long (from face of
head to end) and that includes a 1/8" ca= ptive groove for the O-ring and
1/4" of threads.


I would l= ove to talk to you about your instrument and mine. I have been
fiddlin= g with the filtering to detect earthquakes, and have wondered if I
cou= ld use it to detct earth tides, I understand that the output goes downto DC. I built box of hard foam-core insulation around the istrument and=
it has really helped with temperature control and has minimized
re= -adjusting it.


Hope this helps- George
Subject: BB-13 plug....more From: mongo@......... Date: Sat, 21 Mar 2009 17:42:02 +0000 Anyone who has a BB-3 seismometer: would you be willing to send me some detailed photos of the plug I'm after? I could probably have one machined locally if I had more details about it. Bob PSN-Alaska http://wulik.com __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: BB-13 plug....more From: "Geoffrey" gmvoeth@........... Date: Sat, 21 Mar 2009 14:15:18 -0700 Is it possible for you to post a photo of which you speak. I tried to look this bb3 thing up but no photos. It appears to be a foreign ( non usa ) instrument. I have found hardwiring things together in a permanent fashion is best when you are dealing with geophones. Ideally they have an unlimited lifetime. ----- Original Message ----- From: To: Sent: Saturday, March 21, 2009 10:42 AM Subject: BB-13 plug....more > Anyone who has a BB-3 seismometer: would you be willing to send me some detailed photos of the plug I'm after? I could probably > have one machined locally if I had more details about it. > > Bob > PSN-Alaska > http://wulik.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) Subject: Re: BB-13 plug....more From: Angel sismos@.............. Date: Sun, 22 Mar 2009 12:41:48 +0000 Hello Mongo, Here is a link to the Geotech bb13 manual. there is a parts diagram at the end, are you looking for part number 37? angel Saturday, March 21, 2009, 5:42:02 PM, you wrote: > Anyone who has a BB-3 seismometer: would you be willing to send me > some detailed photos of the plug I'm after? I could probably have > one machined locally if I had more details about it. > Bob > PSN-Alaska > http://wulik.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. -- Best regards, Angel __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: re: BB-13 plug.... From: mongo@......... Date: Sun, 22 Mar 2009 17:05:14 +0000 Geoffrey, Why would I be asking for photos if I could send a photo of what I'm look= ing for? All I have is a parts manual. And...the Teledyne Geotech BB-13= seismometer was designed and built in the US. It's no longer in product= ion and no parts are available. For everyone's benefit: The BB-13 seismometer comes with a mass locking = plug used to keep the mass locked during shipping and handling. This plu= g is aluminum, threaded, and screws into the top center of the seismomete= r. Once the seismometer is installed, the mass locking plug is removed a= nd replaced with a similar plug or "cap" to seal the hole. I'm after tha= t replacement plug or cap. And since it replaces the mass locking plug, = I already know the size and thread information. I'd just like a photo of= this plug or cap from another BB-13 owner/operator to make sure I build = one like it was supposed to be built. Thanks to all for their input. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Teledyne Geotech 42.50 From: "Dale Hardy" photon1@........... Date: Mon, 23 Mar 2009 08:51:06 +1100 Hello all I have acquired a "Teledyne Geotech 42.50" and need a link to a = operating manual and circuit diagram of the amplifier regards Dale
Hello all
I have acquired a "Teledyne Geotech = 42.50" and need=20 a link to a operating manual and circuit diagram of the = amplifier
regards
Dale
 
Subject: WinQuake question for Larry From: Brett Nordgren brett3nt@............. Date: Thu, 26 Mar 2009 16:14:12 -0400 Larry, When I do an FFT on a PSN file, the result is normalized to fill the screen vertically. Is there any way to extract the normalization factor so that I could use the results to generate a calibrated noise spectrum? Brett __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: WinQuake question for Larry From: Larry Cochrane lcochrane@.............. Date: Fri, 27 Mar 2009 23:29:38 -0700 Brett, Brett Nordgren wrote: > Larry, > > When I do an FFT on a PSN file, the result is normalized to fill the screen > vertically. Is there any way to extract the normalization factor so that I > could use the results to generate a calibrated noise spectrum? Not within WinQuake. With the current version of WQ you can export the raw FFT data so you can analyze the FFT data using other programs like MATLAB or Excel. To do this create an FFT Window and use the File / Export menu items. The resulting file will look like this: Freq,Real,Imaginary,Magnitude 0.000190735,-0.0925326,0.182551,0.409328 0.00038147,-0.17057,-0.0860256,0.38207 0.000572205,0.110639,-0.0927722,0.288774 0.000762939,-0.0952175,0.178415,0.404466 0.000953674,-0.15761,-0.0518402,0.331834 0.00114441,0.0554941,-0.136885,0.295412 0.00133514,0.02051,0.0920337,0.188583 .... The first number is the frequency then the real and imaginary numbers from the FFT function and then the magnitude. The magnitude is calculated using the following C code mag = hypot(Real[i] , Imag[i] ); Regards, Larry Cochrane Webtronics __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: WinQuake question for Larry From: Brett Nordgren brett3nt@............. Date: Sat, 28 Mar 2009 09:54:54 -0400 Larry, Many thanks. I downloaded the (very) new WinQuake and now have the FFT data exported. I think that it is exactly what I was looking for. Now to get educated on spectral density stuff. Brett At 11:29 PM 3/27/2009 -0700, you wrote: >Brett, > >Brett Nordgren wrote: >>Larry, >>When I do an FFT on a PSN file, the result is normalized to fill the >>screen vertically. Is there any way to extract the normalization factor >>so that I could use the results to generate a calibrated noise spectrum? > >Not within WinQuake. With the current version of WQ you can export the raw >FFT data so you can analyze the FFT data using other programs like MATLAB >or Excel. To do this create an FFT Window and use the File / Export menu >items. The resulting file will look like this: > >Freq,Real,Imaginary,Magnitude >0.000190735,-0.0925326,0.182551,0.409328 >0.00038147,-0.17057,-0.0860256,0.38207 >0.000572205,0.110639,-0.0927722,0.288774 >0.000762939,-0.0952175,0.178415,0.404466 >0.000953674,-0.15761,-0.0518402,0.331834 >0.00114441,0.0554941,-0.136885,0.295412 >0.00133514,0.02051,0.0920337,0.188583 >... > >The first number is the frequency then the real and imaginary numbers from >the FFT function and then the magnitude. The magnitude is calculated using >the following C code > >mag = hypot(Real[i] , Imag[i] ); > >Regards, >Larry Cochrane >Webtronics __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: WinQuake question for Larry From: "Geoffrey" gmvoeth@........... Date: Sat, 28 Mar 2009 09:20:38 -0700 Hello You Math experts; By Spectral Density are you by chance figuring the area under the curve ? Which I believe to be a calculus thingy ? Regards; geoff ----- Original Message ----- From: "Brett Nordgren" To: Sent: Saturday, March 28, 2009 6:54 AM Subject: Re: WinQuake question for Larry > Larry, > > Many thanks. I downloaded the (very) new WinQuake and now have the FFT > data exported. I think that it is exactly what I was looking for. > > Now to get educated on spectral density stuff. > > Brett > > > At 11:29 PM 3/27/2009 -0700, you wrote: >>Brett, >> >>Brett Nordgren wrote: >>>Larry, >>>When I do an FFT on a PSN file, the result is normalized to fill the >>>screen vertically. Is there any way to extract the normalization factor >>>so that I could use the results to generate a calibrated noise spectrum? >> >>Not within WinQuake. With the current version of WQ you can export the raw >>FFT data so you can analyze the FFT data using other programs like MATLAB >>or Excel. To do this create an FFT Window and use the File / Export menu >>items. The resulting file will look like this: >> >>Freq,Real,Imaginary,Magnitude >>0.000190735,-0.0925326,0.182551,0.409328 >>0.00038147,-0.17057,-0.0860256,0.38207 >>0.000572205,0.110639,-0.0927722,0.288774 >>0.000762939,-0.0952175,0.178415,0.404466 >>0.000953674,-0.15761,-0.0518402,0.331834 >>0.00114441,0.0554941,-0.136885,0.295412 >>0.00133514,0.02051,0.0920337,0.188583 >>... >> >>The first number is the frequency then the real and imaginary numbers from >>the FFT function and then the magnitude. The magnitude is calculated using >>the following C code >> >>mag = hypot(Real[i] , Imag[i] ); >> >>Regards, >>Larry Cochrane >>Webtronics > > > __________________________________________________________ > > 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: WinQuake question for Larry From: Brett Nordgren brett3nt@............. Date: Sat, 28 Mar 2009 15:53:00 -0400 Geoff, I am definitely not the one to be giving the real answers to this. I'm just (re)learning this stuff, myself. It is my impression that the FFT, properly calibrated, is itself a spectral density curve, in my case based on ground velocity. Much more commonly seen is a plot of power density, indicating how much noise power is at each frequency (in each frequency band). Such plots are based on the squares of the velocity numbers. Randall Peters suggests http://physics.mercer.edu/hpage/CSP/cumulative.html that the Cumulative Spectral Power curve, which is pretty much like the integral you mention, has some advantages over the un-integrated curve, though the latter is what is now in general use for defining instrument and site noise. You can find the power spectral density curves for most instruments/sites in the various research networks. The above is about 20% more than I know about the subject, which covers a lot of math--mostly probablility theory and lots of calculus. I suspect not for the faint of heart. Regards, Brett At 09:20 AM 3/28/2009 -0700, you wrote: >Hello You Math experts; > >By Spectral Density are you by chance >figuring the area under the curve ? >Which I believe to be a calculus thingy ? > >Regards; >geoff __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Unknown event From: "tchannel" tchannel@............ Date: Sun, 29 Mar 2009 08:27:08 -0600 Hi Folks, Today March 29th about 02:35am,MDT, 07:35utc, I recorded an = event. At least it looks just like an earthquake, but I see nothing = posted for this time. Did anyone record anything around 07:35 utc? We had a large wind storm about that time, but I don't think its weather = related. Thanks, Ted
Hi Folks, Today March = 29th about=20 02:35am,MDT,  07:35utc, I recorded an event.  At least it = looks just=20 like an earthquake, but I see nothing posted for this time.   = Did=20 anyone record anything around 07:35 utc?
We had a large wind storm about that = time, but I=20 don't think its weather related.
 
Thanks, Ted
Subject: Re: Unknown event From: "Geoffrey" gmvoeth@........... Date: Sun, 29 Mar 2009 08:02:32 -0700 Here At GVA I saw Nothing Yet I had My Threshold Set Quite Sensitive. I should Have seen Any Event Of 4.0 or greater at 6 degrees away. I am not sure exactly what MDL that represents. It is like a 6.5 (RICHTER) almost anywhere in the world. That does not mean that something did not happen like a nuke in North Korea or something. ----- Original Message ----- From: "tchannel" To: "psn" Sent: Sunday, March 29, 2009 7:27 AM Subject: Unknown event Hi Folks, Today March 29th about 02:35am,MDT, 07:35utc, I recorded an event. At least it looks just like an earthquake, but I see nothing posted for this time. Did anyone record anything around 07:35 utc? We had a large wind storm about that time, but I don't think its weather related. Thanks, Ted __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Unknown event From: Bob Hancock icarus@......... Date: Sun, 29 Mar 2009 09:20:34 -0700 Ted- The stations at Blue Mountain, Oregon (BMO), and Hailey, Idaho (HLID), both part of the US Array, show no activity. Here is a link for additional stations in your area. A review of the stations in Idaho found nothing in the time you mentioned. http://www.mines.uidaho.edu/~quakes/seismograms.htm Bob Hancock On Mar 29, 2009, at 7:27 AM, tchannel wrote: > Hi Folks, Today March 29th about 02:35am,MDT, 07:35utc, I recorded > an event. At least it looks just like an earthquake, but I see > nothing posted for this time. Did anyone record anything around > 07:35 utc? > We had a large wind storm about that time, but I don't think its > weather related. > > Thanks, Ted http://www.mi= nes.uidaho.edu/~quakes/seismograms.htm

Bob = Hancock



On Mar 29, = 2009, at 7:27 AM, tchannel wrote:

Hi Folks, Today March = 29th about 02:35am,MDT,  07:35utc, I recorded an event.  = At least it looks just like an earthquake, but I see nothing posted for = this time.   Did anyone record anything around 07:35 = utc?
We had a large = wind storm about that time, but I don't think its weather = related.
 
Thanks, = Ted

= Subject: Re: Unknown event From: "tchannel" tchannel@............ Date: Sun, 29 Mar 2009 10:29:10 -0600 Hi Folks, Thanks for your input, I see nothing, from the surrounding = stations either. I guess it was the wind storm. Unusual however, no = wind noise before or after this 20 signature, even though the wind was = still blowing hard. I will email this .psn if anyone would like to see = it. It looked very much like an earthquake, and not like something = coming from the local area. I will keep looking, but it must have been = the wind. Thanks, Ted ----- Original Message -----=20 From: Bob Hancock=20 To: psn-l@................. Sent: Sunday, March 29, 2009 10:20 AM Subject: Re: Unknown event Ted- The stations at Blue Mountain, Oregon (BMO), and Hailey, Idaho (HLID), = both part of the US Array, show no activity. Here is a link for = additional stations in your area. A review of the stations in Idaho = found nothing in the time you mentioned. http://www.mines.uidaho.edu/~quakes/seismograms.htm Bob Hancock On Mar 29, 2009, at 7:27 AM, tchannel wrote: Hi Folks, Today March 29th about 02:35am,MDT, 07:35utc, I recorded = an event. At least it looks just like an earthquake, but I see nothing = posted for this time. Did anyone record anything around 07:35 utc? We had a large wind storm about that time, but I don't think its = weather related. Thanks, Ted
Hi Folks,  Thanks for your input, = I see=20 nothing, from the surrounding stations either.  I guess it was the = wind=20 storm.   Unusual however, no wind noise before or after this = 20=20 signature, even though the wind was still blowing hard.   I = will email=20 this .psn if anyone would like to see it.   It looked very = much like=20 an earthquake, and not like something coming from the local = area.   I=20 will keep looking, but it must have been the wind.
 
Thanks, Ted
----- Original Message -----
From:=20 Bob = Hancock=20
Sent: Sunday, March 29, 2009 = 10:20=20 AM
Subject: Re: Unknown = event

Ted-

The stations at Blue Mountain, Oregon (BMO), and Hailey, Idaho = (HLID),=20 both part of the US Array, show no activity.  Here is a link for=20 additional stations in your area.  A review of the stations in = Idaho=20 found nothing in the time you mentioned.

http://www.m= ines.uidaho.edu/~quakes/seismograms.htm

Bob Hancock



On Mar 29, 2009, at 7:27 AM, tchannel wrote:
Hi Folks, Today March = 29th about=20 02:35am,MDT,  07:35utc, I recorded an event.  At least it = looks=20 just like an earthquake, but I see nothing posted for this = time.  =20 Did anyone record anything around 07:35 utc?
We had a large wind storm about = that time, but=20 I don't think its weather related.
 
Thanks,=20 = Ted

<= /HTML> Subject: Re: John Lahr From: Robert McClure bobmcclure90@......... Date: Sun, 29 Mar 2009 21:33:26 -0400 Hi all, Dr. John Lahr, USGS Emeritus Geophysicist, passed away on March 14, 2009, at the age of 64, from malignant brain cancer. John was very active in putting seismometers in schools around the country through the Seismographs in Schools Program of the Incorporated Research Institutions for Seismology (IRIS), for which he taught teacher workshops, traveled to schools throughout the country, worked with many more teachers via e-mail and phone, and helped in the development and trouble-shooting of the equipment and software. He was also mentor to and colleague of many of us in the PSN network. We shall miss him greatly. John's obituary was published March 27 in the Corvallis Gazette Times: http://www.gazettetimes.com/articles/2009/03/27/news/obituaries/3obi03_lahr0327.txt Please also see the following web site, which John had set up for his wife, Jan, to chronicle his struggle with cancer: http://johnsnoggin.blogspot.com/ I believe his web site, http://www.jclahr.com/ is to be maintained by Kay Wyatt __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: John Lahr From: "Kay Wyatt" kwyatt@............. Date: Sun, 29 Mar 2009 19:34:15 -0700 Thank you, Robert. I also wanted to mention that the tribute page for John Lahr is at www.jclahr.com If you are interested in submitting a tribute please let me know. The Lahr family has been very touched at all the people that have shared how John Lahr touched their lives. My email address is kwyatt@.............. I am in particular need for someone to comment on John's contributions to the PSN network and amateur seismology. In addition, The Lahr Family and IRIS have established the John C. Lahr Educational Seismology Fund. You can find information about this newly established fund at www.jclahr.com Thanks, Kay Wyatt ----- Original Message ----- From: "Robert McClure" To: Cc: ; ; ; Sent: Sunday, March 29, 2009 6:33 PM Subject: Re: John Lahr > Hi all, > > Dr. John Lahr, USGS Emeritus Geophysicist, passed away on March 14, > 2009, at the age of 64, from malignant brain cancer. > > John was very active in putting seismometers in schools around the > country through the Seismographs in Schools Program of the > Incorporated Research Institutions for Seismology (IRIS), for which he > taught teacher workshops, traveled to schools throughout the country, > worked with many more teachers via e-mail and phone, and helped in the > development and trouble-shooting of the equipment and software. He was > also mentor to and colleague of many of us in the PSN network. We > shall miss him greatly. > > John's obituary was published March 27 in the Corvallis Gazette Times: > > http://www.gazettetimes.com/articles/2009/03/27/news/obituaries/3obi03_lahr0327.txt > > Please also see the following web site, which John had set up for > his wife, Jan, to chronicle his struggle with cancer: > > http://johnsnoggin.blogspot.com/ > > I believe his web site, http://www.jclahr.com/ is to be maintained by > > Kay Wyatt > __________________________________________________________ > > 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: John Lahr From: "Kay Wyatt" kwyatt@............. Date: Sun, 29 Mar 2009 19:34:15 -0700 Thank you, Robert. I also wanted to mention that the tribute page for John Lahr is at www.jclahr.com If you are interested in submitting a tribute please let me know. The Lahr family has been very touched at all the people that have shared how John Lahr touched their lives. My email address is kwyatt@.............. I am in particular need for someone to comment on John's contributions to the PSN network and amateur seismology. In addition, The Lahr Family and IRIS have established the John C. Lahr Educational Seismology Fund. You can find information about this newly established fund at www.jclahr.com Thanks, Kay Wyatt ----- Original Message ----- From: "Robert McClure" To: Cc: ; ; ; Sent: Sunday, March 29, 2009 6:33 PM Subject: Re: John Lahr > Hi all, > > Dr. John Lahr, USGS Emeritus Geophysicist, passed away on March 14, > 2009, at the age of 64, from malignant brain cancer. > > John was very active in putting seismometers in schools around the > country through the Seismographs in Schools Program of the > Incorporated Research Institutions for Seismology (IRIS), for which he > taught teacher workshops, traveled to schools throughout the country, > worked with many more teachers via e-mail and phone, and helped in the > development and trouble-shooting of the equipment and software. He was > also mentor to and colleague of many of us in the PSN network. We > shall miss him greatly. > > John's obituary was published March 27 in the Corvallis Gazette Times: > > http://www.gazettetimes.com/articles/2009/03/27/news/obituaries/3obi03_lahr0327.txt > > Please also see the following web site, which John had set up for > his wife, Jan, to chronicle his struggle with cancer: > > http://johnsnoggin.blogspot.com/ > > I believe his web site, http://www.jclahr.com/ is to be maintained by > > Kay Wyatt > __________________________________________________________ > > 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: Unknown event From: Bob Hancock icarus@......... Date: Sun, 29 Mar 2009 23:11:23 -0700 Hi ted - Interesting - Following is my take - just that of another amateur. Looking at it without spreading, I see an increase in amplitude that appears to start about 0732:55, and then a sharp increase in amplitude about 0737:11. When I changed the X scale to 15 seconds, I see the large wave amplitude and overlaid on that is a smaller, higher frequency wave, possibly your background noise. The thing that stands out to me is that I do not see any wave pattern that I recognize. I have see many events where the P wave and sometimes the S wave are lost in the background noise - you appear to have moderate background noise. The focal mechanism can also suppress the P & S waves. However excluding all body waves (P, S, etc, etc, etc, etc) I don't see anything that looks like a Love or Rayleigh wave. The sharpness of the onset at 0732:11 is not typical of either Love or Rayleigh wave, and again typically, their frequencies are much longer 15-30 seconds. The Love wave is typically a large wave and on the transverse channel. You will not see it on the radial or vertical channels. In other words, if the signal is 90 degrees to the sensor, you will see Love waves, but no Rayleigh waves. If the sensor is aligned with the incoming ray path of the event, you will not see Love waves, but will see Rayleigh waves. In other words, in your location, Boise, ID, you will see Rayleigh waves from all the Transpacific teleseismic events, but no Love waves. On events from the north such as the recent event North of Svalbard, you will see Love waves, but no Rayleigh waves. If the event were to occur in Seattle, you would see both waves. Another indicator is the frequency of the large waves. Again typically, Love and Rayleigh waves have much longer frequencies that the 2 to 3 seconds that I see. I am not saying absolutely because with a single station, you cannot orientate the direction the signal came from, but based upon everything that I see I would be hard pressed to call it an earthquake. I looked at the frequency of the signal FFT (Linear), and found the frequency to be broad based. When I used a notch filter to remove the all data from 0.4 to 1 hz, the signal was still there and very clear. I also played around with both high and low pass filter, and the bandpass filter. Still nothing was recognizable Summary - The overall frequency is higher than would be expected for a seismic event. The shape of the waves are not typical of seismic event waves. I did not recognize any seismic waves. Could it be wind - possibly, but without recorded weather to correlate the wind velocity with sensor activity, that becomes another had call. If you feel that there is good correlation, then wind is a strong possibility, but that is call you must make. Your seismogram extends for over 20 minutes past the sharp increase in amplitude at 0737. When the seismogram ends, the base amplitude is still higher than when the seismogram begins. There are a number of articles on the PSN web site about calibration. I would suggest that when you have time, you look at calibrating your instrument. You are currently displaying milivolts, but if your had the instrument calibrated, you would have a much better idea of magnitude and then be able to compare that with nearby stations. Ted - my apologies, I have written a lot of words, but really said nothing. I guess the sudden onset and gradual decline in amplitude is what is catching my attention. Like I said earlier, if that matches the wind then that is probably the answer, if not, I am not certain what to say except something obviously excited your sensor - most likely something other than an earthquake, but I will leave that answer to you. Cheers Bob On Mar 29, 2009, at 7:27 AM, tchannel wrote: > Hi Folks, Today March 29th about 02:35am,MDT, 07:35utc, I recorded > an event. At least it looks just like an earthquake, but I see > nothing posted for this time. Did anyone record anything around > 07:35 utc? > We had a large wind storm about that time, but I don't think its > weather related. > > Thanks, Ted
Hi ted = - 

Interesting - Following is my take - = just that of another amateur.

Looking at it = without spreading, I see an increase in amplitude that appears = to start about 0732:55, and then a sharp increase in amplitude about = 0737:11.  When I changed the X scale to 15 seconds, I see the large = wave amplitude and overlaid on that is a smaller, higher frequency wave, = possibly your background noise.

The thing that = stands out to me is that I do not see any wave pattern that I recognize. =  I have see many events where the P wave and sometimes the S wave = are lost in the background noise - you appear to have moderate = background noise.  The focal mechanism can = also suppress the P & S waves.  However excluding all = body waves (P, S, etc, etc, etc, etc) I don't see anything that looks = like a Love or Rayleigh wave.  The sharpness of the onset at = 0732:11 is not typical of either Love or Rayleigh wave, and again = typically, their frequencies are much longer 15-30 seconds. =  The Love wave is typically a large wave and on the transverse = channel.  You will not see it on the radial or vertical channels. =  In other words, if the signal is 90 degrees to the sensor, you = will see Love waves, but no Rayleigh waves.  If the sensor is = aligned with the incoming ray path of the event, you will not = see Love waves, but will see Rayleigh waves.

In = other words, in your location, Boise, ID, you will see Rayleigh waves = from all the Transpacific teleseismic events, but no Love waves. =  On events from the north such as the recent event North of = Svalbard, you will see Love waves, but no Rayleigh waves.  If the = event were to occur in Seattle, you would see both = waves.

Another indicator is the frequency of = the large waves.  Again typically, Love and Rayleigh waves have = much longer frequencies that the 2 to 3 seconds that I see.  I am = not saying absolutely because with a single station, you = cannot orientate the direction the signal came from, but based upon = everything that I see I would be hard pressed to call it an = earthquake.

I looked at the frequency of the = signal FFT (Linear), and found the frequency to be broad based. =  When I used a notch filter to remove the all data from 0.4 to 1 = hz, the signal was still there and very clear. I also played around with = both high and low pass filter, and the bandpass filter.  Still = nothing was recognizable 

Summary = -

The overall frequency is higher than would be = expected for a seismic event.

The shape of the = waves are not typical of seismic event waves.

I = did not recognize any seismic waves.

Could it = be wind - possibly, but without recorded weather = to correlate the wind velocity with sensor activity, that = becomes another had call.  If you feel that there is good = correlation, then wind is a strong possibility, but that is call you = must make.

Your seismogram extends for over 20 = minutes past the sharp increase in amplitude at 0737.  When the = seismogram ends, the base amplitude is still higher than when the = seismogram begins.

There are a number of = articles on the PSN web site about calibration.  I would suggest = that when you have time, you look at calibrating your instrument. =  You are currently displaying milivolts, but if your had the = instrument calibrated, you would have a much better idea of magnitude = and then be able to compare that with nearby = stations.

Ted - my apologies, I have written a = lot of words, but really said nothing.  I guess the sudden onset = and gradual decline in amplitude is what is catching my attention. Like = I said earlier, if that matches the wind then that is probably the = answer, if not, I am not certain what to say except something obviously = excited your sensor - most likely something other than an earthquake, = but I will leave that answer to = you.

Cheers

Bob








On Mar 29, 2009, at 7:27 AM, = tchannel wrote:

Hi Folks, Today March = 29th about 02:35am,MDT,  07:35utc, I recorded an event.  = At least it looks just like an earthquake, but I see nothing posted for = this time.   Did anyone record anything around 07:35 = utc?
We had a large = wind storm about that time, but I don't think its weather = related.
 
Thanks, = Ted

= Subject: Rayleigh and Love waves From: Tangazazen@....... Date: Mon, 30 Mar 2009 04:53:38 EDT Hi Bob, I was most interested in your surface wave comments.Here in England local earth quakes are rare so most events detected are teleseismic. I have a pendulum seismometer that resolves both X and Y axis components independently ( broadband 50 seconds ). If I plot the N-S verses E-W components during the first few minutes of a teleseismic event one gets a form that indicates the direction of arrival. The Svalbard event you mention shows a form whose major axis is along the NNW-SSE, consistent with it's location relative to England. For the recent Tonga event M7.8, the X-Y plot has a majors axis virtually north- south consistent with the shortest path though China, Siberia and the north pole. Inspection of the individual seismographs show an initial strong radial component relative to the transverse as would be expected. The last local event was 2 years ago ( M 4.7 ) so I have to make the most of teleseismic events! Regards Martin
Hi Bob,
 
  I was most interested in your surface wave comments.Here in Engl= and=20 local earth quakes are rare so most events detected are teleseismic.
 
I have a pendulum seismometer that resolves both X and Y axis component= s=20 independently ( broadband 50 seconds ). If I plot the N-S verses E-W=20 components during the first few minutes of a teleseismic event one gets a fo= rm=20 that indicates the direction of arrival. The Svalbard event you mention show= s a=20 form whose major axis is along the  NNW-SSE, consistent with it's=20 location relative to England. For the recent Tonga event M7.8, the= X-Y=20 plot has a majors axis virtually north- south consistent with the=20 shortest path though China, Siberia and the north pole.
Inspection of the individual seismographs show an initial strong radial= =20 component relative to the transverse as would be expected.
 
The last local event was  2 years ago ( M 4.7 ) so I have to make=20= the=20 most of teleseismic events!
 
 
Regards Martin  
Subject: Re: Unknown event From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@......... Date: Mon, 30 Mar 2009 10:56:52 +0000 Hello Can I take a look at this event. I might be able to tell you if this is a earthquake or something else. Regards. J=F3n Fr=EDmann. On sun, 2009-03-29 at 08:27 -0600, tchannel wrote: > Hi Folks, Today March 29th about 02:35am,MDT, 07:35utc, I recorded an > event. At least it looks just like an earthquake, but I see nothing > posted for this time. Did anyone record anything around 07:35 utc? > We had a large wind storm about that time, but I don't think its > weather related. > =20 > Thanks, Ted __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Rayleigh and Love waves From: Bob Hancock icarus@......... Date: Mon, 30 Mar 2009 11:58:34 -0700 Hi Martin - With two horizontal channels, you an use the amplitude of the P wave arrivals to determine a great circle path through your station. However that is insufficient information for you to determine which of two inbound headings the signal came from. For that information, you need the initial motion on the P waves from both horizontal channels and the vertical channel. Bob Hancock On Mar 30, 2009, at 1:53 AM, Tangazazen@....... wrote: > Hi Bob, > > I was most interested in your surface wave comments.Here in > England local earth quakes are rare so most events detected are > teleseismic. > > I have a pendulum seismometer that resolves both X and Y axis > components independently ( broadband 50 seconds ). If I plot the N-S > verses E-W components during the first few minutes of a teleseismic > event one gets a form that indicates the direction of arrival. The > Svalbard event you mention shows a form whose major axis is along > the NNW-SSE, consistent with it's location relative to England. For > the recent Tonga event M7.8, the X-Y plot has a majors axis > virtually north- south consistent with the shortest path though > China, Siberia and the north pole. > Inspection of the individual seismographs show an initial strong > radial component relative to the transverse as would be expected. > > The last local event was 2 years ago ( M 4.7 ) so I have to make > the most of teleseismic events! > > > Regards Martin
Hi Martin = -

With two horizontal channels, you an use the = amplitude of the P wave arrivals to determine a great circle path = through your station.  However that is insufficient information for = you to determine which of two inbound headings the signal came from. =  For that information, you need the initial motion on the P waves = from both horizontal channels and the vertical channel. =  

Bob = Hancock


On Mar 30, 2009, at 1:53 AM, = Tangazazen@....... = wrote:

Hi Bob,
=
 
  I was most interested in your surface wave = comments.Here in England local earth quakes are rare so most events = detected are teleseismic.
 
I have a pendulum = seismometer that resolves both X and Y axis components independently ( = broadband 50 seconds ). If I plot the N-S verses E-W components = during the first few minutes of a teleseismic event one gets a form that = indicates the direction of arrival. The Svalbard event you mention shows = a form whose major axis is along the  NNW-SSE, consistent with = it's location relative to England. For the recent Tonga event = M7.8, the X-Y plot has a majors axis virtually north- = south consistent with the shortest path though China, Siberia and = the north pole.
Inspection of the individual seismographs = show an initial strong radial component relative to the transverse as = would be expected.
 
The last local event = was  2 years ago ( M 4.7 ) so I have to make the most of = teleseismic events!
 
 
=
Regards = Martin  

= Subject: Re: Rayleigh and Love waves From: Tangazazen@....... Date: Mon, 30 Mar 2009 15:43:45 EDT Hi Bob, Exactly, which is why I quoted both headings. The Svalbard event did exhibit a reasonable P and S, which gave me a distance, A southern heading would put the event in the middle of the Sahara desert, a bit unlikely thought! Unfortunately Tonga is in the quite zone relative to England so I only receive the surface wave. That takes about an hour and ten minutes to get here. That's plenty of time to determine when and from what direction it's arriving. The seismic output of the mercury tiltmeter and the vertical broadband are omnidirectional and not so informative unless the signal to noise ratio is good. . Regards Martin
Hi Bob,
 
     Exactly, which is why I quoted both headi= ngs.=20 The Svalbard event did exhibit a reasonable P and S, which gave me a=20 distance,  A southern heading would put the event in the middle of= the=20 Sahara desert, a bit unlikely thought!
 
Unfortunately Tonga is in the quite zone relative to England so I only=20 receive the surface wave. That takes about an hour and ten minutes to g= et=20 here. That's plenty of time to determine when and from what direct= ion=20 it's arriving.
 The seismic output of the mercury tiltmeter and the vertical=20 broadband are omnidirectional and not so informative unless the signal to no= ise=20 ratio is good. .
 
Regards Martin
Subject: OLDER SEISMOMETERS FOR SALE From: "James Allen" jcallen1@........... Date: Mon, 30 Mar 2009 21:15:37 -0700 I met a gentleman via email, Matt, that has a number of older = seismometers for sale, with some on EBay, a Kinemetrics vertical and = horizontal and a ranger. One of the item numbers is 110369876034, that = listing will take you to the other two he has. He also would like help = in identifying a number of other seismometers he has that he has not = listed as yet. The URL for the pictures is = http://s271.photobucket.com/albums/jj139/shostang/Seismology/ He would = really appreciate list members help in identifying the units he has. ----- Original Message -----=20 From: Bob Hancock=20 To: psn-l@................. Sent: Monday, March 30, 2009 11:58 AM Subject: Re: Rayleigh and Love waves Hi Martin - With two horizontal channels, you an use the amplitude of the P wave = arrivals to determine a great circle path through your station. However = that is insufficient information for you to determine which of two = inbound headings the signal came from. For that information, you need = the initial motion on the P waves from both horizontal channels and the = vertical channel. =20 Bob Hancock On Mar 30, 2009, at 1:53 AM, Tangazazen@....... wrote: Hi Bob, I was most interested in your surface wave comments.Here in = England local earth quakes are rare so most events detected are = teleseismic. I have a pendulum seismometer that resolves both X and Y axis = components independently ( broadband 50 seconds ). If I plot the N-S = verses E-W components during the first few minutes of a teleseismic = event one gets a form that indicates the direction of arrival. The = Svalbard event you mention shows a form whose major axis is along the = NNW-SSE, consistent with it's location relative to England. For the = recent Tonga event M7.8, the X-Y plot has a majors axis virtually north- = south consistent with the shortest path though China, Siberia and the = north pole. Inspection of the individual seismographs show an initial strong = radial component relative to the transverse as would be expected. The last local event was 2 years ago ( M 4.7 ) so I have to make = the most of teleseismic events! Regards Martin =20
I met a gentleman via email, = Matt, that has a=20 number of older seismometers for sale, with some on EBay, a Kinemetrics = vertical=20 and horizontal and a ranger.  One of the item numbers is = 110369876034, that=20 listing will take you to the other two he has.  He also would like = help in=20 identifying a number of other seismometers he has that he has not listed = as=20 yet.  The URL for the pictures is ht= tp://s271.photobucket.com/albums/jj139/shostang/Seismology/ =20 He would really appreciate list members help in identifying the units he = has.
----- Original Message -----
From:=20 Bob = Hancock=20
Sent: Monday, March 30, 2009 = 11:58=20 AM
Subject: Re: Rayleigh and Love=20 waves

Hi Martin -

With two horizontal channels, you an use the amplitude of the P = wave=20 arrivals to determine a great circle path through your station. =  However=20 that is insufficient information for you to determine which of two = inbound=20 headings the signal came from.  For that information, you need = the=20 initial motion on the P waves from both horizontal channels and the = vertical=20 channel.  

Bob Hancock


On Mar 30, 2009, at 1:53 AM, Tangazazen@....... = wrote:
Hi Bob,
 
  I was most interested in your surface wave comments.Here = in=20 England local earth quakes are rare so most events detected are=20 teleseismic.
 
I have a pendulum seismometer that resolves both X and Y axis=20 components independently ( broadband 50 seconds ). If I plot = the N-S=20 verses E-W components during the first few minutes of a teleseismic = event=20 one gets a form that indicates the direction of arrival. The = Svalbard event=20 you mention shows a form whose major axis is along = the  NNW-SSE,=20 consistent with it's location relative to England. For = the recent=20 Tonga event M7.8, the X-Y plot has a majors axis virtually = north-=20 south consistent with the shortest path though China, Siberia = and the=20 north pole.
Inspection of the individual seismographs show an initial = strong radial=20 component relative to the transverse as would be expected.
 
The last local event was  2 years ago ( M 4.7 ) so I have = to make=20 the most of teleseismic events!
 
 
Regards=20 Martin  

= Subject: Designing a new vertical sensor From: "tchannel" tchannel@............ Date: Tue, 31 Mar 2009 09:27:30 -0600 Hi Folks, With the help of the PSN group, I have made several different = sensors. At least one sensor for each concept I have seen. From all = the designs, my favorite is a simple Vertical. It is a long spring = with a mass, magnet and coil. This approach has been my best sensor. = It is limited by its period, 1.5 seconds but it is very sensitive, easy = to build and nothing to maintain. It records all the earthquake, near = and far, big and small. However it could be better. I know there are many approaches, but I wish to build another vertical, = starting with this design and improving it. I would like to correspond = with someone interested in helping me. Before I begin we could review = the design and look at ideas on how to enhance the various parts. I = would like someone's opinion as to what to expect = if:................."What If I doubled the mass"?.............."What if = I doubled the magnets"? "How could I reduce the noise"? etc. Free time is in short supply, and I understand, but email me if = interested. I can do all the work, I think, but could use some = direction, rather than a series of trials and errors. Thanks, Ted
Hi Folks,  With the help of the = PSN group, I=20 have made several different sensors.   At least one = sensor for=20 each concept I have seen.  From all the designs, my favorite is a = simple=20 Vertical.   It is a long spring with a mass, magnet and=20 coil.   This approach has been my best sensor.   It = is=20 limited by its period, 1.5 seconds but it is very sensitive, easy to = build and=20 nothing to maintain.   It records all the earthquake, near and = far,=20 big and small.   However it could be better.
 
I know there are many approaches, but I = wish to=20 build another vertical, starting with this design and improving = it.  =20 I would like to correspond with someone interested in helping = me.  =20 Before I begin we could review the design and look at ideas on how = to=20 enhance the various parts.   I would like someone's opinion as = to what=20 to expect if:................."What If I doubled the = mass"?.............."What=20 if I doubled the magnets"?
"How could I reduce the noise"? =20 etc.
 
Free time is in short supply, and I = understand, but=20 email me if interested.   I can do all the work, I think, but = could=20 use some direction, rather than a series of trials and = errors.
 
Thanks, Ted
http://www.youtube.com/watch?v=3DHJ8Oq0nn4LM