Subject: Re: Student Question... From: "Jan D. Froom" froom@............. Date: Wed, 29 Sep 1999 17:19:34 -0700 Thank you for the replies to our student question. Per Ken's suggestion, we'd like to let the students pursue this a bit more by collecting sand from various beaches around the world, and testing their hypotheses. If any of you have access to beach sand, and would be willing to send it to us, we'll let you see the results of the kids work. Sharon Redford is the teacher, and she says they need about a 1/2 cup. Mail to: Sharon Redford South Valley Junior High School of Science and Technology 385 IOOF Avenue Gilroy, CA 95020 USA THANKS again! Jan "Kenneth J. De Nault" wrote: > I would commend the student for his hypothesis and ask him to propose some > method for testing his hypothesis, such as examining the iron content of sand > from Alaska. You might also ask him to make a prediction concerning the iron > content of sands as one goes toward the south pole. > > I would not tell him he is "wrong" but would encourage him to be a scientist. > All of us "scientists" have proposed "wrong" hypothesis. > > Ken De Nault. > > P.S. The "iron" content is most probably the mineral magnetite. This is a > dense, iron oxide mineral whose concentration is a function of many factors, > among which is availability in the source rock, the energy of the transport > mechanism, and the energy of the depositional environment. As a dense mineral, > it tends to be concentrated by the removal of the less dense, and generally much > more abundant, silicate minerals. > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: More diamagnetism tid-bits From: meredithlamb@.............. Date: 29 Sep 1999 17:29:25 -0700 Hi all, From Robert Lamb: "Got to reviewing past editions of "HCP", (Handbook of Chem & Physics), and caught onto apparent disparagement of diamagnetism data - older copies are from turn-of-century data and CARBON WAS BEST!! (over bismuth) Then from 1970 on, HCP used French Institute data which put carbon down. Even 1997 copy here in library shows no tables of diamagnetism data, but does have nice graph of the elements only. Suspect that anisotrophism maybe involved, like many crystalline structures." Meredith Lamb Signup for your free USWEST.mail Email account http://www.uswestmail.net _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Student Question... From: doug doug@............. Date: Wed, 29 Sep 1999 15:37:01 -0700 Jan wrote: > If any of you have access to beach sand, and would be willing to send it to us, > we'll let you see the results of the kids work. I can get some sand from Santa Cruz CA beaches. I assume it would be better to get the sand from somewhere along the unpopluated shores say between SC and SF, to avoid the human factor as much as possible (dredging effects etc). I would be interested in hearing about the test methods they use and it would also be interesting to see the results. BTW I am doing something a bit similar, using mobile wireless internet servers with GPS and monitors for CO2, CO, temp, humidity and other conditions. The idea is that as I roam around I will be always connected to the net and always collecting data. Over time the collective data will fill in a map showing the different conditions. I am doing this more as a network experiment/demo rather than for scientific purposes, but the data might be interesting to watch and graph. On a similar note at my home in the santa cruz mountains I am already monitoring temperatures inside, outside, aquariums, fridge, freezer, hottub, relative humidity inside and outside, barometer, wind speed and direction, rain guage, and aquarium conditions: temp, pH, conductivity, oxygen reduction potential. Soon to be added: absolute humidity, dewpoint, wet bulb temp, solar radition, particle counting, etc. I will show you all my sensor pages in a while, right now the system is down for some rewiring and calibration of devices. Eventually I want to internet enable an infrared spectrometer and automatically cycle through calibrations for various ambient air elements (this will be done by adding TCP/IP ethernet interfaces and using tiny uniquely addressible switches to push the buttons). Finally, I eventually want to use the same idea for automated liquid chromatography analysis of the elements in the sea water in my mini reef aquarium. Here's the aquarium now: http://207.214.112.10/video.html?select=yes Note that right now it's night on the reef, so you'll have to check it out in the daytime. You can move the camera around and zoom in close on sea anenomes, corals, sponges, feather dusters, hermit crabs, snails cleaner shrimp, and the clownfishes and sailfin tang. Also note that you are fighting over the camera so don't be surprised if it moves. Please don't walk away and leave the camera in "auto image update" mode or you'll be hammering my server (this will be fixed soon). The aquarium follows a seasonal variation of sunrise and sunset, and an incandecent bulb with dimmer simulates moonrise and set along with intensity changes for phases. Powerheads simulate tide changes every six hours, other pumps create random surges [*]. I can also invoke all of these functions over the net through a GUI, and soon the system will email me, page me, then call me if alarm states are reached, or if anyone is foolish enough to break in (which will result in ftp'd images offsite over the net). I am right now putting together a stepper motor/dispenser assembly which will automatically feed the fish, and the ultimate goal is to automate partial water changes including mixing of sea water. I have most of the parts for this and am getting really close. I still need to find a way to monitor nitrates, calcium, strontium, molydbenum, and iodine (these are additives that need to be regularly dispensed). I am also struggling with methods of powder dispensation (sea salt mix) and would love to hear any ideas as to how I might do this (assume that I have a fixed weight or volume that I want to dispense via software event). Also, if you can tell me how to effectively automate glass cleaning you will be my hero (note that I must apply forces at various angles using a long handled brush to clean the glass, the magnet based scrapers are not good enough ruling out simple linear actuation of magnetically moved scrapers :( Oh, and since I am way off topic for the list ... maybe I should add some underwater seismic activity too? [*] I heard the Sean-Thomas can actually sense the tides with his broadband instrument. Wow. I think it would be fascinating if this data could drive my tide simulation in the aquarium. If you are willing to give it a try, I would love to write some code to do this :) Always having fun, Doug PS. Some kids never grow up ... soon I am going to break the record for the largest pile of toys :) Woo hoo! _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: More diamagnets From: doug doug@............. Date: Wed, 29 Sep 1999 16:36:05 -0700 You guys _had_ to show me this diamagnetism letivation stuff. Yikes. Now I'm gonna gave to add that to my toybox too. LOL -- Doug Bill wrote: > the following found on the net. thought some one might be interested...... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: More diamagnets From: Karl Cunningham karlc@....... Date: Thu, 30 Sep 1999 08:28:50 -0700 Bill -- Do you have the URL from which the HTML pages were taken? I'd like to check out the rest of the site. Thanks, Karl Cunningham La Mesa, CA. PSN station #40 karlc@....... At 10:04 PM 9/29/1999 -0500, you wrote: >the following found on the net. thought some one might be interested...... >bill NJ0X _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Mexico City Quake From: Mike Lozano mikel@....... Date: Thu, 30 Sep 1999 12:05:08 -0500 Hi gang! CNN just broke in with news of a major quake in Mexico City. They've got a helicopter in the air with pictures. Any of you guys out there got a fix on the epicentral location or magnitude? Mike Lozano Senior Meteorologist KCCI Television mikel@....... -0- _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: MEXICO QUAKE From: "Francesco" franuc@...... Date: Thu, 30 Sep 1999 19:30:23 +0200 Now, it's running LQ and LR phase. M more than 6.6 Francesco I.E.S.N. Italy _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: RE: Mexico City Quake From: Oguzhan Aydogmus-HRB oaydogmus@................ Date: Thu, 30 Sep 1999 19:49:15 +0200 m:7,4 > ---------- > From: Mike Lozano[SMTP:mikel@........ > Reply To: PSN-L Mailing List > Sent: 30 Eyl=FCl 1999 Per=FEembe 20:05 > To: PSN-L Mailing List > Subject: Mexico City Quake >=20 > Hi gang! >=20 > CNN just broke in with news of a major quake in Mexico City. They've > got a helicopter in the air with pictures. Any of you guys out there > got a fix on the epicentral location or magnitude? >=20 > Mike Lozano > Senior Meteorologist > KCCI Television > mikel@....... > -0- >=20 > _____________________________________________________________________ >=20 > Public Seismic Network Mailing List (PSN-L) >=20 > To leave this list email listserver@.............. with the body of > the=20 > message: leave PSN-L >=20 _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: MEXICO QUAKE From: Canie Brooks canie@........... Date: Thu, 30 Sep 1999 10:41:22 -0700 NEIC posted as 7.5Ms 99/09/30 16:31:13 16.15N 96.71W 33.0 7.5Ms A OAXACA, MEXICO Canie At 07:30 PM 9/30/99 +0200, you wrote: >Now, it's running LQ and LR phase. > >M more than 6.6 > >Francesco I.E.S.N. Italy > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: R: Mexico City Quake From: "Francesco" franuc@...... Date: Thu, 30 Sep 1999 19:44:48 +0200 OK. With a best analisys of the traces with winquake , Ms 7.1 or more. Later, we will post the files. Francesco _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Mexico City Quake From: "John Krempasky" johnk@....... Date: Thu, 30 Sep 1999 13:51:01 -0400 -----Original Message----- From: Mike Lozano To: PSN-L Mailing List Date: Thursday, September 30, 1999 12:58 PM Subject: Mexico City Quake >Hi gang! > >CNN just broke in with news of a major quake in Mexico City. They've >got a helicopter in the air with pictures. Any of you guys out there >got a fix on the epicentral location or magnitude? NEIC has 7.6 Ms in Southern Oaxaca. Actually a pretty good distance away from Mexico City. Worst damage is going to be in obscure places without a permanent international media presence so at least initially the damage won't seem that bad. Until people get to Oaxaca. Appears to be just onshore so at least there won't be much chance of a tsunami. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: MEXICO QUAKE From: TORBEN THAMS tobythams@................ Date: Thu, 30 Sep 1999 11:18:17 +0100 P-Wave arrived at my station at 16:42:32 UTC I have a new (experimental) setup, and this is the first quake I have registered. I am in Southern California at N 33 degrees 53.94 min W 117 degrees 56.14 min Toby Thams _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: More diamagnetism: Material sources, papers, AC diamagnetism (for Karl) From: "Charles R. Patton" charles.r.patton@........ Date: Thu, 30 Sep 1999 20:57:34 -0700 What a wonderful information hunt! Almost as good as Myst! Anyway, material sources. Belmont Equipment Co. Western Office & Warehouse 743 Dunn Way Placentia, CA 92670-6884 is a source of EDM carbon. They carry graphite from Union POCO, Ameri-Graph, Airco, UCAR (Union Carbide) and Great Lakes. I borrowed a manual for POCO Graphite, Inc., a Unocal Co., in Decatur, Texas, -- yes it is a division of the Unocal oil company. The manual explains how the stuff is made. They start with calcined petroleum coke (amorphous carbon.) The coke is then milled to various particle sizes and mixed with coal tar pitch. This mixture is then pressed or extruded into billets. The billets are baked in an oxygen-free atmosphere to drive off the volatiles from the pitch. The result is an amorphous carbon product, which is held together with carbonaceous pitch residue. This carbon is transformed to graphite (graphitized) by further heat treating at extremely high temperatures. Belmont cuts it up and can machine to order for use by the tool and die customer. My friend indicated to me that he allocates about $4 / cu.in for the graphite cost. Just for comparison, the costs from McMaster-Carr (who are not the cheapest, but certainly one of the easier companies to deal with for small, odd lot quantities) is shown below. They can be accessed on the web at: http://www.mcmaster.com/ $0.448/cu.in (5.3 cu.in / $2.38 for =BE=94 dia. x 12=94 long copper co= ated welding rods) $0.853/cu.in (72 cu.in / $61.43 for 6 x 12 x 1 carbon arc welding plates) Based on this, I=92m ordering a couple of =BE=94 welding rods. Best bang= for the buck, if they work. But it will be awhile before the results are in. I know the =BC=94 rods I have are diamagnetic, so I=92m encouraged. = (I tried one local welding store for carbon rods. They would only sell in box quantities of 50, which for 3/16 was about $15, but they didn=92t hav= e =BE and I=92m not interested in about $100 worth of carbon rods, so I passed.) Diamagnetic properties: I found some interesting tables for values of magnetic properties, including diamagnetic properties, of various substances: goto: http://www.backto-newton.com/backtonewton/magnetism.html and then click on Table I, II, and III where a R.J. Hengstebeck has listed quite a few substances in conjunction with a dissertation on a new theory of magnetism. As to the rest of his magnetic theory, I am not a physicist, so I=92m totally unqualified to comment. Perhaps someon= e else might want to. At: http://enpc1644.eas.asu.edu/Carbon/elemagpr.htm is a table indicating that diamond and graphite should be almost identical in diamagnetic performance. (For those of you with a lot of loose cash lying about!) At: http://curricula.mit.edu/6.013/chapter9/9.4.html is part of a course (?) on magnetism with a table containing diamagnetic and magnetic values. And for Karl at: http://curricula.mit.edu/6.013/chapter9/9.5.html which is the next page of the previous course, a discussion of AC diamagnetism (they call =94Artificial Diamagnetism=94) caused by conducti= ve spheres. You can equivalently think of shorted turns as rejecting a magnetic field, and thereby equivalently say the slug is diamagnetic. So use whatever analogy is most convenient, you=92re right too! Well that=92s probably a lot more than you ever wanted to know about the subject, but enjoy. Charles R. Patton _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: More diamagnets From: "bill" nj0x@............ Date: Thu, 30 Sep 1999 23:15:46 -0500 I went to infoseek search and typed in diamagnets and it came back with bunches of sites. wasn't much more than what i sent. there are some other ones that look interesting. sorry I didn't make note of the html. bill -----Original Message----- From: Karl Cunningham To: PSN-L Mailing List Date: Thursday, September 30, 1999 10:29 AM Subject: Re: More diamagnets >Bill -- > >Do you have the URL from which the HTML pages were taken? I'd like to >check out the rest of the site. > >Thanks, > >Karl Cunningham >La Mesa, CA. >PSN station #40 >karlc@....... > >At 10:04 PM 9/29/1999 -0500, you wrote: >>the following found on the net. thought some one might be interested...... >>bill NJ0X > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: More diamagnetism From: meredithlamb@.............. Date: 30 Sep 1999 22:36:44 -0700 Charles Patton, WoW! You hauled in some very good material to ponder over. I have to say I don't understand it all. I hear this "POCO" graphite seems to have unique properties, but as yet, exactly what it is I don't know. How it racks up to "standard" graphite is a unknown. I've also read there is some 12 million combinations of carbon with the other elements. Maybe their manufacturing process somehow differs from the others? From my expeditions to surplus outlets, its kind of a gamble on whether the stuff you get is diamagnetic or not. Anymore, I take along a nice thick piece of neodymium for testing on the spot. If its a piece of DC motor commutator brush, I hold the cable end lightly, and see the reaction of the carbon/graphite fairly well. Carbon rods can be tested simarily by lightly holding the end, or a short length of scotch tape can help. Have run into pieces where one end is paramagnetic, and the other end is diamagnetic. One never knows. Likewise, I've seen same carbon manufacturers, but their products can have varying responses, from one piece to the next. I used to think it was the manufacturer, but, anymore, one has to also consider the possibility of the material being somehow subjected to varying elements, and internal variance factors that make or break; the ideal diamagnetism. Speculation.... Its doesn't seem like their is any guarantee whatsoever, on what one gets, from any source. Another factor I had misconceptions on: The color of the graphite tells very little about its diamagnetism...test them all, whether very black, or grayish black. Thanks for the huge effort. I especially like the tables, as my nearest library doesn't have such. Thanks, Meredith Lamb Signup for your free USWEST.mail Email account http://www.uswestmail.net _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: More diamagnetism: Material sources, papers, AC diamagnetism (for Karl) From: offutt@............ (Warren Offutt) Date: Fri, 1 Oct 1999 04:05:58 -0600 (MDT) Charles Patton's post rang a bell: At the New York World's Fair, 1939-1940, I recall seeing discs of aluminum (several inches in diameter) levitated several inches above an AC powered magnet. It seems to me I recall seeing this described in popular science magazines of the 1950s as well. A long time ago, and memory is fallible, but I think it is correct. warren _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Diamagnetism; Magnetic Suspension From: "Mark Robinson" other@............... Date: Fri, 1 Oct 1999 22:39:48 +1200 Gentlepersons , I have seen a thing made here in New Zealand which hangs an object beneath an energised pole piece. the abject had a piece of what llooked like ferrite in it, and I assumed that the pole piece was was energised with a high frequency, and further that the suspension relied on hysteresis to provide the stable position which was about 25mm below the energised pole piece. The suspended object was a globe weighing a couple of hundred grams. I tried to find the manufacturers, or any reference on the web, but no luck. If I do, I will post further regards Mark _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Levitating objects From: meredithlamb@.............. Date: 1 Oct 1999 07:25:26 -0700 Hi Warren, Perhaps (?), what you saw at the 1939 Worlds fair, was akin to this web site. They are trying to commerilize their display projucts. See: http://www.teslev.com/teslev/morephot.html which is part of: http://www.teslev.com/teslev/levinfo.html I note the netherlands web site seems to have more pictures than previous. It also makes reference to the above, and Martin Simons commercial unit for sale: http://www-hfml.scikun.nl/hfml/levitate.html Meredith Lamb Signup for your free USWEST.mail Email account http://www.uswestmail.net _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Levitating objects (correction) From: meredithlamb@.............. Date: 1 Oct 1999 08:12:55 -0700 Warren and all, I see my references hit the not found computer wall. Try: http://www-nwi.sci.kun.nl/index-eng.html then, go to organization, click physics, then, scroll down to Research Departments. See, the Experimental solid state physics I (and) specifically click "High Field Magnet Laboratory". Then click, "Some (serious) fun in high magnet fields". Then look for "levitating displays", and click that. At the bottom of this page, is a clickable reference to "more photos". All these "displays" use some energy, but specifics are not spelled out, as its a commercial firm still in R&D, as they claim. Long route to go, but it should get you there. Meredith Lamb Signup for your free USWEST.mail Email account http://www.uswestmail.net _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: More diamagnetism: Material sources, papers, AC diamagnetism (for From: Doug Crice dcrice@............ Date: Sat, 02 Oct 1999 05:31:38 -0700 The levitating aluminum plate is a different phenomena. You put the plate over an AC-powered electromagnet and the varying magnetic field induces eddy currents in the plate. The eddy currents flowing in the aluminum create another magnet with the same polarity which causes the aluminum plate to be repelled by the electromagnet. Of course it only works with an AC field. Doc Edgerton, who you might know as the inventor of the strobe light, made an underwater seismic energy source called a "boomer" which had a metal plate snugged up against a coil. He would charge up a capacitor (to several joules) and then dump the charge into the coil. The large current in the coil induced eddy currents in the metal plate which made it bend away from the coil, push against the water, and make a pretty good pop in the ocean. The boomer was a relatively high-frequency seismic source and is still used for shallow, high-resolution seismic reflection surveys. He made another seismic energy source which ran on the same power supply called a sparker. A few thousand volts from a capacitor is discharged into an electrode trailing behind the boat. The discharge would vaporize the salt water creating a small explosion and of course seismic energy. The sparker was lower frequency than the boomer and is used for deeper (hundreds of meters) surveys. Doug Crice Warren Offutt wrote: > > Charles Patton's post rang a bell: At the New York World's Fair, > 1939-1940, I recall seeing discs of aluminum (several inches in diameter) > levitated several inches above an AC powered magnet. > > It seems to me I recall seeing this described in popular science magazines > of the 1950s as well. > > A long time ago, and memory is fallible, but I think it is correct. > > warren > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L -- Doug Crice web site http://www.georadar.com GeoRadar Inc. e-mail dcrice@............ 19623 Via Escuela Drive phone 408-867-3792 Saratoga, CA 95070 USA fax 408-867-4900 _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: HS-10-1 From: Arie Verveer ajbv@............ Date: Sun, 03 Oct 1999 13:40:50 +0800 Hi, I've just set up one of the group buys (Hs-10-1) geophones. All seems to be working well. But I was wondering, what is the range on the period adjustment screw? It appears to have some unlabeled scale. Any help on the range and the best way to set the device to 1 Hz ? I hope to achieve some better response to distance quakes with this Z axis device. The channel designation : ..au1 East-West high frequency ..au2 Geospace HS-10-1 Z axis (This replaced E-W low frequency) ..au3 N-S high frequency ..au4 N-S Low frequency Regards Arie _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: HS-10-1 From: S-T Morrissey sean@........... Date: Sun, 3 Oct 1999 13:54:40 -0500 (CDT) Arie, The period and the mass centering of the HS-10-1 are both accomplished by adjusting the same part. The HS-10s that I have were originally encased in deep borehole pressure cases, so they have no dials or indicators. Some versions have a screw adjustment for the position (and so the strength) of the calibrator magnet. For adjustments, there is a rod protruding from the case inside the calibrator assembly (which may not be complete). The rod, about 1/8" dia, has an approx. 3/8" dia threaded bushing attached to it with a setscrew (or two). The threads of the bushing are engaged by the astitizing spring that controls the period. The upper (in Z) end of the rod may have the calibration coil installed, with fine coilly leads running to the terminal strip. There is a three-mark index or scale marked in the inside of the cut-aways in the cylinder of the calibrator housing. The lower end of the white nylon cal coil assembly should be aligned with the middle mark to center the mass. To adjust the centering, loosen the setscrews on the threaded bushing and move it appropriately. The mass position may change as the screws are tightened. The period is adjusted by changing the length of the small spring, which is done by rotating the threaded bushing to engage or release PART of A TURN of the spring. I make a mark on the 1/8" shaft to indicate the position for centering before I loosen it to rotate it. Naturally the adjustments interact. Sometimes the mass position will have to be raised slightly to get 1 second; slightly tilt the seis to test this. I have been able to get periods from 0.8 to 1.1 seconds. I use a function generator, a frequency/period counter, and an oscilloscope to set the period. The generator drives the calibration coil (or a bridge with the main coil), and one axis (time) of the oscilloscope, which is operated in X_Y mode. THe seis signal coil connects to the other axis. Usually the normal input is used for the signal because it has more gain or sensitivity. The function generator is adjusted for a flat-line lissajous (sp?) display, and a period (frequency) counter on the function generator indicates the seismometer period. THis method can be accurate to a millisecond, especially if you can finely adjust the function generator to see the elipse pattern collapse to a line and then reverse. In liew of the test equipment, look at the amplified signal and measure the length of time for ten oscillations with a stopwatch. The adjustment of the period is really not that critical, and +,- 5% is probably adequate for a critically damped sensor. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Levitation notes From: meredithlamb@.............. Date: 3 Oct 1999 15:56:23 -0700 Hi all, Just made another stand for levitation of magnets. Have noted several items that maybe of interest. Am using carbon brushes. Four rectangular straight side carbons per the bottom plate and 4 per the top carbon plate. The carbon mounting surfaces are fiberboard, rectangular pieces. I didn't note any differece with the slight areas "open" to exposure. The neodymium magnet I used is a "wing" shape, about 9/16" long, 7/16" wide and 1/8" thick. The weight is about 2/10's ounce. Initial floating attempts, all yielded no better than a point on the magnet making contact somewhere on the carbon. I then introduced a rectangular magnet to the side of the floating magnet, and this seemed to worsen or correct the magnet angle. The distance of the rectangular magnet is about 7" away; but it will wildly vary with different setups. Of course, now it floats. Maybe this could be called a bias/correction magnetic field. One will have to maneuver such around the area of their own setup. Unlike a round disk magnet, these wing shapes, are not directly centered under the vertical magnet above. Its not much, but its there, at least from this first attempt. The "bias magnet" angle, seems to control the alignment of the floating magnet. They both have the same angle. This suggests a means of control of length direction, if desired. The height adjustments of the ferrite donut magnet are much more sensitive in adjustment than with a very small disk magnet (Radio Shack cat. no. 64-1895). I'am guessing this wing magnet is at least 20 times the weight of the Radio Shack magnet. Along with the heavier weight, the vertical oscillation period of the wing magnet is noticeably longer, perhaps between 1-2 seconds. Fun when it works, frustration when it doesn't. Meredith Lamb Signup for your free USWEST.mail Email account http://www.uswestmail.net _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Levitation notes From: JIm Hannon jmhannon@........ Date: Sun, 03 Oct 1999 18:05:21 -0500 meredithlamb@.............. wrote: > Hi all, > > Just made another stand for levitation of magnets. > Have noted several items that maybe of interest. > > Am using carbon brushes. Four rectangular straight > side carbons per the bottom plate and 4 per the > top carbon plate. The carbon mounting surfaces > are fiberboard, rectangular pieces. I didn't note > any differece with the slight areas "open" to > exposure. > > The neodymium magnet I used is a "wing" shape, > about 9/16" long, 7/16" wide and 1/8" thick. The > weight is about 2/10's ounce. > > Initial floating attempts, all yielded no better > than a point on the magnet making contact > somewhere on the carbon. I then introduced a > rectangular magnet to the side of the floating > magnet, and this seemed to worsen or correct > the magnet angle. The distance of the rectangular > magnet is about 7" away; but it will wildly vary > with different setups. Of course, now it floats. > Maybe this could be called a bias/correction > magnetic field. One will have to maneuver such > around the area of their own setup. > > Unlike a round disk magnet, these wing shapes, > are not directly centered under the vertical > magnet above. Its not much, but its there, at > least from this first attempt. > > The "bias magnet" angle, seems to control the > alignment of the floating magnet. They both > have the same angle. This suggests a means of > control of length direction, if desired. > > The height adjustments of the ferrite donut > magnet are much more sensitive in adjustment > than with a very small disk magnet (Radio Shack > cat. no. 64-1895). I'am guessing this wing > magnet is at least 20 times the weight of the > Radio Shack magnet. > > Along with the heavier weight, the vertical > oscillation period of the wing magnet is > noticeably longer, perhaps between 1-2 seconds. > > Fun when it works, frustration when it doesn't. > > Meredith Lamb > Meredith, Those "wing" shaped magnets probably came from harddrive voice coil actuators. "Some" of them have both a north and south pole on each side rather than just a north pole one one side and a south pole on the other. This could explain your tipping problem. -- Jim Hannon http://soli.inav.net~jmhannon/ 42,11.90N,91,39.26W WB0TXL _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Levitation notes From: meredithlamb@.............. Date: 3 Oct 1999 16:34:23 -0700 On Sun, 03 October 1999, JIm Hannon wrote: > > Meredith, > Those "wing" shaped magnets probably came from harddrive voice coil > actuators. "Some" of them have both a north and south pole on each side > rather than just a north pole one one side and a south pole on the other. > This could explain your tipping problem. > > -- > Jim Hannon > http://soli.inav.net~jmhannon/ > 42,11.90N,91,39.26W > WB0TXL Hi Jim, No, these magnets are the normal 2 pole types. However they are from such, but, of the older type...i.e., 4 normal 2 pole magnets per assembly. Newer ones were 4 pole, with either one magnet per assembly, and rarer, 2 such magnets per assembly. Interesting note, somewhere in my internet travels, one site mentioned that some of the early (~1972)"super magnets", were a composite of platinum and another/more ingredients. Likely they were very limited in production. I would agree; a 4 pole would have alot of problems floating...ha. I noted the same tipping effect on my first levitation stand also, but didn't pursue it, at the time. Thanks, Meredith Lamb Signup for your free USWEST.mail Email account http://www.uswestmail.net _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: HS-10-1 From: Larry Cochrane cochrane@.............. Date: Sun, 03 Oct 1999 23:27:43 -0700 Hi Arie, At 01:40 PM 10/3/99 +0800, you wrote: >Hi, I've just set up one of the group buys (Hs-10-1) geophones. All seems >to be working well. But I was wondering, what is the range on the period >adjustment >screw? It appears to have some unlabeled scale. Any help on the range and the >best >way to set the device to 1 Hz ? Please see S-T Morrissey response. I didn't even know it had a period adjustment until your message! After reading your email message I took a closer look at the sensor. I took it offline to but it on the bench and I swear to god no more then 2 minutes later we had a Ml 2.8 event near by. Talk about Murphy's law....This would have been a nice event to record with my new sensor (*.lc9 files)... > >I hope to achieve some better response to distance quakes with this Z axis >device. >The channel designation : > >.au1 East-West high frequency >.au2 Geospace HS-10-1 Z axis (This replaced E-W low frequency) >.au3 N-S high frequency >.au4 N-S Low frequency Dave Nelson, should I update Arie's station information or can you do it? -Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: HS-10-1 From: Arie Verveer ajbv@............ Date: Mon, 04 Oct 1999 19:21:51 +0800 Hi Sean-Thomas, Thanks for the great info on the HS-10-1. A super explanation. Regards Arie _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Hilger and Watts seismograph? From: Doug Welch welch@................... Date: Mon, 4 Oct 1999 20:00:26 -0400 (EDT) I have just recently picked up what I believe to be a seismograph made by Hilger & Watts (SG 416). However, it has no manual and I am keen to locate documentation (or at the very least, its detection characteristics). Can anyone on this list help (or provide a good lead)? Many thanks, Doug Welch _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Ricther Scale From: "David Wilson" davidbw@.......... Date: Tue, 5 Oct 1999 17:01:29 +1300 When I was young events where measures on the 'Open Ended Ricther = Scale". When was the end sealed and has this changed the calibration?
When I was young events where measures on the 'Open = Ended=20 Ricther Scale".
 
When was the end sealed and has this changed the=20 calibration?
Subject: Re: Hilger and Watts seismograph? From: Doug Crice dcrice@............ Date: Tue, 05 Oct 1999 05:22:43 -0700 A web search suggests that Hilger & Watts seems to be a manufacturer of surveying instruments. This may be a collimator which is a device to ensure that a surveying instrument is positioned over a station, sort of an optical plumb bob. Doug Welch wrote: > > I have just recently picked up what I believe to be > a seismograph made by Hilger & Watts (SG 416). However, > it has no manual and I am keen to locate documentation > (or at the very least, its detection characteristics). > Can anyone on this list help (or provide a good lead)? > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Software advice From: offutt@............ (Warren Offutt) Date: Tue, 5 Oct 1999 06:52:15 -0600 (MDT) Hello all, can anyone suggest where I can find software for shallow, short range seismic studies? Here, in the mountains of south central New Mexico, water-well drilling (typically 500 foot depth) sometimes yields expensive disappointments. I'd like to experiment with active seismic probing similar to petroleum prospecting, but much shorter range and depth, to better understand the subsurface features. Acoustic sources, sensor arrays and data acquisition all appear straightforward, but where can I find analytical software? warren _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Software advice From: Doug Crice dcrice@............ Date: Tue, 05 Oct 1999 06:21:38 -0700 Warren Offutt wrote: > can anyone suggest where I can find software for shallow, short range > seismic studies? > Typically, refraction surveys are used for ground water investigations. You should start by reading up on the method, which is described in virtually all introductory books on exploration geophysics. It's not particularly difficult to perform the calculations by hand with a pocket calculator or using graphical methods. You can read a brief description at http://www.naevageophysics.com/seismics.html A short but comprehensive booklet by Bruce Redpath is available free from Geometrics on their web site at http://www.geometrics.com/env.html Commercial software is available from Rimrock Geophysics in Lakewood, Colorado (phone 303-985-2522 if the area code hasn't changed) and Interpex at http://www.interpex.com/ Interpex has a broad range of software for exploration geophysics. Rimrock is operated by a retired USGS geophysicist. I would guess that there may be some free programs available, but I don't have a source. A properly designed and manufactured exploration seismograph is a joy to use, maybe you could line up some corporate sponsors to buy you one of the Geometrics units. There are many used systems available which are adequate for refraction surveys. Doug Crice _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Ricther Scale From: John Lahr lahr@................... Date: Tue, 5 Oct 1999 08:11:23 -0600 (MDT) Hi David, The end is still open. What made you think otherwise? News accounts frequently get this wrong, and say that the Richter scale runs from 0 to 10. Actually very small earthquakes have negative magnitudes. The largest recorded so far is the 9.5 Chile earthquake in 1960. JCLahr > From: "David Wilson" > When I was young events where measures on the 'Open Ended Ricther Scale". > > When was the end sealed and has this changed the calibration? _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Finger list From: John Lahr lahr@................... Date: Tue, 5 Oct 1999 08:44:48 -0600 (MDT) The USGS finger list is just shows the latest 21 events. For a list covering the past two weeks, check out the CNSS and Canadian National Net experimental Combined Catalog at http://www.cnss.org/cnss.cat.html JCLahr _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: R: Ricther Scale From: "Liberio Rossi" l.rossi@....... Date: Tue, 5 Oct 1999 17:18:22 +0200 -----Messaggio originale----- Da: John Lahr A: psn-l@.............. Data: marted=EC 5 ottobre 1999 16.23 Oggetto: Re: Ricther Scale >Hi David, > >The end is still open. What made you think otherwise? News accounts >frequently get this wrong, and say that the Richter scale runs >from 0 to 10. Actually very small earthquakes have negative magnitudes. >The largest recorded so far is the 9.5 Chile earthquake in 1960. > >JCLahr > >> From: "David Wilson" >> When I was young events where measures on the 'Open Ended Ricther Scal= e". >> >> When was the end sealed and has this changed the calibration? > >OK Lahr I agree with you that Ricther scale can be negative! >Regards Liberio Rossi l.rossi@.................................................................. ___ ________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: geophysics journal URL From: robert barns 75612.2635@.............. Date: Tue, 5 Oct 1999 14:52:07 -0400 Hi gang, From Physics Today, Oct. '99, p68: "The American Geophysical Union and the Geochemical Soc. have created a= n on-line journal dedicated to interdisciplinary research in geochemistry a= nd geophysics. One aim of "Geochemistry, Geophysics Geosystems" -or G-Cubed= for short-is to keep publication costs and subscription rates low...Anoth= er reason for going all-electronic is to enable authors to publish very larg= e data sets which paper journals could never afford to print. Access to th= e journal will be free at least the first year. The first issue is set to = be posted on the journal's Web site www.g-cubed.org in early Dec., prior to the AGU's fall meeting and the journal will be updated weekly." Another URL I have found useful is joe.mehaffey.com This contains an enormous amount of info on GPS. There is an informative= discussion on GPS timing in the Information Section dated 18 Apr. '99. I bought a digital wrist watch (Zeit, $110 incl. shipping) about 3 week= s ago which uses timing signals from WWVB (60 kHz) in Colorado. It works perfectly here in NJ (but I don't like digital watches). It has= not been off WWV by more than 0.5 sec. (the limit of checking) and it skipped Sept. 31 like it should. I can hardly believe that it can reciev= e a sig. at 60kHz (wave length about 3 miles) but it does. See this at = www.topixgallery.com Bob Barns _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Hilger and Watts seismograph From: John Taber taber@............. Date: Wed, 6 Oct 1999 09:28:00 +1300 (NZDT) Doug, I have a Hilger and Watts manual for the SG450 (Wilmore MKII). From earlier discussions with Dave Nelson, there are some similarities between the SG416 and SG450, so if no one has an SG416 manual I can send you a copy of mine. Cheers, John Taber _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Hilger and Watts seismograph From: meredithlamb@.............. Date: 5 Oct 1999 14:46:28 -0700 On Tue, 05 October 1999, John Taber wrote: > > Doug, > > I have a Hilger and Watts manual for the SG450 (Wilmore MKII). From > earlier discussions with Dave Nelson, there are some similarities > between the SG416 and SG450, so if no one has an SG416 manual I can > send you a copy of mine. > > Cheers, > > John Taber John Taber, Is the suspension system on the seismo like a Wood-Anderson, with its mass on a taut wire?? Kind of a british variety? Am vaugely guessing? Thanks, Meredith Lamb Signup for your free USWEST.mail Email account http://www.uswestmail.net _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Charles Patton levitation suggestion... From: meredithlamb@.............. Date: 5 Oct 1999 15:52:53 -0700 Hey Charles, Your idea of using rods set flat side by side on a board (actually 2 boards), for carbon levitation does work. I got a number of .242" diameter carbon rods, and tried it with wide 2 pole (normal) neodymium magnets. One was a "wing" shape, and another with 5 points, and they both worked. I used eight side by side, but it would have worked with less...depending on the width/length of the neo floated. Afew very interesting effects showed up right away with this type of surface: One; when disturbed it wasn't unusual for the floating neo to bang against the top and bottom of the carbon/rod sandwich, they seemed to have wider range in other words. Probably not surprising for the undulating surface instead of a flat surface. Two; both of this neo magnets floated without the aid of additional "bias magnets", to offset dragging tilts. They weren't perfect but no point touched the carbon. Regardless, I used acouple magnets on either side, which helped correct tilts from the horizontal, and sometimes they acted to assist centering between the carbon layers. It was definately easier to float neodymium magnets overall. I even floated the little Radio Shack Cat No. 64-1895 neo disk quite easily over these rods. There may be explanations, I think the rods were more diamagnetic than my smooth surface carbon brushes. The rods were laid out where from the end view, the rods sat vertically aligned atop each other (not like a rod nestled in the valley of the opposing rods/carbons/plate). ....................................... Sometimes, I think a old but very large meter movement, with its torsion spring, could provide somewhat of a "scale" with diamagnetics? One might have to remove the meter magnet and mount something like the tiny radio Shack magnet on the end of the pointer? Speculating. ........................ Another minor side note, I used my string /beam balance to note the repulsion diamagnetics in my hand coming close. Water is diamagnetic. Thanks for the rod side by side suggestion, Meredith Lamb I would expect some limit on rod size v/s neo floated; but thats the only size I have. Signup for your free USWEST.mail Email account http://www.uswestmail.net _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Charles Patton levitation suggestion... From: "Charles R. Patton" patton@.......... Date: Tue, 05 Oct 1999 17:13:20 -0700 Great Meredith! I appreciate the feedback. How long were the rod pcs you used? My own luck with the EDM carbon is mixed so far. The big hunk I was given attracts the magnet -- not so good for this experiment. But two =BE" sq. by 1" act just fine =96 they=92re just not big enough for an experiment. = I need to go back to the mold maker and see if he thinks he gave me some impregnated carbon. Still haven=92t ordered the carbon rods from McMaster-Carr. Maybe tomorrow. I=91ve also tried to get some bismuth from a metal dealer, but he hasn=92t called back. I have a couple more names to try. I=92m concerned about getting bismuth shot from Precision Reloading as the purity/composition is an unknown. Regards, Charles R. Patton charles.r.patton@........ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Meeting of Educational networks at AGU? From: Larry Cochrane cochrane@.............. Date: Tue, 05 Oct 1999 18:14:17 -0700 Hi Robert, At 05:55 PM 10/4/99 -0400, Bob Phinney wrote: >I need to convene a meeting of people who operate educational >networks, both the PEPP crowd and other groups. AGU Sunday for >half a day is the best time. > >However, I fear that people are already ultrascheduled for that period. >Are you available? I should be able to make it, but I don't want to have to pay over $100.00 to get into the AGU. Will this meeting be part of the AGU meeting or will/can we have it somewhere else? > >Ed and Larry(s) , we haven't chatted in a long time, and >much has changed in the PEPP situation. I am hoping to decentralize >the relationship between PEPP and the university-sponsored networks, but >set up some technical coordination to simplify the work of starting and >operating stations. I have a draft plan, but first, we need to >try to grab an AGU time slot, if it's possible. I'm not sure if Edward will be coming out to the AGU this time. The last time I talked to him he wasn't sure if he was going to the meeting. He would have to pay out of his own pocket since he is not presenting anything this time. Another possibility for a meeting is with Lind Gee at Berkeley. We have been talking about having a PSN meeting at the Berkeley Seismo Lab sometime around AGU. Yesterday I had a meeting with Lind, Catherine Johnson and two men (sorry I don't remember their names) from IRIS. I was there to talk about PSN helping out setting up some sensors in schools around here. We did talk a little about the PSN meeting. It was suggested that maybe IRIS people could also attend. Maybe you and other PEPP people could also be there? Regards, Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: HS-10-1 From: Larry Cochrane cochrane@.............. Date: Tue, 05 Oct 1999 19:10:35 -0700 Sean-Thomas, Thanks for the info. I'm not sure if these sensors have a calibration coil. If they did would there be another set of wires coming out of the sensor? The sensor we got only have 2 wires, some have three but the third is only a ground wire. There is no resistance between the ground wire and the other two wires. Is it possible that you need to open up the sensor to gain access to the calibration coil? Can you elaborate on how you can test the period using a bridge and the main coil? Do you use three resistor with the same resistance as the coil and place the coil as the forth leg of the bridge? One more thing. Do you know what loading resistor is used for critical damping if the main coil resistance is around 400 ohms. GeoSpace's web page does not have this information. Again, thanks for all of your help. Regards, Larry Cochrane Redwood City, PSN At 01:54 PM 10/3/99 -0500, you wrote: >Arie, > >The period and the mass centering of the HS-10-1 are both accomplished >by adjusting the same part. The HS-10s that I have were originally >encased in deep borehole pressure cases, so they have no dials or >indicators. Some versions have a screw adjustment for the position >(and so the strength) of the calibrator magnet. > >For adjustments, there is a rod protruding from the case inside >the calibrator assembly (which may not be complete). The rod, about >1/8" dia, has an approx. 3/8" dia threaded bushing attached to it >with a setscrew (or two). The threads of the bushing are engaged by >the astitizing spring that controls the period. The upper (in Z) end >of the rod may have the calibration coil installed, with fine coilly >leads running to the terminal strip. > >There is a three-mark index or scale marked in the inside of the >cut-aways in the cylinder of the calibrator housing. The lower end >of the white nylon cal coil assembly should be aligned with the middle >mark to center the mass. To adjust the centering, loosen the setscrews >on the threaded bushing and move it appropriately. The mass position >may change as the screws are tightened. > >The period is adjusted by changing the length of the small spring, which >is done by rotating the threaded bushing to engage or release PART of >A TURN of the spring. I make a mark on the 1/8" shaft to indicate the >position for centering before I loosen it to rotate it. Naturally the >adjustments interact. Sometimes the mass position will have to be >raised slightly to get 1 second; slightly tilt the seis to test this. >I have been able to get periods from 0.8 to 1.1 seconds. > >I use a function generator, a frequency/period counter, and an oscilloscope >to set the period. The generator drives the calibration coil (or a bridge >with the main coil), and one axis (time) of the oscilloscope, which is operated >in X_Y mode. THe seis signal coil connects to the other axis. Usually >the normal input is used for the signal because it has more gain or >sensitivity. The function generator is adjusted for a flat-line lissajous (sp?) >display, and a period (frequency) counter on the function generator >indicates the seismometer period. THis method can be accurate to >a millisecond, especially if you can finely adjust the function generator >to see the elipse pattern collapse to a line and then reverse. > >In liew of the test equipment, look at the amplified signal and measure >the length of time for ten oscillations with a stopwatch. > >The adjustment of the period is really not that critical, and +,- 5% >is probably adequate for a critically damped sensor. > >Regards, >Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Charles Patton levitation suggestion... From: The Lahrs JohnJan@........ Date: Tue, 05 Oct 1999 20:38:22 -0600 At 05:13 PM 10/5/99 -0700, Charles Patton wrote: > I’m concerned about getting bismuth shot from Precision >Reloading as the purity/composition is an unknown. I'll second that concern. The shot that I melted is less effective than the carbon. John John C. Lahr 1925 Foothills Road Golden, CO 80402 (303) 215-9913 http://lahr.org/john-jan I am only one, But still I am one. I cannot do everything, and because I cannot do everything, I will not refuse to do the something that I can do. Edward Everette Hale _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: HS-10-1 From: S-T Morrissey sean@........... Date: Tue, 5 Oct 1999 22:45:02 -0500 (CDT) Larry, Unfortunately I am unfamiliar with the various configurations of the HS-10-1. I would assume that the period adjusting spring is part of the design of all the sensors, even without a calibration coil. I have a file at the U. that might have more info. For calibration with a bridge in the signal coil/amplifier circuit, a simple resistive bridge is sufficient. I designed one into the remote calibrator for the remote telemetry stations using the L4-C; most did not have cal coils because the USGS tried to save $$; or the coils were burned out (a 1.5 V battery will do it). The bridge is in the conventional shape of a diamond; the upper right resistor being the seismometer AND its' parallel damping resistor; for starters this could be about twice the coil resistance (I can repeat the info on determining the damping R if you need it). So in your case, the seis is 400 ohms, damped by 800 ohms, for a net value of (400*800)/(400+800)=267 ohms. The resistor at the upper left has to match this to balance the bridge. So I would install a 500 ohm 10-turn potentiometer. The lower two bridge Rs should be about 100 times the seis R, so I would use 27k (1%) ohms. This high value helps limit the calibration current and isolates the amplifier. Match the 27ks with a meter if necessary. Now consider the bridge as a baseball park, with home plate at the bottom, 1st base is at the right, 2nd at top, etc. The seismometer is connected from 1st to 2nd, with 1st being the common or ground connection. The amplifier is connected between 3rd and 1st, again with 1st being ground. The signal generator must have a floating output (use large capacitors from the ground side if it does not), and is connected thru a large (1 meg ohm) pot to home plate and 2nd base. It does not take much current to drive the seismometer with the signal coil. To balance the bridge, clamp the seis by laying it on its side (some seises, like the L4-C, totally short out in some horizontal positions). Look at the amplifier output (scope, meter, digitizer), and with a handy sine wave like 1 to 10 hz, adjust the balance pot (between 2nd and 3rd) for a minimum output. Keep the voltage low so the amplifier isn't saturated. What this does is to make the currents in each side of the bridge equal: half the current flows from home to 2nd via 1st, and the other half via 3rd. If the 27k resistors are equal, the voltage drop across them will be equal, and none of the calibration DRIVE signal will be seen by the amplifier. However, it IS flowing through the seis signal coil, so when the seis is set upright (unclamped), the voltage produced by the motion of the mass will be present at the amplifier via the balance pot from 2nd to 3rd, which is relatively small (270 ohms) compared to the amplifier input R of 10k to 100k ohms. For some seismometers with large inductances, a capacitor needs to be placed across the balance pot; it needs the same reactance as the seis inductance at the average calibration frequency. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Charles Patton levitation suggestion... From: meredithlamb@.............. Date: 5 Oct 1999 22:08:06 -0700 On Tue, 05 October 1999, "Charles R. Patton" wrote: > > Great Meredith! > I appreciate the feedback. How long were the rod pcs you used? I way overdid it....I used 6" long pieces, with 8 laid side by side. I'am pretty sure one doesn't need much more than say....1/4", over the diameter of the neo being levitated. Your two diamagnetic pieces would easily float the dinky Radio Shack neo, and probably up to 1/2" diameter disk, is my guess. For such a small deal you will need spacers to separate the carbons, or, mount them on wood/plastic whatever thats not magnetic. I glued mine on fiberboard and use corner bolts/nuts to adjust the distance. I'am kind of trying all sizes in that assembly, so, I'am not too restricted on magnets diameter (2" X 6"). The big problems arise with thick stuff, and their lower surface repulsion/area effects...their is a limit on weight I'am afraid. I've got up to 3/10s ounce fairly easily, but, my chunkiest neo, with a weight of 1 & 3/4 ounce, just can't quite float free....1/2" thick, but little surface area. Hmmmmm, maybe I should put steel disks on the ends to increase the surface area, if I can find something, sometime; guess its worth a try. If you get the RS pill neo, the distance doesn't seem to be too critical; measure the neo, and put a equal thickness on each side, it should pop and float readily. I've seen the RS neo float with up to 4 thicknesses on each side, it really depends on the overhead ferrite magnet and of course your carbon. I can't speculate on bismuth, I've not tried that yet. I've heard some say its better, and others not as good. Perhaps the point with bismuth is that one can make any size, and have it work to some degree right off the bat; whereas, carbon is a real shot in the dark in comparison. If one just wants to float something, the success would seem to be on the bismuth side overall. Regardless of source, I've yet to hear anyone tell of total failure with bismuth, whether it be shotgun shell load or whatever. The ultra pure stuff seems to be out of reach price wise. I'am not even sure that the ultra pure stuff is that much better than shotgun shell load? As the size of the floating neo increases in thickness, less space is available (with my carbon that is), and often I can only float it with about .015" spacing each side of the neo. The carbon rods improved that here, it looks like about .025" or so each side. I wonder what a super grade carbon would do? When I get ready to shove my assemblys under the ferrite, I cup my hand over the nearest to the magnet side, otherwise the neo can rocket up to the ferrite. The mystery continues.... Meredith Lamb Signup for your free USWEST.mail Email account http://www.uswestmail.net _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Software From: offutt@............ (Warren Offutt) Date: Wed, 6 Oct 1999 08:54:06 -0600 (MDT) Can anyone help on the following search for info? The Sept 98 edition of Explorer (Pub of American Assoc of Petroleum Geologists) noted that Chris Liner had some public domain software for 3-d analysis. However, the URL at AAPG apparently took it off their web site at end of 1998 or so ... Can anyone suggest how to contact Chris Liner and/or locate a copy of this software? Any tips or leads greatly appreciated .... Regards, warren _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Software From: "Mark Robinson" other@............... Date: Thu, 7 Oct 1999 04:42:51 +1300 http://douze.utulsa.edu/~cll/ChrisLiner.html > Can anyone help on the following search for info? > > The Sept 98 edition of Explorer (Pub of American Assoc of > Petroleum Geologists) noted that Chris Liner had some > public domain software for 3-d analysis. However, the > URL at AAPG apparently took it off their web site at > end of 1998 or so ... > > Can anyone suggest how to contact Chris Liner and/or locate > a copy of this software? > > Any tips or leads greatly appreciated .... > > Regards, > warren > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Hilger and Watts seismograph From: John Taber taber@............. Date: Thu, 7 Oct 1999 16:18:08 +1300 (NZDT) Meredith, I'm not familiar with the Wood-Anderson suspension, but the Wilmore uses leaf springs for the mass. You can get some idea from the picture I've scanned in at http://www.quaketrackers.ac.nz/Testdir/wilmore.html John Meredith Lamb wrote: > >Is the suspension system on the seismo like a >Wood-Anderson, with its mass on a taut wire?? >Kind of a british variety? Am vaugely guessing? _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Charles Patton levitation suggestion... From: George Harris gjharris@............. Date: Wed, 06 Oct 1999 16:02:21 -0400 Regarding materials with negative susceptibilities: Perhaps I have missed something along the way, but there are a number of materials with higher negattive susceptibilities than carbon. The handbook of Chemistry and Physics (59 th edition - 1979) lists the following: Carbon or diamond -6 Bismuth (solid) -280 Aluminum Sulfate (anhydrous) -93 Aluminum Sulfate Hydrate (Al2(So4)3.18H2O -323 Calcium Carbonate -38 Ammonium Nitrate -34 Ammonium Sulfate -67 The values stated are per gram, so the specific gravities are probably important also. It would seem that the crystal form should be the best if available. Have any of these been tried? George Harris _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Hilger and Watts seismograph From: Karl Cunningham karlc@....... Date: Wed, 06 Oct 1999 22:28:00 -0700 John -- Very interesting picture. Do you have the legend? I'm curious what some of the numbers are pointing to. Karl Cunningham La Mesa, CA. PSN Station #40 karlc@....... At 04:18 PM 10/7/99 +1300, you wrote: >Meredith, > >I'm not familiar with the Wood-Anderson suspension, but the Wilmore >uses leaf springs for the mass. You can get some idea from the picture >I've scanned in at >http://www.quaketrackers.ac.nz/Testdir/wilmore.html _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Forward: Science Fair From: Larry Cochrane cochrane@.............. Date: Thu, 07 Oct 1999 01:33:06 -0700 All, I received this today. Can anyone help Stuart. Please respond to him directly since he is not on the list. -Larry >From: ERICHHC@....... >Date: Wed, 6 Oct 1999 22:23:27 EDT >Subject: Science Fair PLEASE READ >To: cochrane@.............. >X-Mailer: AOL 4.0 for Windows 95 sub 27 > >To whomever could be of help, > >I am in 9th grade and doing an experiment on earthquakes. I need help with >the seismology section of my report. I am doing an experiment to determine if >it is possible to tell from a home made seismograph from which direction the >force of an earthquake originates. I am having difficulty in doing the >experiment and trying to create both the variables and the controls for my >study. Could anyone in this department be of help in my study to give me >some direction of how to accomplish this experiment. > >Thank you, > >Stuart Bern > >MESTUWHORU@....... > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Forward: Science Fair From: John Lahr lahr@................... Date: Thu, 7 Oct 1999 08:22:43 -0600 (MDT) Dear Stuart, In order to determine the direction from a seismic station to an earthquake, three seismometers need to be run at the seismic station. One for up/down (vertical) motion, one for east/west (horizontal) motion and one for north/south (horizontal) motion. This is a tall order indeed! You might want to consider building the table-top seismology demonstration that is described here: http://lahr.org/john-jan/TableTop/index.html This setup uses a single vertical seismometer, so you will not be able to investigate the direction the waves are traveling. However you could experiment with the effect of friction on the size and frequency of earthquakes. Hope this helps a bit. Cheers, JCLahr ################################## John C. Lahr ################################# Seismologist ################################ U.S. Geological Survey ############################### Geologic Hazards Team, MS966 ############################## PO Box 25046 #############################/############################## ############################/############################### Denver, Colorado 80225-0046 ################################ Phone: (303) 273-8596 ################################## Fax: (303) 273-8600 ################################### lahr@........ ##################################### http://giseis.alaska.edu/lahr http://lahr.org/john-jan _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Forward: Science Fair From: GeE777@....... Date: Thu, 7 Oct 1999 11:39:33 EDT Hello, I invented a 3 component geophone and an apparatus to plant this geophone in shallow holes. It also helps align and level the geophone using a compass and level on the handle of the planting tool. (US patent no. 5,007,031 Granted on April 9,1991) I liked the idea of planting the geophone a few feet below the surface to reduce surface noise and planted in more compacr soil. I use a Vernier Software program and hardware with three channel inputs. This works well with nearby seismic events. The software has the ability to mathematically "rotate" the two horizontal geophone elements to help find the direction to the event. Contact me if I can be of more help. Best of Luck, George Erich GeE777@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Charles Patton levitation suggestion... From: meredithlamb@.............. Date: 7 Oct 1999 09:25:58 -0700 On Wed, 06 October 1999, George Harris wrote: > > Regarding materials with negative susceptibilities: > > Perhaps I have missed something along the way, but there are a number of > materials with higher negattive susceptibilities than carbon. The handbook > of Chemistry and Physics (59 th edition - 1979) lists the > following: > > Carbon or diamond -6 > Bismuth (solid) -280 > Aluminum Sulfate (anhydrous) -93 > Aluminum Sulfate Hydrate (Al2(So4)3.18H2O -323 > Calcium Carbonate -38 > Ammonium Nitrate -34 > Ammonium Sulfate -67 > > The values stated are per gram, so the specific gravities are probably > important also. It would seem that the crystal form should be the best if > available. Have any of these been tried? > > George Harris > George, Thanks for the above info. Without the benefit of having any such book and reference, its nice to see such. As I understand it, alot of the recent editions lack any such reference. Part of the mystery with only carbon and bismuth is that theres no guarantee (especially with carbon) that there will even be a diamagnetic field, and indeed it can be paramagnetic (magnetic). As I understand it, some carbon can outperform bismuth. As far as the above reference this immediately brings up the question of what was used to derive thier figures. I would suggest its only drawn from afew samples, and the variation of chemical analysis in their samples probably were only a small portion. I've read where some carbon, has a value of up to -450...but, part of the same "rod" can fail far below that, or even be magnetic. The real mystery is just what it is, that makes some with a certain value, and another sample so very different, from the other? Your calcium carbonate (chalk)reference was very interesting. The crystalline varietys come in calcite and aragonite. The so called "iceland" spar" variety of calcite, too me, might be a interesting object to check out in rock shops, mainly because they would be more likely to have a nice flat surface if any is found that is diamagnetic. Iceland spar is the stuff that shows the double refraction...i.e, a printed page underneath (on better clear specimens), will show a doubling of the print or words. However, being as I've not yet checked it out, who knows what the results would be. I'am also probably concerned that certain specimens may be better than others...but I'am just speculating. Thanks for references, time will tell, with calcite. Overall, I think the mystery continues... Thanks, Meredith Lamb Signup for your free USWEST.mail Email account http://www.uswestmail.net _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Small Event on oct 6 From: "D. Hill" n0ssy@.......... Date: Thu, 07 Oct 1999 10:57:55 -0600 Did anyone record a small event for the Colorado area on Oct. 6 around 23:55 UCT (I'm at my office and guessing on exact time.) I see a small defelection on the ANMO site in New Mexico at 23:54, but I can not find anything on the internet about any activity for this area /time frame. Dewayne Hill _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: ground emissions From: Doug Sutherland doug@............. Date: Fri, 8 Oct 1999 03:16:13 -0700 Hi There, I was just reading some info on the web about ambient air analyzers, and I found a page for a company called Tekran that has a really sensitive mercury detector (12 parts per quadrillion). On their site they say that one of the potential uses of this is for "seismic prediction through the detection of increased ground emissions". Sounds interesting. I am curious to hear some expert opinions on this subject, and I'm wondering if there are currently projects underway to attempt predication based on mercury or other ground emissions. Doug _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Small Event on oct 6 From: David Wolny dwolny@............. Date: Fri, 8 Oct 1999 06:15:30 -0600 (MDT) Dewayne, I recorded an event with a P arrival of 23:54:00. I had it at ML 3.4. Looks like it might be NE Wyoming. Meredith, did you pick this one up? Dave Wolny Mesa State College 39.07N 108.55W On Thu, 7 Oct 1999, D. Hill wrote: > Did anyone record a small event for the Colorado area on Oct. 6 around > 23:55 UCT (I'm at my office and guessing on exact time.) > > I see a small defelection on the ANMO site in New Mexico at 23:54, but > I can not find anything on the internet about any activity for this area > /time frame. > > Dewayne Hill _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Small Event on oct 6 From: meredithlamb@.............. Date: 8 Oct 1999 07:31:25 -0700 On Fri, 08 October 1999, David Wolny wrote: > > Dewayne, > > I recorded an event with a P arrival of 23:54:00. I had it at ML 3.4. > Looks like it might be NE Wyoming. > > Meredith, did you pick this one up? > > Dave Wolny > Mesa State College > 39.07N 108.55W > > On Thu, 7 Oct 1999, D. Hill wrote: > > > Did anyone record a small event for the Colorado area on Oct. 6 around > > 23:55 UCT (I'm at my office and guessing on exact time.) > > > > I see a small defelection on the ANMO site in New Mexico at 23:54, but > > I can not find anything on the internet about any activity for this area > > /time frame. > > > > Dewayne Hill > Dewayne and Dave, I checked with reading Dewaynes email, but my old recording Packard Bell had froze up. Its starting to do that more often especially in the last 2 weeks. I leave the monitor turned off, so I don't notice these sporadic hang ups right away. I leave it off, when I'am not staying in the area, as I've seen some monitors catch fire over the years. Meredith Lamb Signup for your free USWEST.mail Email account http://www.uswestmail.net _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Small Event on oct 6 From: John Lahr lahr@................... Date: Fri, 8 Oct 1999 08:38:02 -0600 (MDT) Hi Dave, Are you set up to send arrival times to the NEIC? This one could be helpful, although an arrival from the north would help the most. JCLahr >Dewayne, >I recorded an event with a P arrival of 23:54:00. I had it at ML 3.4. >Looks like it might be NE Wyoming. >Meredith, did you pick this one up? >Dave Wolny >Mesa State College >39.07N 108.55W _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Diamagnetic levitation materials From: "Charles R. Patton" patton@.......... Date: Fri, 08 Oct 1999 16:31:02 -0700 I found another site posting magnetic susceptibilities. Go to: http://www.reade.com/Particle_Briefings/magnetic_susceptibilities.html Unfortunately, the aluminum sulfates mentioned in George Harris=92 list below are not in this list. George Harris posted the following magnetic susceptibility list from the handbook of Chemistry and Physics (59 th edition - 1979) Carbon or diamond -6 Bismuth (solid) -280 Aluminum Sulfate (anhydrous) -93 Aluminum Sulfate Hydrate (Al2(So4)3.18H2O -323 Calcium Carbonate -38 Ammonium Nitrate -34 Ammonium Sulfate -67 Thanks for the additional information, but now I am bothered. I understood from other comments that bismuth was supposed to have the highest constant, but aluminum sulfate hydrate is shown with bigger numbers. Is there some independent reference where we can verify that number? Usually the CRC handbook gives the reference for the data. Could you please post that? Thanks. A small bit of discussion on the above materials. Aluminum sulfate hydrate is soluble in water but decomposes above 86 degrees C. So to get a reasonable solid piece, you could probably slowly, ever so slowly, evaporate a solution leaving behind a cake/crystalline mass. From that viewpoint, ammonium sulfate would be much easier to do something with. It decomposes at 235 degrees C. So you could spray onto a hot surface, building up a shape that would be pretty much void free or boil off the water to leave a solid cake with probably some porosity. The minus 67 number is still better than the minus 6 of carbon, even taking into account densities. My carbon rods are in from McMaster-Carr, so maybe this weekend I=92ll slice=92n=92dice up a test panel=92s worth. A quick test shows that they= are diamagnetic at least. Charles R. Patton charles.r.patton@........ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: ZOLLNER SEISMOGRAPH From: RADIOTEL@....... Date: Sat, 9 Oct 1999 20:14:51 EDT Has anyone heard of the "Zollner" seismograph or horizonal pendulum seismograph utilizing the Zollner suspension. I understand that it solves the boom piviot problem by using two wires which are kept in tension. Therefore, there is no boom pivot contact and hence no friction. Has anyone built one of these? How does it compare to a Lehman seismograph? Jim Allen Cerritos, Calif. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Diamagnetic materials variation From: meredithlamb@.............. Date: 9 Oct 1999 21:39:34 -0700 Hi diamagnetic fans....ha Bob Lamb has forwarded me copys of the Handbook of Chemistry & Physics, relating to the magnetic susceptibility of the elements and inorganic compounds; for the year 1988. Eleven pages of fine print, extensive list which also jumps into various compounds/mixtures. Most interesting besides the list; is where they give more than one value for afew items. Bismuth is one of those, -10.5 (s)on one, and -280.1 (I) on another. The (s) and (I) is not defined. A number of items on the list also exhibit a variation of values. Tin is another one, with +3.1 (White tin)to -37.0 for (gray tin). They do maintain the same value for carbon, but that is obviously wrong as I've had paramagnetic carbon samples more often than diamagnetic samples. I doubt there is any public reference to any range of values, that represent the whole carbon spectrum; which encompasses samples from a broad range of manufacturers, sources, etc. I can't see any manufacturer striving for ultra pure carbon (which doesn't guarantee diamagnetic results) for whatever use it finds. The normal eddy current materials like, copper, silver, gold, are obviously useless for levitation; although they make good dramatic demonstrations of repulsion and eddy current combinations. Tin, zinc, and lead is a unknown too me. Another obvious problem is well known and that is temperature variations strongly affect the floating neo magnet. Even a sudden open door and cooler air, can make the neo drop out of suspension. The larger the neo magnet the more pronounced the effect becomes. Whether other strong magnets like samarium do the same is unknown, and their samples are scarce on the surplus scene I think. Too add to the complexity, the magnet manufacturers also vary their formulas, methods, granularity etc., and this too me, is just another sample of variations of any material, depending on the "cook's" recipes. ....ha. I've had a number of the same magnets, and have had to adjust for variations on each individual one...they all vary somewhat, especially on the diamagnetic levitation scene. Bob reports testing some aluminum sulfate, but while diamagnetic, it wasn't near as dramatic as the listed value of -323.0, and, he says: "but no obvious "strong" diamag apparent - prob. less then Rochelle salt, quartz & few others I tried." Sodium cloride is listed at -30.3 on the 1988 list, quartz is not listed. Am getting to the point that I look upon each element as having different personalities just like humans...they are all different from one sample to the next, especially in diamagnetics. Purity also doesn't guarantee a uniformity in diamagnetism. I have some carbon rods with statements of purity probably going beyond 99.999%, with impurity up to some 4 parts per million, and yes, their diamagnetism varys from one rod to the next....some obviously weaker than another in diamagnetism "levels". Still; these aren't really any better than some 3 other levitation carbon brush assemblys I have. Now...it sure would be nice if levitation co-operated over the years; we might all be running levitation seismometers now.... The mystery continues... Cheers......ha. Meredith Lamb Signup for your free USWEST.mail Email account http://www.uswestmail.net _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re[2]: ZOLLNER SEISMOGRAPH From: angel rodriguez angel@............ Date: Sat, 9 Oct 1999 21:52:48 -0400 Hello RADIOTEL, Saturday, October 09, 1999, 4:14:51 PM, you wrote: Rac> Has anyone heard of the "Zollner" seismograph or horizonal pendulum Rac> seismograph utilizing the Zollner suspension. I understand that it solves the Rac> boom piviot problem by using two wires which are kept in tension. Therefore, Rac> there is no boom pivot contact and hence no friction. Has anyone built one Rac> of these? How does it compare to a Lehman seismograph? Rac> Jim Allen Rac> Cerritos, Calif. Rac> _____________________________________________________________________ Rac> Public Seismic Network Mailing List (PSN-L) Rac> To leave this list email listserver@.............. with the body of the Rac> message: leave PSN-L Hi, I made a wire under tension pivot that works very well for me. see it at www.barriles.com/gardengate Warmly, Angel angel@............ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: new program From: The Lahrs JohnJan@........ Date: Sat, 09 Oct 1999 23:59:09 -0600 Hi Dewayne, I took a look at your seismic file generated by the DaTaq AD. I could convert it to psn format with wdq2psn, but there were too many samples to view with WinQuake. So, I wrote another program, wdqtrim, that reads a long .wdq file generated by the DaTaq AD and generates a psn formatted file with a subset of the data. The programs are located here: http://lahr.org/john-jan/psn/source_files/ John * John C. and Jan H. Lahr * * JohnJan@........ * * 1925 Foothills Road * * Golden, Colorado 80401-1718 * * (303) 215-9913 * * http://lahr.org/john-jan * * http://giseis.alaska.edu/lahr * _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: URL correct? From: offutt@............ (Warren Offutt) Date: Sun, 10 Oct 1999 05:57:52 -0600 (MDT) Angel mentioned that a picture of his tension-hinge seismo was posted on www.barriles.com/gardengate Is this address correct? I get a not found error ... warren _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: URL correct? From: Nick & Sophie Caporossi nickcap@............. Date: Sun, 10 Oct 1999 08:22:52 -0400 Hi Warren: Yes, I don't seem to have any trouble getting it. Try: >http://www.barriles.com/gardengate/ Nick At 05:57 AM 10/10/99 -0600, you wrote: > >Angel mentioned that a picture of his tension-hinge seismo was posted >on > > www.barriles.com/gardengate > >Is this address correct? I get a not found error ... > >warren _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Diamagnetic materials variation From: Karl Cunningham karlc@....... Date: Sun, 10 Oct 1999 09:59:57 -0700 Meredith -- A couple of comments: At 09:39 PM 10/9/99 -0700, you wrote: >Bismuth >is one of those, -10.5 (s)on one, and -280.1 (I) >on another. The (s) and (I) is not defined. A >number of items on the list also exhibit a >variation of values. Tin is another one, with >+3.1 (White tin)to -37.0 for (gray tin). I don't know for sure, but I think the different susceptibilities for bismuth and tin are for different crystal structures. Many materials' molecules can come together in more than one way, depending on the conditions present (temperature, pressure, rate of cooling, etc.) while the crystals are forming. >Purity also doesn't guarantee a uniformity in >diamagnetism. I have some carbon rods with >statements of purity probably going beyond >99.999%, with impurity up to some 4 parts per >million, and yes, their diamagnetism varys >from one rod to the next....some obviously >weaker than another in diamagnetism "levels". >Still; these aren't really any better than >some 3 other levitation carbon brush assemblys >I have. Many properties of compounds can be changed dramatically by *very* small changes in impurities. I don't know if this is the case here, but I wouldn't rule it out. >Bob reports testing some aluminum sulfate, but >while diamagnetic, it wasn't near as dramatic >as the listed value of -323.0, and, he says: >"but no obvious "strong" diamag apparent - >prob. less then Rochelle salt, quartz & few >others I tried." Sodium cloride is listed at >-30.3 on the 1988 list, quartz is not listed. For quartz, see SiO2 (listed under silicon as silicon oxide in the chart). That is the chemical compound of quartz, but again is the issue of matching the crystal structure. >Now...it sure would be nice if levitation >co-operated over the years; we might all be >running levitation seismometers now.... I also wish that springs would be a bit more cooperative with regard to temperature effects. Karl Cunningham La Mesa, CA. PSN Station #40 karlc@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Zollner-Wenner suspension From: S-T Morrissey sean@........... Date: Sun, 10 Oct 1999 13:08:23 -0500 (CDT) Regarding wire suspensions in seismometers: These have been experimented with since the earliest years of seismometers for making pendulum sensors for horizontal motion. Clearly the most basic is a plumb-bob on a string. But to constrain the degrees of freedom of this mass, two or more suspension wires are neeeded, or else a flat flexure is used as for the pendulum of a grandfather clock. The thin flexure strip is adequate to keep the dish-shaped mass from rotating and banging on the door. For more complete restraint four wires are used as a pair of inverted Vs, one at each end of a rod-like horizontal boom or mass. An example of this is the assembly of in-line chrome balls that are suspended from a wooden frame as an office toy (that actually demonstrates conservation of momentum). This suspension is also used for the dashpots to damp the motion of the Wiechert 80kg inverted pendulum seismometer of the early 1900s. The wires suspend a shaft supporting the pistons that translate within the fixed cylinders. The wires are about 20 cm long (high?) to minimize up and down motion. A number of early optical mirror and moving coil horizontal sensors were made, some with suspensions over a meter high. (a 1 meter simple pendulum has a period of 2 seconds). However, it was quickly realized that longer period sensors were only practical with horizontal boom configurations, as the Bosch-Omori 25kg horizontal sensors of the 30s. The interesting variable is the attachment of the pivot end of the boom at the support post. Some (Milne-Shaw) used a compressional pivot; later a tension member from the back of the support post was preferred, as in large horizontals today. An extreme of the second tension wire is the Zollner suspension, where the taught wire extends as far below the boom as the upper suspension is above the boom. This still required some points of attachment to fix the axis of rotation, and in the Wenner seismometer these became crossed flexures. THis provided a fairly rugged way to suspend a large mass and boom while using lightweight flexures to fix the axis of rotation. It also required a cavity in the pier. The Zollner-Wenner wires had problems with bow-string oscillations which would vibrate from local noises like steps and shorten slightly. In the Wood-Anderson, which is an extreme case of the Zollner opposed wires, the vibration of the wires is damped by oil cups. (The copper mass itself is magnetically damped). Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: mb5.5 Irian Jaya From: Arie Verveer ajbv@............ Date: Mon, 11 Oct 1999 09:06:39 +0800 Subject: Posted event in Wrong Mailing list From: Arie Verveer ajbv@............ Date: Mon, 11 Oct 1999 09:13:11 +0800 Hi, Sorry about this, I posted an event in the wrong mailing list. Arie _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Diamagnetic materials variation From: meredithlamb@.............. Date: 11 Oct 1999 20:22:12 -0700 Karl, Tnks for the reply. Crystallization could well have an impact on whether there is or isn't diamagnetism, I just don't know. Impurities could well also play a part...perhaps even as low as .005 parts in a million. Of course being as the likely hood of finding out, could go on forever......we'll leave that up to others. Have done and seen enough with carbons problems with temperature effects, to where, I'll probably go more into bismuth as the "sandwich" element of choice. Although its not the carbon being floated, it strongly responses to temperature and that changes the diamagnetism level, with the magnet being floated. Another note; Bob Lamb forwarded me a 1/2 ounce neo shaped like a tooth. Was able to float it, but had to do frequent adjustments to keep it from contact. The entire sandwich was carbon. I also used acouple bar magnets on the side of the sandwich to eliminate tilting for the most part. Bob also forwarded some bismuth. I used that for the bottom half, and carbon for the top. Strange combo but it works. ................ Some time back someone wanted the internet address for Colorado Futurescience, article on "Testing the Superconductors", that was forwarded to PSN. Seems there is two, one is a mirror. http://www.futurescience.com http://www.websom.com/cfsc/welcome.html The orginal article of "testing the super conductors", no longer appears anywhere on the site. They sell small superconductor kits, and go into other "different" subjects. Thanks, Meredith Lamb Signup for your free USWEST.mail Email account http://www.uswestmail.net _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Re[2]: ZOLLNER SEISMOGRAPH From: RADIOTEL@....... Date: Tue, 12 Oct 1999 00:06:46 EDT THANKS SEAN AND ANGEL The information you provided was thought provoking. However, for now I think I will stick with a regular Lehman suspension and my velocity copy of Sean's STM-8 which works very well for Quakes in California. Jim Allen Cerritos, Calif. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: WASS , was Diamagnetic materials variation From: Ed Thelen ethelen@........ Date: Mon, 11 Oct 1999 21:09:59 -0700 Greetings Meredith Lamb and any other WASS survivors I have given Larry Cochrane all of the old WASS Newsletters that I had. He and PSN seems a very worthy successor :-) (For those of you not in "the inside", WASS was "World Amateur Seismological Society". It was active (at least a quarterly news letter) from before 1971 when I joined to 1977?. We had a paid up mailing list of about 125 mostly passive members (the usual thing). In 1977? I could not find any other poor burned-out fool to be editor/publisher/mailer/treasurer/major-author ... and the "organization" died.) A Meredith Lamb had already been a long time WASS member and had been very helpful. :-) Cheers Ed Thelen P.S. Hope I did not violate too much etiquette. Just joined the Mailing List. meredithlamb@.............. wrote: > > Karl, > .... > > Thanks, > > Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: WASS , was Diamagnetic materials variation From: EK kerls@...... Date: Mon, 11 Oct 1999 23:29:22 -0500 And Cheers to you , Ed Thelen , and welcome to the Mailing List Major Edward E. Kerla A.R. Ed Thelen wrote: > Greetings Meredith Lamb > > and any other WASS survivors > > I have given Larry Cochrane > all of the old WASS Newsletters that I had. > He and PSN seems a very worthy successor :-) > > (For those of you not in "the inside", > WASS was "World Amateur Seismological Society". > It was active (at least a quarterly news letter) > from before 1971 when I joined to 1977?. > We had a paid up mailing list of about 125 > mostly passive members (the usual thing). > In 1977? I could not find any other poor burned-out fool > to be editor/publisher/mailer/treasurer/major-author ... > and the "organization" died.) > > A Meredith Lamb had already been a long time WASS member > and had been very helpful. :-) > > Cheers > Ed Thelen > > P.S. Hope I did not violate too much etiquette. > Just joined the Mailing List. > > meredithlamb@.............. wrote: > > > > Karl, > > > ... > > > > Thanks, > > > > Meredith Lamb > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Diamagnetic levitation materials From: George Harris gjharris@............. Date: Mon, 11 Oct 1999 21:44:45 -0400 "Charles R. Patton" wrote:the > highest constant, but aluminum sulfate hydrate is shown with bigger > numbers. Is there some independent reference where we can verify that > number? Usually the CRC handbook gives the reference for the data. > Could you please post that? Thanks. The CRC reference states thus: A more extensive listing of the magnetic susceptibilities of inorganic compunds as well as those for organic may be found in Constantes Selectionees Diamagnetism Relaxation Paramagnetique, Volume 7. The table (it contains about 360 items in the CRC) is abridged from the above reference by permission of the authors. George Harris _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Replica of Chinese Seismograph From: Doug Crice dcrice@............ Date: Tue, 12 Oct 1999 06:24:42 -0700 e-Bay has a replica of the original Chinese seismograph for sale. The seller is in Hong Kong, so I would guess that this is out of the Chinese handicraft industry. There's a picture at: http://cgi.ebay.com/aw-cgi/eBayISAPI.dll?ViewItem&tc=ps&item=179657643 _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Notes on diamagnetic material From: meredithlamb@.............. Date: 12 Oct 1999 09:47:36 -0700 Hi all, Forgot to mention, in the Handbook of Chemistry & Physics, circa 1988, for diamagnetic materials, the (s) symbol means "solid", and the (l) symbol means liquid. This note was forwarded to me by Robert Lamb. One could delve forever with different materials, but I would think, the carbon and bismuth are the more cheaper and less toxic materials for levitation. For those interested in more extensive experimentation, I would suggest checking out this commercial web site, for more magnets: http://www.wondermagnet.com/dev/magnets.html The items #9, #10 and #13 would all work and are bigger than the Radio Shack pill magnet. I only got the #13 (a ring neo) from this site. One has to go to the ordering info, to check on availability. The ring and disk neo's are alot easier to levitate. Their is one curved neo, that might interest the traditional coil/magnet crowd, there too, but mounting two such magnets could be somewhat of a challenge to keep them apart. Check out the humor pictures, and references to other sites. Its worth the time to browse and see. Meredith Lamb Signup for your free USWEST.mail Email account http://www.uswestmail.net _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Discussion list of interest to some PSN-L members From: Doug Welch welch@................... Date: Tue, 12 Oct 1999 15:22:34 -0400 (EDT) Folks, I have recently initiated a list for discussion and distribution of observations of geomagnetic phenomena. Its members are usually amateur observers of geomagnetism who have constructed (or are considering constructing) magnetometers to monitor geomagnetic activity. I'm sure that there are many PSN-L members who have overlapping interests and encourage any and all of you to subscribe and participate. There are two ways to go about subscribing: 1) Go to the URL http://mailman.mcmaster.ca/mailman/listinfo/magnetometry-l and follow directions there. 2) Send an e-mail to magnetometry-l-request@................... with the word help in the subject or body of the message for further instructions. You must be a subscriber to post messages. Best regards, Doug Welch _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Levitation heavyweight champ... From: meredithlamb@.............. Date: 12 Oct 1999 13:39:38 -0700 Hi all, Just got a ring magnet from All Electronics Corporation. Its their cat #MAG-50. Its 1.240" in outside diameter, .840" inside diameter, by .250" thick. My postal scale (non-precision)says about ..8 ounce. Am getting the strong feeling that for maximum weight, its the ring magnets that work better than even disk magnets. More mass could mean more enertia stabilility, if temperature problems can be controlled. This is the largest weight I've seen. It floats with one of my carbon units, and acouple side bar magnets. I was surprised! It will be interesting to try bismuth with this sometime. All electronics identifies it as a neodymium magnet; but I have suspicions it could be another element like samarium or ?; as it doesn't seem to have the magnetic attraction of my other neo's...i.e., weaker overall. They come unplated, and have a silver-gray with a tinge of yellow color to them. With this size, vertical vibrations seems to be easily displayed by eye, with the magnet tipping back and forth horizontally. Check out: http://www.allcorp.com See magnetic devices. For the coil/magnet crowd: All Electronics also has a curved neo magnet, but this is nickel plated. 1.735" length X 1.435" X .245" thick. $5.50 plus shipping handling; probably a very good buy if one can build a mechanism to keep the magnets apart. Believe the curve face is somewhere in the neighborhood of some 3-4" diameter, which means one could add magnets for larger coils other than small relay coils. Very nice clean unit, except for some glue deposits on the outside back. Probably a cheaper and better buy than the Forcefield unit, of the prior message. Meredith Lamb Signup for your free USWEST.mail Email account http://www.uswestmail.net _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: quake coming in From: meredithlamb@.............. Date: 12 Oct 1999 18:59:32 -0700 Hi all, Notice some long period waves coming in. Fairly strong vertical response, but moderate horizontals output. Perhaps a deeper than normal quake? Meredith Lamb Signup for your free USWEST.mail Email account http://www.uswestmail.net _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: New event From: barry lotz gbl@....... Date: Tue, 12 Oct 1999 19:18:50 -0700 Looks like Alaska is sending us a message. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Levitation heavyweight champ... From: barry lotz gbl@....... Date: Tue, 12 Oct 1999 19:29:46 -0700 Meredith I have thought of maybe taking apart a speaker magnet and replacing the donut with something similar to the curved magnets you mentioned. One may need something like 3 to form a circle and 2-3 to form the thickness. It seems like this magnet material may be stronger than a conventional speaker magnet. Barry meredithlamb@.............. wrote: > --snip-- > Hi all, > Check out: http://www.allcorp.com > See magnetic devices. > > For the coil/magnet crowd: > All Electronics also has a curved neo magnet, > but this is nickel plated. 1.735" length X > 1.435" X .245" thick. $5.50 plus shipping > handling; probably a very good buy if one > can build a mechanism to keep the magnets > apart. Believe the curve face is somewhere > in the neighborhood of some 3-4" diameter, > which means one could add magnets for > larger coils other than small relay coils. > Very nice clean unit, except for some glue > deposits on the outside back. Probably a > cheaper and better buy than the Forcefield > unit, of the prior message. > > Meredith Lamb > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Have large event happening can anyone say were it is coming from. From: EK kerls@...... Date: Tue, 12 Oct 1999 21:50:27 -0500 Maj. Edward Kerls A.R. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: large event From: EK kerls@...... Date: Tue, 12 Oct 1999 21:52:05 -0500 I have event coming in can anyone say were it is Maj.Edward E. kerls _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: WWW.SEISMICNET.COM outage From: Larry Cochrane cochrane@.............. Date: Tue, 12 Oct 1999 21:57:45 -0700 All, Today starting around 11:25 am local time (PDT) my ISP (PacBel ) had several outages lasting a few hours each time. My DSL line is back up again but who knows for how long. This is the first outage I've had for over two months but the fact it lasted for 4 hours the first time and then again for 3 hours is pretty bad.... -Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: large event From: "J. D. Cooley" cooleyj@............ Date: Tue, 12 Oct 1999 22:16:47 -0700 At 07:52 PM 10/12/99 , you wrote: >I have event coming in can anyone say were it is >Maj.Edward E. kerls > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L > 13Oct1999 01:33:40.3 54.7N 161.2W 33 MS=6.3 M*NEI ALASKA PENINSULA _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: large event From: EK kerls@...... Date: Wed, 13 Oct 1999 00:47:39 -0500 To J.D. Cooly ; You wouldn't happened to be the J.D> Cooly from around Athens Texas. Maj. Edward >e. Kerls "J. D. Cooley" wrote: > At 07:52 PM 10/12/99 , you wrote: > >I have event coming in can anyone say were it is > >Maj.Edward E. kerls > > > > > >_____________________________________________________________________ > > > >Public Seismic Network Mailing List (PSN-L) > > > >To leave this list email listserver@.............. with the body of the > >message: leave PSN-L > > > > 13Oct1999 01:33:40.3 54.7N 161.2W 33 MS=6.3 M*NEI ALASKA PENINSULA > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Alaska Quake From: S-T Morrissey sean@........... Date: Wed, 13 Oct 1999 01:02:45 -0500 (CDT) Per NEIS: 99/10/13 01:33:40 54.72N 161.19W 33km (deep) 6.3Ms Alaska Peninsula. Nice 60-second+ surface waves here at St. Louis. Did not clip the 12-bit RS digitizer. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Some list rules...was Re: large event From: Larry Cochrane cochrane@.............. Date: Tue, 12 Oct 1999 23:23:51 -0700 All, Lately I have been seeing some emails to the list with "Thanks for the Info..." type messages as well as other message with no interest to the rest of the list members. PLEASE, too keep the bandwidth down on my system this type of message should be sent directly to the sender. When you hit the reply button, the To: address is set to the list address. If the message you are sending only is for the sender please change the To: field. Thanks, Larry Cochrane Redwood City, PSN P.S. I don't mean to pick on Maj. Edward Kerls by reply to this message. But its a good example of what should NOT be sent to the list... At 12:47 AM 10/13/99 -0500, you wrote: >To J.D. Cooly ; You wouldn't happened to be the J.D> Cooly from >around Athens Texas. >Maj. Edward >e. Kerls > >"J. D. Cooley" wrote: > >> At 07:52 PM 10/12/99 , you wrote: >> >I have event coming in can anyone say were it is >> >Maj.Edward E. kerls _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Levitation heavyweight champ... From: meredithlamb@.............. Date: 13 Oct 1999 00:14:39 -0700 On Tue, 12 October 1999, barry lotz wrote: > > Meredith > I have thought of maybe taking apart a speaker magnet and replacing the > donut with something similar to the curved magnets you mentioned. One may > need something like 3 to form a circle and 2-3 to form the thickness. It > seems like this magnet material may be stronger than a conventional speaker > magnet. > Barry Hi Barry, I can't visualize how it would be easy to do that without complicated machining, and, the coil would likely be very large in diameter...not the original coil of the speaker, and also the center pole would also have to be made very large for maximum gauss. Nothing of the original speaker assembly would be of any use, if I understand your description. These magnets when stood upright need separation...the inside curve can't touch any steel attachment of the back polarity. I'am guessing one would need 6 to 8 of these magnets to form a circle (with slight separation) and special everything machining and coil size. I think you are thinking of a different shape than what they are...i.e., a rectangular piece, with a total thickness curve all over, and 1/2 the thickness is one pole, and the other half, is the other pole. If they were magnetized 1/2 the length .....then one could try as you describe. If you are thinking of using the original speaker assembly, and discarding the ferrite magnet donut, and, using flat neo's, then, one could do that. One would need enough neo's for the desired thickness of course. That could make a experimental approach, to check on the old versus the neo change over gauss field of the narrow gap. Economically it probably wouldn't be worth the effort, I would think. The original idea I was thinking of, is too use 2 pieces facing each other, with or without a center pole....i.e., a regular general "U" magnet affair. Sounds rather easy, but, these magnets somehow have to be mechanically held apart, otherwise they crash together into each other and go into pieces, or, implode might be a better description. Still.... they could be useful for that odd diameter coil, that doesn't fit what you/one has. More than likely the inside curve won't match the coil curve of the existing coil, and you wouldn't get the "max" gauss. Even here a steel center pole would probably be needed for the coil for max gauss. Matching the coil to the magnet is a real pain, on the homebrew scene. If one has a 3 piece old magnet assembly where you can move the iron on the ends, attaching these to the inside may work out OK...if the magnet had too big a gap to begin with....but, that depends on the coil of course. One would still need a lockdown on the iron pieces. One note on these magnets....make sure you order say, the outside curve to be like South and the inside to be north...and the other piece to be the opposite, with the inside south, and the outside north...otherwise they repell of course, if they were both the same. All Electronics may or may not consider this....so use the remarks section of the order form, if, you want these curved neo's. Take care, Meredith Lamb Signup for your free USWEST.mail Email account http://www.uswestmail.net _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: New WinQuake beta release and new PSN Explorer program. From: Larry Cochrane cochrane@.............. Date: Wed, 13 Oct 1999 02:00:47 -0700 Greetings, Today I released a new WinQuake (WQ) beta release. Links to the new release can be found here: http://www.seismicnet.com/software.html. This release has the following features as will as some bug fixes; The event, or seismograph, window now displays the time and amplitude of the cursor as you move it within the window. This information is displayed on the Status Bar. For the amplitude the number is in A/D counts. For the X or time axis WQ will display the time down to the millisecond, if you zoom down to a 10 second or less X Scale. Too get 1 ms resolution WQ interpolates the mouse location between samples since a true 1 ms resolution would require a sample rate of 1K hz. I fixed several problems around saving event files as SAC binary files. WQ now save the event time in the proper field. The problem is I'm not sure if I'm doing it right. If you have access to another program that can read SAC binary files and if that program can display the event time please contact me...I also save the event magnitude in the USER1 field. As far as I can tell there is no defined field for this??? I noticed that the SAC binary created by the IRIS Spyder (http://dmc.iris.washington.edu/DOCS/spyder_alt.htm) system was using USER1 for this info. Unfortunately they do not fill in the event time, so I can't check to see if I'm doing the event time correctly. The major new thing with this release is the PSN Explorer program I wrote in the last few weeks. First some background.. When I started using HTML help files for WQ, Netscape users had no problem using them. People using M$ Internet Explorer would run into a little problem with going to the correct part of the web page. With Netscape, WQ could open a local (on the users hard disk) web page file and have the browser go to the proper section within the help page. Internet Explorer would open the correct page, but would not go to the HTML name tag (sometimes called a bookmark) within the page. Too get around this problem I used a new feature in VC++ 6.0 that lets you create your own program and use Internet Explorer 4.0 (and above) to display web pages within the users program window. Buy creating this new program I fixed the help problem and also was able to easily add a feature to the PSN Explorer that allows the user to download event files from a web page and have WQ open the new file after the FTP download. Heres how too use it. In WQ I added a new tool bar icon next to the report icon and menu items under View. Selecting the New Event File item, WQ will open the PSN Explorer program, or use one that is already open, to display the New Event File page at http://www.seismicnet.com/cgi-dos/event.exe. The user can then select either the GIF image link, this will be displayed by PSN Explorer, and / or select the PSN event file link. If the event file is selected the program will download the file using FTP and then send a message to WQ, using DDE (a way of communicating between programs In Windows), that tells WQ to open the new event file. Before using this feature you must select a directory that will be used for downloads. This only needs to be done once. If you download the new release and find any problems please let me know as soon as possible. I want to get WQ out of beta soon. The next thing, the part I hate the most, is updating the documentation.... -Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: R: New WinQuake beta release and new PSN Explorer program. From: "Francesco" franuc@...... Date: Wed, 13 Oct 1999 19:29:08 +0200 Hello Larry I've downloaded the new beta version (.exe file) to upgrade 6.3.3 v. I don't found the icon or menu items about PSNExplorer on toolbar. Althought, I've run the program fron executable file in the directory and it's work well, as the other WQ new features. At least, it's impossible to read the "help" file; this is the error message: "unable to open web broswer", "no default web broswer; can't display web page". (I use MSExplore 5.1). I'm waiting your notice Regards Francesco _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Levitation heavyweight champ... From: barry lotz gbl@....... Date: Wed, 13 Oct 1999 19:25:30 -0700 Meredith I looked at the All electronics catalogue and you are correct. I was thinking of curvature in a different direction. I have some neo magnets that are in the order of 1/4" thick and are curved in the other plane, like the magnets of a harddrive. I bought them at a surplus store a few years ago for $1 each. As many of you may have experienced with surplus stores, you buy a few things thinking they may be of use in the future but when the future comes and you need a couple more the surplus store has sold them all. I see the shape in the All electronics catalogue but they are very thin, and therefore to many would be required to replace the donut. The search goes on. :) Barry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: LEHMAN CONSTRUCTION From: RADIOTEL@....... Date: Wed, 13 Oct 1999 22:40:38 EDT I am a bit confused regarding the construction of a Lehman (Garden Gate) seismo. Text books at the local university library indicate Garden Gate seismographs with mass of 25 kg or more. However, simular seismographs made by PSN members use masses of about 7 lbs. Why the difference? Is the larger mass more or less sensitive? Additionally, in the text book examples reflecting the principle of the Garden Gate seismograph, they all show the boom slightly tilted down towards the mass end. However, most instructions I have seen on the list I believe states that one should "level" the boom. Which is best for sensitivity - and if the boom should be tilted to what degree is appropriate? A number of pictures on PSN web sites show a long thin rod as part of the boom suspension. Others just show a turn-buckle. What purpose does the long thin rod serve? Any clarification would be appreciated. Jim Allen Cerritos, Calif. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: System backup again. Backup mail server? From: Larry Cochrane cochrane@.............. Date: Thu, 14 Oct 1999 15:23:50 -0700 All, Thanks to PacBell, my system (www.seismicnet.com, webtronics.com and psn.quake.net, they all come to the same computer) was down for almost 2 days. I'm not a happy camper! As of around 2.00 PM local time my DSL service started working again. Hopefully it will stay up this time...It has been up for short periods of time and then down for very long periods of time. This brings up sometime I have been thinking about. We really need a backup mail list server somewhere away from N. California. If/when we have a large local event my system could be down for a long time. If you have access to a system that has a full time connection to the Net and would be willing to host the backup list please let me know. I don't want to use one of the free services. I'm a firm believer in "you get what you pay for"... -Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Speaker magnet replacement From: "Charles R. Patton" patton@.......... Date: Thu, 14 Oct 1999 16:07:08 -0700 A quick comment on this thread. If you find thin, single poled crescents as opposed to dual-poled crescents (i.e., if you check one face of the crescent, and it has one N or S pole it is single poled as opposed to having a N on one end of the face and a S on the other end of the same crescent face which would be a dual poled unit.), you could easily use them to replace the ferrite magnets in the speaker if you just place a flux bar (soft iron, cast iron, steel, basically any ferrous, relatively high permeability metal) to fill the vertical height to make the combination height equal to the old ferrites being replaced. (look at following in fixed spacing type such as Courier or Line Printer) Sliced view from side of only 1/2 of a symmetrical structure +--Voice Coil Gap | V +--------+ +----------+ | | | | <---Original flux plate | | +----------| | | | | | | | | <---added flux conductor/spacer | | | | | | | | | | +--------+ | | | | <---new high energy magnet | +-----+--------+-+ | | | <-orginal lower flux plate +-------------------------+ P.S. You could use the dual-poled units by grinding a line on the face to mark two equal halves then snapping the magnet into two pieces by using a vise and a hammer or board. The magnets are brittle and don=92t bend, they break. Then you could lay up the magnet pieces with the poles all in one direction. Charles R. Patton _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Lastest Winquake - possible bug From: Larry Cochrane cochrane@.............. Date: Thu, 14 Oct 1999 16:12:28 -0700 Hi Arie, Now that I can send email again.... Looks like the problem is with Win95. According to Microsoft you need to have Internet Explorer 3.0 or later loaded on the system for the Trackmouse event to work. By loading IE, a new DLL (IMHO the whole concept of DLLs was a VERY bad move by M$. The DLL situation is a total mess) is loaded so that the function can be called by WQ. You should not have this problem with Win98 or NT 4.0 (not sure about NT 3.51). -Larry At 08:38 PM 10/13/99 +0800, you wrote: >Hi Larry, I just copied the latest version of Winquake over the Old version >(2.62). >When the Program Icon is clicked the following message is returned. > >The Winqk32.exe file is linked to missing export COMCTL.DLL:_TrackmouseEvent > >I'm running Win95. I can test it on a WinNt system tomorrow if you like? > >All the Best > >Arie > > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: LEHMAN CONSTRUCTION From: Karl Cunningham karlc@....... Date: Thu, 14 Oct 1999 16:24:28 -0700 Jim -- For the regular Lehman design, the amount of mass used does not affect the sensitivity of the seismometer, per se. However, a larger mass makes the instrument less sensitive to convection currents and reduces the effect of any friction in the boom hinge. On the other hand, a larger mass means a more heavy-duty suspension system and perhaps more friction in the hinge. So it is a tradeoff, and there is really no right answer. If you intend to put build this system into a feedback seismometer (such as the VBB approach), there are other design considerations that have a direct relation to the size of the mass. If this is in your plans, do what those design considerations dictate. I'd go with a smaller mass (7 lb or less seems like a good amount) because it is easier to work with and hurts less when you drop it on your foot. Suspension methods (even for amateurs) have improved quite a bit since the original articles were published, which allows the use of smaller masses without sacrificing performance. The use of flexures is generally preferred in the suspension -- they provide a stable hinge with very little friction. In diagrams, the tilt toward the mass end is often exaggerated for the sake of the illustration. In practice it usually amounts to a millimeter or less, and is most easily adjusted by turning the leveling screws in the seismometer base. This adjustment directly affects the period of the seismometer. The longer the period, the more you will be able to see longer-period signals, and the less stable the mass centering becomes. You will probably that with longer periods, you will be re-centering the mass fairly often. Others probably have had more experience with this than I, but periods longer than 20 seconds or so become significantly less stable. A suspension wire is easy to use but can contribute parasitic vibrations itself -- it can vibrate just like a guitar string. Using a rod for the top suspension can increase the frequency of these vibrations enough to be above the frequencies of interest, and this can be filtered out of the signal. Hope this helps. Ask if you have more questions. Karl Cunningham La Mesa, CA. PSN station #40 karlc@....... At 10:40 PM 10/13/1999 EDT, you wrote: >I am a bit confused regarding the construction of a Lehman (Garden Gate) >seismo. >Text books at the local university library indicate Garden Gate seismographs >with mass of 25 kg or more. However, simular seismographs made by PSN >members use masses of about 7 lbs. Why the difference? Is the larger mass >more or less sensitive? >Additionally, in the text book examples reflecting the principle of the >Garden Gate seismograph, they all show the boom slightly tilted down towards >the mass end. However, most instructions I have seen on the list I believe >states that one should "level" the boom. Which is best for sensitivity - and >if the boom should be tilted to what degree is appropriate? >A number of pictures on PSN web sites show a long thin rod as part of the >boom suspension. Others just show a turn-buckle. What purpose does the >long thin rod serve? >Any clarification would be appreciated. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: LEHMAN CONSTRUCTION From: TORBEN THAMS tobythams@................ Date: Thu, 14 Oct 1999 17:25:21 +0100 Hi Jim: I completed a modified Lehman prototype just in time to catch the September 30 quake in Mexico. I was test driving it, even though I had not yet installed the damper. I got a very clear signal of both the P and S waves, somewhat to my surprise. My unit uses a 7 pound pendulum mass. The important point is that the top node (where the wire exits the upright post) is slightly off-set from an imaginary vertical line through the knife-edge of the boom, the off-set being toward the mass. You may look at it as if the top of the vertical post is tilted slightly toward the weight. This off-set should be on the order of about 5 mm. Without this off-set, the pendulum will not be able to find a null point, where it will come to rest. If the off-set is in the opposite direction, the boom will try to swing in the wrong direction. It takes a bit of fiddling - and patience - to find the right tilt, and I would recommend using three leveling screws for the base instead of shims. I use three 5/16 wing bolts. Also, remember that the larger the off-set, the sooner the boom will come to a rest, but the less sensitive the pendulum becomes. Toby Thams Fullerton, Calif. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Neodymium hazard From: meredith lamb mlamb1@.......... Date: Thu, 14 Oct 1999 21:00:11 +0000 I bought afew neo's from Forcefield awhile back and they sent a warning with the shipment: Do not attempt to drill, cut, or machine these until doing some research. They are brittle, so odds are, as soon as you try, the magnet will break. They also lose their field when overheated (200-300deg F. depending on the magnet). If overheated too much, they burn, super hot, and super fast, like magnesium. The fumes given off by combustion are extremely toxic. If you were to try dilling these, the dust will build up on the bit, and one spark could set it off, so...DON'T TRY! They also recommend gloves when handling these magnets. Also obviously keep away from computers, monitors, tv sets, cassette tapes, floppy discs, and people with pacemakers. Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: LEHMAN CONSTRUCTION (and convection currents) From: Ed Thelen ethelen@........ Date: Thu, 14 Oct 1999 21:54:17 -0700 Convection Currents - I solved 'em for me Karl Cunningham wrote: > > Jim -- > > For the regular Lehman design, the amount of mass used does not affect the > sensitivity of the seismometer, per se. However, a larger mass makes the > instrument less sensitive to convection currents and reduces the effect of > any friction in the boom hinge. On the other hand, a larger mass means a > more heavy-duty suspension system and perhaps more friction in the hinge. > So it is a tradeoff, and there is really no right answer. > Ah - convection currents - the "3 A.M. blues" - The seismometer runs fine *except* about 3 A.M. Then, some nights, there are these slow swings all over the place for maybe 10 minutes (or longer!). The following insulated box and heater system eliminated the "3 A.M. Blues". It worked "perfectly" with a light (?12 ounce?) pendulum garden gate type horizontal seismometer adjusted to a 30 second period. ------------------------------------ I figured the "3 A.M. blues" were air currents inside the insulated box protecting the seismometer. I figured the air currents were caused when 1) the outside got colder than inside the box 2) cooled the top of the insulated box, 3) and the top of the air inside, 4) and the cool top air, now an unstable thermal inversion layer, 5) "rotated" to the bottom of the insulated box 6) until some sort of thermal equilibrium was established. So - goals - make an insulated box that: 1) the top of the inside of the insulated box was always warmer than the bottom of the insulated box 2) keep out the creepy crawly things - spiders to professionals 3) easy to examine (for level, etc.) without disturbing 4) reasonably easy access for leveling, etc. There is probably nothing original about the following box. I imagine most stubborn long period folk wind up re-discovering the following box. So - the bottom and sides of the box 1) I got some 2" thick expanded Styrofoam from the local home depot type store, 2) cut to generous box size - I tended to make "garden gate" seismometers about 12x14x14 inches - so 24 inch squares on the sides was fine - I am lazy and did not bevel the corners - 3) "glue" the sides with the usual window caulking or paste. Just butt the end of one piece to the side of another piece - no particular art. (Real chemical glues dissolve the foam in an instant.) 4) place the "glued" sides surrounding the area where you want to put the seismometer. I am assuming a concrete slab or pillar. (I did not caulk the sides to the concrete, and had no problem - but securing the sides to the cement would reduce your worries of kicking the box over.) 5) dose the concrete and insides of the box with all the non-styrofoam dissolving insecticides in your house 6) now - to keep out ground moisture, and a possible mildew problem, lay a sheet of 6x6 foot thin plastic - like 1 mil painter's "drop cloth" - on the concrete bottom and up the sides. Trim and hold in place (seal) with your handy duct tape - (it will last in this application) and - the top of the box 7) I divided the top into 2 equal areas - both made of the 2 inch styrofoam - neither glued down to the sides or anything - just gravity holds them in place (OK - I cheated - styrofoam just floats away with the slightest excuse - A big block Styrofoam can probably levitate from static electricity! I used a big old Mexican sombrero as a weight to hold the two half tops on. It also helped keep the cat off the box!) a) One half of the top holds the heater (under the top) (two 4 watt night lights in electrical series - reduce heating and lasts forever) I used a piece of sheet aluminum, like for roofing, to spread the heat of the lamps over the top of this half of the box. The electric wires for the heater were twisted, and entered the box through a little notch in the top of the styrofoam side - on the other side from the electronics wires. I laid cotton in the notch to help keep insects out. This half of the top is moved only when you have to do something really major with the instrument b) - a thin plastic window, say 3/32" or 1/8 inch clear plastic covers the open part of the box. You can look through this without disturbing the seismometer too much, and show your friends how you waste your evenings. (My wife said my friends were "victims" when I forced them to look at my machinery.) - another 2 inch thick piece of styrofoam normally covers the above plastic window. Now install the seismometer - place a hard plastic slab say 1/4 inch thick on the thin plastic at the bottom of the box - this will protect the thin plastic from the twisting effects seismometer leveling screws - place the seismometer on the thick plastic an do a rough preliminary level, period, and damping adjustment. - turn on the heater and electronics - might as well let the system sit, warming and stabilizing for several days before thinking of serious adjustments. General comments: a) I was afraid the air in the top would get heat, heat the copper pipe of the sensor, travel down the copper pipe and the heated pipe would create its own air currents. That did not seem to happen enough to notice. I had considered lining the inside vertical walls of the box with sheet aluminum or copper to try to smooth the temperature difference from the warm top and the cooler bottom. The box worked very well for my purposes with out the temperature smoothing metal. b) I mounted all the electronics boards - selectable damping resistors - chopper op amp - analog to digital converter, etc. on a little stand so they would be high in the box. This way, any heat they produced would disturb air "only" in the top of the box. c) I tended to make quite light (1 pound or less) pendulums! Hinges, pivots, flex wires, or what ever are interesting enough with 1 pound - seven pounds might as well be a ton. d) The above box and heater system worked "perfectly" with a light pendulum garden gate type horizontal seismometer adjusted to a 30 second period. e) Another remaining worry was that the expansion differential between the concrete, the plastic, and the copper frame of the sensor would cause slippage (and a big step function). It seemed to be OK - I did not have to go to temperature control. I do tend to use thin leveling screws that can probably bend enough to handle the strains due to differential expansion without slipping. The box was in a "protected" shed in the relatively stable climate of coastal California. Potentially if the unit had to operate over a wider temperature range, some sort of thermostatically controlled environment might be necessary to handle differential expansions. (It would be wonderful to have your sensor in a cave of bedrock and practically zero temperature changes. :-) ------------------------------------- You know, sometimes I miss those long slow rolling seismic waves coming in from the Tonga islands. A real kick. Cheers Ed Thelen _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Lehman Mass/Period From: S-T Morrissey sean@........... Date: Fri, 15 Oct 1999 00:16:48 -0500 (CDT) Jim, As has been pointed out, the size of the mass is a determining tradeoff in the design features that affect the noise of the sensor. Bigger is better, but it really puts demands on the suspension and base design. The largest comercial horizontal mass is in the Sprengnether S5100, which is 11 kg., requiring a massive cast aluminum base and frame. This was meant to provide enough power output from expected ground motions to drive a 90-second galvanometer for a long- period photographic system magnification of 6000 at 30 seconds (which few stations achieved). Modern fedback garden-gate horizontals have masses of less than 1 kg. This is because little or no power is produced by the seis (dissipative damping is a noise source anyhow). A small mass reduces the demands for strength and rigidity of the base and the suspension, expecially the hinges or flexures. The period of a horizontal seismometer is determined by the angle that the boom makes with the horizontal, assuming that the restoring forces of the suspension are minimal. The natural period: Tn = 2*pi*sqrt(L/(g*sine i)) where L is the boom length in cm, g=980cm/sec^2, i is the angle that the boom makes wrt the horizontal; (if i is measured in radians, i is small, sine i = i). For example, a 40 cm boom hanging vertically as a simple pendulum ( an angle of 90 degrees) has a period of 1.3 seconds. (a one second clock pendulum is 24.8 cm). When tilted horizontally to about 4 degrees, the period is 5 seconds. At about a 1 degree angle, it is 10 seconds, and at about 0.23 deg. it is 20 seconds. So the period is changing with inverse of the square root of the angle, which is why long periods are so unstable. But unstable also means sensitive to smaller ground motions. Note that the size of the mass is not involved.o In setting up a horizontal seismometer, the boom is usually set parallel to the base, which is leveled. This is the infinite-period situation; then the front or mass end of the baseplate is lowered as the period is measured by timing several oscillations until a reasonable period is achieved. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: John Cole's Lehman experiments From: "Frank Cooper" fxc@....... Date: Fri, 15 Oct 1999 00:44:22 -0500 Hi, John Cole of Pearland, Texas, has been doing some very productive research in improving and finding cheap ways to construct a Lehman. He has been using two Lehman sensors (side by side) with a N - S orientation to check out the results of using various coil sizes. He has a coil winding machine and has wound and used coils with 6,000 to 16,000 turns. He has found, for example, that a 14,000 turn coil will give approximately 20% better results than a 12,000 turn using the same size wire. (The two giant surplus magnets used with his two Lehman sensors have approximately the same magnetic flux density.) He has discovered that Radio Shack speaker magnets (one mounted above the other in a wooden framework and not connected in any way) are just as effective as the giant war surplus magnets he has been using. The giant magnets are extremely hard to find but the RS magnets are plentiful, cheap, and often can be obtained free in discarded bad speakers. He has even broken a single magnet into two pieces and used the two parts to effectively detect earthquakes. John discovered a method of easily increasing the period of the Lehman pendulum up to 16 seconds or so by decreasing the friction at the pivot point. He did this well over a year ago by using a ball bearing at the pivot point. (The period of my Lehman was increased from 12 sec to 16 seconds using John's method.) I have noticed that several other amateur seismologists recently have switched to John's method. John has been detecting earthquakes that none of the Texas stations have been reporting via PSN "event" (except for the Corpus Christi station). You have not heard from John because he has been using two Angus-Esterline chart recorders in conjunction with his two Lehman detectors. This should change soon, however, as John is now using Larry's a/d card and amp and hopefully will begin uploading quakes to PSN "event" within a few weeks. My hat is off to John because of his productive research. You can see some of the results on his SEISMOLOGY IN PEARLAND, TEXAS web page at: http://freeweb.pdq.net/fxc/four.html I congratulate science teachers Don Wheeler and Pat Schneider of Carroll High School in Monroe, Louisiana. Don and Pat recently visited John and me to study our seismograph stations. They returned to Monroe and obtained funding to construct a seismograph station at Carroll HS in Monroe. I do not think it will be long before you will see their seismograms on PSN "event." You can see their picture on my SEISMOLOGY IN FRIENDSWOOD, TEXAS web page at http://freeweb.pdq.net/fxc/ Frank Cooper, Friendswood, Texas. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: WASS From: Larry Cochrane cochrane@.............. Date: Thu, 14 Oct 1999 22:37:49 -0700 Thanks Ed and welcome to the group. The binder that Ed gave me has lots of history in it. Theres even a note in one of the newsletters when Meredith got married. What I would like to do, with Ed's permission, is keep it until the next PSN meeting in December? and let people look at it there. After that, maybe we could send it around to other members on the list who would like to see it. Maybe create a list and have each reader send it to the next on the list etc. The last person on the list would be Ed so he can have it back. Anyway, just a thought.... -Larry Cochrane Redwood City, PSN At 09:09 PM 10/11/99 -0700, Ed Thelen wrote: Greetings Meredith Lamb and any other WASS survivors I have given Larry Cochrane all of the old WASS Newsletters that I had. He and PSN seems a very worthy successor :-) (For those of you not in "the inside", WASS was "World Amateur Seismological Society". It was active (at least a quarterly news letter) from before 1971 when I joined to 1977?. We had a paid up mailing list of about 125 mostly passive members (the usual thing). In 1977? I could not find any other poor burned-out fool to be editor/publisher/mailer/treasurer/major-author ... and the "organization" died.) A Meredith Lamb had already been a long time WASS member and had been very helpful. :-) Cheers Ed Thelen _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: John Cole's web page url correction From: "Frank Cooper" fxc@....... Date: Fri, 15 Oct 1999 00:56:35 -0500 Hi, In the message I sent a few minutes ago to psn members regarding John Cole's Lehman research I gave the wrong url for John's web page. The html at the end of the url should be htm. The correct url is http://freeweb.pdq.net/fxc/four.htm Sorry for the error, Frank Cooper, Friendwood, Texas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: John Cole's Lehman experiments From: Larry Cochrane cochrane@.............. Date: Thu, 14 Oct 1999 23:37:10 -0700 At 12:44 AM 10/15/99 -0500, Frank Cooper wrote: >I congratulate science teachers Don Wheeler and Pat Schneider of Carroll >High School in Monroe, Louisiana. Don and Pat recently visited John and me >to study our seismograph stations. They returned to Monroe and obtained >funding to construct a seismograph station at Carroll HS in Monroe. I do not >think it will be long before you will see their seismograms on PSN "event." >You can see their picture on my SEISMOLOGY IN FRIENDSWOOD, TEXAS web page at >http://freeweb.pdq.net/fxc/ > >Frank Cooper, Friendswood, Texas. I got the paperwork from Don and Pat the other day. The A/D card for Carroll HS will ship tomorrow and this weekend I will be getting the system together for Monroe HS. Its great that we are getting some more schools online. -Larry Cochrane Redwood City, PSN PS: My DSL service has been up for over 8 hours now so hopefully the nightmare is over... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Lastest Winquake - possible bug From: "Francesco" franuc@...... Date: Fri, 15 Oct 1999 08:40:58 +0200 Hi Larry, I think that you lost my mail with the shotdown of your isp.. That's the problem : I not found in the new release the PSNExplorer icon or menù items. To run this feature I can make a shortcut from exe.file. So all work fine (psn archive files address is not active???). However, later I will repost the original message to you Francesco _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: larger seismometer mass From: S-T Morrissey sean@........... Date: Fri, 15 Oct 1999 11:57:25 -0500 (CDT) OK everyone, before I get more mail on the subject: Re largest commercial mass of seis: there are larger: An oversight on my part, as I was only thinking of long period seismometers in the context of the Lehman questions. I suggested the S5100 series because almost 400 three-component sets were made, mostly for the WWNSS.(Worldwide Network of Standard Seismographs) of the late '50s. To be technically correct (as asked!), the LP-Z is 11.201kg, and the LP horizontals are 10.678kg. A number of PSNers have these seismometers, some in operation, like at Merediths' station. Larger masses (much) were in the 1-second Big Benioff short period seismometers of the WWNSS. Also, even larger masses were used in individual experiments, but not in large quantities. I have had considerable experience with these big Benioff seismometers with 100 kg net masses; in fact I am still operating one of the Geotech prototype verticals (c1956) in our vault at SLM. I have had to relocate several sets, like from the old FLO (Florissant, MO), station (I called a safe moving company) and from ADK (Adak, AK). Even when the masses are removed, the 3/4" thick steel frame leaves over 200 pounds to deal with. The spring for the vertical weighs over 20 pounds. Fortunately, Geotech realized that when high power output( to drive a 2 hz galvanometer to a photographic magnification of 100k or more) was not necessary, just the moving coil portion of the variable reluctance transducer had enough mass at about 14 kg. So they built the "baby" Benioff, of which I still have two sets in service with telemetry. The transducer is hugh, with 8 windings, and an inductance of 5 henries, which has to be accounted for in the transfer function, since the inductive pole is at 4.5hz. But for all its size and complexity, the output is only 135V*sec/meter, or about half the open-circuit output of an L4-C (5500ohm coil) . With electronic amplification, this is the main consideration. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Kinemetrics was PC-based seismograph From: Greg ghost@............. Date: Fri, 15 Oct 1999 09:58:06 -0700 A while back there was a discussion on this rumor. I said I wouldn't post again until I heard the details from Kinemetrics. Well, it seems to be very difficult to get the full details. Here's what took so long to get: The system does exist. It's called the Earthscope. The rest of the information is in the form of a fax I recieved, scanned, converted to gif format and uploaded to the web server. There are two sizes of gif files for visual clarity. It's the same fax, but the larger one is in greyscale and the smaller one is black/white. I should have had the computer recieve the fax, but the machine is quieter and uses less electricity. http://www.azstarnet.com/~ghost/earthscope2.gif is the smaller file. http://www.azstarnet.com/~ghost/earthscope.gif is the larger file, if you can't read the smaller one. It's not on their website yet, but when it is, it will probably be about the same information. http://www.kmi.com/ or http://www.kinemetrics.com/ If you wanted one, you'd have to call and ask them about the price and any other details. The rumor suggested a price of $500. End of discussion on my end. ,Greg _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: New WQ beta release; Was Re: Latest Winquake - possible bug From: Larry Cochrane cochrane@.............. Date: Fri, 15 Oct 1999 18:44:56 -0700 All, After thinking about this some more I decided too make another release that fixes the DLL problem Arie discovered. I don't want to force people who are running Win95 with a old copy of Internet Explorer (IE), or if they only have Netscape on the system, to install a new version of IE. What I did is create a new release that has two winqk32.exe files. One is for Win95 users with IE 3.0 or later and all of the other operating systems. Another exe is for Win95 uses that can't run the other exe. BTW I did test WQ and the new Psn Explorer program on a beta release 3 of Win2000. It seems to work fine. I updated the page at http://www.seismicnet.com/software.html with new links for the 95 version. I also update the Release readme file with info on the two winqk32.exe files. I sent Arie a copy of the Win95 version and he confirmed that the new exe works on his Win95 system with only Netscape installed. Unfortunately these system will not work with the new PSN Explorer program since it needs IE 4.0 or later install on the system. If you downloaded the new beta release in the last few days please download it again and install the new version. The version number is still called 2.6.4 but in the About dialog box the release date will be 10/14/99. If you have the special Win95 version this will also be displayed in the dialog box. I think in the process of releasing 2.6.4 the other day I zipped the wrong exe file. So please make sure you have the version with the release date of 10/14/99. Sorry about that.... Regards, Larry Cochrane Redwood City, PSN >Date: Thu, 14 Oct 1999 16:12:28 -0700 >To: Arie Verveer >From: Larry Cochrane >Subject: Re: Lastest Winquake - possible bug >Cc: psn-l@.............. >In-Reply-To: <38047D5A.1D1A3109@............> > >Hi Arie, > >Now that I can send email again.... > >Looks like the problem is with Win95. According to Microsoft you need to have Internet Explorer 3.0 or later > loaded on the system for the Trackmouse event to work. By loading IE, a new DLL (IMHO the whole concept > of DLLs was a VERY bad move by M$. The DLL situation is a total mess) is loaded so that the function can be >called by WQ. You should not have this problem with Win98 or NT 4.0 (not sure about NT 3.51). > >-Larry > > >At 08:38 PM 10/13/99 +0800, you wrote: >>Hi Larry, I just copied the latest version of Winquake over the Old version >>(2.62). >>When the Program Icon is clicked the following message is returned. >> >>The Winqk32.exe file is linked to missing export COMCTL.DLL:_TrackmouseEvent >> >>I'm running Win95. I can test it on a WinNt system tomorrow if you like? >> >>All the Best >> >>Arie >> >> >> _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: R: New WinQuake beta release and new PSN Explorer program. From: Larry Cochrane cochrane@.............. Date: Fri, 15 Oct 1999 19:05:45 -0700 Hi Francesco and other beta testers, Please down the software again. You have the wrong version. After downloading and installing the new exe, verify that you have the proper version by opening the About dialog box (Help/About menu items). You should see the release date of 10/14/99. If you still have the same problem, your system does not have a default browser defined. Go to the Control Panel and open the Internet Options dialog box. I think you can open this dialog box from within IE somewhere in the menu items. Select the program tap and make sure the "Internet Explorer should check to see whether it is the default browser" check box is checked. If you restart IE it should fix the problem. You will also need to restart WQ. -Larry Cochrane Redwood City, PSN At 07:29 PM 10/13/99 +0200, you wrote: >Hello Larry >I've downloaded the new beta version (.exe file) to upgrade 6.3.3 v. >I don't found the icon or menu items about PSNExplorer on toolbar. >Althought, I've run the program fron executable file in the directory and >it's work well, as the other WQ new features. >At least, it's impossible to read the "help" file; this is the error >message: "unable to open web broswer", "no default web broswer; can't >display web page". (I use MSExplore 5.1). > >I'm waiting your notice > >Regards >Francesco _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Northern California PSN meeting From: Larry Cochrane cochrane@.............. Date: Fri, 15 Oct 1999 22:46:18 -0700 All, I got this from Lind Gee the other day. She is a seismologist at the Berkeley Seismo Lab (BSL) and involved with the IRIS (www.iris.edu) Education and Outreach program. I had a meeting with her and other IRIS members a few weeks ago. >Regarding the PSN meeting in December, the >BSL would be happy to host the meeting at >our facilities on the UC Berkeley campus. Before >AGU is a little troublesome (people will be >working on their presentations), but either one >evening during AGU or the following Friday (12/17) >or Saturday (12/18) would be fine. My preference >would be for either Friday or Saturday, but Thursday >might be possible. It seems as if Catherine will >be able to attend. Catherine is from IRIS and is also part of the E & O program. I thought it would be a nice change of pace if we have the next meeting at another location. The last two meetings have been at the USGS in Menlo Park around the time of the AGU in December. So who's interested, and what day and time should we have it? Maybe Sat. would be best for most people? If people from IRIS, and maybe PEPP, are there, the meeting should be geared around setting up and supporting system in schools. I'm sure after the meeting we can have a tour of their lab. Regards, Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Quake now... From: meredithlamb@.............. Date: 16 Oct 1999 02:59:02 -0700 Big quake smearing SDR now. Start around 09:50 UTC. Meredith Lamb Signup for your free USWEST.mail Email account http://www.uswestmail.net _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Quake now... From: Larry Cochrane cochrane@.............. Date: Sat, 16 Oct 1999 03:03:29 -0700 CNN reporting an event near Los Angles. CA -Larry At 02:59 AM 10/16/99 -0700, you wrote: >Big quake smearing SDR now. Start around >09:50 UTC. > >Meredith Lamb >To leave this list email listserver@.............. with the body of the >message: leave PSN-L > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Quake now... From: Canie canie@........... Date: Sat, 16 Oct 1999 03:03:04 -0700 so far a 7.0 Joshua Tree - and quite a few aftershocks too Canie At 02:59 AM 10/16/99 -0700, you wrote: >Big quake smearing SDR now. Start around >09:50 UTC. > >Meredith Lamb > > > >Signup for your free USWEST.mail Email account http://www.uswestmail.net > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Quake now... From: Stephen & Kathy mortskm@....... Date: Sat, 16 Oct 1999 03:10:20 -0700 meredithlamb@.............. wrote: > > Big quake smearing SDR now. Start around > 09:50 UTC. > > Meredith Lamb > > Signup for your free USWEST.mail Email account http://www.uswestmail.net > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L I show it as approx 100 sec P to S from my station Stephen Mortensen near Pilot Hill Ca 38.828N 120.978W _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Big Socal quake felt From: fred@............ (Fred Bruenjes) Date: Sat, 16 Oct 1999 03:10:20 -0700 (PDT) a little before 3am, 10/16/99: Just got a woken up by a large quake here in Ramona (near San Diego, CA). USGS ISAIAH website has mag at 6.6, no make that 7.0, which seems high as shaking didn't last very long. Epicenter in Joshua Tree (out in desert). SCEC website is down. No damage here. Fred -------------------------------------- Fred Bruenjes http://www.moonglow.net _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: R: Quake now... From: "Francesco" franuc@...... Date: Sat, 16 Oct 1999 12:14:40 +0200 Large S coming now Southern California? Francesco I.ES.N. ITALY _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: R: Quake now... From: "Francesco" franuc@...... Date: Sat, 16 Oct 1999 12:18:34 +0200 SPKIF phases now M 6.6????? Southern California Francesco I.E.SN. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Big Socal quake felt From: Seisguy@....... Date: Sat, 16 Oct 1999 06:19:01 EDT In a message dated 10/16/1999 3:13:11 AM Pacific Daylight Time, fred@............ writes: << a little before 3am, 10/16/99: Just got a woken up by a large quake here in Ramona (near San Diego, CA). USGS ISAIAH website has mag at 6.6, no make that 7.0, which seems high as shaking didn't last very long. Epicenter in Joshua Tree (out in desert). SCEC website is down. No damage here. >> We felt it also here in San Diego........ Mike _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: R: Quake now... From: Seisguy@....... Date: Sat, 16 Oct 1999 06:21:10 EDT In a message dated 10/16/1999 3:20:13 AM Pacific Daylight Time, franuc@...... writes: << Large S coming now Southern California? >> Most definately!!!!!!! Biggest shake I've ever felt in San Diego.... Mike _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: SOCAL From: "Francesco" franuc@...... Date: Sat, 16 Oct 1999 12:27:13 +0200 ALL THE PHASES. NOW LQ LR Francesco _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: R: R: Quake now... From: "Francesco" franuc@...... Date: Sat, 16 Oct 1999 12:41:19 +0200 Someone know the exact origin time? Until now, very very large q and r vawes Francesco _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: R: R: Quake now... From: Seisguy@....... Date: Sat, 16 Oct 1999 06:52:13 EDT In a message dated 10/16/1999 3:51:10 AM Pacific Daylight Time, franuc@...... writes: << Someone know the exact origin time? Until now, very very large q and r vawes Francesco >> Arrival time in San Diego 2:48am, 7:48UTC Mike _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: R: R: Quake now... From: "J. D. Cooley" jdcooley@....... Date: Sat, 16 Oct 1999 04:19:19 -0700 At 12:41 PM 10/16/99 +0200, you wrote: >Someone know the exact origin time? > >Until now, very very large q and r vawes > >Francesco Magnitude : 7.0 ME Time : 16 Oct 1999 02:46:44 AM PDT : 16 Oct 1999 09:46:44 UTC Location : 32 mi. N of Joshua Tree, CA : 47 mi. ESE of Barstow, CA : 14 mi. SE of HECTOR (quarry) : 4 mi. NE of the Pisgah Fault Coordinates : 34 deg. 35.73 min. N, 116 deg. 16.09 min. W Depth : 3.7 miles ( 6.0 km) Quality : Fair Event ID : 9108645 _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: 1989-1999 From: "Francesco" franuc@...... Date: Sat, 16 Oct 1999 13:22:33 +0200 It will be surely a coincidence, but.... 17/10/89 Ms 7.0 Loma Prieta 16/10/99 Ms 7.3 Ramona ??? Regards to all Francesco _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Your Event File From: Larry Cochrane cochrane@.............. Date: Sat, 16 Oct 1999 14:57:42 -0700 George and other PSN stations, Yes the date is a big problem with your files. Please submit files with UTC as the time zone. Not only is the file name incorrect but the start time in the header is wrong. This is worse then the file name. We don't have too many standards but using UTC time is one of them. I deleted your files. Please resubmit them with the correct time in them. You can adjust the time in the header using WinQuake. You will need to add 7 hours to your event files. -Larry Cochrane Redwood City, PSN At 02:12 PM 10/16/99 -0700, you wrote: >Larry- > I just realized a disadvantage of running my DAQ computer on local time! >In this instance, my file name (derived from the date) is different from >everyone else who uses UTC! Would you mind renaming the followint file to >991014x.tsr so it will be filed with the rest of the Lakeport quakes? Thanks > >>Date: Sat, 16 Oct 1999 13:59:08 -0700 (PDT) >>From: Event Processor >>To: gbush@....... >>Subject: Your Event File >> >>Your event file has been processed. >> >>Event File Upload Status: >> >>Input Name Archive Path & Name Status >>991015bn.tsr \quakes\9910\991015a.tsr Upload Ok >> >>Thanks for the upload! >> > > >George Bush >Sea Ranch, CA, USA >38.74N, 123.5W > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: More "weekend" levitation photos... From: meredith lamb mlamb1@.......... Date: Sat, 16 Oct 1999 16:55:49 +0000 Hi all, Put up 2 quickie pages, on 2 different levitation devices. One is the commercial Marty Simon device, and the other is my monster (in comparison) levitation stand. Total photos for the most part....it will help you "float" through the weekend.... http://users2.50megs.com/diamagnetics/page001.html The original "weekend" page has also been moved to this site; and is the above, less the /page001.html stuff. No real index at this time. It still has a crude experimental seismic use appeal to me. Total winter outside here.....snow all over the place. Thanks, Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: RE:clocks and earthquakes From: Larry Cochrane cochrane@.............. Date: Sat, 16 Oct 1999 16:22:01 -0700 FYI... >From: "Bob & Mary Holmström" >To: "'Larry Cochrane'" >Subject: RE:clocks and earthquakes >Date: Sat, 16 Oct 1999 15:54:15 -0700 >X-MSMail-Priority: Normal >X-Mailer: Microsoft Outlook 8.5, Build 4.71.2173.0 >X-MimeOLE: Produced By Microsoft MimeOLE V4.72.3110.3 >Importance: Normal >X-MIME-Autoconverted: from 8bit to quoted-printable by mail.europa.com id QAA21426 > > >Larry, > >I thought you might be interested in how the latest earthquake effected >Bryan Mumford's clocks and how his instrument recorded the event. > > http://www.bmumford.com/mset/tech/quake/index.html > >Bob Holmström > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Big Socal quake felt From: Doug doug@............. Date: Sat, 16 Oct 1999 18:00:19 -0700 I was in las vegas preparing to do a tech talk for a company having a training session there. Felt it loud and clear in my hotel room, it shook and rolled, and I even heard it. But I I was almost delirious from lack of sleep so I thought I was dreaming! Local radio in vegas stated it was equivalent of magnitude 5. I am bummed out because I have still not set up my station here in los gatos, I needed the machines for a network transition that just completed. I keep missing the california quakes! Hopefully I will have it up and running soon. -- Doug _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Quake now... From: Ken Navarre kjn@.......... Date: Sat, 16 Oct 1999 22:28:42 -0700 (PDT) On Sat, 16 Oct 1999, Larry Cochrane wrote: > CNN reporting an event near Los Angles. CA Finally, I can get a cell phone site... We were camping in Red Rock Canyon at the western edge of the Mojave when it hit at 2:46 a.m. Lots of rolling lasted for about 30 seconds. Bobbie & I had probably been waken by the mag 6 foreshock and were wide awake as the 7.0 blew through. I was going nuts with no access to a cell site to get some info. Our only outlet was a 2 meter ham repeater. Fortunately we were able to get a satellite path so we were able to watch the LA tv stations for info. Lots of aftershock action... but you already know that... Socal doesn't have as much telemetry activiy as we have in the north. Guess on my next adventure I'll bring along my LC-4... :) Ken _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: PSN Explorer From: Arie Verveer ajbv@............ Date: Sun, 17 Oct 1999 14:04:12 +0800 Hi, If you haven't tried Larry's upgrade and PSN explorer, I do suggest you give it a go. With a few mouse clicks with "PSN explorer" you can download "SEED or WQ" data into winquake. The only thing is that you need to install IE 4 or 5. I, now use Netscape for mail and browsing and IE for PSN Explorer. When I click on the PSN explorer Icon it uses IE 5. I believe if you are in Winquake and have Netscape running and click on the PSN explorer menu button in Winquake it will use Netscape, and take you to the PSN data files. You can then download (FTP) that "associated" file to Winquake. But its better to use the PSN explorer program via its icon to launch the full PSN explorer options or have IE running and use the Winquake menu button. Downloading "SEED" data is so easy. PSN explorer gets the thumbs up. Arie _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Strong motion sensor design From: Larry Cochrane cochrane@.............. Date: Sun, 17 Oct 1999 01:14:24 -0700 All, At the IRIS E & O (Education and Outreach) meeting I attended the other day I brought up that a inexpensive strong motion sensor is need that could be deployed in schools and other locations. This sensor could be placed in schools that are in areas that can have large local events. Since many schools are now connected to the Internet these sensors could be part of a strong motion array notifying authorities of the amount of shaking at a given location, assuming the Internet connections stays up long enough to get the data out... In a private email John Tabor in New Zealand wrote this about strong motion data: >Cheap strong motion is another area that most of the groups are >interested in. As I think was mentioned on the list, established >networks aren't interested in more short-period data, but they are >very interested in more strong motion data, particularly if it can be >transmitted in near-realtime. That is one of the things our >funding agency wants us to pursue, so I'd pleased if we can work >together. So I think there is a need for am inexpensive device like this, and I would like to add it to my product line as my first sensor. I see a need to be able to supply sensors with my existing hardware and software. Not everyone wants or can build a sensor... I see being able to supply strong motion data as the most important data that we could supply to the professional community. As John points out, established networks aren't interested in more short-period data. I would add that long period data is also not needed? The PEPP project is finding this out. They now have a number of sensor deployed at schools, but no one has the time, or the money, too look at the data from their long period devices. I found this out at the IRIS E & O meeting I attended a few days ago. Also, deploying sensitive long period sensors in a school, and finding a teacher who will maintain it, has been a problem from them. Building, setting up and maintain a strong motion accelerometer should be a lot easier then a high gain long period device, and senor location would be a lot less critical. But the amount of events the device records would be a lot less and only useful in areas with large local events. Maybe a device could be built that could also act as a medium gain short period device as well as a strong motion sensor? If the device had the dynamic range, it could have two outputs per channel orientation, one with a +-2 G acceleration output and another more sensitive channel that could record the smaller local / regional events. So could an inexpensive device be built like this? When I first got the Kinemetrics FBA-23A strong motion sensor I have online, I opened it up. Each component (X-Y-Z) is identical with very little electronics per channel. I don't want to duplicate it as that would be a patent problem etc. Maybe we as a group can come up with a clever design that won't run into patent or copyright type of problems. Regards, Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Strong motion sensor design From: Arie Verveer ajbv@............ Date: Sun, 17 Oct 1999 21:26:03 +0800 Hi, In mid august, Doug ( Doug ) mentioned a project that was working on using a simm-sized micro controller that implements TCP/IP for a strong motion devices. Since then I have purchased two of these controller boards and the company that provides them are about to release an upgrade to the software the makes it easier to access I/O through the units programming language, Java. They have already released the documentation. Given easy access to the high speed hardware it would be simple to add some A/D chip. At the moment the device's supported I/O is a "one wire interface" and serial port. I'm looking forward to the upgrade and access to the "real" I/O. My vote is for Doug's concept for the strong motion device for the schools. Though the controller boards should have the better I/O software. Better I/O means a huge range of possibilities. The device could then be plugged into a local school network. All you need to do is give it a "IP" address. This coupled with a good 12 bit multi-channel A/D chip and support software would make an impressive interface. A/D chip -> LTC1290 ? The boards are cheap and powerful: see http://www.ibutton.com/TINI/ I'm not sure about the strong motion sensor, it all depends on what level of quake the schools want to record. Maybe the "MOUSE" on your computer is a strong motion device. It even tells you direction and intensity of the ground movement. Don't laugh. Arie _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Quake now... From: "steve hammond" shammon1@............. Date: Sun, 17 Oct 1999 08:42:45 -0700 Ken, where are you going next? ... Regards, Steve Hammond -----Original Message----- From: Ken Navarre To: PSN-L Mailing List Date: Saturday, October 16, 1999 10:29 PM Subject: Re: Quake now... > >On Sat, 16 Oct 1999, Larry Cochrane wrote: >> CNN reporting an event near Los Angles. CA > >Finally, I can get a cell phone site... We were camping in Red Rock >Canyon at the western edge of the Mojave when it hit at 2:46 a.m. Lots >of rolling lasted for about 30 seconds. Bobbie & I had probably been >waken by the mag 6 foreshock and were wide awake as the 7.0 blew >through. I was going nuts with no access to a cell site to get some >info. Our only outlet was a 2 meter ham repeater. > >Fortunately we were able to get a satellite path so we were able to watch >the LA tv stations for info. Lots of aftershock action... but you >already know that... > >Socal doesn't have as much telemetry activiy as we have in the north. >Guess on my next adventure I'll bring along my LC-4... :) > >Ken > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Strong motion sensor design From: "Jan D. Froom" froom@............. Date: Sun, 17 Oct 1999 09:17:49 -0700 Strong motion is well and good.... but if you don't provide something that the students can relate to.... you're not going to get interest or usage. One of the neat things about living in Gilroy and having all the faults.... Is that in the morning when I met with the students.... On several occasions, I'd have a student come in and ask if anyone felt the earthquake that evening.... none had. So we'd look at what we had recorded.... and sure enough there would be an event.... When we calculated it's distance and drew a circle on the map..... CAZAM!... the line went right through the student's house (or very close to it). Now that creates interest, enthusiasm and knowledge. Jan Froom South Valley Jr. High Gilroy, CA Larry Cochrane wrote: > All, > > At the IRIS E & O (Education and Outreach) meeting I attended the other day > I brought up that a inexpensive strong motion sensor is need that could > be deployed in schools and other locations. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Strong motion sensor design From: JIm Hannon jmhannon@........ Date: Sun, 17 Oct 1999 11:39:09 -0500 Arie Verveer wrote: > Hi, In mid august, Doug ( Doug ) mentioned a > project that was working on using a simm-sized micro controller that > implements TCP/IP for a strong motion devices. Since then I have > purchased two of these controller boards and the company that > provides them are about to release an upgrade to the software the makes > it easier to access I/O through the units programming language, Java. > They have already released the documentation. Given easy access to the > high speed hardware it would be simple to add some A/D chip. At the > moment the device's supported I/O is a "one wire interface" and serial > port. I'm looking forward to the upgrade and access to the "real" I/O. > > My vote is for Doug's concept for the strong motion device for the schools. > Though the controller boards should have the better I/O software. > Better I/O means a huge range of possibilities. > > The device could then be plugged into a local school network. All you need > to do is give it a "IP" address. This coupled with a good 12 bit multi-channel > A/D chip and support software would make an impressive interface. > A/D chip -> LTC1290 ? > > The boards are cheap and powerful: see http://www.ibutton.com/TINI/ > Arie I second the idea of using the TINI board for the processor and network interface. For the sensors it seems like the silicon sensors used in the USGS design would meet most requrements. I would however eliminate the hand tweaked low pass filters of the USGS design by using Delta-Sigma A/D Converters such as the Burr Brown ADS1210 Without a lot of effort you can get 20 bits out of these converters and they are inexpensive. -- Jim Hannon http://soli.inav.net~jmhannon/ 42,11.90N,91,39.26W WB0TXL _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Joshua Tree Quake From: "Rex Klopfenstein, Jr." rklopfen@......... Date: Sun, 17 Oct 1999 13:35:51 -0400 The surface waves from the California quake saturated by N/S sensor and almost saturated my the E/W sensor. I have posted waveforms (.gif) files on my website. -- Rex Klopfenstein, Jr. Bowling Green, OH rklopfen@......... http://www.wcnet.org/~rklopfen _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Strong motion sensor design From: barry lotz gbl@....... Date: Sun, 17 Oct 1999 10:50:14 -0700 Jim,Arie,& Doug I like the idea also, in fact the 1211 ADC has a 4 channel mux. I am downloading info on the simm but what are the power requirements? Would it be a possibility in a remote location with a cell phone? Keep us informed of what you all find out. I think I'll purchace one myself. Barry JIm Hannon wrote: > Arie Verveer wrote: > > > Hi, In mid august, Doug ( Doug ) mentioned a > > project that was working on using a simm-sized micro controller that > > implements TCP/IP for a strong motion devices. Since then I have > > purchased two of these controller boards and the company that > > provides them are about to release an upgrade to the software the makes > > it easier to access I/O through the units programming language, Java. > > They have already released the documentation. Given easy access to the > > high speed hardware it would be simple to add some A/D chip. At the > > moment the device's supported I/O is a "one wire interface" and serial > > port. I'm looking forward to the upgrade and access to the "real" I/O. > > > > My vote is for Doug's concept for the strong motion device for the schools. > > Though the controller boards should have the better I/O software. > > Better I/O means a huge range of possibilities. > > > > The device could then be plugged into a local school network. All you need > > to do is give it a "IP" address. This coupled with a good 12 bit multi-channel > > A/D chip and support software would make an impressive interface. > > A/D chip -> LTC1290 ? > > > > The boards are cheap and powerful: see http://www.ibutton.com/TINI/ > > Arie > > I second the idea of using the TINI board for the processor and network interface. > > For the sensors it seems like the silicon sensors used in the USGS design would > meet most requrements. I would however eliminate the hand tweaked low pass filters > of the USGS design by using Delta-Sigma A/D Converters such as the Burr Brown > ADS1210 Without a lot of effort you can get 20 bits out of these converters and > they are inexpensive. > > -- > Jim Hannon > http://soli.inav.net~jmhannon/ > 42,11.90N,91,39.26W > WB0TXL > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Strong motion sensor design From: The Lahrs JohnJan@........ Date: Sun, 17 Oct 1999 11:47:42 -0600 At 09:17 AM 10/17/99 -0700, Jan wrote: >Strong motion is well and good.... but if you don't provide something that the >students can relate to.... you're not going to get interest or usage. Hi Jan, I totally agree. Strong motion can only be part of the package, because at any one school there could be years between interesting records. At least in California the obvious solution is to have two gain levels, so that small events will be picked up for everyday review and interest but large, rare events will still be captured on scale. In Colorado, as in much of the US, we need to rely both on high gain and long period sensitivity, as teleseisms will provide the only week to week activity of note. The best bet would be to for this area would be to have three outputs: high and low gain high frequency and high gain low frequency. Of course this could be done with one broad band, high dynamic range sensor, if the cost and maintenance were within reason. John John C. Lahr 1925 Foothills Road Golden, CO 80402 (303) 215-9913 http://lahr.org/john-jan I am only one, But still I am one. I cannot do everything, and because I cannot do everything, I will not refuse to do the something that I can do. Edward Everette Hale _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Strong motion sensor design From: Doug doug@............. Date: Sun, 17 Oct 1999 11:00:40 -0700 Hi Arie, I am pleased to hear that you are playing with Java and the TINI interfaces. I have a box of them here. I also know the engineers and executives at dallas semiconductor who makes these. I also work for Sun (JavaSoft), so I have access to every kind of tech support possible for both TINI and Java. I am using Java and Jini to control my house and reef aquarium. Check out these screen shots of my home control application, which works from anywhere in the world. I have run it from as far away as texas, and soon it will be run from dubai, milan, and paris in the next several weeks: http://www.los-gatos.net/jinihouse.html I would be happy to work with you and others on this idea of using Java and TINI for an interface to strong motion sensors. Although it is not there yet, dallas plans to add RMI (remote method invocation) and Jini support on TINI. This would be a very powerful set of tools to sensors to "gracefully" join or leave a large network of devices, and protocols exist for detecting failure (duration based leases) and triggering events (distributed event protocol). Effectively, this means that an earthquake could become a Jini distributed event, and results could easily propagate to any interested parties. One could also envision remote calibration and other nice things as a result of using Jini's protocols. I would love to hear from USGS on this, and I wonder if they have contemplated Jini for connecting sensors. BTW I am working with other companies to help Jini enable other related devices such as 1-wire temp sensors and such. This stuff is very powerful and very affordable. I think it just might be a good way for schools etc to get sensors online, AND potentially offers a way for USGS to easily query all devices that are out there. -- Doug On Sun, 17 Oct 1999, you wrote: > Hi, In mid august, Doug ( Doug ) mentioned a > project that was working on using a simm-sized micro controller that > implements TCP/IP for a strong motion devices. Since then I have > purchased two of these controller boards and the company that > provides them are about to release an upgrade to the software the makes > it easier to access I/O through the units programming language, Java. > They have already released the documentation. Given easy access to the > high speed hardware it would be simple to add some A/D chip. At the > moment the device's supported I/O is a "one wire interface" and serial > port. I'm looking forward to the upgrade and access to the "real" I/O. > > My vote is for Doug's concept for the strong motion device for the schools. > Though the controller boards should have the better I/O software. > Better I/O means a huge range of possibilities. > > The device could then be plugged into a local school network. All you need > to do is give it a "IP" address. This coupled with a good 12 bit multi-channel > A/D chip and support software would make an impressive interface. > A/D chip -> LTC1290 ? > > The boards are cheap and powerful: see http://www.ibutton.com/TINI/ > > I'm not sure about the strong motion sensor, it all depends on what level > of quake the schools want to record. > > Maybe the "MOUSE" on your computer is a strong motion device. It even tells > you direction and intensity of the ground movement. Don't laugh. > > Arie > > > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Midwest? From: lesratite@........ Date: Wed, 13 Oct 1999 14:20:39 -0500 Anybody here in the Midwest? I am considering building a Lehman's here in Illinois, to monitor our New Madrid fault. Was wondering if it is worth the trouble. Most of you folks seem to be in / near California where there's lots of action. Les Vaughn lesratite@........ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Midwest? From: JIm Hannon jmhannon@........ Date: Sun, 17 Oct 1999 14:49:21 -0500 lesratite@........ wrote: > Anybody here in the Midwest? > I am considering building a Lehman's here in Illinois, to monitor our New > Madrid fault. > Was wondering if it is worth the trouble. > Most of you folks seem to be in / near California where there's lots of > action. > > Les Vaughn > lesratite@........ > > _____________________________________________________________________ Sure, We are here in Iowa. Your Lehman would probably peg out from a good New Madrid quake. But it will also be able to see quakes all around the world. You can watch the California quakes from a safe distance :). -- Jim Hannon http://soli.inav.net~jmhannon/ 42,11.90N,91,39.26W WB0TXL _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Midwest? From: "Rex Klopfenstein, Jr." rklopfen@......... Date: Sun, 17 Oct 1999 16:46:30 -0400 I have built the Shackleford-Gundersen design because it takes less floor space and I have no trouble seeing quakes all over the World. I am sure that the Lehman will give similar results if properly. I have some pictures of my S-G at my homepage along with some of the major quakes since June. lesratite@........ wrote: > Anybody here in the Midwest? > I am considering building a Lehman's here in Illinois, to monitor our New > Madrid fault. > Was wondering if it is worth the trouble. > Most of you folks seem to be in / near California where there's lots of > action. > > Les Vaughn > lesratite@........ > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L -- Rex Klopfenstein, Jr. Bowling Green, OH rklopfen@......... http://www.wcnet.org/~rklopfen _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Strong motion sensor design From: Larry Cochrane cochrane@.............. Date: Sun, 17 Oct 1999 15:43:28 -0700 Some comments; I understand that the system also needs either a high / medium gain short or long period device so that smaller or teleseismic events can be recorded to keep up the interest. There are plenty of plans on the Internet on how to make a long period device. For a short period device a new or used geophone can be used. What is missing is a good simple design for a SM type sensor. Also, to be used as a teaching device it should be rather large (like the size of a geophone) with a clear case. This is one reason I would like to stay away from a solid-state chip device like the one offered by EGG. I also have some other reservations about them, but more about that later. I see the discussion quickly turned to the A/D and TCP/IP part of the project. I see this as the easy part. The hard part, for me, is the actual mechanical part of the sensor. After all, I already have an A/D card and event files can be placed on the Internet using existing hardware and software....So I would like to keep the discussion focused on the sensor. If the sensor produces a voltage output, then any A/D converter can be used. I see this like stereo equipment. Some people like the all in one receiver, others like myself like to have each component separate so that each part can be changed without replacing the whole thing. Solid State devices like the EGG part; Heres some problems I have with them. First they are expensive. In small numbers each component costs over $100.00. Apparently they have temperature and calibration problems. EGG also offers a calibrated and temp compensated unit, but I'm sure at a much higher cost. From an email I read from John Evens at the USGS, who is using the non compensated part, also records temperature and does some post processing of the data. I just don't like this at all! Its hard enough to deal with the data and this would be one more thing to worry about. The part would be only available from EGG. When I called them early this year, lead times just to get a sample was over 6 weeks. I just don't have a good feeling about them supply small numbers too use. I'm also not sure what the overall dynamic range of the part is, since I haven't p[lay with one. How much better are they over the ADXL type of parts from Analog Devices? Besides the cost of the part there is still more electronics that would be need to make the chip device into a real sensor. One still needs buffering, filtering, power supply etc. Since some external electronics is needed, why not also have all of the parts needed to make a complete sensor on it and make the mechanical part? Maybe the device could also be sold as a kit, if it's not to hard to make. In fact, if its too hard to make then it will probably be hard to produce, so it needs to be as simple as possible. We have a lot of clever people out there I'm sure we can come up with something.... Regards, Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Midwest? From: john c cole johnccole@........ Date: Sun, 17 Oct 1999 19:41:18 -0500 les i live in houston texas. houston is not known for seismic activity.in the last year i have recorded about a hundred or more events . i have two leahman detectors up and running and i get anything that a professional detector would get .frank cooper lives nearby in frindswood , tx and he gets the same results. you have the ideal location for a seismic detector. anything recorded in your area is of a high interest to seismologist . can you build a leahman seismic detector that will enable you to record events world wide as well as local events? the answer is yes, yes yes. so, do it and good luck. john c cole ___________________________________________________________________ Get the Internet just the way you want it. Free software, free e-mail, and free Internet access for a month! Try Juno Web: http://dl.www.juno.com/dynoget/tagj. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Strong motion sensor design From: JIm Hannon jmhannon@........ Date: Sun, 17 Oct 1999 21:28:26 -0500 Larry Cochrane wrote: > Some comments; > > Besides the cost of the part there is still more electronics that would be > need to make the chip device into a real sensor. One still needs buffering, > filtering, power supply etc. Since some external electronics is needed, why > not also have all of the parts needed to make a complete sensor on it and > make the mechanical part? Maybe the device could also be sold as a kit, if > it's not to hard to make. In fact, if its too hard to make then it will > probably be hard to produce, so it needs to be as simple as possible. > > We have a lot of clever people out there I'm sure we can come up with > something.... > > Regards, > Larry Cochrane > Redwood City, PSN > Ok Larry now I see where you are coming from. Only covering the strong motion range say +/- 2 g it is not hard to come up with a lot of different ideas for sensor. The real challenge as I see it is in the details of the design. That is picking a design that is easy to manufacture the parts or using a design that can be build from common parts such as the STM-8. The very first sensor I built consisted of a small weight glued to the cones of two speakers. It easily detected footsteps across the basement on a concrete floor. We should try and nail down a few specifications so that the discussion don't get too far out in left field. How about +/- 2 g max acceleration with 16 bits of dynamic range. (How does this match the low end of a geophone sensitivity?) What about frequency response? ( 0.01 to 10.0 Hz). -- Jim Hannon http://soli.inav.net~jmhannon/ 42,11.90N,91,39.26W WB0TXL _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Strong motion sensor design From: Arie Verveer ajbv@............ Date: Mon, 18 Oct 1999 14:31:36 +0800 Hi, How about this for an idea. We substitute "Salt Water" or a similar conductive viscous liquid in a "Mercury tilt meter". I did a little math's and came out with this startling result. If we had two containers 3 inches in diameter placed 2 foot apart that is connected with a 1/8 inch diameter tube and then, use "salt water" as a conducting fluid. The tilt meter would have a natural frequency of 26 seconds with a dampening factor of 0.89. Cup's 3 inches separation 2 foot period -> 26sec dampening 0.89 2 " 3 " 22sec 0.73 As regards the electronics, Larry's "Shackleford-Gundersen" electronics board is basically all you need. One thing that should be taken into account, as the water temperature changes the dampening factor changes. The devices period stays nearly the same. We may need to substitute the water or add anti freeze in some cold climates. My seismometer froze !! Or boiled away !! I'm sure there is a few problems that have been missed. Just an Idea. Arie > > Only covering the strong motion range say +/- 2 g it is not hard to come up with a > lot of different ideas for sensor. The real challenge as I see it is in the > details of the design. That is picking a design that is easy to manufacture the > parts or using a design that can be build from common parts such as the STM-8. > > The very first sensor I built consisted of a small weight glued to the cones of > two speakers. It easily detected footsteps across the basement on a concrete > floor. > > We should try and nail down a few specifications so that the discussion don't get > too far out in left field. How about +/- 2 g max acceleration with 16 bits of > dynamic range. (How does this match the low end of a geophone sensitivity?) What > about frequency response? ( 0.01 to 10.0 Hz). > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Neodymium hazard From: jmhannon@.................... Date: Mon, 18 Oct 1999 07:33:35 -0500 Whenever I hear something described as extremely toxic I want to know more. The material safety data sheets for neodymium list it as mildly toxic. Neodymium oxide's only listed hazard is causing lung irritation if inhaled. Just about everything fits that description. Neodymium certainly burns. Misch metal contains about 18% Neodymium. Lighter flints are made of misch metal. If burning Neodymium is a health hazard why aren't there warnings for lighters? Perhaps it is the other ingredients in the magnets that is the problem? Or possibly it is the magnet vendor being over cautious. Jim Hannon meredith lamb on 10/14/99 04:00:11 PM Please respond to PSN-L Mailing List To: psn-l cc: Subject: Neodymium hazard I bought afew neo's from Forcefield awhile back and they sent a warning with the shipment: Do not attempt to drill, cut, or machine these until doing some research. They are brittle, so odds are, as soon as you try, the magnet will break. They also lose their field when overheated (200-300deg F. depending on the magnet). If overheated too much, they burn, super hot, and super fast, like magnesium. The fumes given off by combustion are extremely toxic. If you were to try dilling these, the dust will build up on the bit, and one spark could set it off, so...DON'T TRY! They also recommend gloves when handling these magnets. Also obviously keep away from computers, monitors, tv sets, cassette tapes, floppy discs, and people with pacemakers. Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Request for data? From: Karl Cunningham karlc@....... Date: Mon, 18 Oct 1999 08:27:13 -0700 Hi All -- A fellow at work this morning said there was a report on TV last night that an agency (he didn't know who) is looking for data from personal seismic monitoring stations for the Hector event. Anybody know anything about this? Karl Cunningham La Mesa, CA. PSN station #40 karlc@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Neodymium hazard From: meredith lamb mlamb1@.......... Date: Mon, 18 Oct 1999 10:11:06 +0000 jmhannon@.................... wrote: > Whenever I hear something described as extremely toxic I want to know more. The > material safety data sheets for neodymium list it as mildly toxic. Neodymium > oxide's only listed hazard is causing lung irritation if inhaled. Just about > everything fits that description. Neodymium certainly burns. Misch metal > contains about 18% Neodymium. Lighter flints are made of misch metal. If burning > Neodymium is a health hazard why aren't there warnings for lighters? Perhaps it > is the other ingredients in the magnets that is the problem? Or possibly it is > the magnet vendor being over cautious. > > Jim Hannon > Jim, Your addition to the subject was educationally enlightening; thanks. The last 2 sentences above, probably covers it all, in the sense of todays "sue-um" atmosphere. I've handled neodymium for afew years now. Most of the material is either painted or nickel plated. Some has had patches with the paint or nickel torn away (usually from the magnet being removed from the original steel plate they were mounted on). Its "supposed" to oxidize rapidly. I've only seen acouple pieces with obvious oxidation (powdery residue thereon). Usually, instead of paint, I just use a felt tip pen made by Sanford, and their Sharpie brand permanent marker. That creates a thin type of plastic covering, which "may" last some time, to limit oxidation. This is the same pen which one can use to draw out a circuit on a copper circuit board, and etch away the rest of the copper..... crude.....but it works fair I suppose. Aside from the hazard issue, about the most obvious value I see in neodymium (or samarium), is that there really isn't any other material to use, as the older alnico variety are either being depleted, or their strength for the individual project may leave little or no choice. Too be fair, the bulky alnico or ferrite indeed can be quite effective in certain applications. For what little time the magnets are actually handled in real life, the biggest hazard remains the pinched fingers aspect. I'am not really up to licking the rocks (magnets).....ha. Thanks, Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Diamagnetic materials variation From: John Hernlund hernlund@....... Date: Mon, 18 Oct 1999 10:30:37 -0700 (MST) On Sun, 10 Oct 1999, Karl Cunningham wrote: > Meredith -- > A couple of comments: > At 09:39 PM 10/9/99 -0700, you wrote: > >Bismuth > >is one of those, -10.5 (s)on one, and -280.1 (I) > >on another. The (s) and (I) is not defined. A > >number of items on the list also exhibit a > >variation of values. Tin is another one, with > >+3.1 (White tin)to -37.0 for (gray tin). > I don't know for sure, but I think the different susceptibilities for > bismuth and tin are for different crystal structures. Many materials' > molecules can come together in more than one way, depending on the > conditions present (temperature, pressure, rate of cooling, etc.) while the > crystals are forming. A good reference for mineral crystalline phases is Liu and Bassett, "Elements, Oxides, Silicates: High Pressure Phases with Implications for the Earth's Interior" Oxford Monographs on Geology and Geophysics No. 4. Oxford University Press, 1986. For the most part, different crystalline phases are more difficult to make by temperature alone. Often pressure is also required to make these things happen. Bismuth has at least 6 known crystal structures at room temperature, however ~2.5 GPa pressure is necessary to gain the first transition. We use this as a high pressure/low temperature calibrant at most facilities in the world by observing resistivity changes while the press is squeezing. Bismuth may be melted at around 260-270 C but doesn't have any other crystal phases from the first (standard conditions phase) to the melt. John Hernlund E-mail: hernlund@....... WWW: http://www.public.asu.edu/~hernlund/ ****************************************************************************** _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Strong motion sensor design From: Gregory Bajuk gbajuk@........................ Date: Mon, 18 Oct 1999 11:35:42 -0700 (PDT) On Sun, 17 Oct 1999, Larry Cochrane wrote: > Some comments; > > I understand that the system also needs either a high / medium gain short > or long period device so that smaller or teleseismic events can be recorded > to keep up the interest. There are plenty of plans on the Internet on how > to make a long period device. For a short period device a new or used > geophone can be used. What is missing is a good simple design for a SM type > sensor. Also, to be used as a teaching device it should be rather large > (like the size of a geophone) with a clear case. This is one reason I would > like to stay away from a solid-state chip device like the one offered by > EGG. I also have some other reservations about them, but more about that > later. For Simplicity and ease of display inside a plexiglass tube the use of springs, weights, magnets and coils of wire would probably work for the strong motion sensor. And would be easier to put together as a kit that the average person could build. The book "How to build Earthquake, Weather, and Solar Flare Monitors" By G. Giusti has many ideas as I'm sure do many members of PSN. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Strong motion ideas From: S-T Morrissey sean@........... Date: Mon, 18 Oct 1999 13:50:57 -0500 (CDT) Following Jim H.s comments about using a speaker as a seismometer, I have also experimented with the idea by laying a car-stereo speaker on its back (magnet side) and putting half a dozen 1/4" lead shot balls (Sports Authority) in the cone so that it drops about half its range of movement. It does make a nice VERY short period sensor, since the rigidity of the cone support is pretty high. The mechanical resonance of most speakers is in the range of 30 to 100 hz, depending on the size. Adding mass lowers the frequency, but this is limited by the cone's range of motion or the strength of the support in the case of a horizontal configuration where the added mass has to be glued to the cone and makes it sag. I did not estimate the actual output, but the 60db (x1000) seismic amplifier produced a reasonable signal. I also experimented with a 6" speaker by adding a small leaf spring to raise the cone so that more mass could be added. The spring was a tapered inverted V, with a fine wire from the point to a bracket epoxied to the center of the cone, and pulled tight so the tapered spring looks like a fishing pole with a giant fish on the line. This looked promising as a way to increase the added mass to lengthen the period, but it never achieved anything near 1 second. Maybe a 15" speaker might get there. I considered adding a VRDT displacement transducer to a weighted speaker to use feedback to extend the period, but never did. I suspect that the compliance of the speaker suspension has a large thermal coefficient. Another experiment I did to make a strong-motion seis or sorts was to take a taught-band micro-ammeter and turn it on edge with "O" up and add a small weight (fine solder) to the pointer to bring it down to mid range. With a 2000 ohm coil it has considerable output. The mechanical period was about 0.5 seconds (2hz). I tried to fix the core of a miniature LVDT (Schaevitz 005MHR) to the pointer, but gave up on the alignment problem. A VRDT, with its open construction, would be better if a lightweight sensing vane could be used. A horizontal configuration requires that the mechanical centering be over-adjusted to move the pointer to center scale. Unfortunately, a quality 4" taught-band meter costs over $100. I expect that a jeweled movement would have too much stiction. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Home Page Web Question From: John Lahr lahr@................... Date: Mon, 18 Oct 1999 14:22:55 -0600 (MDT) Dear Robert, The best place to start getting information for a home-built seismic system is with the Public Seismic Network. The web site URL for one of the principal PSN sites is: http://psn.quake.net/ The mailing list sign up and list archive are here: http://psn.quake.net/maillist.html This is an active and friendly group that is very willing to help people get started in seismology. They also post seismograms on the web site so you can see how a quake looked at a different location. Good luck with your system. JCLahr ################################## John C. Lahr ################################# Seismologist ################################ U.S. Geological Survey ############################### Geologic Hazards Team, MS966 ############################## PO Box 25046 #############################/############################## ############################/############################### Denver, Colorado 80225-0046 ################################ Phone: (303) 273-8596 ################################## Fax: (303) 273-8600 ################################### lahr@........ ##################################### http://giseis.alaska.edu/lahr http://lahr.org/john-jan > ----- Begin Included Message ----- > > >From bhyland@........... Wed Sep 22 07:26 MDT 1999 > Date: Wed, 22 Sep 1999 08:26:24 -0500 > From: Robert Hyland > Organization: PEI Electronics > To: "Madeleine D Zirbes, Lakewood, CO " > Subject: Home Page Web Question > > Good Morning; > I am interesting in constructing a home seismomenter and connect it > to my home computer as a recording device. Do you have any suggestions > as to where I might look for help and or simple plans? I am an > electrical engineer, but having problems in how to anchor the sensors to > the earth. > Any help would be appreciated. > > Thank you > Robert Hyland > Madison, Alabama > bhyland@........... > roberth@.......... > > > > ----- End Included Message ----- > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Home Page Web Question From: John Lahr lahr@................... Date: Mon, 18 Oct 1999 14:37:52 -0600 (MDT) Dear Claud, The best place I know of to get information for a home-built seismic system is with the Public Seismic Network. The web site URL for one of the principal PSN sites is: http://psn.quake.net/ The mailing list sign up and list archive are here: http://psn.quake.net/maillist.html This is an active and friendly group that is very willing to help people get started in seismology. They also post seismograms on the web so you can see how a quake was recorded at a different locations around the world. Hope to hear from you via the PSN. Cheers, JCLahr ################################## John C. Lahr ################################# Seismologist ################################ U.S. Geological Survey ############################### Geologic Hazards Team, MS966 ############################## PO Box 25046 #############################/############################## ############################/############################### Denver, Colorado 80225-0046 ################################ Phone: (303) 273-8596 ################################## Fax: (303) 273-8600 ################################### lahr@........ ##################################### http://giseis.alaska.edu/lahr http://lahr.org/john-jan From: "johnw" To: "<\"Madeleine D Zirbes, Lakewood, CO \"" Subject: WEB QUESTION Date: Sun, 25 Jul 1999 08:16:37 -0500 Greetings, I want to find out if there is an amateur monitoring program available. If so what kind of equipment, etc I would need to be a part of it. I have been in contact with another amateur with similar interests in Seismology. It would be helpful to be able to compare notes. Sincerely, Claud Lowe 1322 Rock Island #21 Irving, Tx 75060 _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: RE:clocks and earthquakes From: Bill Scolnik wls@......... Date: Mon, 18 Oct 1999 18:09:15 -0400 I've been running an experimental record on a Fedchenko Clock which is a very precise Russian pendulum clock Ca 1960. The clock has a very high Q - the pendulum runs in a tank at 6mm pressure - and I noticed that on Saturday Morning at approximately 6:04am EDT there was a substantial change in the clock rate. When I checked my seismometer records for the period, I saw a powerful surface wave arriving at the same time and lasting for about 6 minutes. It caused a rate change of about 2ms which is really very large for the clock. I've put a record of the clock rate up showing the rate before, during and after the quake as well as the Winquake record showing the arrival here in Oakland, NJ. I'm embarrassed to say that the Winquake record is off by about 5 minutes because I haven't set the computer clock in a couple of months. The clock graph starts at 5:59 EDT and the first disturbance is at 6:03:28 EDT. Although it is known that earthquakes can stop clocks, I'm all the way over on the east coast thousands of miles away and I don't think it has ever been shown before that a precision clock can change rate under these circumstances. Bill S The clock (Microset) graph is The Winquake graph is _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: clocks and earthquakes From: Doug Crice dcrice@............ Date: Mon, 18 Oct 1999 16:13:55 -0700 Bill Scolnik wrote: > > I'm embarrassed to say that the Winquake > record is off by about 5 minutes because I haven't set the computer clock > in a couple of months. Hey folks, don't forget you can get UTC time at http://www.bldrdoc.gov/timefreq/javaclck.htm There's a program you can download to automatically synchronize your clock. It's only good to a second or so because of network delays, but at least it gets the hour right. I always have a problem with that. Doug Crice _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Strong motion ideas From: barry lotz gbl@....... Date: Mon, 18 Oct 1999 18:24:16 -0700 Sean Thomas I like the speaker idea. I think I'll pursue that a little with on-sale R.S. woofers. Maybe trimming the cone would aid in the response. Synthetic cone material may be less susceptible to moisture and environmental fluctuations. Barry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Pressure Enclosure Questions From: "Rex Klopfenstein, Jr." rklopfen@......... Date: Mon, 18 Oct 1999 21:24:55 -0400 Sean I have been looking at your pressure enclosure drawings. I have one question. Is the point of the base design to keep the pressure on both sides of the aluminum plate the same? -- Rex Klopfenstein, Jr. Bowling Green, OH rklopfen@......... http://www.wcnet.org/~rklopfen _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Pressure Enclosure Questions From: S-T Morrissey sean@........... Date: Mon, 18 Oct 1999 21:38:30 -0500 (CDT) Rex, re. The pressure enclosure using the aquarium: Yes, the idea is to have no pressure differential across the 1/4" aluminum plate that the seismometer is standing on. The aquarium above and the 1/2" polycarbonate plate under the aluminum support plate are clamped together with flat 1/4" gaskets to form the seal. In fact, there are large openings in the aluminum plate. The 25-conductor cable is fed through a sealed DB-25 adapter in the polycarbonate plate. This plate also has some large (1"dia) holes that are taped over with clear 3M tape to prevent any large pressure difference from inside to outside that might cause an implosion of the aquarium. This idea still has problems. The main one is that the top edges of the $9 aquarium that become the seal to the aluminum plate when it is inverted are not straight. I'm not sure that this is typical; both of the ones I bought have the problem of a gap of about 1/32". I recommend taking a straight edge into the pet store. I have had to use very expensive "super-soft" neoprene from McMaster Carr to get the seal to work. I am also using much stronger springs in the latches (27lbs/in), and am considering using 8 latches rather than 6. I put a dial barometer inside to test the seal by sucking on a tube through a valve in the base. The case will maintain a 1"(Hg) vacuum for several hours. I haven't tried it on the "live" STM-8 here. So I don't have any data on how well it works; the pressure noise has periods from tens of seconds to 20 minutes or more. If the barometric noise gets serious here on a windy day, I can significantly reduce it by switching the VBB operating period down to 40 seconds, since the barometric buoyancy varies directly with the square of the period. Regards, Sean-Thomas BY the way, I hope to send out a bunch of SASE envelopes soon; I have brought most of the drawings and schematics up to date. Unfortunately, improvements are always in progress, like a revamp of the oscillator to use a MAX voltage reference and a CD4060 crystal oscillator. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Pressure Enclosure Questions From: S-T Morrissey sean@........... Date: Mon, 18 Oct 1999 21:38:30 -0500 (CDT) Rex, re. The pressure enclosure using the aquarium: Yes, the idea is to have no pressure differential across the 1/4" aluminum plate that the seismometer is standing on. The aquarium above and the 1/2" polycarbonate plate under the aluminum support plate are clamped together with flat 1/4" gaskets to form the seal. In fact, there are large openings in the aluminum plate. The 25-conductor cable is fed through a sealed DB-25 adapter in the polycarbonate plate. This plate also has some large (1"dia) holes that are taped over with clear 3M tape to prevent any large pressure difference from inside to outside that might cause an implosion of the aquarium. This idea still has problems. The main one is that the top edges of the $9 aquarium that become the seal to the aluminum plate when it is inverted are not straight. I'm not sure that this is typical; both of the ones I bought have the problem of a gap of about 1/32". I recommend taking a straight edge into the pet store. I have had to use very expensive "super-soft" neoprene from McMaster Carr to get the seal to work. I am also using much stronger springs in the latches (27lbs/in), and am considering using 8 latches rather than 6. I put a dial barometer inside to test the seal by sucking on a tube through a valve in the base. The case will maintain a 1"(Hg) vacuum for several hours. I haven't tried it on the "live" STM-8 here. So I don't have any data on how well it works; the pressure noise has periods from tens of seconds to 20 minutes or more. If the barometric noise gets serious here on a windy day, I can significantly reduce it by switching the VBB operating period down to 40 seconds, since the barometric buoyancy varies directly with the square of the period. Regards, Sean-Thomas BY the way, I hope to send out a bunch of SASE envelopes soon; I have brought most of the drawings and schematics up to date. Unfortunately, improvements are always in progress, like a revamp of the oscillator to use a MAX voltage reference and a CD4060 crystal oscillator. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Strong motion sensor design From: Larry Cochrane cochrane@.............. Date: Mon, 18 Oct 1999 20:05:02 -0700 At 09:28 PM 10/17/99 -0500, Jim Hannon wrote: >Ok Larry now I see where you are coming from. >Only covering the strong motion range say +/- 2 g it is not hard to come up with a >lot of different ideas for sensor. The real challenge as I see it is in the >details of the design. That is picking a design that is easy to manufacture the >parts or using a design that can be build from common parts such as the STM-8. > Exactly! >The very first sensor I built consisted of a small weight glued to the cones of >two speakers. It easily detected footsteps across the basement on a concrete >floor. > I like that. Maybe you are on to something here. If one could add some mass and a position loop could a speaker be user as s SM detector? Was two speakers used for X and Y motion or were they used together somehow? >We should try and nail down a few specifications so that the discussion don't get >too far out in left field. How about +/- 2 g max acceleration with 16 bits of >dynamic range. (How does this match the low end of a geophone sensitivity?) What >about frequency response? ( 0.01 to 10.0 Hz). The SM sensor should have +- 2 g max acceleration, this should produce a +- 5 or +-10 volt output. It should be accurate to within +- 5% or 10%?? over the operating temperature range of the device. I don't think the operating temp should be too extreme. If needed power can be used to either cool or heat the device. I don't think super low power should be a big design criteria. Since the data will most likely be collected using a PC, 110 v (or 220 v) should be handy. A UPS should be added by the user so that the sensor and computer will keep recording if the power goes down. The dynamic range should be 16 bits or better. If a sensor could be built with very good dynamic range then the unit could have two outputs. One at +- 2g and another more sensitive channel with maybe .2 or .02 g max output. This maybe asking too much for one sensor? Maybe the same mechanical and electronics parts, with a little tweaking, could be made to look like a short-period, higher gain device that could be used to record the smaller events? I think the frequency response should be higher, in the 25 hz range. The low end of .01 hz sounds good. The FBA-23 I have has a DC output. If I rotate one of the horizontal channels vertically I get a constant 1 g output, or about 5 volts DC. The sensor I have has a +- 2 g = +- 10 v output. I high and low pass the signal out of the FBA-23 at .07 hz (~14 sec) and 20 hz. Regards, Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Strong motion sensor design From: "Al Allworth" allworth@.............. Date: Tue, 19 Oct 1999 01:40:50 -0700 Hello All, My first sensor was made from a device called a "limited angle torquer" available from surplus. It has a magnet rotating in a stator winding supported by low friction ball bearings. I built an arm to mount a weight of about 5 Lbs at a distance of about 7 or 8 inches. It was tilted a few degrees from vertical and had a period of about 4 seconds. I more than saturated my chart recorder on the Landers event and aftershocks around a 3.0 (several years ago) at a distance of about 150 miles. The garage could have fallen on it without breaking it. I also made a smaller version out of a pen driver from a chart recorder that worked equally as well but you could hold it in your hand. Using a heavy mass helps to overcome some of the friction problems with these kinds of devices. There are pen drivers built like a large version of a meter that could probably be made to work but I never found one when I was looking for stuff like that. There must be a simple and cheap way to get something for strong motion. ____________________________________ Al Allworth allworth@.............. Gold Beach On The Beautiful Southern Oregon Coast ____________________________________ ----- Original Message ----- From: Larry Cochrane To: PSN-L Mailing List Sent: Monday, October 18, 1999 8:05 PM Subject: Re: Strong motion sensor design > At 09:28 PM 10/17/99 -0500, Jim Hannon wrote: > > >Ok Larry now I see where you are coming from. > >Only covering the strong motion range say +/- 2 g it is not hard to come > up with a > >lot of different ideas for sensor. The real challenge as I see it is in the > >details of the design. That is picking a design that is easy to > manufacture the > >parts or using a design that can be build from common parts such as the > STM-8. > > > > Exactly! > > >The very first sensor I built consisted of a small weight glued to the > cones of > >two speakers. It easily detected footsteps across the basement on a concrete > >floor. > > > > I like that. Maybe you are on to something here. If one could add some mass > and a position loop could a speaker be user as s SM detector? Was two > speakers used for X and Y motion or were they used together somehow? > > >We should try and nail down a few specifications so that the discussion > don't get > >too far out in left field. How about +/- 2 g max acceleration with 16 bits of > >dynamic range. (How does this match the low end of a geophone > sensitivity?) What > >about frequency response? ( 0.01 to 10.0 Hz). > > The SM sensor should have +- 2 g max acceleration, this should produce a +- > 5 or +-10 volt output. It should be accurate to within +- 5% or 10%?? over > the operating temperature range of the device. I don't think the operating > temp should be too extreme. If needed power can be used to either cool or > heat the device. > > I don't think super low power should be a big design criteria. Since the > data will most likely be collected using a PC, 110 v (or 220 v) should be > handy. A UPS should be added by the user so that the sensor and computer > will keep recording if the power goes down. > > The dynamic range should be 16 bits or better. If a sensor could be built > with very good dynamic range then the unit could have two outputs. One at > +- 2g and another more sensitive channel with maybe .2 or .02 g max output. > This maybe asking too much for one sensor? Maybe the same mechanical and > electronics parts, with a little tweaking, could be made to look like a > short-period, higher gain device that could be used to record the smaller > events? > > I think the frequency response should be higher, in the 25 hz range. The > low end of .01 hz sounds good. The FBA-23 I have has a DC output. If I > rotate one of the horizontal channels vertically I get a constant 1 g > output, or about 5 volts DC. The sensor I have has a +- 2 g = +- 10 v > output. I high and low pass the signal out of the FBA-23 at .07 hz (~14 > sec) and 20 hz. > > Regards, > Larry Cochrane > Redwood City, PSN > > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Strong motion sensor design From: "Mark Robinson" other@............... Date: Tue, 19 Oct 1999 22:32:28 +1300 I don't know about cheap, but General scanning make pen motors. It seems from their website that they don't make the GM20, with which I am familiar, any more, but they have a GM 100 here : http://www.gsilumonics.com/c03oem_gal_frame/galvoframe.html there seems to be a range of styles available including 2 degree types which may be the most appropriate for this application. They also do a series of closed loop scanners which include very accurate integrated capacitive position sensors and associated electronics. While this would be a more accurate sensor, it would also be WAY too expensive. I have emailed them to see if they still do the GM20. regards all Mark From: Al Allworth > My first sensor was made from a device called a "limited angle torquer" > available from surplus. It has a magnet rotating in a stator winding > supported by low friction ball bearings. I built an arm to mount a weight of > about 5 Lbs at a distance of about 7 or 8 inches. It was tilted a few > degrees from vertical and had a period of about 4 seconds. I more than > saturated my chart recorder on the Landers event and aftershocks around a > 3.0 (several years ago) at a distance of about 150 miles. The garage could > have fallen on it without breaking it. I also made a smaller version out of > a pen driver from a chart recorder that worked equally as well but you could > hold it in your hand. Using a heavy mass helps to overcome some of the > friction problems with these kinds of devices. > > There are pen drivers built like a large version of a meter that could > probably be made to work but I never found one when I was looking for stuff > like that. > > There must be a simple and cheap way to get something for strong motion. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Strong motion sensor design From: "Mark Robinson" other@............... Date: Tue, 19 Oct 1999 22:54:22 +1300 And then I began to think properly .... the head actuator assembly from a dead disk drive would be just about ideal for this, and every school would already have one... all they need to do is put the hacksaw through it and tie on a weight ... now where is a dead disk drive _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Pressure Enclosure Questions From: "Rex Klopfenstein, Jr" rklopfen@......... Date: Tue, 19 Oct 1999 08:45:11 -0400 Sean I am planning to build my case out of some 1/2" (actually 0.46") acrylic plastic. We received an order at work and the trucking company broke the corners off of some large sheets. The insurance company just told us to keep the damaged sheets. I have a plastic blade for my 10" table saw and the glue operation is rather easy. I built some pressure tight enclosures for an automotive air leak test fixture we sold Honda several years ago. I also have a piece of 1/2" alum tool plate for the base. I am also planning to use a 25 pin gender changer to pass through lower cover. Have to check to see if the plug will hold pressure? This will permit me to easily remove the entire VBB from case without a solder iron! If the gender changer does leak, I have several MS connectors that are tight and have the advantage of using a 90 degree plug to reduce the 'off floor' height of base. By the way, I have most of the parts made for my VBB and plan to post some photos on my website later this week when I get the photo developed. I have just a few little things to finish up and then on to the final assembly. After that I can start to debug and test my electronics. S-T Morrissey wrote: > Rex, > re. The pressure enclosure using the aquarium: > -- Rex Klopfentein, Jr. rklopfen@......... http://www.wcnet.org/~rklopfen _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Strong motion sensor design From: Karl Cunningham karlc@....... Date: Tue, 19 Oct 1999 08:39:08 -0700 When thinking about using loudspeakers for strong motion sensors, don't overlook putting a negative impedance converter in parallel with the speaker. It's a simple circuit with one op-amp and a few resistors that can make the speaker into a closed-loop transducer with an acceleration output that can be easily integrated to velocity. Being closed loop, it can get around many of the problems of the speaker suspension. A few years ago a surplus store had parts from a force-balance weighing scale. It was very much like a loudspeaker but without the cone and used flexures for the suspension. It was only $5, but when I went back to get more, they were all gone. If anyone has a source of something like this, it could pretty easily make a SM sensor. Karl Cunningham La Mesa, CA. PSN station #40 karlc@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Strong motion sensor design From: Doug Crice dcrice@............ Date: Tue, 19 Oct 1999 09:27:04 -0700 Karl Cunningham wrote: > > When thinking about using loudspeakers for strong motion sensors, don't > overlook putting a negative impedance converter in parallel with the > speaker. > > It's a simple circuit with one op-amp and a few resistors that can make the > speaker into a closed-loop transducer with an acceleration output that can > be easily integrated to velocity. Let's not lose sight of the fact that strong-motion seismographs are traditionally acceleration recording devices, not velocity sensors like sensitive seismographs. If you want to make data accepted by the establishment, it might go easier if you give them the same information they are used to. An acceleration measuring device needs to measure force generated by a mass pushing on something (think electronic scale, not moving coil). _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: pressure feedthrough From: S-T Morrissey sean@........... Date: Tue, 19 Oct 1999 11:52:53 -0500 (CDT) Rex, The windfall 1/2" acrylic is certainly a way to go since you have the means to make clean enough cuts for a pressure tight case. You might have noticed the common 12" x 24" dimensions that I am using so as to be able to use pre-cut sizes from McMaster-Carr. For the DB-25 connector feedthrough: I looked at a gender-mender and decided that the pins were not sealed. So I built one into the feedthrough by using a male solder-cup connector on the bottom and a long machine-pin PC board female on top. I removed the shell halves (drill the rivets at the screw holes) from the top connector so I could separate the halves of the insert that holds the pins. THe inside (long pin side) of the shell and the insert are discarded. Then I cut/filed the upper half (connector pin side)of the insert so it would fit through the the hole in the 1/2" polycarbonate panel, which was about the standard DB-25 panel opening. Then I soldered the long pins into the solder cups with the "outside" half of the insert in place. The insert can then be removed and the assembly was then pushed up through the cutout from the bottom and the opening filled with RTV sealant. Then the upper half of the insert and the outer half of the metal frame are installed with long 4-40 screws all the way through the frame of the lower connector. The seismometer is already equipped with a ribbon cable and a DB-25 connector. The 25 conductors are more that what is needed, but the convenience of the color-coded cable makes it easy to work with (I use it for much of the internal wiring of the multi-period electronics box), and the "extra" leads can all be tied together and used for ground. The 25-conductor ribbon cable has a right-angle connector on it (the clamp-together-without-a-shell-but-with-a-strain-relief kind), so minimum clearance under the case is needed. I use the 1 1/4" long brass torpedo-like fishing weights drilled/tapped 1/4-28 as feet for the aluminum support plate, and the shorter ones for the seismometer itself to rest on the support plate. By the way, it helps to have the motor-driven mechanical zeroing operating before one seals the seis into a pressure case. I think I have described it before. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: larger seismometer mass From: angel rodriguez angel@............ Date: Tue, 19 Oct 1999 11:07:14 -0400 Hi All, I'm looking for the address or some other contact for a company in China that make broadband seismograph. any informtion would be appreciate. thanks Angel _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: EQ humor from ca.earthquakes From: Larry Cochrane cochrane@.............. Date: Tue, 19 Oct 1999 14:20:15 -0700 Anyone on this list missing some equipment Courtesy of Yahoo.com Body Report Turns Out False - (RESEDA) -- A report of a body buried along the Los Angeles River turns out to be something completely different. A man called police yesterday afternoon. He said he saw a man and woman burying an object inside the boundaries of the river bed in Reseda. Officers found two half-buried bags along a dirt embankment. When they cut one of the bags open, they found a plastic box and called for the bomb squad. The items turned out to be seismic monitoring equipment. Now police have to determine who owns it. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: A2DMax use with EMON From: "Randall Pratt" randallpratts@.............. Date: Tue, 19 Oct 1999 17:47:22 -0700 I am new to the list and just completed the electronics for a Lehman that is next to be built. I have used the A2DMax circuit from Sky and Telescope and a pre-amp and filter circuit found on the net from Fred Bruenjes. As I read the EMON documentation I find an option to link a collection routine for other AD inputs. Can someone tell me how to do this or how to set a current option to collect from the printer port and this AD setup? Thanks. Randy Pratt randallpratts@.............. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Strong motion sensor design From: John Taber taber@............. Date: Wed, 20 Oct 1999 18:03:48 +1300 (NZDT) I agree with both John and Jan that a strong motion sensor should be an add-on to a high gain system (either long or short period depending on the local seismicity). The schools will primarily use the high gain data, but since a recording system is already in place, you can add strong motion for much less cost than at a new installation. Larry wrote: >What is missing is a good simple design for a SM type >sensor. Also, to be used as a teaching device it should be rather large >(like the size of a geophone) with a clear case. I'd be more inclined to work towards a design that was concerned most with low cost and an acceptable noise level, than considering its teaching potential because the seismometer can be used for that. I'd also agree that it would be better to have the frequency response extend to 25 Hz. I think you could get away with a low end of 0.1 Hz for most free field sites. Regards, John Taber _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: clocks and earthquakes From: twleiper@........ Date: Wed, 20 Oct 1999 03:34:53 -0400 There actually is an excellent program for keeping your computer "on time". It is free (care ware) and it corrects for propogation delay on the web by pinging and timing. It uses multiple time standards such as the Naval Observatory and NIST, etc. If you are running 95/98 and IE4.X you can just download it at http://www.arachnoid.com/lutusp/ftp/abouttime_msie.zip. I have used this program for years and it cured my back ache, increased my potency, and gives my laundry brighter colors and whiter whites at the same time. On Mon, 18 Oct 1999 16:13:55 -0700 Doug Crice writes: >Bill Scolnik wrote: >> >> I'm embarrassed to say that the Winquake >> record is off by about 5 minutes because I haven't set the computer >clock >> in a couple of months. > >Hey folks, don't forget you can get UTC time at > >http://www.bldrdoc.gov/timefreq/javaclck.htm > >There's a program you can download to automatically synchronize your >clock. It's only good to a second or so because of network delays, >but >at least it gets the hour right. I always have a problem with that. > >Doug Crice > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of >the >message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Strong motion sensor design From: ted@.......... Date: Wed, 20 Oct 1999 10:25:44 -0400 The discussion of a standardized system is very valuable. I believe the closer it gets to being a "turnkey" system, the more it will appeal to high school teachers who have no extra time to spend on maintenance. Finding a good place for the sensor can be tricky. Some schools are using temporary trailers for classrooms. Others (like my son's school in San Jose where I maintained a system for 2 years) have very springy floors built over a large crawl space. We ended up putting the sensor on concrete blocks in the crawl space - to which the only entrance was an 18" square trap door in the floor of a closet. This leads me to believe that PSN members should serve a consulting role, assessing the situation before inviting a teacher or school to commit time or funds. Ted _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: New WQ beta release and PSN Explorer From: RLLaney@....... Date: Wed, 20 Oct 1999 12:10:29 EDT Hi Larry: I downloaded the new release dated October 14, 1999 for Windows 95 and IE >3.0, but I am not seeing the PSN icon and I get an error message "Unable to open web browser" when I click on HELP (when the browser is open). I get the same message when I click on the New File button. I am using IE 5.0 on AOL. I went into the WinQuake directory and double clicked on the psnexplorer.exe file and brought up the IE window, but when I tried the link to WinQuake nothing happened. I tried using Netscape and also got the same error message that the web browser couldn't be opened. Is anyone else is having similar problems with the new release? Thanks. Bob Laney Herndon, VA _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Strong motion sensor design From: jmhannon@.................... Date: Wed, 20 Oct 1999 11:35:35 -0500 Lets summarize the requirements so far: Frequency response DC to 25 Hz Max. acceleration + - 2 g Noise level 61 ug or better (16 bits) Environmental Conditions Habitable, Fixed Comments: These requirements indicate that the device is an accelerometer. In this case the freq. response to DC is a freebie. The fundamental things you need to build an accelerometer like this is a mass supported by springs that has a resonant frequency above 25 Hz. You need to be able to sense the "position" of the mass. A coil and magnet could be used for feedback/damping. The position sensor could be a differential capacitor bridge or a VRDT. Given this the loudspeaker still looks like a viable approach. You would probably need an additional spring to get the resonance up to 25 Hz. The speaker cone and spider would help constrain the mass motion to one axis. The voice coil would be used for damping/feedback. From my somewhat limited personal experiences with strong motion quakes the 25 Hz upper response frequency may be a little excessive. I sure wish there were an easy way to make the spiral flexures used in geophones. Jim Hannon _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Strong motion sensor design From: Greg ghost@............. Date: Wed, 20 Oct 1999 11:07:48 -0700 jmhannon@.................... wrote: > I sure wish there were an easy way to make the spiral flexures used in > geophones. I don't know about the material, but there are free/cheap plans to build a cutting CO2 laser available. I have a copy myself. I wanted to try cutting materials (laser engraving) when I had the time and money. With computer control it would be easy to cut almost any shape in thin materials. ted@.......... wrote: > floor of a closet. This leads me to believe that PSN members should serve a > consulting role, assessing the situation before inviting a teacher or school to > commit time or funds. If I only knew what I was doing myself. ;) I was trying to talk the local community college geology teacher into getting an instrument. She said that money was the primary concern and making something was almost out of the question. The Guralp PEPP instrument was the most attractive to her. Hey, the biology students have microscopes, why not give the geology students a seismometer? :) ,Greg _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Strong motion sensor design From: Doug Crice dcrice@............ Date: Wed, 20 Oct 1999 11:17:01 -0700 I believe those springs are made by chemical etching, similar to the process for making your own PC boards. Probably the material is copper berylium sheet spring stock. Greg wrote: > > jmhannon@.................... wrote: > > I sure wish there were an easy way to make the spiral flexures used in > > geophones. > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Strong motion sensor design From: jmhannon@.................... Date: Wed, 20 Oct 1999 13:33:04 -0500 I am sure etching is the way they are made. The problem is it ain't easy to do. I am going to give it a try here one of these days but I suspect my home brew results will be less than desirable. Right now I am writing a postscript program to print out the tool. Jim Hannon Doug Crice on 10/20/99 01:17:01 PM Please respond to PSN-L Mailing List To: PSN-L Mailing List cc: Subject: Re: Strong motion sensor design I believe those springs are made by chemical etching, similar to the process for making your own PC boards. Probably the material is copper berylium sheet spring stock. Greg wrote: > > jmhannon@.................... wrote: > > I sure wish there were an easy way to make the spiral flexures used in > > geophones. > _ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Strong motion sensor design From: jmhannon@.................... Date: Wed, 20 Oct 1999 13:49:57 -0500 I did a little design calculation based on the 25 Hz upper frequency response of the sensor. The resonant frequency of the sensor needs to be above 25 Hz. So to see what ball park we are in I calculated the 1 g deflection of the mass with a resonant frequency of 30 Hz. This works out to be 0.275 mm. This gives a total deflection of 0.55 mm at 2 g. This is not much. We could get away with a simple cantilever beam design or thin solid metal disks for the spring. Jim Hannon _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Northern California PSN meeting From: Edward Cranswick cranswick@........ Date: Wed, 20 Oct 1999 16:18:34 -0600 Larry- I just got back from my second trip to Turkey and am catching up on email: I for one would love to go to a PSN meeting at Berkeley because I could just be a tourist there and suck down espresso's without having to do the bureaucratic shuffle with my USGS Menlo Park colleagues. Assuming I make it back from a third trip to attend an Izmit EQ meeting in Istanbul the first week of December and have enough bucks and pozzazz (is that with an "o", or an "a", or an "i" or what?) to cruise out to the Coast to attend AGU, I'll be at the SeismoLab on 17-18 Dec. We could also do that number with Bob Phinney and PEPP at the same time. -Edward Larry Cochrane wrote: > All, > > I got this from Lind Gee the other day. She is a seismologist at the > Berkeley Seismo Lab (BSL) and involved with the IRIS (www.iris.edu) > Education and Outreach program. I had a meeting with her and other IRIS > members a few weeks ago. > > >Regarding the PSN meeting in December, the > >BSL would be happy to host the meeting at > >our facilities on the UC Berkeley campus. Before > >AGU is a little troublesome (people will be > >working on their presentations), but either one > >evening during AGU or the following Friday (12/17) > >or Saturday (12/18) would be fine. My preference > >would be for either Friday or Saturday, but Thursday > >might be possible. It seems as if Catherine will > >be able to attend. > > Catherine is from IRIS and is also part of the E & O program. I thought it > would be a nice change of pace if we have the next meeting at another > location. The last two meetings have been at the USGS in Menlo Park around > the time of the AGU in December. > > So who's interested, and what day and time should we have it? Maybe Sat. > would be best for most people? If people from IRIS, and maybe PEPP, are > there, the meeting should be geared around setting up and supporting system > in schools. I'm sure after the meeting we can have a tour of their lab. > > Regards, > Larry Cochrane > Redwood City, PSN > > > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: A2DMax use with EMON From: ted@.......... Date: Wed, 20 Oct 1999 14:33:17 -0400 Randall, Jan Froom wrote the parallel port interface used by EMON. Please contact him at froom@............. and he will (I'm sure) be happy to send you the code, documentation etc. that you will need to use the parallel port input option. You may need to write some assembler code, or have someone do it for you. I'd be happy to oblige if it's not too complicated, but Jan's the expert. Regards, Ted "Randall Pratt" on 10/19/99 08:47:22 PM Please respond to PSN-L Mailing List To: PSN-L@.............. cc: Subject: A2DMax use with EMON I am new to the list and just completed the electronics for a Lehman that is next to be built. I have used the A2DMax circuit from Sky and Telescope and a pre-amp and filter circuit found on the net from Fred Bruenjes. As I read the EMON documentation I find an option to link a collection routine for other AD inputs. Can someone tell me how to do this or how to set a current option to collect from the printer port and this AD setup? Thanks. Randy Pratt randallpratts@.............. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Strong motion sensor design From: Edward Cranswick cranswick@........ Date: Wed, 20 Oct 1999 23:21:26 -0600 PSN- The "Public Seismic Network Newsletter", December, 1991 issue (first and last), editor: Benjamin Gardner, called for a three-component seismic data acquisition unit (SDAU) with an acceleration response of 0.00001 - 1.0 g in the the frequency band, DC - 20 Hz, and a total cost of $500. I only have a hardcopy of this tome, but one day I mean to scan it and put it on the Web. -Edward -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: New WQ beta release and PSN Explorer From: Larry Cochrane cochrane@.............. Date: Thu, 21 Oct 1999 01:14:31 -0700 Hi Bob, If you are running the right version of WinQuake you should see a new tool bar icon "New Events" (if you move the mouse over it) next to the "Event Report" item. You should also see the "New Event Files" menu item under the "View" menu. Selecting either the tool bar icon or the menu item your system should start the PSN Explorer web browser. If it doesn't start, make sure that the psnexplorer.exe file is in the same directory as winqk32.exe is in. Also, don't rename either winqk32.exe or psnexplorer.exe. For all of this to work, the file names must not be changed. If this doesn't help, is your version of IE 5 a special version for AOL, or did you download it from Microsoft? In the past I think AOL has had their own web browser. -Larry Cochrane Redwood City, PSN At 12:10 PM 10/20/99 EDT, you wrote: >Hi Larry: > >I downloaded the new release dated October 14, 1999 for Windows 95 and IE >>3.0, but I am not seeing the PSN icon and I get an error message "Unable to >open web browser" when I click on HELP (when the browser is open). I get the >same message when I click on the New File button. I am using IE 5.0 on AOL. >I went into the WinQuake directory and double clicked on the psnexplorer.exe >file and brought up the IE window, but when I tried the link to WinQuake >nothing happened. I tried using Netscape and also got the same error message >that the web browser couldn't be opened. > >Is anyone else is having similar problems with the new release? > >Thanks. > >Bob Laney >Herndon, VA > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Hilger and Watts seismograph From: John Taber taber@............. Date: Fri, 22 Oct 1999 11:27:54 +1300 (NZDT) Karl, I've finally added the legend to the picture of the inside of the Wilmore seismograph at http://www.quaketrackers/Testdir/wilmore.html John Karl wrote: >Very interesting picture. Do you have the legend? I'm curious what some >of the numbers are pointing to. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Strong motion sensor design From: George Harris gjharris@............. Date: Thu, 21 Oct 1999 20:19:13 -0400 jmhannon@.................... wrote: > I did a little design calculation based on the 25 Hz upper frequency response of > the sensor. > The resonant frequency of the sensor needs to be above 25 Hz. So to see what > ball park we are in I calculated the 1 g deflection of the mass with a resonant > frequency of 30 Hz. This works out to be 0.275 mm. This gives a total > deflection of 0.55 mm at 2 g. This is not much. We could get away with a simple > cantilever beam design or thin solid metal disks for the spring. The idea of using a simple spring/mass sounds good if the sensing system has high resolution. The natural frequency of any mass on a vertical spring system is directly related to the 1 G deflection. In fact the natural frequency is the same as that of a pendulum of the same length as the deflection. That is to get a spring mass system to have a 1 second natural period requires a system which will deflect about 12 inches in 1 G. The most efficient simple spring system is a flat spring having a triangular shape. That is, the mass is attached to one point of the spring which is clamped along the opposite side. Having a voice coil driver and an optical pickup on the mass would seem to make a simple rugged feedback system. If low frequencies are to be sensed, the deflection should be as much as possible to make the resonant frequency low so that the sensor does not need as much gain. The feedback corner frequency must be well above the natural frequency to make the feedback system simple. I have worked with berrylium copper springs. An ideal way to make them is to form the spring in the soft state. Hardening is then done by heating to about 600 degrees F. for an extended period. This process makes about the best springs which can be fabricated. An etched spring can be made by drawing the shape with the resist pen used for printed circuits on one side and applying a sheet of adhesive resist on the back. I would be glad to work with anyone in the bay area to see if we can come up with a simple construction. George Harris - Benicia, CA - gjharris@............. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Hilger and Watts seismograph From: John Taber taber@............. Date: Fri, 22 Oct 1999 16:42:40 +1300 (NZDT) As Jan just pointed out to me I left out part of the URL for the Wilmore seismograph picture. It should be http://www.quaketrackers.ac.nz/Testdir/wilmore.html Sorry about that. John Taber _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Strong motion sensor design From: "steve hammond" shammon1@............. Date: Thu, 21 Oct 1999 21:11:24 -0700 I have to agree. A standardized system is the ideal solution. But I may have a slightly different view than most. I believe the effective way to deliver a reasonable costing package is to develop standardized training and support for the unit. The real cost is not in the initial unit. Like you Ted, in the schools in the San Jose area we installed systems in during the early 90's, we faced all sorts of environmental, support issues, scheduling, and training issues. So, the voice of reason tells me we are overlooking the most import point. We tend to believe that the teacher likes this technical stuff-- for the most part, they don't-- and we should recognize how different their view point is towards the equipment. We want them to care for it. They want it to be a learning aid. From the five schools we put seismic systems in (one elementary, one Jr. high, four high schools), only one of the teachers was skilled enough to perform diagnostics when something went wrong. Many of the teachers had little if an PC skills. I say the less technical the better. There is also a real problem when processing of the data. Most teachers don't have five minuets extra to... So, if the standard system includes a three component design, and then a strong motion sensor or two is added, the operational issues and data handling issues are compounded. If you go that route, I feel the design should include a fully automated data handling capability. The students and teachers can access the information via a web site from home or a school. That way homework assignments or special projects could include the use of the web and exchanging data with other schools is then a simple task. Anyway, that's my cents worth. Regards, Steve Hammond PSN Aptos, California "Stylish living in the epicenter site of Loma Prieta" -----Original Message----- From: ted@.......... To: PSN-L Mailing List Date: Wednesday, October 20, 1999 7:24 AM Subject: Re: Strong motion sensor design > >The discussion of a standardized system is very valuable. I believe the closer >it gets to being a "turnkey" system, the more it will appeal to high school >teachers who have no extra time to spend on maintenance. > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Small Quake in Arkansas From: "Finke, John E." Finke@........... Date: Fri, 22 Oct 1999 12:01:49 -0400 Did anyone record the small event yesterday morning that was centered near Donipahn, Missouri? If so, I am interested in seeing the record, if it is available. Thanks John Finke, P.E., S.E. finke@........... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Fw: EQ MAG 3.9 MISSOURI-ARKANSAS BORDER REGION From: "Erich Kern" ekern@......... Date: Fri, 22 Oct 1999 09:40:55 -0700 -----Original Message----- From: MINSCH@................ To: bigquake@................... Date: Thursday, October 21, 1999 4:48 AM Subject: EQ MAG 3.9 MISSOURI-ARKANSAS BORDER REGION U.S. GEOLOGICAL SURVEY NATIONAL EARTHQUAKE INFORMATION CENTER World Data Center A for Seismology Reply to: sedas@................. (internet) sedas@................. (internet - alternate) The following is from the United States Geological Survey, National Earthquake Information Center: Preliminary hypocenter for earthquake of 1999 Oct 21, MISSOURI-ARKANSAS BORDER REGION: latitude 36.7 degrees north, longitude 91.1 degrees west, origin time 08 17 56.4 utc, depth shallow, magnitude 3.9 mbLg. The earthquake was felt in the Jonesboro, Arkansas area. There have been no reports of damage. Stations used: OXF P 081839.0 WVT P 081841.8 PLAL P 081844.8 HKT P 081953.6 PLVA P 081955.8 JSC P 082000.8 BLA P 082002.5 LHS P 082005.2 EYMN P 082040.9 ISCO P 082049.5 -------------------------------------------------------------------------- To unsubscribe from this email list send mail to: majordomo@................... and put unsubscribe bigquake in the body of the message. Please leave the subject line blank when unsubscribing. *-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-* For an alternative Email list with links to NEIC web pages but no arrival times, check out: http://geology.usgs.gov/eq/eq_subscribe.html *-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-* Please do not set up a sub-list of addresses to which these messages will be forwarded. This makes maintenance of the list very difficult. Thanks! -------------------------------------------------------------------------- _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Planned visit to Hector event site From: GeE777@....... Date: Fri, 22 Oct 1999 14:51:10 EDT hello all I plan to visit the hector event site in the next few days and take some pictures. I am wondering if any PSN members in Southern California would like to go as a group. Contact me if interested through PSN or the address below. Maybe someone with USGS would like to be a guide. George Erich GeE777@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Small Quake in Arkansas From: "Rex Klopfenstein, Jr" rklopfen@......... Date: Fri, 22 Oct 1999 15:39:10 -0400 Yes, I will post the .gif file on my website along with WinQuake data files tonight "Finke, John E." wrote: > Did anyone record the small event yesterday morning that was centered > near Donipahn, Missouri? > > If so, I am interested in seeing the record, if it is available. > > Thanks > John Finke, P.E., S.E. > finke@........... > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L -- Rex Klopfentein, Jr. rklopfen@......... http://www.wcnet.org/~rklopfen _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Planned visit to Hector event site From: Canie Brooks canie@........... Date: Fri, 22 Oct 1999 13:58:45 -0700 Be sure to schedule that trip with the 'authorities' - the entire rupture is on the 29 Palms Marine Base - they have live ordinance training going on out there! I received this notice: >To SCEC Community, > >1. Please remember that access to the 29 Palms Marine Base must be >coordinated with Karl Gross, his cell number is 213/ 503-4365. We have >had reports of two individuals entering the base without >clearance. Please do not jeopardize the access of others by making >unauthorized entries on the base. So you might want to check with Karl above the the number given. I was out last weekend and there is some damage to be seen off the base: http://www.basicso.com/~canie/hector1.htm - there is also a link there for another couple of sites that have pictures of quake damage. (USGS and Charles Watson's site) Canie At 02:51 PM 10/22/99 -0400, you wrote: >hello all > >I plan to visit the hector event site in the next few days and take some >pictures. >I am wondering if any PSN members in Southern California would like to go as >a group. > >Contact me if interested through PSN or the address below. Maybe someone >with USGS would like to be a guide. > >George Erich >GeE777@....... > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Small Quake in Arkansas From: RLLaney@....... Date: Fri, 22 Oct 1999 17:05:41 EDT John: I recorded an event on 10/21/99 @ 08:17:59 UTC, New Madrid Region, Missouri. It is posted on the PSN web page. Regards, Bob Laney Herndon, VA _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Planned visit to Hector event site From: Greg Lyzenga lyzenga@................. Date: Fri, 22 Oct 1999 14:06:06 -0700 >hello all > >I plan to visit the hector event site in the next few days and take some >pictures. >I am wondering if any PSN members in Southern California would like to go as >a group. > >Contact me if interested through PSN or the address below. Maybe someone >with USGS would like to be a guide. > >George Erich >GeE777@....... > Hi George (and all): This sounds really interesting, but unless you have some very special inside connection, you may be disappointed. The Marines have been carrying out an extensive live-fire exercise in the area. This combined with the fact that the area of the earthquake rupture is littered with unexploded ordnance means that they have been *extremely* restrictive in allowing access to the site, by ground or by air. I have heard of a couple people who tried to gain unauthorized access and were detained. So I hate to be a wet blanket, but you may want to consider this first. - Greg (who's been trying to find a way to get out there since Saturday) |Gregory A. Lyzenga *** (909) 621-8378 |Dept. of Physics, Harvey Mudd College *** fax (909) 621-8887 |Claremont, CA 91711-5990 _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: O Dear Sorry From: Nick & Sophie Caporossi nickcap@............. Date: Fri, 22 Oct 1999 22:43:20 -0400 The previous message was intended for Bob Laney. Nick _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: New Madrid Event File From: Larry Cochrane cochrane@.............. Date: Sat, 23 Oct 1999 21:08:23 -0700 All, I posted a new event file on my system from a new station in Leavenworth, Kansas. See message below. The event file name is 991021a.KS1. I needed to correct the start time of the event so that the P and S match the location calculated by WinQuake. Other then that, Kevin recorded the event very nicely. His station was 440 km (~270 miles) from the event. Regards, Larry Cochrane Redwood City, PSN >Date: Sat, 23 Oct 1999 18:02:51 -0500 >To: cochrane@.............. >From: n0cwr@......... >Subject: Hi > >Hi Mr. Cochrane. > >I think we had a pretty good read here on the New Madrid using your A/D board, >pickup coil, magnet and plans for a Lehmann sensor. >I failed to notice that the WWV receiver we were using had detuned so the >time was off a bit. > >Just thought I would post the raw file to you and screen capture to >see if you had any thoughts or suggestions. > >I am baby sitting the equipment in my garage for my son. >He constructed the equipment for a Kansas University class. >He is a Geology major there and until he graduates and moves to a place of >his own the equipment is running here. I am trying to talk him into locating >a used geophone in hopes he may be able to use at his apartment until he >graduates and finds himself a better location. At that time maybe we can see >you about "populating" the second channel of the A/D board for both sensors. > >Thanks for all your great doucumentation, equipment and assistance! >Kevin Schavee >Leavenworth, Kansas. > > > > > > > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Strong motion sensor design From: jmhannon@.................... Date: Mon, 25 Oct 1999 13:06:57 -0500 George, Could you tell me more about the advantages of a triangular shape for the spring as opposed as a retangular shape. Also I would like more info on heat treating the berrylium copper. Jim Hannon George Harris on 10/21/99 07:19:13 PM Please respond to PSN-L Mailing List To: PSN-L Mailing List cc: Subject: Re: Strong motion sensor design The most efficient simple spring system is a flat spring having a triangular shape. That is, the mass is attached to one point of the spring which is clamped along the opposite side. Having a voice coil driver and an optical pickup on the mass would seem to make a simple rugged feedback system. If low frequencies are to be sensed, the deflection should be as much as possible to make the resonant frequency low so that the sensor does not need as much gain. The feedback corner frequency must be well above the natural frequency to make the feedback system simple. I have worked with berrylium copper springs. An ideal way to make them is to form the spring in the soft state. Hardening is then done by heating to about 600 degrees F. for an extended period. This process makes about the best springs which can be fabricated. An etched spring can be made by drawing the shape with the resist pen used for printed circuits on one side and applying a sheet of adhesive resist on the back. I would be glad to work with anyone in the bay area to see if we can come up with a simple construction. George Harris - Benicia, CA - gjharris@............. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: HS-10 - PSN presentation From: Larry Cochrane cochrane@.............. Date: Tue, 26 Oct 1999 02:22:38 -0700 Hi Dick, I think some presence at the next ESSSA meeting would be an excellent idea. Unfortunately I don't think there is a "canned" presentation about the PSN. This would be a nice thing to have. Maybe someone on the PSN-L list can help... Regards, Larry Cochrane Redwood City, PSN At 04:28 PM 10/25/99 -0400, you wrote: >Larry, sorry for the delay in letting you know that the HS-10 arrived in >good working order. I was at the ESSSA meeting in Memphis and combined it >with a little vacation. That reminds me. The ESSSA is a broad based group >of seismologists and some geologists (USGS, teachers and consultants) who >by and large have never heard of PSN. I thought that both they and we >could gain if there was some relationship. They are a great bunch and >because the meeting is very small, i.e. about 50-100 people, there is a >good working relationship, even with amateurs like me. What do you think >of the idea of making a presentation at next years meeting, which will be >at Georgia Tech in Atlanta. Has anyone put together a "canned" >presentation. If so, I would be more than happy to make the presentation. > >Dick > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Strong motion sensor design From: Doug Crice dcrice@............ Date: Tue, 26 Oct 1999 05:49:50 -0700 A rather nice print of a 1917 Bosch Seismograph for sale on eBay at http://cgi.ebay.com/aw-cgi/eBayISAPI.dll?ViewItem&tc=ps&item=188361549 The 2-wire suspension is reminiscent of recent discussions on the PSN net. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: IBM article on PSN From: "Jan D. Froom" froom@............. Date: Tue, 26 Oct 1999 21:22:36 -0700 In 1999 IBM did an article on those of us that were involved in the PSN. I've put a copy out on my web page: http://www.launchnet.com/froom/psn.htm I'd suggest we recruit Steve Hammond to write a "canned" presentation on and for the PSN! Jan.... Larry Cochrane wrote: I think some presence at the next ESSSA meeting would be an excellent idea. Unfortunately I don't think there is a "canned" presentation about the PSN. This would be a nice thing to have. Maybe someone on the PSN-L list can help... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Does WINQUAKE do maps ? From: "Jan D. Froom" froom@............. Date: Wed, 27 Oct 1999 11:51:57 -0700 Ted led me to believe that WINQUAKE had a function for drawing maps with the distance of an event shown as a circle around the receiving station. However I don't see any mention of maps in Larry's documentation. Is Ted just getting old and imagining things............ again. Jan... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Does WINQUAKE do maps ? From: Stephen & Kathy mortskm@....... Date: Wed, 27 Oct 1999 14:01:21 -0700 Jan D. Froom wrote: > > Ted led me to believe that WINQUAKE had a function for drawing maps with the > distance of an event shown as a circle around the receiving station. However I > don't see any mention of maps in Larry's documentation. Is Ted just getting old > and imagining things............ again. > > Jan... Under the "View" menu click on the "Locate Event" tab! Stephen near Pilot Hill Ca 38.828N 120.978W _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Does WINQUAKE do maps ? From: Larry Cochrane cochrane@.............. Date: Wed, 27 Oct 1999 14:35:23 -0700 Jan, WinQuake version 2.6 (currenly in beta) has the map feature you are looking for. You can download it here: http://www.seismicnet.com/software.html. Download the full release. After unzipping the file in a temp directory copy all of the files over to the directory containing WinQuake. Make sure you are not running WinQuake when you do the copy. -Larry Cochrane Redwood City, PSN At 11:51 AM 10/27/99 -0700, you wrote: >Ted led me to believe that WINQUAKE had a function for drawing maps with the >distance of an event shown as a circle around the receiving station. However I >don't see any mention of maps in Larry's documentation. Is Ted just getting old >and imagining things............ again. > >Jan... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: VBB Construction Progress From: "Rex Klopfenstein, Jr." rklopfen@......... Date: Wed, 27 Oct 1999 22:39:31 -0400 I have finally assembled the mechanical portion of my version of the VBB. I have posted several photographs of my VBB unit. I still have to wire the unit and test the circuit boards I built. -- Rex Klopfenstein, Jr. Bowling Green, OH rklopfen@......... http://www.wcnet.org/~rklopfen _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: VBB Construction Progress From: meredithlamb@.............. Date: 27 Oct 1999 20:29:48 -0700 On Wed, 27 October 1999, "Rex Klopfenstein, Jr." wrote: > > I have finally assembled the mechanical portion of my version of the > VBB. I have posted several photographs of my VBB unit. I still have to > wire the unit and test the circuit boards I built. > > -- > Rex Klopfenstein, Jr. > Bowling Green, OH > rklopfen@......... > http://www.wcnet.org/~rklopfen Rex, Your mechanical version is very well done indeed. Envy is the word...ha. Meredith Lamb Signup for your free USWEST.mail Email account http://www.uswestmail.net _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: USGS Open House Photos From: meredith lamb mlamb1@.......... Date: Wed, 27 Oct 1999 20:42:52 +0000 Hi all, Madeleine Zirbes of USGS NEIC put up a web site with photos of the USGS open house of August 27th and 28th. They are divided into four groups, and its also technically interesting to watch as the pictures change automatically. http://openhouse.cr.usgs.gov/photos.html For my computer sometimes its slow to get them at the moment I checked, but they all eventually came through; one has to give it time. One also may have to use the position cursor to see them all. Thanks Madeleine for all the work and effort, it was very nice. Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Strong motion sensor design From: George Harris gjharris@............. Date: Wed, 27 Oct 1999 21:11:56 -0400 jmhannon@.................... wrote: > George, > Could you tell me more about the advantages of a triangular shape for the spring > as opposed as a retangular shape. Also I would like more info on heat treating > the berrylium copper. > > Jim Hannon > Jim, The optimum shape for a spring is such that all parts are subjected to the same stress. If you analyze a triangular spring clamped on one side and loaded at the opposite point, the stress is equal at all points of the spring. A flat rectangular spring with the same base can be loaded with the same force, but it will not deflect as much as the triangular. Thus the triangular spring has absorbed more energy with the same maximum force. Beryllium copper is what is known as a precipitation hardened metal. That is the beryllium is dissolved in the copper when it is made and cooled quickly. In this condition it is about as soft as copper, though it is better if it is rolled thinner, since it hardens it somewhat, and results in a higher yield strength after heat treatiing. The heat treating process requires that it be heated in a reducing atmosphere (or clamped so that oxygen cannot get to the surface). There are a variety of heat treatments depending on how high you want the yield strength to go. I believe that the optimum one is around 600 deg. F for an hour. Any experienced heat treating shop ( specially ones who make springs) will have the proper equipment. The temperature is rather critical if the highest properties are to be achieved. What happens during the heat treatent is that tiny particles of beryllium precipitate out in the grains of copper. This ties the copper grains together in such a way that they cannot slide to elongate, thus leading to very high strengths. Due to the fact that the bending modulus of copper is about 1/2 that of steel, it is possible to store twice as much energy in a copper spring as a steel one of the same size. Another major advantage of beryllium copper is that the spring can be formed while soft to an exact final shape. To maintain the shape is must be clamped to a piece of stainless or similar material during the heat treatment. George Harris _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Great Quakes on The Learning Channel (TV) From: meredith lamb mlamb1@.......... Date: Wed, 27 Oct 1999 20:56:57 +0000 The Learning Channel on TV will present "Great Quakes" on Sunday Oct 31st, from 7 p.m. to 11 p.m., and Wednesday, November 3rd, from 8 p.m. to 2 a.m.; and Saturday, November 6th, from 5 p.m. to 8 p.m. This is all Eastern/Pacific Time in the U.S.A. They also have extensive web site coverage on their web site of earthquake related public news at: http://tlc.discovery.com/tlcpages/greatquakes/greatquakes.html Be sure to click on the "Vunerable Cities", "Quake Tech" and "Media Gallery". They have apparently went all out on presentation here, which is very commendable. Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Pier in the crawlspace? From: Marchal van Lare vanlare@.............. Date: Fri, 29 Oct 1999 08:41:56 -0400 Hi all, Last July I asked your advice in building a Lehman. Thanks to the advice you gave me, I have completed the project. I will use Larry's equipment to start recording in the near future. Now I have to find a good location to place my Lehman. I have two options: to place it in a separate room or in the crawlspace = beneath the house. There is not much room in the crawlspace (1 meter) and the soil consists of sand and clay. Sometimes (after wet weather conditions over a long period of time) there is also the problem of water in it. I guess a pier will tilt due to the different soil conditions? What do you suggest? Thanks in advance, Marchal van Lare -Nieuwvliet, The Netherlands _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Pier in the crawlspace? From: dwebb2@.............. Date: Fri, 29 Oct 1999 09:29:33 -0400 Marchal, Congratulations on completing your system. I too have built a Lehman and used it in both a crawlspace and vault environment. My crawlspace was rather damp as well. I dug down a foot and built a concrete pad for the system but kept the electonics in th e house but as close as possible. You might consider sealing the concrete to prevent moisture transmission. I also covered the seismometer with a box made of insulating foam that gave some level of moisture protection and good temperature control. If t he unit you made is the typical one of galvanized pipe and oil damping, it will survive almost any assalt. If the base tips ov er time, merely relevel the unit. Have fun, it's a great hobby. Dick Webb Raleigh, NC, USA PSN-L Mailing List wrote: > Hi all, Last July I asked your advice in building a Lehman. Thanks to the advice you gave me, I have completed the project. I will use Larry's equipment to start recording in the near future. Now I have to find a good location to place my Lehman. I have two options: to place it in a separate room or in the crawlspace = beneath the house. There is not much room in the crawlspace (1 meter) and the soil consists of sand and clay. Sometimes (after wet weather conditions over a long period of time) there is also the problem of water in it. I guess a pier will tilt due to the different soil conditions? What do you suggest? Thanks in advance, Marchal van Lare -Nieuwvliet, The Netherlands _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Internet Discovery channel article From: meredithlamb@.............. Date: 29 Oct 1999 10:39:49 -0700 Hi all, Theres a interesting short article on "New Tech Predicts Volcanoes" (eruptions) at: http://eagle.online.discovery.com/news/briefs/ brief5.html?ct=3819ef53 Here, GPS (Global Position System) antennas gave location points in longitude, latitude and height, along with comparison tiltmeters, seismographs for verification agreements. The article suggests a more "instant" appraisal for certain volcanoes and their monitoring thereof. Meredith Lamb Signup for your free USWEST.mail Email account http://www.uswestmail.net _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: VBB Construction Progress From: barry lotz gbl@....... Date: Fri, 29 Oct 1999 18:56:42 -0700 Rex Nice photos. I hope to be able to show some photos as soon as I create a web page. I changed STM's design slightly. I was continuously removing and replacing the the leaf spring for various reasons. I finally cut the non bearing side of the aluminum that supports the brass leaf spring support rods away. That way instead of trying to keep the leaf spring in place while inscrewing the flexures , I simply squeeze the ends of the leaf spring together slightly and it comes out from beneath the beam. Regards Barry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: International Volcano cams site From: meredithlamb@.............. Date: 29 Oct 1999 19:00:41 -0700 Hi all, I thought a good followup to the previous volcano article, might be a nice site that leads to various other volcano cams around the world. See: http://educeth.ethz.ch/stromboli/livecams/ index-e.html Mt. Etna has been very active of late. I especially check this site even at night, as it can show the red glow from lava and whatnot. You will have to time the viewing for the natural sun lighting conditions around the world. This site doesn't show all the cams, probably because most of these are temporary. Meredith Lamb Signup for your free USWEST.mail Email account http://www.uswestmail.net _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: removing STM leaf spring From: S-T Morrissey sean@........... Date: Fri, 29 Oct 1999 21:59:40 -0500 (CDT) Barry and Rex, Regarding removing the leaf spring: I generally never bother to bolt down the lower spring support bracket by installing the nuts on the bolts under the main baseplate. The pressure of the spring keeps the bracket in place with only the 1/4" bolts dropped thru the holes. This makes removing the spring rather easy. The single bolt to the boom is loosened and the nut removed. Then the spring is (VERY CAREFULLY) squeezed closed by gripping from both sides. THis frees it from the boom and lifts the lower bracket from the base. Then all the pressure is transferred to one hand to remove the assembly. What Barry suggests has the advantage that the point of attachment under the boom is not disturbed, which is an important consideration since this effects the mechanical period. Before I remove the bracket from the boom, I mark its position carefully. I will give Barry's idea some further thought. Although the brass support rods are free to rotate during assembly to allow the self- alignment of the flexures along the direction of maximum tension, (I actually twang the spring several times to make sure that they align) they must not rotate during the normal operation of the seismometer. On another subject, namely the feedback coil/magnet: I have recently been able to fabricate the magnet assembly with bought parts and wind a 4-layer flat-wound coil (not scramble wound: every turn is precisely placed) that has a cross-section per side of 0.5 x 0.022" (#36 wire).. Once I determine the actual constants, I will write up a description and a list of the parts (from McMaster Carr). The pricy item is the rare-earth ring magnet at $28. However, it results in a repeatable outcome without dealing with stereo speakers, and the additional coil clearance (0.032") solves the problem of the coil jamming when moved in a short arc. THe ideas can be applied to any hardware/magnet/coil options. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: More on a strong motion sensor From: Larry Cochrane cochrane@.............. Date: Fri, 29 Oct 1999 22:41:26 -0700 All, Several days ago I received a strong motion sensor prototype from one of our members Roger Baker in Texas, USA. I placed some pictures of it here http://www.seismicnet.com/strongmotion/. The first picture show an overall view of the device and the others show a closer look at the end of the boom. The boom is made from a hack saw blade. The device is forced-balanced with an optical displacement sensor using a red LED and photo transistor with an interrupter mounted on the end of the pendulum. The device uses a disk drive head actuator with the coil (~133 ohms) mounted on the pendulum. Mounted on the frame, made of wood, are two flat magnets. The device worked right out of the box. It has two outputs, one is a low gain output and another higher gain. The low gain output gives a nice DC change of voltage as one rotates the device 90 degrees. It looks like the device has a 2.45 v / g output. The higher gain output needs to have an offset pot adjusted so that the output is in a linear range. I think this can be fixed by AC coupling this output. Connecting a scope to this output I can see me jumping around on the ground similar to what a geophone would pick up. What Roger has given me (BTW, thanks a lot Roger!) is a mechanical structure and electronics that I can improve on. As I told Roger, I do ok with electronic and software design, but mechanical design and construction are hard for me to do. I have a lot of questions about what can be done to improve and make this type of sensor more reproducible etc. For now I have two questions.... The first one is about the natural period of the pendulum when trying to construct an accelerometer. I understand that to create an accelerometer one can use a pendulum and a displacement sensor, and for frequencies below the period of the pendulum you will be recording acceleration. The device Roger gave me has a period of around 8-10 hz. A little low..I will be shortening the boom it to increase the period, but I was wondering if the feedback or output can be modified so that it has a flat response to acceleration even if the pendulum period is lower then what you want to record? If I understand how Sean-Thomas's VBB sensor works, the feedback is controlled so that the sensor produces a flat response to velocity, and that the actual period of the pendulum is not that important. Can the same thing be done with acceleration, or does the period of the pendulum need to be above the max frequency? I ask this more for curiosity. I think it will be easy to simply shorten the pendulum to get a 20 - 30 hz natural period and use the more simple force-balance feedback setup. My other question, for now, is about using light, and photo transistor and LEDs in particular, for the displacement sensor. The parts are easy to get but I wonder about linearity, temperature and long term stability. Any thoughts???? This weekend I will be checking the linearity and temperature stability. Long term stability is harder to check for.... Regards, Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: VBB Construction Progress From: Karl Cunningham karlc@....... Date: Sat, 30 Oct 1999 07:25:33 -0700 Barry, et al: To compress the spring in a controlled way, I made a clamp out of some 3/8" square aluminum bars and some 10-32 threaded rods. With one clamp on each side of the leaf spring, I can slowly and very controllably compress the leaf spring by tightening nuts on the threaded rods. Karl At 06:56 PM 10/29/1999 -0700, you wrote: >Rex > Nice photos. I hope to be able to show some photos as soon as I create a >web page. I changed STM's design slightly. I was continuously removing >and replacing the the leaf spring for various reasons. I finally cut the non >bearing side of the aluminum that supports the brass leaf spring support >rods away. That way instead of trying to keep the leaf spring in place while >inscrewing the flexures , I simply squeeze the ends of the leaf spring >together slightly and it comes out from beneath the beam. >Regards >Barry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: HS-10 Conversion to Horizontal From: Dick Webb dwebb2@.............. Date: Sat, 30 Oct 1999 11:57:00 -0400 Hi, Recently, I obtained two HS-10 seismometers that are of the bore hole variety. They are vertical and I am interested in converting them to horizontals. Can this be done and if so how. Dick _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: More on a strong motion sensor From: barry lotz gbl@....... Date: Sat, 30 Oct 1999 10:40:47 -0700 Larry et al 2=A2 : If I understand it correctly, with a force feedback system, th= e voltage/current measured is that required to restore the sensor to the ne= utral position. It would seem that with a system which has a strong mechanical restoring force that the system would be less sensitive ??? What would t= he feedback be used for? I guess if the feedback force is strong relative to= the mechanical restoring force you can get the sensor to have any desired re= sponse with electronics. eg , if the mechanical restoring force is directed back= to null before the the desired response time, that the feedback force would = would actually be directed away from null ??? Barry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: More on a strong motion sensor From: Karl Cunningham karlc@....... Date: Sat, 30 Oct 1999 13:59:52 -0700 Another 2=A2... The following is what I think I know about this stuff. Please tell me if I am off base on any of it. =20 As you say, Barry, there will be a mechanical restoring force and another one from the feedback. Consequently, for a given acceleration, there will be an amount of deflection with just the mechanical system, and a smaller amount of deflection with the feedback turned on. If you take the ratio of these two deflections, it is approximately the loop gain of the closed-loop system. And the loop gain is an indication of how well it measures acceleration. As you point out, a strong mechanical system (large spring constant) requires a good feedback system (sensitive position detector, high gain, and strong feedback coil), because you want the feedback to do most of the work. This ratio depends on the frequency of the acceleration signal because the mechanical response to acceleration depends on the frequency. And also the frequency response of the feedback system has a direct bearing on loop gain vs frequency. Most feedback systems of this type have a differential term, a proporational term, and an integral term. The differential term is the predominant one due to stability requirments. This results in a feedback system with highest gain at higher frequencies, and relatively low gain at low frequencies. =20 As has been noted before, above the natural period of the mechanical system its response is proporational to displacement, and below it is proporational to acceleration. Since displacement is the double integral of acceleration, the response to acceleration falls off at 12db/octave above the natural period. The combination of the response of the mechanical and feedback systems determines the loop gain, which determines the accuracy of the feedback system in measuring acceleration. The gain of the mechanical system is flat to acceleration at lower frequencies, but the gain of the feedback system falls off as frequency goes lower (usually at 6db/octave). So loop gain suffers at low frequencies. And as frequency increases above the natural period, the gain of the mechanical system falls off at 12db/octave and the gain of the feedback system increases at 6db/octave. The combination falls off at 6db/octave, so loop gain suffers at high frequencies too. You can use a mechanical system with a relatively large spring constant (not much deflection for a given acceleration), but the feedback system has to be that much better (to keep the loop gain high) at all frequencies of interest. Check some numbers and see how it measures up. I'd be happy to crunch some numbers if anyone is interested. By the way, the VBB system normally produces a velocity output, but the current through the feedback coil is proportional to acceleration, and that signal can be used as well. Karl Cunningham La Mesa, CA. PSN Station #40 karlc@....... At 10:40 AM 10/30/1999 -0700, you wrote: >Larry et al >2=A2 : If I understand it correctly, with a force feedback system, the >voltage/current measured is that required to restore the sensor to the neutral >position. It would seem that with a system which has a strong mechanical >restoring force that the system would be less sensitive ??? What would the >feedback be used for? I guess if the feedback force is strong relative to= the >mechanical restoring force you can get the sensor to have any desired response >with electronics. eg , if the mechanical restoring force is directed back= to >null before the the desired response time, that the feedback force would would >actually be directed away from null ??? >Barry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: HS-10 Conversion to Horizontal From: Doug Crice dcrice@............ Date: Sat, 30 Oct 1999 17:31:38 -0700 Dick Webb wrote: > > Hi, > > Recently, I obtained two HS-10 seismometers that are of the bore hole > variety. They are vertical and I am interested in converting them to > horizontals. Can this be done and if so how. > Are you sure they are verticals? It is common to find two horizontals and a vertical in a borehole geophone. Anyway, the difference between them is the springs that hold the mass centered. Vertical geophones springs have to hold up the mass against gravity. It is not likely that you could take one apart, change it, and put it back together. However, you might be able to bias the geophone by putting a little DC current into the coil, then AC coupling it to the amplifier. Sort of an electrical spring. Use a resistor large enough to not over-damp the geophone. Feels a little klutzy, but what are we for if not to try innovation solutions. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Bounced messages From: Larry Cochrane cochrane@.............. Date: Sun, 31 Oct 1999 15:15:39 -0800 All, If you recently posted a message to this list you may get back a message that looks like this: >-------------------------------------------------------------------------- >psn-l@.............. is not allowed to post to the list. >Please contact root@.............. if you have any problems. >-------------------------------------------------------------------------- This is not a problem with my mail server. It looks like the problem is with the user nicholas@............ mail system. I removed this email address from the list so the problem should clear up in a few days. It looks like messages sent to that address are bouncing back directly to the list. Bounced messages should go to another address so my mail server can handle the error properly. -Larry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: aerial photos From: "steve hammond" shammon1@............. Date: Sun, 31 Oct 1999 20:15:22 -0800 My brother sent me this URL. Many of you many not know about this Microsoft site. I didn't. It contains aerial photos of the USA. I found it very interesting. Some are from the USGS and some are from the Russian Spin2 satellite. Regards, Steve Hammond PSN Aptos, California -----Original Message----- From: Larry Hammond To: shammon1@............. Date: Friday, October 29, 1999 6:58 AM Subject: FW: aerial photos > >Interesting.. FYI.. Larry > >-----Original Message----- >From: Jean Kammer [mailto:kamerlot@........ >Sent: Thursday, October 28, 1999 11:45 PM >To: Larry Hammond (E-mail) >Subject: aerial photos > > >Thought you might find this of interest. > > > http://terraserver.microsoft.com/image.asp?S=14&T=1&X=151&Y=1434&Z=18&W=1 > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: More on a strong motion sensor From: Larry Cochrane cochrane@.............. Date: Sun, 31 Oct 1999 22:33:54 -0800 Karl, Thanks for the detailed explanation.Things are becoming a little clearer about pendulums picking up acceleration, velocity and displacement. At 01:59 PM 10/30/99 -0700, Karl wrote: >Another 2¢... The following is what I think I know about this stuff. >Please tell me if I am off base on any of it. >You can use a mechanical system with a relatively large spring constant >(not much deflection for a given acceleration), but the feedback system has >to be that much better (to keep the loop gain high) at all frequencies of >interest. Check some numbers and see how it measures up. I'd be happy to >crunch some numbers if anyone is interested. That would be a big help. What information would you need for the number crunching? > >By the way, the VBB system normally produces a velocity output, but the >current through the feedback coil is proportional to acceleration, and that >signal can be used as well. Yes, but does the output at that point have a flat freq. response to acceleration above the period of the pendulum or does it fall of at the 12db/octave or 6db/octave rate? -Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: More on a strong motion sensor From: Karl Cunningham karlc@....... Date: Mon, 01 Nov 1999 08:58:33 -0800 Larry -- Glad to help. >Karl, >That would be a big help. What information would you need for the number >crunching? Off the top of my head, I think I would need the feedback circuit, the characteristics of the feedback transducer (voice coil, or whatever), and either the period or the amount of mass and the spring constant. These may not all be easy to come up with, but some relatively simple experiments can be done to figure it out. The calculations are very similar to what Sean-Thomas has posted on his web site for the VBB, except for the circuit equations. >Yes, but does the output at that point have a flat freq. response to >acceleration above the period of the pendulum or does it fall of at the >12db/octave or 6db/octave rate? If the loop gain is high enough, the acceleration response should be flat with repsect to frequency. The idea is that if the loop gain is high, the feedback will be maintaining the mass in a fixed position with respect to the base (and the earth). If this is the case, then the current in the coil has to be proporational to acceleration (barring any friction in the mechanical system), independent of frequency. Of course, the response will drop off at the extremes, but this will be predicted by loss of loop gain at these frequencies. Saying it another way, the loop gain also determines the measurement accuracy, and for our purposes inaccuracy is approximately the inverse of loop gain. With a loop gain of 10, the inaccuracy will be within about 0.1 (10%). I would think that determining acceleration amplitude within 10% is probably good enough for us. Loop gain in the center of the frequency range will probably be much higher -- maybe 100 or more. -- Karl _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: low gain VBB From: S-T Morrissey sean@........... Date: Tue, 2 Nov 1999 13:08:35 -0600 (CST) Barry, In high-gain/low-gain recording it is desirable that the signals be identical for purposes of interpretation. The VBB system has a dynamic range of over 120db, or 10^6:1, which is why it needs 24-bit digitizing for a single gain level. For the affordable world of 16-bit (~10,000:1) recording, a low gain channel of 1/100 the high gain will realize most of the dynamic range while still recording something once in a while. A lower gain "low-gain", like 1/1000 will give more of a total range approaching 24-bits (16x10^6:1), but will very rarely record much. If the VBB signal is typically 2000 volts/meter/second, 1/1000 th of it is 2 v/m/s. So if the digitizer is +,- 10 volts, it will clip at a velocity of 5 meters/second. In acceleration this is about 0.8m/sec^2, or about 0.13 of g, at 1 second (hz ). Modifying the feedback parameters of the VBB is not a good idea. THey exactly describe your response at the VBB output. The way I realize a low gain signal is to attenuate the output after the final line-driver amplifier. This is a 5x to 20x gain amp after the 1000-second high pass filter. I use precision resistors with the total as low as practical without loading the op-amp. Like a total of 10k ohms made with 9.9k and 100 ohms for a 100:1 ratio. If your high-pass filter follows your line amplifier, you will need to buffer it with another amplifier. However, I would place the filter before the line-driver so you can have identical high and low gain signals. This also avoids the added noise of stringing together many amplifiers: the fewer the better. (the VBB only needs three). With a 5x gain, an output of 10 000 v/m/s will clip (at 10 volts) at 1 millimeter/second. If the amplifier noise floor is 10 microvolts, the equalivent noise would be 10 nanometers/second. Somewhere I have data on earthquake magnitude/distance figures in terms of the velocity output of a seismometer. Regards, Sean-THomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Obtaining lead on the cheap side From: meredith lamb mlamb1@.......... Date: Wed, 03 Nov 1999 03:00:30 +0000 Hi all, Had to have my car worked on today. It took so long to do, that I walked alot around the immediate neighborhood. Along the way, in the parking areas, were alot of scattered pieces of tire rim balance weights of lead and steel hangers. The shop area has asphalt paving, and is only about a year old. What started as a walk ended up as a scavenger hunt. I ended up with acouple pounds of lead. The paving area was kept clean, but these weights are heavy and often escape sweeper pickup. Besides being in the open areas, the cracks along the curb were good places to accumulate, as well as dip areas the sweeper machines can't get too. Even found a lead battery terminal connector. I don't particularly have too much adversion to scavenging material, but it might have been better to do it on a day of the week when the shop/s are closed, and relatively free of cars. Naturally the most pieces were found close too or adjacent to the shop; but some fresher piece were likely tossed by cars leaving the area too. Naturally, it will have to be melted down, and the steel discarded. But....what the heck.....its free....., and, harder to find commercial sources more and more. If you're shy.....wear dark glasses......ha. Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: More on a strong motion sensor From: barry lotz gbl@....... Date: Tue, 02 Nov 1999 20:52:53 -0800 Hi Karl I would be interested in any force feedback formulas you might have so I can try to predict the performance of my sensor. I was going to try STM's formulas with values for the integration portion such that it can be ignored and the diff and proportional set according to the values I am currently using for my FB horizontal. Barry Ps would posting something on your website be possible? Karl Cunningham wrote: > Larry -- > > Glad to help. > > >Karl, > >That would be a big help. What information would you need for the number > >crunching? > > Off the top of my head, I think I would need the feedback circuit, the > characteristics of the feedback transducer (voice coil, or whatever), and > either the period or the amount of mass and the spring constant. These may > not all be easy to come up with, but some relatively simple experiments can > be done to figure it out. > > The calculations are very similar to what Sean-Thomas has posted on his web > site for the VBB, except for the circuit equations. > > >Yes, but does the output at that point have a flat freq. response to > >acceleration above the period of the pendulum or does it fall of at the > >12db/octave or 6db/octave rate? > > If the loop gain is high enough, the acceleration response should be flat > with repsect to frequency. The idea is that if the loop gain is high, the > feedback will be maintaining the mass in a fixed position with respect to > the base (and the earth). If this is the case, then the current in the > coil has to be proporational to acceleration (barring any friction in the > mechanical system), independent of frequency. Of course, the response will > drop off at the extremes, but this will be predicted by loss of loop gain > at these frequencies. > > Saying it another way, the loop gain also determines the measurement > accuracy, and for our purposes inaccuracy is approximately the inverse of > loop gain. With a loop gain of 10, the inaccuracy will be within about 0.1 > (10%). I would think that determining acceleration amplitude within 10% is > probably good enough for us. > > Loop gain in the center of the frequency range will probably be much higher > -- maybe 100 or more. > > -- Karl > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Obtaining lead on the cheap side From: "Raul J. Alvarez" ralvarez@........ Date: Tue, 02 Nov 1999 22:24:25 -0700 Hi Meredith, Have an easier way to get lead weights. Just ask the shop! My experience has been they just give them to you. No need for them to dispose of "hazardous waste". Raul _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Temperature Logger From: Arie Verveer ajbv@............ Date: Wed, 03 Nov 1999 15:16:58 +0800 Hi, This product may be of interest; if you want to do some checking of the seismograph's response to temperature. Its a cheap way to log the temperature against time. The kit which contains a "reader" that plugs into to serial port of your computer plus one stand alone DS1921 Thermochron chip. The chip is about the 5/8 inch diameter and is self contained with a battery and temperature logger. The whole kit cost $25, extra DS1921 chips are around $11 dollars U.S. see: http://www.ibutton.com/ibuttons/thermochron.html I have one that logs the temperature near the seismographs. It may be interesting to monitor ground water temperature near a fault area.? Arie _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Event Operated Sound Recorder From: "Mark Robinson" other@............... Date: Thu, 4 Nov 1999 00:07:01 +1300 I thought this program may be of interest to people who want some sort utility sound or seismo recorder. http://www.davee.com/scanrec.html regards all Mark Mark G Robinson | ZL2TOD | other@............... Box 8770, Auckland 1035, New Zealand Phone +64-9-846-3296 | Fax +64-9-849-7408 ------------------------------------------------ 04 Nov 1922 Tutankamen's tomb is opened. 04 Nov 1937 Dr. Brian Finbar Miram Edwards born in Ireland. 04 Nov 1952 Ike wins the White House in a landslide vote. 04 Nov 1956 Soviet tanks crush a popular uprising in Hungary. 04 Nov 1980 Ronald Reagan, Hollywood actor, becomes President of the United States of America. 04 Nov 1984 The incident on which the film Red October is based is rumoured to have occurred. 04 Nov 1992 George Clinton wins the Whitehouse versus George Bush and Ross Perot. 04 Nov 1997 Jenny Shipley is elected Prime Minister designate by the National Party caucus deposing The Great Helmsman, Jim Bolger. 04 Nov 1997 Alf Hunt born of Sam. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Obtaining lead on the cheap side From: meredith lamb mlamb1@.......... Date: Wed, 03 Nov 1999 18:02:56 +0000 "Raul J. Alvarez" wrote: > Hi Meredith, > Have an easier way to get lead weights. Just ask the shop! My experience > has been they just give them to you. No need for them to dispose of > "hazardous waste". > > Raul > Raul, I got a chuckle out of the above response....I didn't think of that....ha. However, it could be of value to try over time for those seeking lead for their seismo/s. There would likely be a variety of possible responses from the individual shops. The best aspect of this, is that it could be a source world wide, wherever theres motor vehicles....there is a service center/shop somewhere. Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: More on a strong motion sensor From: Karl Cunningham karlc@....... Date: Wed, 03 Nov 1999 11:50:27 -0800 Barry -- I'd me happy to write up some formulas. The equations will be similar to Sean-Thomas' VBB with the exception that the output is taken from a different place. And of course all the independent variables have to change too. I'll have a look at it and see what I come up with. -- Karl At 06:39 AM 11/3/1999 -0800, you wrote: >Hi Karl > I would be interested in any force feedback formulas you might have so I can >try to predict the performance of my sensor. I was going to try STM's formulas >with values for the integration portion such that it can be ignored and the >diff and proportional set according to the values I am currently using for my >FB horizontal. >Barry > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: More on a strong motion sensor From: Karl Cunningham karlc@....... Date: Wed, 03 Nov 1999 13:48:13 -0800 Barry -- You might be interested in the following document, written by Brett Nordgren (he used to regularly post to this list). It is an analysis of Sean-Thomas' equations describing the VBB, and takes them apart term by term. http://members.home.net/nordgren/public/loop3.pdf I found it an invaluable aid toward understanding the equations involved. -- Karl _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: lead disks From: S-T Morrissey sean@........... Date: Wed, 3 Nov 1999 18:27:21 -0600 (CST) I always admire Meredith's resourcefulness. But I am leary about the idea of melting lead. We used to do it in the Aleutians to cast 1 pound lead sinkers for catching Halibut, but always outside in the wind. But to aviod lead poisoning and possibly more convenient: A ready source of handy lead disks is McMaster-Carr: (630-833-0300; no minumum, take charge cards) Some examples: 2 3/4 od x 13/32 id x 1/2" thick 1 1/4 lbs # 90385k22 $ 7.83 4 1/2 od x 25/64 id x 1/2" thk 3 1/4 lbs # 90385k32 $ 13.68 4 1/2 od x 25/64 id x 1" thk 6 1/2 lbs # 90385k34 $ 24.40 6 " od x 25/64 id x 1/2" thk 5 3/4 lbs # 90385k42 $ 18.66 6" od x 25/64 id x 1" thk 11 1/2 lbs # 90385k44 $ 33.52 (two of this last are used in the S5100 long period vertical seis) Up to: (for sailboad ballast or a VERY large seis) 13" od x 41/64 id x 1" thick 54 lbs # 90385k74 $ 124.97 They are somewhat roughly cut; I am using the smallest size in newer versions of the VBB vertical and in another new instrument development. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Ring magnets, lead & new seismo From: meredith lamb mlamb1@.......... Date: Thu, 04 Nov 1999 03:08:35 +0000 Sean-Thomas, Thanks for the references to the ring magnets and metal lead disks from McMaster-Carr. The disks would really simply and expedite seismos suitable for them, with their mounting holes. I note the ring magnets are of the machineable epoxy bonded type. Supposedly easy to machine, but new too me. I don't think your coil winding procedure and/or machinery has been brought up in any kind of detail yet. Any possiblity of such? You mentioned another "new instrument development". How about afew scavenger scraps of info...like is it a vertical or horizontal, possible period, size etc....pretty please.....ha. Of course a web photo would be delightful to see, even if its still in the developmental stage. Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Obtaining lead on the cheap side From: SW6079@....... Date: Wed, 3 Nov 1999 22:56:14 EST Liked your post, Meredith. I have also found that I can get huge donut magnets removed from defunct microwave ovens from repair shops usually just for the asking. Lots of fun and practical uses for these. Mike. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: low gain VBB From: barry lotz gbl@....... Date: Wed, 03 Nov 1999 20:49:22 -0800 Sean Thomas I'm a little confused. If one uses a 24 bit digitizer wouldn't the gain be 1000 times lower so that full scale would be still less than the ref voltage? If that is the case, I was experimenting with MathCad and If I increase the feedback capacitor substantially then the bandwidth goes up and the gain goes down. Then one could amplify the gain to get the high gain response if a 16 bit digitizer was used. I realize that this would amplify the noise also. I would be very interested in any correlations you might have for velocity vs distance vs magnitude. This would help in selecting appropriate gain levels. Regards Barry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: low gain for 16-bit adc From: S-T Morrissey sean@........... Date: Fri, 5 Nov 1999 00:46:38 -0600 (CST) Barry, The combination of a VBB instrument and a 24-bit digitizer is designed to get an on-scale record of a maximum likely magnitude near-field quake, like a 7.0 at 1000km distance, while still having good signal-to-noise (SNR) for a minimal quake of interest, like a 3.0 at 100 km. In his Harvard thesis on the VBB seismograph system (including the VBB sensor and the digitizer), J.M.Steim demonstrates these parameters in considerable detail with nice graphics. I hope to find time this weekend to make a table of the data to show what a PSN seis should expect to be able to record. Like one gets roughly similar amplitudes (within a factor of 10) for a M6.0 at 3 degrees (330km), a 8.0 at 30deg, and a 3.0 at 10km. So for a VBB seis, if the digitizer limit level is 20 volts and the output 2000 V*sec/m, the clipping level is 10mm/second ground velocity. The minimal signal is the noise floor of the displacement transducer, which, with proper amplifiers, could be assumed to be 10 micro-volts or less, or 5 nanometers/sec. So the digitizer should try to encompass this range. A common 24-bit digitizer has a maximum voltage of 40 volts for use with VBB seises with 20 volt maximum outputs. 24-bits is 16 777 216 counts, or 419 430 counts/volt. Inverting, this is 2.38 microvolts/count, or about 0.4 times the expected noise floor of 10 microvolts. Any additional amplifiers will only raise this noise level, which is why they are low or unity gain. So with a 16-bit digitizer, we need to have a maximum value of 1 volt or less to avoid the need for additional amplification. With 1 volt full scale, the least count is 15.3 microvolts. If we want to push the noise floor, a 10x line amplifier would be needed, or, as you suggest, the VBB feedback can be modified for higher output (but this has its own problems). With a 10x amp, assuming that it doesn't clip or add considerably more noise, an output of 20 000 V*sec/m into a 1-volt digitizer will limit at 50 microns/second. The least count will be 0.76 nanometers/second, about 1/10th the expected noise floor. But the clipping at 50u/sec will limit recording of large events. SO, we also need a lower gain. Since the input to the 10x amplifier is (often) also the high pass filter (the high-pass removes the DC thermal noise, etc), dividing its output by 100 is preferable to using the unfiltered output for a low gain channel. So after a 100:1 divider the low gain is 200 V*sec/m, which at a clip level of 1 volt of the 16-bit digitizer is 5mm/second, with a least count of 76 nanometers/second. While the 100:1 is not the difference between 16 and 24 bits (=256:1), the low gain will still usually record some data, where a 1000:1 low gain will be a pretty dull channel. And the result will cover data from 5mm/second to lower than the instrument noise floor. I think that Larry's digitizer is 10 volts full scale. This would still work, but with an upper limit of 0.5 millimeters/second and a least count value of 7.6 nanometers/second (using the values above). Then the 100:1 low gain would have a range of 50mm/second to a least count value of 0.76 microns/second, which would put it in the range of moderate strong motion recording. For the experimental STM-8 VBB here at the farm, I am still using the Radio Shack digital multimeter as a 12-bit digitizer. The maximum is 200 millivolts, with a minimum of 0.1 millivolt. With a VBB signal of 5.29mv*second/micron (aka 5293 V*sec/m), the maximum signal is 37.8 microns/second and the minimum is 18.9 nanometers/second. The 6-second microseisms today run about 2 millivolts, or 0.38 microns/sec. Since 6 seconds is close to 2*pi, so w (omega) ~=1, the displacement is also about 0.38 microns. With a minimum value of 0.1 millivolt, the noise threshold (again at 6 seconds) is about 0.02 microns (20 nanometers). (I need to use another 10x gain to see the sensor self noise.) So it has good sensitivity to small signals, but does clip on larger quakes like Izmet, Turkey, and the recent central Mexico event. The 7.0 in S.CA (Hector Mines) clipped for half an hour. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Why a duck? Re: Strong motion sensor design From: Edward Cranswick cranswick@........ Date: Fri, 05 Nov 1999 06:58:04 -0700 PSN- Having no techno-smarts left, I cannot talk much about hardware/software and all I can do is wave my arms in an attempt to motivate the building of strong motion sensors. The bottom line is that strong motion sensors operate in the range of groundmotion where the rubber of earthquakes hits the road of public consciousness. We have just finished an intial report on what we did in Turkey with respect to strong motion studies, and the website will give you some idea about that. The point is that that there is alot more potentially and actually hazardous groundmotion out there than there are govenment employees and other professonals to keep an eye on it. Ask not what Hi-Tech can do for you but rather what you can do for Hi-Tech: if you can't make an on-scale record of the shaking which makes your house fall on your head, you might as well depend on your house to be your strong motion recorder .. . . -Edward -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: IBM article on PSN From: Edward Cranswick cranswick@........ Date: Fri, 05 Nov 1999 07:27:34 -0700 Jan- I thought the original article was published about 1991. Certainly this one has got a slight muddle of dates plus/minus 1 year or so and a few other facts are confused: I know I drank alot in college but I don't remember going to Cornell, I thought it was Columbia . . . but maybe that's why I never got any graduate degree there because I was enrolled somewhere else or something. I guess I won't argue too much about being an "eccentric Colorado geologist" though there might be some in Colorado who would not give me the credit for that origin. And as far as my wife and the KGB is concerned . . . well, one day we'll write the real story. But anyway, it really was you and Steve and Richard and Ted and Bob and other members of the IBM mafia who had already started operating what were still pipe dreams for me. -Edward "Jan D. Froom" wrote: > In 1999 IBM did an article on those of us that were involved in the PSN. > I've put a copy out on my web page: > http://www.launchnet.com/froom/psn.htm > > I'd suggest we recruit Steve Hammond to write a "canned" presentation on > and for the PSN! > > Jan.... > > Larry Cochrane wrote: > I think some presence at the next ESSSA meeting would be an excellent > idea. > Unfortunately I don't think there is a "canned" presentation about the > PSN. > This would be a nice thing to have. Maybe someone on the PSN-L list can > > help... > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: IBM article on PSN From: "Jan D. Froom" froom@............. Date: Fri, 05 Nov 1999 07:12:31 -0800 Edward..... Those of us that are members of E Clampus Vitus (not sure if we're a Historical Drinking Society or a Drinking Historical Society) have a tendency to embelishing our facts when we don't know what we're talking about. But yea the article was published in 1991, I put it on my web site in 1999; how's that? Jan Edward Cranswick wrote: > Jan- > I thought the original article was published about 1991. Certainly this > one has got a slight muddle of dates plus/minus 1 year or so and a few other > facts are confused: I know I drank alot in college but I don't remember > going to Cornell, I thought it was Columbia . . . but maybe that's why I _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Why a duck? Re: Strong motion sensor design From: ted@.......... Date: Fri, 5 Nov 1999 12:40:32 -0500 I understand your concern. Lots of PSN members live in seismically active areas so they provide the opportunity you recognized years ago to "densify" the network of data recording in urban areas. Other PSN members move to states whose nicknames derive from sitting on kilometers of plutonic rock. (Hint hint). Hey, somebody has to provide data for triangulation! The question is, should you put the strong motion sensor in the attic so less of the house will fall on it? Ted (don't take me for granite) Blank _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Why a duck? Re: Strong motion sensor design From: Doug Crice dcrice@............ Date: Fri, 05 Nov 1999 09:59:52 -0800 ted@.......... wrote: > >> The question is, should you put the strong motion sensor in the attic so > less of the house will fall on it? > I'm relatively sure you're speaking tounge-in-cheek, but your first strong-motion sensor should be placed on solid (or what passes for solid in your area) ground. If you put the sensor in the structure, especially the attic, it will record the natural resonances of the building, not the ground spectra which are of interest to structural engineers and microzonation enthusiasts. Large high rise buildings typically have at least three strong-motion seismographs, one in the basement, one in the roof and one in the middle, wired together with a common time base. The purpose is of course to record the driving force in the basement and the structural response of the building to the shaking. It's a tool for better aseismic design of structures. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Why a duck? Re: Strong motion sensor design From: JIm Hannon jmhannon@........ Date: Fri, 05 Nov 1999 17:40:08 -0600 Edward Cranswick wrote: > PSN- > Having no techno-smarts left, I cannot talk much about hardware/software > and all I can do is wave my arms in an attempt to motivate the building of > strong motion sensors. The bottom line is that strong motion sensors operate in > the range of groundmotion where the rubber of earthquakes hits the road of > public consciousness. We have just finished an intial report on what we did in > Turkey with respect to strong motion studies, and the website > -Edward > > -- > Edward Cranswick Tel: 303-273-8609 > US Geological Survey, MS 966 Fax: 303-273-8600 > PO Box 25046, Federal Center cranswick@........ > Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". > Edward, You might be able to answer one Techie question I have about strong motion sensors. What Upper frequency response would be desirable? -- Jim Hannon http://soli.inav.net/~jmhannon/ 42,11.90N,91,39.26W WB0TXL _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Why a duck? Re: Strong motion sensor design From: barry lotz gbl@....... Date: Fri, 05 Nov 1999 18:23:02 -0800 Ted As a side note, There is a soil structure interaction to be considered on larger buildings. The tail can partially wag the dog. Regards Barry Doug Crice wrote: > ted@.......... wrote: > > > >> The question is, should you put the strong motion sensor in the attic so > > less of the house will fall on it? > > > > I'm relatively sure you're speaking tounge-in-cheek, but your first > strong-motion sensor should be placed on solid (or what passes for solid > in your area) ground. If you put the sensor in the structure, > especially the attic, it will record the natural resonances of the > building, not the ground spectra which are of interest to structural > engineers and microzonation enthusiasts. > > Large high rise buildings typically have at least three strong-motion > seismographs, one in the basement, one in the roof and one in the > middle, wired together with a common time base. The purpose is of > course to record the driving force in the basement and the structural > response of the building to the shaking. It's a tool for better > aseismic design of structures. > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: VRDT vs magnetism From: S-T Morrissey sean@........... Date: Sat, 6 Nov 1999 00:55:29 -0600 (CST) Jim, On Oct 21 you asked about my concerns of the effect of external DC magnetic fields on the VRDT. This is in the context of my remarks about keeping the VRDT a sufficient distance from the large feedback magnet, in this case, the large magnet from a 10" stereo woofer. The problem arises because of the all-ferrous construction necessary for the VRDT to work as an inductive bridge. The problem arises when the moving or sensing vane gets magnetized by induction and is attracted to the outer transformer cores. It WILL work with a non-ferrous vane, but at about 1/100th of the sensitivity, probably by eddy-current power absorbtion. Having the vane magnetized introduces an astatic instability that the feedback tries to "play" with, making noise. Since the vane is magnetized by moving it in proximity to the large magnet, I demagnetize it with a tape-head demagnetizer after it is installed. along with the ferrous cores. (a #10 wire loop in a solder gun will also work, with care, or course.) There is also an induced magnetism caused simply by being within the fringing field of the large permanent magnet: it magnetizes the transformer cores as well as the vane. It can be minimized by installing the VRDT so the axis of the cores is parallel and symmetric to the fringing field. This is usually the case with a VBB seis if both the VRDT and the magnet are in the same plane. Magnetic shielding can also be used. I have used small fruit cans around the magnet to contain the fringing fields, and square spice cans around the VRDT to shunt the stray fields around it. This will allow proximities of less than an inch to the permanent magnet; note that the shield cans must not actually touch the magnet structure. In the STM-8 vertical, the VRDT is about 4" from the bottom of the magnet, and doesn't seem to have a problem. In a new instrument with a rare-earth disk magnet, they will be 2" apart, so I am planning on a shield around the magnet assembly. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Hector Mine Events From: Karl Cunningham karlc@....... Date: Sat, 06 Nov 1999 09:43:27 -0800 Hi All -- I have finally caught up with the myriad aftershocks from the Hector Mine earthquake. My force-balance instrument detected around 1000 aftershocks during 15 or so days the month of October. I've placed a zip file on my web site that contains all the events files for the month of October, if anyone is interested. It is about 4MB in size. The .KC1 files are from the velocity output, and the .KC2 files are acceleration. The url for the file is http://www.jps.net/karlc/oct_events.zip Larry will be putting some selected event files on the PSN events archive. Karl Cunningham La Mesa, CA. PSN Station #40 karlc@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Why a duck? Re: Strong motion sensor design From: RADIOTEL@....... Date: Sat, 6 Nov 1999 20:45:48 EST Does EMON7 support the Radio Shack Digital Multimeter. I understand that it is a 12 bit unit and is now on sale for $49.95. Jim Allen Cerritos, Calif. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Copper plate damping From: Marchal van Lare vanlare@.............. Date: Sun, 7 Nov 1999 14:30:46 -0500 Hi all, For a long time I considered to use oil to damp my Lehman. I find it a quite messy business though. I want to use copper plate damping. I suppose the thinner the plate, the more damping it gives. Is this correct? Does the size of the plate matter? May be anyone knows other ways to dampen a seismograph? Thanks in advance. Best regards, Marchal van Lare -Nieuwvliet, The Netherlands= _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Copper plate damping From: JIm Hannon jmhannon@........ Date: Sun, 07 Nov 1999 14:27:11 -0600 Marchal van Lare wrote: > Hi all, > > For a long time I considered to use oil to damp my Lehman. > I find it a quite messy business though. > > I want to use copper plate damping. I suppose the thinner the plate, > the more damping it gives. Is this correct? Does the size of the plate > matter? > > May be anyone knows other ways to dampen a seismograph? > > Thanks in advance. > > Best regards, > > Marchal van Lare > -Nieuwvliet, The Netherlands > _____________________________________________________________________ Damping occurs with the copper plates due to the current generated in the plates by the magnetic field. Thinner plates will have a higher electrical resistance and hence less current and hence less damping. Actually the difference is small enough to not worry about the thickness of the plates. The plate needs to big enough to intercept the magnetic field of the magnet you are using for the damping or just a little larger than the magnet. The amount of damping can be adjusted by changing the distance from the plate to the magnet or magnets. -- Jim Hannon http://soli.inav.net/~jmhannon/ 42,11.90N,91,39.26W WB0TXL _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: S G Seismo. From: Al Frielink allink@........... Date: Sun, 07 Nov 1999 17:33:08 -0500 To All In making an S G Seismometer is there any reason why the coil/magnet combination couldn't be used as the sensor used in my Lehman? I enjoy reading the e-mail from the PSN. Thanks. Al. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: PSN WEB SITE From: RADIOTEL@....... Date: Sun, 7 Nov 1999 18:11:25 EST Is PSN web site down? I just attempted to access it a few minutes ago and received a message that Internet Explorer could not connect to it at this time. Jim Allen Cerritos, Calif. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: low gain for 16-bit adc From: barry lotz gbl@....... Date: Sun, 07 Nov 1999 19:09:34 -0800 Sean Thomas Thanks for the explaination. The numbers are much easier for me to understand. What I'm trying to work with is the sensor in my garage and the computer 30' away in the house. The 6-pole LP in the house is to eliminate the noise in the shielded wire. Is there an optimum load resistor in the house which I should use to minimize noise from the low current? I currently (no pun intended) use a 20-30k load resistor on the cable end in the house. Regards Barry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Lehman damping From: S-T Morrissey sean@........... Date: Sun, 7 Nov 1999 23:57:41 -0600 (CST) Marchal, Hydraulic and eddy-current damping were mainly used on mechanical direct-recording seismometers of decades ago. Some hybrid moving- coil sensors were made, though. The Sprengnether "H" series of the late 40's had a moving-coil output for a galvanometer and a copper bar damper. The bar is about 2" square and 3/8" thick, since thicker provides for greater induced currents. The magnet had a shunting mechanism to vary the field and hence the damping. However, the damping was not very predictable, and varied with the position of the copper bar in the gap of the large U channel magnet. And a word about the word damp: To damp is to attenuate the amplitude of a repetitive motion; ie: damping. To dampen is to throw water on something: dampening a towel. Here is an edited repeat of a previous mote about damping seismometers: Re electromagnetic damping: Most moving coil seismometers only use resistive damping. If properly calculated, no other damping is needed or should be used. THis uses the motion of the main signal coil to generate a voltage that induces a current in a resistor connected in parallel with it to dissipate the energy of the motion and thus damp it. It is very predictable and easy to do. The loss of signal output that results is easily made up by additional (about x2) gain of the amplifier. Damping is generally expressed in relation to what is needed for "critical" damping, which means that after a step input, the output returns to a zero output voltage as rapidly as possible without overshooting. This damping has a value of 1. But it has a price, namely significant loss of the signal in the damping resistor. So generally damping is set at 0.8 of critical, which cuts the loss by about half, but the overshoot to an impulse input is minimal. Much less than 0.8, the natural period of the seismometer will dominate the response. On the other hand, if a fairly broad response is desired, and the seis and the amplifier have enough output and/or gain, damping as high as 2 can be used. Note that actually calculating the proper resistor depends on how much you know about the geophone or seismometer. The manufacturers data will sometimes even give the value for critical damping. But if the geophone is a mystery device, a generally good approximation is to measure the resistance of the coil and use that value for the damping resistor. To calculate the value of the damping resistor to be used, one first has to know or determine the open circuit damping, called Bo. It is the mechanical air-dashpot function of the coil movement, and is often listed in the specifications for the seismometer. For most seismometers, it ranges from 0.2 to 0.4, where a value of 0.8 is for critical damping. It can also be determined from the logrithmic decrement of the free oscillations of the undamped seismometer. For starters, it can be assumed to be 0.3. Then the motor constant and resistance of the main coil have to be determined or found in the specifications. For a home=made device, this is done by balancing an added weight with a measured current. If 1 gram is balanced by 1 ma, the constant is 9.8*1gm/1ma Newtons/Ampere. Conveniently enough a Newton/Ampere = a Volt/meter/second = V*sec/m. For a horizontal, a V shaped thread with 90 degrees at the bottom will pull each upper end sideways with half the weight hung at the bottom. The electromagnetic damping Bem needed is determined by subtracting the Bo from the required total Bt. Bem = Bt - Bo (If you don't know your Bo, use a value of 0.3) Then the damping resistor is calculated by: Bem = G^2 / (2*omega*M*(Rs + Rd), or Rd = [G^2 / (Bem*2*omega*m)] - Rs Where Bem is the electromagnetic damping, G is the main coil constant, omega is the angular frequency, equivalent to 2*pi/Tn, where Tn is the natural period, and M is the mass. For an L4-C, with a 5500 ohm coil, with G = 270 V/m/sec, Bo = 0.27, we want Bt to be 0.77, so Bem = 0.5, M = 1 kgm, omega = 2*pi (1 second) we calculate a damping resistor Rd of 6102 ohms for critical damping. For an S5000 Long Period Seis, with a 500 ohm coil, G = 100 V/m/sec, Bo = 0.1, we want a flatter response with Bt = 1, so Bem = 0.9, omega = 2*pi/15 (seconds), M = 11 kg, we calculate a resistor of 705 ohms for Bt = 1 (the LP is over damped for a broader response). For an HS-1 4.5 hz geophone with a 1250 ohm coil, G = 41 V/m/sec, and Bo = 0.28; we want critical damping with Bt = 0.8, so Bem = 0.52, omega = 2*pi*4.5 (hz), M = 0.022kg, we calculate Rd = 1348 ohms. This method of damping is the only method currently being used on velocity sensors. The method is so exact that often the resistor for Rd is installed inside the smaller geophones at the factory. Metal-film resistors are used for lower noise. When one is connecting a seismometer to an amplifier with a low input impedance Ra, that value is in parallel with the seismometer, so must be taken into account. So if Ra = 10k ohms, and Rd is to be 5k ohms, the actual resistor to be used is Rs = Rd*Ra/(Ra-Rd), or in this case Rs = 10k ohms. Generally very high input impedance amplifiers are not used because of noise considerations, so this detail is often overlooked. Unfortunately I have no idea what the constants for a Lehman might be. I note that the coil is 1/4 pound of # 34 wire which has 8310 feet per pound and 2168 ohms per pound at 20 deg.C. So assuming the coil is about 500 ohms, I would try a damping resistor of about 1000 ohms, unless you can determine or know the constant G of the main coil and can calculate the value. You will need to know the mass and the period of the seismometer. With this type of damping, the response should be flat to velocity from roughly the natural period to whatever low-pass filter you have in your amplifier. (BTW another place to check to see if the shorter p-wave phases are being filtered out). Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Why a duck? Re: Strong motion sensor design From: Edward Cranswick cranswick@........ Date: Sun, 07 Nov 1999 23:07:27 -0700 Jim- The minimum upper frequency of the band of flat response is about 20 Hz. Most sites where there is strong motion have an f_max of 5-10 Hz, i.e., a frequency above which earthquake-produced ground accelerations crash because of the low-pass filtering effects and site response of the Earth. Above this frequency, the spectral amplitude steeply decays with increased frequency at rates of 12-24 dB/octave (6 dB is a factor of 2 in amplitude, i.e., a bit-amp; 1 octave is a factor of two in frequency), i.e., f**-2 to f**-4. It is important that the instrument have a flat response at least one octave above f_max so that one can clearly distinguish between instrument and Earth response. At sites that are on rock very close to the epicenter -- Mark Halliday has a PSN station at site like this in Ben Lomond, near Santa Cruz, CA -- f-max will be higher, and the instrument should have a flat response to ~50 Hz. -Edward JIm Hannon wrote: > Edward Cranswick wrote: > > > PSN- > > Having no techno-smarts left, I cannot talk much about hardware/software > > and all I can do is wave my arms in an attempt to motivate the building of > > strong motion sensors. The bottom line is that strong motion sensors operate in > > the range of groundmotion where the rubber of earthquakes hits the road of > > public consciousness. We have just finished an intial report on what we did in > > Turkey with respect to strong motion studies, and the website > > -Edward > > > > -- > > Edward Cranswick Tel: 303-273-8609 > > US Geological Survey, MS 966 Fax: 303-273-8600 > > PO Box 25046, Federal Center cranswick@........ > > Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". > > > > Edward, > You might be able to answer one Techie question I have about strong motion sensors. > What Upper frequency response would be desirable? > -- > Jim Hannon > http://soli.inav.net/~jmhannon/ > 42,11.90N,91,39.26W > WB0TXL > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Copper plate damping From: John Hernlund hernlund@....... Date: Mon, 08 Nov 1999 04:00:52 -0700 (MST) On Sun, 7 Nov 1999, Marchal van Lare wrote: > I want to use copper plate damping. I suppose the thinner the plate, > the more damping it gives. Is this correct? Does the size of the plate > matter? The thicker plate will damp more, because its conductivity will be higher. Another thing you can do to adjust the damping is to cut slits in the copper, which block eddy currents larger than the distance between two slits from developing. This reduces the damping effect. Other types of cuts will work also, like simple perforation. The trouble with this type of damping is that it is difficult to quantify...you can measure it later on but adjustment of the damping for fine tuning of the instrument is surely a hassle. The most easily adjusted damping is the resistor across coils arrangement. John Hernlund E-mail: hernlund@....... WWW: http://www.public.asu.edu/~hernlund/ ****************************************************************************** _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Copper plate damping From: Marchal van Lare vanlare@.............. Date: Mon, 8 Nov 1999 07:44:37 -0500 On Mon, 8 Nov 1999, John Hernlund wrote: >The most easily adjusted damping is the resistor across coils arrangement.< Hi Jim, Sean, John and all, How is this resistor across coils arrangement made? = Best regards, Marchal van Lare -Nieuwvliet, The Netherlands _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: large event it's running From: "Francesco" franuc@...... Date: Mon, 8 Nov 1999 18:21:48 +0100 Large event is coming from 30' Preliminary location: India-Pakistan border region M ~7 Sations: Osimo, Lucca, Italy Francesco
Large event is coming from = 30'
Preliminary location: India-Pakistan = border=20 region
M ~7
 
Sations: Osimo, Lucca, = Italy
 
Francesco
Subject: Re: S G Seismo. From: meredith lamb mlamb1@.......... Date: Mon, 08 Nov 1999 10:24:30 -0800 Al Frielink wrote: > To All > In making an S G Seismometer is there any reason why the coil/magnet > combination couldn't be used as the sensor used in my Lehman? > I enjoy reading the e-mail from the PSN. > Thanks. > Al. Al, It would work for short period use, generally related to the period of your S-G, but I suspect the longer period phases would be greatly attenuated, due solely to the mechanical nature of the S-G compared to the mechanical "amplification" arrangement on the Lehman. Most S-G's use sensors with position displacement sensing and not coil and magnet induction; to sense the longer periods. On the other hand, it would make it interesting to try, as I've never heard of a coil and magnet induction S-G, as of this writing. I would think its "range", would be much greater than a geophone due to its longer period....unless you get like a 1hz geophone....in comparison to the "normal" 8-10-12-20 hz typical amateur geophone. If you live in a seismic area, the coil and magnet might be interesting to try; but if you don't, I would suggest trying other methods of sensing. If you live in a city/town with or near alot of seismic noise sources, you will see alot of false triggers with coil & magnet sensing. With a displacement sensor, and earthquakes "L" waves, real records will be much more obvious. Personally, I think the S-G's are the easiest route for amateurs, and with care in construction they can mimic the output of alot of coil & magnet horizontal instruments. The "zeroing" factor is simple gravity for S-G's, and with its much smaller size, the tilt factor and leveling adjustments is alot less frequent than a "Lehman". I use a linear (mostly) Hall sensor circuit myself, created by Robert Lamb, in two S-G's. Going further, one could even incorporate more than one type of sensor in a single S-G, with additional lead in wires compensation in construction.....you could try induction, capacitive, Hall, optical light sensors or any other possible method combination. Take care, Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Copper plate damping From: RADIOTEL@....... Date: Mon, 8 Nov 1999 22:05:37 EST Hi Marchal I have tried resistive damping but with limited success. I am currently using copper plate damping with a 1/4x4"x2" copper plate on my Lehman with a magnet on each side of the plate. This arrangement has thus far proven to be the easiest for me in obtaining adjustments, etc. However, I do plan to experiment with resistive damping in the future. Lots of luck in your efforts - Let us know which method worked for you. Jim Allen Cerritos, Calif. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Francesco's large event coming from 30' From: "Danie Overbeek" danieo@............ Date: Tue, 9 Nov 1999 10:25:36 +0000 Hi all I can confirm Francesco's report of large event: Arrival of P wave buried in microseisms but looks like 1999 11 08 1657 UT Arrival of S wave 1999 11 08 1706 UT My station is at E 28d 8' 20" S 26d 9' 15" Sensor: Golitsyn pendulum + moving coil transducer. Recorder, drum at 500 mm/hour Cheers all Danie Overbeek. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Copper plate damping From: jmhannon@.................... Date: Tue, 9 Nov 1999 07:13:53 -0600 RADIOTEL@....... on 11/08/99 09:05:37 PM Please respond to PSN-L Mailing List To: psn-l@.............. cc: Subject: Re: Copper plate damping Hi Marchal I have tried resistive damping but with limited success. I am currently using copper plate damping with a 1/4x4"x2" copper plate on my Lehman with a magnet on each side of the plate. This arrangement has thus far proven to be the easiest for me in obtaining adjustments, etc. However, I do plan to experiment with resistive damping in the future. Lots of luck in your efforts - Let us know which method worked for you. Jim Allen Cerritos, Calif. _____________________________________________________________________ One thing you will find about resistive damping is that if the coupling between the coil and the magnet is insufficient you will be unable to get enough damping even with the coil shorted. If this situation occurs you should try and improve the coupling as it will increase the sensistivity of your instrument also. Jim Hannon _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Francesco's large event coming from 30' From: Greg ghost@............. Date: Tue, 09 Nov 1999 11:00:59 -0700 Danie Overbeek wrote: > My station is at E 28d 8' 20" > S 26d 9' 15" Isn't that South Africa? If it is, and I think it is, that's got to be a real plus for the PSN. What's next Greenland? Southern Chile? Japan? > Sensor: Golitsyn pendulum + moving coil transducer. > Recorder, drum at 500 mm/hour Could you take a picture or give a little more explanation about your instrument please. I don't think I've heard of it before. Also, if you could describe the soil a little, please. Thanks, Greg _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: resistive damping From: S-T Morrissey sean@........... Date: Tue, 9 Nov 1999 12:18:39 -0600 (CST) Marchal, Taking into mind what Jim H. has pointed out, resistive damping is a much simpler approach than mechanical eddy-current damping in that it does not require any additional construction on your seismometer. But, as Jim points out, it does require a strongly coupled coil-magnet arrangement, and it also requires that the resistance of the coil be low enough to pass the damping current. Some long-period seismometers were equipped with 100 000 ohm coils to produce lots of output voltage, but had to be provided with separate 500 ohm coils for damping. So how do you use resistive damping? You can plug parameters into the formulas, or you can experiment. The damping resistor is simply connected across the output terminals of the signal coil. If you use a speaker coil/magnet with a 4 ohm coil, the damping resistor has to be connected right at the coil, since the external wiring resistance will be more than the 4 ohms needed to damp the seis. To see if your coil/magnet is strong enough to do the job, simply short it at the output terminal. Introduce a small offset and watch the mass move: it should be very sluggish, almost like it was dragging. Then you can replace the short at the output with trial resistors and again observe the effect. I would start with a resistor about equal in value to the resistance of the coil, which you should measure. If the coil is 500 ohms, I would try values from 300 to 1500 ohms in about 100 to 200 ohm steps, or use a variable resistor. With proper damping, the mass should at first move quickly about half the distance it will eventually travel, then slow down and stop and move backwards just ever so slightly. You can observe this with the seismometer pointer or in the output of your digitizer. A very slight (about 3%) overshoot will indicate critical damping, which provides the most output but a very narrow-band response. Less overshoot will be slightly overdamped, with a broader response (a 15 second seis will more easily record 60 second waves), but at a reduced output, which should be no problem with additional amplifier gain.. If you cannot get critical damping with even very low resistance, like 100 ohms, either the coil resistance is too high from using too much very fine wire, or the winding doesn't adequately fill the air gap of the magnet. The air gap must be predominately filled with turns of the coil and not the form for the coil or lots of clearance. The coil must be wound slowly turn-beside-turn, not scramble wound, to get the maximum number of turns inside the gap. And any form used must take up a minimum of space and fit closely to the magnet, preferably with clearances of less than 1 mm. I will later describe a method I use to wind a very compact coil on a temporary form that allows only windings of the coil to fill the magnet gap. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Anecdotal story on magnetic detection of 10/16/99 Mojave quake From: "Charles R. Patton" charles.r.patton@........ Date: Tue, 09 Nov 1999 10:51:07 -0800 ** Anecdotal story on magnetic detection of 10/16/99 Mojave quake ** The following was a letter to the Nov. '99 issue of LOWDOWN, the publication of the Longwave Club of America, and is posted with permission from the author. I thought the group might be interested in the equipment and results. Charles R. Patton ---quoted text follows--- Shake, rattle, and roll. Jay Miller (WA5WHN; wa5whn@............. wonders whether he had an encounter with mother earth's magnetic personality at his home in Albuquerque, NM, on October 16. "A few weeks ago, I had ordered two G8317 EMF detectors from Electronic Goldmine in Scottsdale, AZ {1-800-445-0697 http://www.goldmine-elec.com}. I think they were less than $3.00/each. I did not get the time to test and profile the circuit board. I had plugged a 9VDC battery into both of them and they both seemed to function. While walking in front of my son's audio system, the lights began to light-up and modulate with the change in audio frequencies. This little device does have a directional antenna. Figuring it was sensitive enough to pick up my son's stereo speaker magnets, I had placed the device into a clear plastic case, wired up a 9 VDC supply and left it on facing east-west. Sort of a green LED night light in the bedroom." "Well, this morning at 4 AM MDT, the detector was flashing 3 Green LEDs consistently. I had noticed the flashing lights, and awakened my wife to show her. While facing north/south or vertical, the indicator LEDs would turn off. However, when I would return to facing the little antenna east/west, the same 3 LEDs would light up. I went outside to see if I could spot anything visually. Nothing. When I turned on the radio, I heard there was a 7.0 earthquake in the Mojave Desert. I think this little detector may have picked it up." "Did anyone else have a similar experience?" .... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: S G Seismo. From: Al Frielink allink@........... Date: Tue, 09 Nov 1999 20:16:40 -0500 Meredith Thanks for the quick response to my question. Living in New Jersey I don't see a great deal of seismic activity so I will stick to the normal S G construction. I've had my Lehman running since 1981 and have logged quite a few earthquakes. Thanks again. Al. At 10:24 AM 11/8/99 -0800, you wrote: >Al Frielink wrote: > > > To All > > In making an S G Seismometer is there any reason why the coil/magnet > > combination couldn't be used as the sensor used in my Lehman? > > I enjoy reading the e-mail from the PSN. > > Thanks. > > Al. > >Al, > >It would work for short period use, generally related to the >period of your S-G, but I suspect the longer period phases >would be greatly attenuated, due solely to the mechanical >nature of the S-G compared to the mechanical "amplification" >arrangement on the Lehman. > >Most S-G's use sensors with position displacement sensing and >not coil and magnet induction; to sense the longer periods. > >On the other hand, it would make it interesting to try, as I've >never heard of a coil and magnet induction S-G, as of this >writing. I would think its "range", would be much greater than >a geophone due to its longer period....unless you get like a >1hz geophone....in comparison to the "normal" 8-10-12-20 hz >typical amateur geophone. > >If you live in a seismic area, the coil and magnet might be >interesting to try; but if you don't, I would suggest trying other >methods of sensing. If you live in a city/town with or near alot >of seismic noise sources, you will see alot of false triggers with >coil & magnet sensing. With a displacement sensor, and >earthquakes "L" waves, real records will be much more obvious. > >Personally, I think the S-G's are the easiest route for amateurs, >and with care in construction they can mimic the output of alot >of coil & magnet horizontal instruments. The "zeroing" factor >is simple gravity for S-G's, and with its much smaller size, the >tilt factor and leveling adjustments is alot less frequent than a >"Lehman". I use a linear (mostly) Hall sensor circuit myself, >created by Robert Lamb, in two S-G's. > >Going further, one could even incorporate more than one type >of sensor in a single S-G, with additional lead in wires >compensation in construction.....you could try induction, >capacitive, Hall, optical light sensors or any other possible >method combination. > >Take care, > >Meredith Lamb > > > > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Radio Shack fine coil examples From: meredith lamb mlamb1@.......... Date: Tue, 09 Nov 1999 20:26:43 -0800 Radio Shack has an example of generally fine wound wire on coil forms. Its their #278-13458, which is an assortment of 3 enamel coated magnet wire. The package I have uses this side-by-side wire wound method, but its really machine wound. One coil uses 40 ft (12.2m) of 22 gauge wire (~.7 ohms). One coil uses 75 ft (22.8m) of 26 gauge wire (~3.3 ohms). One coil uses 200 ft (60.9m) of 30 gauge wire (~22.6 ohms). The coil forms are some form of white plastic, about .088" to .1" thick; which don't seem to deform or vary on the inside diameter very much ~ .803 to .807". The thought of using a 3/4" (.750") magnet or pole inside has occurred, as a possible copper damping means, especially with the larger gauge wire. The end flanges are obviously larger in diameter than any of the wire sizes wound on them, at, 1.975". This plastic appears to be tough to cut, and probably tin shears might work somewhat. They are molded plastic, and have the halfs junction with slight extrusions of plastic, which seems to be fairly easy to smooth off. The plastic coil spindles seem to be the toughest I've seen over the years. They are interesting in themselves, and possible seismic uses are varied. They have been around for some time, but I think they could be interesting to see for some, in conjunction with the Sean-Thomas Morrissey recent messages on coils. Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Radio Shack fine coil examples From: "Steve Hammond" shammon1@............. Date: Wed, 10 Nov 1999 09:01:48 -0800 Meredith, I can confirm that these plastic forms hold their shape. I used these for both of my Lehmans and a couple of other seismographs over the years. I also found that a cow magnets work very well with this form and if you fill it with #54 magnet wire you end up with a coil in the 16K range. The forms seem withstand the elements well. One other point, if you wind extremely fine magnet wire onto these forms, be sure and sand the edges smooth using an fine paper. Regards, Steve Hammond PSN Aptos, California ----- Original Message ----- From: meredith lamb To: Sent: Tuesday, November 09, 1999 8:26 PM Subject: Radio Shack fine coil examples > Radio Shack has an example of generally fine wound wire on > coil forms. Its their #278-13458, which is an assortment of 3 > enamel coated magnet wire. The package I have uses this > side-by-side wire wound method, but its really machine wound. > > One coil uses 40 ft (12.2m) of 22 gauge wire (~.7 ohms). > One coil uses 75 ft (22.8m) of 26 gauge wire (~3.3 ohms). > One coil uses 200 ft (60.9m) of 30 gauge wire (~22.6 ohms). > > The coil forms are some form of white plastic, about .088" > to .1" thick; which don't seem to deform or vary on the inside > diameter very much ~ .803 to .807". The thought of using a > 3/4" (.750") magnet or pole inside has occurred, as a possible > copper damping means, especially with the larger gauge wire. > > The end flanges are obviously larger in diameter than any of > the wire sizes wound on them, at, 1.975". This plastic appears > to be tough to cut, and probably tin shears might work somewhat. > They are molded plastic, and have the halfs junction with slight > extrusions of plastic, which seems to be fairly easy to smooth > off. The plastic coil spindles seem to be the toughest I've seen > over the years. > > They are interesting in themselves, and possible seismic uses > are varied. They have been around for some time, but I > think they could be interesting to see for some, in conjunction > with the Sean-Thomas Morrissey recent messages on coils. > > Meredith Lamb > > > > > > > > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: resistive damping From: Marchal van Lare vanlare@.............. Date: Wed, 10 Nov 1999 12:18:03 -0500 Hi Sean and others, I would like to experiment with resistors but what is the best way to do = so? Like in 'method A' or 'method B'? A. )------R----- ) R ) R )------R----- B. )------RRRRR----- ) = ) = )------RRRRR----- = -=3Dwiring )=3Dcoil R=3Dresistance = I hope my text-drawings are clear enough. Thanks in advance for your help. Marchal van Lare= _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: resistive damping From: jmhannon@.................... Date: Wed, 10 Nov 1999 11:38:34 -0600 Marchal, Method A is the correct way to connect the resistance. This is called placing the resistor in parallel with the coil. Your method B would be called placing resistors in series with the coil and will not provide any damping. Jim H _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: SETI From: twleiper@........ Date: Wed, 10 Nov 1999 13:26:45 -0500 As a group of individuals who obviously are used to waiting patiently over long periods time for results, and who also have computers that spend most of their "always on" time taking a few samples a second from the A/D card and "Flying through space" on the screen, I thought the PSN members would be excellent candidates for forming a team for the SETI@home project. This project out of Berkeley uses the wasted capacity of your Pentium 95 machine (or other platform) by giving you a screen saver program that crunches data downloaded via their server from the Arecibo Radio Observatory in PR. It crunches blocks of data about 300K in size and uses 16M of RAM while running. The CPU time required to process each block can be anywhere between hours and weeks depending upon your hardware, and the chance that you actually will get a block that proves to have the tiny CQ from ET is certainly several orders of magnitude lower than recording an M9 before the end of your life, or even that of keeping your Lehman centered for more than a month, so I think it would be the perfect challenge for most of us. The rewards from hopeless endeavors may never be explained... Anyway, go to: http://setiahome.ssl.berkeley.edu and download the software. There is plenty of help and project description on line. Larry could form a group (fill out an on-line form) for PSN and they even have free graphic links to drop on the PSN home page(s). Then PSN users could compete as a team with others such as the seti@SUN team that has processed almost a quarter million blocks with something like 190 YEARS of CPU time accumulated so far... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Series of Earthquakes in Fiji in news From: Doug Crice dcrice@............ Date: Wed, 10 Nov 1999 11:25:34 -0800 This link is a news item regarding a series of earthquakes in Fiji where previously they were unknown. http://asia.dailynews.yahoo.com/headlines/world/article.html?s=asia/headlines/991110/world/afp/Fiji_quakes_worry_authorities.ht ml _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: station maps/list updates From: "David A. Nelson" davenn@........ Date: Thu, 11 Nov 1999 14:58:00 +1300 hi all, been a crazy yr with 3 months out of new zealand, divorce and other things. I'm finally back on track. only last weekend finally got my SDR system back from my friend in another city to the north of me, who was using it whilst I was out of NZ. so I'm finally recording quakes again. ok the long awaited updated to the PSN station maps/database sorry for the delay: Bob Hammond and Nick Caporossi ur updates done Dennis Pope, Rex Klopfenstein, Jr. and Raul Alvarez you 3 have been added to the map and listings Ohhhhhh and Raul yes I gave u station #69 as per requested :)) welcome to u guys, thankyou for ur input, it is good to see the network still growing Dave Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 23 Duncan St., Dunedin, South Is.. New Zealand. http://www.seismicnet.com/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Francesco's large event coming from 30' From: "Danie Overbeek" danieo@............ Date: Thu, 11 Nov 1999 06:45:23 +0000 Date: Tue, 09 Nov 1999 11:00:59 -0700 From: Greg To: PSN-L Mailing List Subject: Re: Francesco's large event coming from 30' Reply-to: PSN-L Mailing List Danie Overbeek wrote: > My station is at E 28d 8' 20" > S 26d 9' 15" Isn't that South Africa? If it is, and I think it is, that's got to be a real plus for the PSN. What's next Greenland? Southern Chile? Japan? > Sensor: Golitsyn pendulum + moving coil transducer. > Recorder, drum at 500 mm/hour Could you take a picture or give a little more explanation about your instrument please. I don't think I've heard of it before. Also, if you could describe the soil a little, please. Thanks, Greg _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Danie replies: Greg is right about my location. It is midway between Johannesburg and its airport. The detector sits on a 4" thick concrete floor which in turn sits on a rock outcrop. Even so, ground tilt is present after soaking rain. Yes I can send photos if you can give me a postal address. I'll gladly give more details but am leaving for Australia in less than a week and hope to be back before the end of November. Cheers Danie. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: SDR NETWORK CONNECTION From: "Francesco" franuc@...... Date: Thu, 11 Nov 1999 13:16:14 +0100 From some weeks I have installed the SDR net connection, between an old = 486 (Win95) and a Pentium III (Win98), with the configuration reported = on SDR documentation. All works fine. Now, I noted a serius problem. Sometimes this is a black-out of dc and the two pc are down. When they restart, SDR (on 486pc) don't run because it unrecognized the = assigned map driver of the net (E:\events). In fact, the other pc it's = more slow to restart. So, all the system it's down until a manual operation. What's to do? Regards Francesco
From some weeks I have installed the = SDR net=20 connection, between an old 486 (Win95) and a Pentium III (Win98), with = the=20 configuration reported on SDR documentation.
All works fine.
 
Now, I noted a serius = problem.
 
Sometimes this is a black-out of = dc  and the=20 two pc are down.
When they restart,  SDR (on 486pc) = don't run=20 because it unrecognized the assigned map driver of the net (E:\events). = In fact,=20 the other pc it's more slow to restart.
So, all the system it's down until a = manual=20 operation.
 
What's to do?
 
Regards
Francesco
Subject: Re: SDR NETWORK CONNECTION From: Mauro Mariotti mariottim@...... Date: Thu, 11 Nov 1999 13:49:55 +0100 Apply a U.P.S. Bye Archimede At 13.16 11/11/1999 +0100, you wrote: >From some weeks I have installed the SDR net connection, between an old 486 (Win95) and a Pentium III (Win98), with the configuration reported on SDR documentation. >All works fine. > >Now, I noted a serius problem. > >Sometimes this is a black-out of dc and the two pc are down. >When they restart, SDR (on 486pc) don't run because it unrecognized the assigned map driver of the net (E:\events). In fact, the other pc it's more slow to restart. >So, all the system it's down until a manual operation. > >What's to do? > >Regards >Francesco > > > > > > > >
From some weeks I have installed the SDR net >connection, between an old 486 (Win95) and a Pentium III (Win98), with the >configuration reported on SDR documentation.
>
All works fine.
>
 
>
Now, I noted a serius problem.
>
 
>
Sometimes this is a black-out of dc  and the >two pc are down.
>
When they restart,  SDR (on 486pc) don't run >because it unrecognized the assigned map driver of the net (E:\events). In fact, >the other pc it's more slow to restart.
>
So, all the system it's down until a manual >operation.
>
 
>
What's to do?
>
 
>
Regards
>
Francesco
> _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: SDR NETWORK CONNECTION From: bc bruce@....... Date: Thu, 11 Nov 1999 08:37:31 -0500 A time delay relay would be one approach. Set the subdominant PC to come up 30 seconds or a minute after the dominant one. Another though, (untested mind you) put a software delay in the autoexec.bat file. Even though windows really use this I believe it still is executed prior to booting windows so you could insert sufficient delay there to allow the other computer to come up before continuing the boot sequence. Bruce At 01:16 PM 11/11/1999 +0100, you wrote: > From some weeks I have installed the SDR net connection, between an old > 486 (Win95) and a Pentium III (Win98), with the configuration reported on > SDR documentation. >All works fine. > >Now, I noted a serius problem. > >Sometimes this is a black-out of dc and the two pc are down. >When they restart, SDR (on 486pc) don't run because it unrecognized the >assigned map driver of the net (E:\events). In fact, the other pc it's >more slow to restart. >So, all the system it's down until a manual operation. > >What's to do? > >Regards >Francesco _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: From: Oguzhan Aydogmus-HRB oaydogmus@................ Date: Thu, 11 Nov 1999 17:10:46 +0200 > Do you know magnitude aftershock in Izmit,Turkey 20 minutes ago _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: R: From: "Giovanni Rotta" rottag@.......... Date: Thu, 11 Nov 1999 16:43:05 +0100 I have a Ml. 6.1. Regards, Giovanni Giovanni Rotta Via F. Pizzigoni, 10 33010 Resia (Udine) I Lat. 46.373 N Long. 13.305 E rottag@.......... http://www.resianet.org ----- Original Message ----- From: Oguzhan Aydogmus-HRB To: 'PSN-L Mailing List' Sent: Thursday, November 11, 1999 4:10 PM > > > Do you know magnitude aftershock in Izmit,Turkey 20 minutes ago > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L > Subject: Re: R: VIRUS ALERT From: The Lahrs JohnJan@........ Date: Thu, 11 Nov 1999 09:09:51 -0700 I just received the virus W32/Ska.exe in the file Happy99.exe from "Giovanni Rotta" DO NOT RUN Happy99.exe. Delete it from your computer. This was a good test of my McAfee antivirus software, as it caught the virus and gave me a warning before I had a chance to run the attachment. Of course I would never run an attachment in any case. John At 04:58 PM 11/11/99 +0100, you wrote: > >Attachment Converted: "e:\EUDORAPRO\EUDORA\Attach\Happy99.exe" > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L > * John C. and Jan H. Lahr * * JohnJan@........ * * 1925 Foothills Road * * Golden, Colorado 80401-1718 * * (303) 215-9913 * * http://lahr.org/john-jan * * http://giseis.alaska.edu/lahr * _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: R: VIRUS ALERT From: bc bruce@....... Date: Thu, 11 Nov 1999 11:21:22 -0500 Thank you, At 09:09 AM 11/11/1999 -0700, you wrote: >I just received the virus W32/Ska.exe in the file Happy99.exe from >"Giovanni Rotta" > >DO NOT RUN Happy99.exe. Delete it from your computer. > >This was a good test of my McAfee antivirus software, as it >caught the virus and gave me a warning before I had a chance to >run the attachment. Of course I would never run an attachment >in any case. > >John > >At 04:58 PM 11/11/99 +0100, you wrote: > > > >Attachment Converted: "e:\EUDORAPRO\EUDORA\Attach\Happy99.exe" > > > > > >_____________________________________________________________________ > > > >Public Seismic Network Mailing List (PSN-L) > > > >To leave this list email listserver@.............. with the body of the > >message: leave PSN-L > > > >* John C. and Jan H. Lahr * >* JohnJan@........ * >* 1925 Foothills Road * >* Golden, Colorado 80401-1718 * >* (303) 215-9913 * >* http://lahr.org/john-jan * >* http://giseis.alaska.edu/lahr * > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: R: turkey aftershock From: "Francesco" franuc@...... Date: Thu, 11 Nov 1999 17:04:36 +0100 By our stations, the preliminary magnitude is ML 5.9 Francesco, I.E.S.N. Italy _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: R: SDR NETWORK CONNECTION From: "Francesco" franuc@...... Date: Thu, 11 Nov 1999 17:08:32 +0100 Wich string or command can I use in autoexec.bat or in subdominance pc for time delay? Francesco _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: R: SDR NETWORK CONNECTION From: Karl Cunningham karlc@....... Date: Thu, 11 Nov 1999 09:26:21 -0800 Download a file called sleep.exe, from Microsoft. It normally comes in the Windows NT Resource Kit, and works just fine in Windows 98 (I haven't tried it in Windows 95, but I suspect it will work). You can include it in a batch file to pause processing by a specified number of seconds. For instance, sleep 30 in a batch file will delay processing by 30 seconds. In other words, the sleep program just waits for 30 seconds, then ends so processing of the batch file can continue. You can download sleep.exe from: ftp://ftp.clinet.fi/.3/ftp.microsoft.com/Products/Oemtest/v1.1/Winstress/str ess/i386/stress/nwcs/nwstress/SLEEP.EXE This URL is probably longer than will fit on one line in your email program. If so you'll have to copy and paste to get the whole URL into your browser. If you have trouble downloading it, I can send it to you as an email attachment. Karl Cunningham La Mesa, CA. PSN station #40 karlc@....... At 05:08 PM 11/11/1999 +0100, you wrote: >Wich string or command can I use in autoexec.bat or in subdominance pc for >time delay? > > >Francesco > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: SDR NETWORK CONNECTION From: twleiper@........ Date: Thu, 11 Nov 1999 15:01:03 -0500 Besides the obvious need for a couple UPS units, you could also change your network settings. On your 486/95 machine which is mapping the P/98 drive, go into right click on "network neighborhood" and click properties. Then double-click on "Client for microsoft networks" and choose the "quick logon" option. This will prevent the mapping of the drive until SDR actually needs to use the connection to report an event. If SDR checks the connection upon start-up (I don't know because I don't use it) you will need an application that delays the startup of SDR. I have such an application which is run in the startup group, and it can execute multiple applications in order at ten second intervals. We use this in some of our systems which run applications that use more RAM while starting than while running, so by launching them one at a time fewer resources are required. Another utility we have can launch SDR with a command from the OTHER machine, so when the slower machine finally boots up it can send the command to launch SDR to the other. There are also several other functions of this application, such as re-booting, checking running applications, maintaing disk space and testing network connections... all from the remote machine. Let me know if you need any of this stuff. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Golitsyn pendulum From: "Ed Thelen" ethelen@........ Date: Thu, 11 Nov 1999 12:05:47 -0800 > > Sensor: Golitsyn pendulum + moving coil transducer. .... > Could you take a picture or give a little more explanation about your > instrument please. I don't think I've heard of it before. It seems the original "Lehman" instrument was developed a long time ago by Boris Golitsyn. Quoting from http://psn.quake.net/sgsenstxt.html which quotes from September, 1975 Scientific American Magazine "The Amateur Scientist" the following " When an amateur builds a seismometer, he is most likely to choose an instrument of the electromagnetic type developed in 1906 by Boris Borisovich Golitsyn, a physicist who was also a prince of the Russian Empire. A seismometer of this type picks up earthquake waves with a pendulum that supports a coil of insulated wire between the poles of a magnet rigidly linked to the earth. The relative motion between the magnet and the coil caused by tremors in the earth generates corresponding electric currents in the coil. The currents can be amplified to operate a pen recorder. " As best I can determine, Lehman in the late 1970's described a particular two vertical strut instrument that he made. Somehow his name stuck to the generic "garden gate" or " Golitsyn" type instruments ever since. I believe that it is mostly PSN folks that use the term Quoting from http://www.seismicnet.com/info/homefaq.txt "CONSTRUCTION INFORMATION - INSTRUMENTS & SENSORS: A very good article was published several years ago in the AMATEUR SCIENTIST by Scientific American. Titled, "How To Build A Simple Seismograph to Record Earthquake Waves at Home" by Jearl Walker. The article was published in Scientific American, 1979, v. 241, No.1, pg 152-161. It described the construction of a horizontal seismic sensor and preamp circuit designed by James D. Lehman. At the time, Mr. Lehman was with the Physics Dept., James Madision University, Harrisonburg, Va., 22807. " The June 1953 issue of Scientific American, "The Amateur Scientist", conducted by Albert G. Ingalls, described a Golitsyn type seismometer - using a vacuum tube amplifier. The availability of amplifiers removed the need for the large mass and some "interesting" circuits to facilitate recording of the early 1900s electrical or mechanical designs. Certainly by 1953, many commercial seismometers were using the "garden gate" or " Golitsyn" design. Most of these designs use a single rigid vertical strut. I have no idea what advantage the Lehman two small vertical strut design has other than the local hardware store might not have large enough diameter copper tubing. Cheers Ed Thelen _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: From: Edward Cranswick cranswick@........ Date: Thu, 11 Nov 1999 13:11:43 -0700 Oguzhan- NEIC says: 99/11/11 14:41:24 40.80N 30.26E 10.0 5.6Ms TURKEY -Edward Oguzhan Aydogmus-HRB wrote: > > Do you know magnitude aftershock in Izmit,Turkey 20 minutes ago > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: SDR NETWORK CONNECTION From: Karl Cunningham karlc@....... Date: Thu, 11 Nov 1999 14:20:37 -0800 Francesco -- I have a similar situation to yours, except my Pentium machine runs Windows NT4. And I have the same problem as you do. When my SDR machine boots, it starts SDR with a .CFG file that uses its local hard disk for saved event files. (The autoexec.bat copies the proper .CFG file into the SDR subdirectory.) If the power has been off, I stop SDR and run a batch file that maps the network drive, copies a different .CFG file for SDR, and then starts SDR again. From then on, SDR runs with the networked drive as the destination for saved events. I then shell to dos from SDR and copy the saved event files to the pentium machine. Using this procedure, no event files are lost (except during the time the power was actually off). I'm not sure if this would work help in your situation. I am happy to provide more details and send you copies of the files if you like. Karl Cunningham La Mesa, CA. PSN station #40 karlc@....... At 01:16 PM 11/11/1999 +0100, you wrote: >>>> ArialFrom some weeks I have installed the SDR net connection, between an old 486 (Win95) and a Pentium III (Win98), with the configuration reported on SDR documentation. All works fine. ArialNow, I noted a serius problem. ArialSometimes this is a black-out of dc and the two pc are down. When they restart, SDR (on 486pc) don't run because it unrecognized the assigned map driver of the net (E:\events). In fact, the other pc it's more slow to restart. So, all the system it's down until a manual operation. ArialWhat's to do? ArialRegards Francesco <<<<<<<< _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: SETI From: Roger Griggs rdg8@......... Date: Thu, 11 Nov 1999 16:43:31 -0800 The URL is bogus, try again. At 01:26 PM 11/10/1999 -0500, you wrote: >As a group of individuals who obviously are used to waiting patiently >over long periods time for results, and who also have computers that >spend most of their "always on" time taking a few samples a second from >the A/D card and "Flying through space" on the screen, I thought the PSN >members would be excellent candidates for forming a team for the >SETI@home project. > >This project out of Berkeley uses the wasted capacity of your Pentium 95 >machine (or other platform) by giving you a screen saver program that >crunches data downloaded via their server from the Arecibo Radio >Observatory in PR. It crunches blocks of data about 300K in size and uses >16M of RAM while running. The CPU time required to process each block can >be anywhere between hours and weeks depending upon your hardware, and the >chance that you actually will get a block that proves to have the tiny CQ >from ET is certainly several orders of magnitude lower than recording an >M9 before the end of your life, or even that of keeping your Lehman >centered for more than a month, so I think it would be the perfect >challenge for most of us. The rewards from hopeless endeavors may never >be explained... > >Anyway, go to: http://setiahome.ssl.berkeley.edu and download the >software. There is plenty of help and project description on line. > >Larry could form a group (fill out an on-line form) for PSN and they even >have free graphic links to drop on the PSN home page(s). Then PSN users >could compete as a team with others such as the seti@SUN team that has >processed almost a quarter million blocks with something like 190 YEARS >of CPU time accumulated so far... > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: SETI From: bc bruce@....... Date: Thu, 11 Nov 1999 19:54:46 -0500 Try this one http://setiathome.ssl.berkeley.edu/ At 04:43 PM 11/11/1999 -0800, you wrote: >The URL is bogus, try again. > >At 01:26 PM 11/10/1999 -0500, you wrote: > >As a group of individuals who obviously are used to waiting patiently > >over long periods time for results, and who also have computers that > >spend most of their "always on" time taking a few samples a second from > >the A/D card and "Flying through space" on the screen, I thought the PSN > >members would be excellent candidates for forming a team for the > >SETI@home project. > > > >This project out of Berkeley uses the wasted capacity of your Pentium 95 > >machine (or other platform) by giving you a screen saver program that > >crunches data downloaded via their server from the Arecibo Radio > >Observatory in PR. It crunches blocks of data about 300K in size and uses > >16M of RAM while running. The CPU time required to process each block can > >be anywhere between hours and weeks depending upon your hardware, and the > >chance that you actually will get a block that proves to have the tiny CQ > >from ET is certainly several orders of magnitude lower than recording an > >M9 before the end of your life, or even that of keeping your Lehman > >centered for more than a month, so I think it would be the perfect > >challenge for most of us. The rewards from hopeless endeavors may never > >be explained... > > > >Anyway, go to: http://setiahome.ssl.berkeley.edu and download the > >software. There is plenty of help and project description on line. > > > >Larry could form a group (fill out an on-line form) for PSN and they even > >have free graphic links to drop on the PSN home page(s). Then PSN users > >could compete as a team with others such as the seti@SUN team that has > >processed almost a quarter million blocks with something like 190 YEARS > >of CPU time accumulated so far... > > > >_____________________________________________________________________ > > > >Public Seismic Network Mailing List (PSN-L) > > > >To leave this list email listserver@.............. with the body of the > >message: leave PSN-L > > > > > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: resistive damping From: Marchal van Lare vanlare@.............. Date: Fri, 12 Nov 1999 07:03:17 -0500 Hi all, I placed a resistance parallel with the coil, but the damping = does not seem to occur. The problem is, the pendulum keeps swinging = (sometimes even visibly!) and for now it did not had any plans to = cease its motion. My coil has a resistance of ~500 Ohm and I am using a 1000 Ohm resistor. A 'diagram' would look like the following: )------R--------> to the amplifier ) R ) R )------R--------> to the amplifier )=3Dcoil R=3Dresistance ----=3Dwiring To show the output of the instrument, I have connected it to an old PC via an old amplifier and 8 bit A/D card (I will have Larry's card in the near future), but the motions of the pendulum keep = saturating the A/D card. Any input? Thanks in advance. Best regards, Marchal van Lare _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: resistive damping From: ted@.......... Date: Fri, 12 Nov 1999 08:37:13 -0500 I'm no expert in the theory, but here's what I do when events like yours happen. I start by putting a piece of wire (no resistance) where you have the resistor today. The boom should stop moving completely and freeze in place. Now start replacing the wire with small resistances, gradually building up to what you need. The higher the resistance, the less damping you will get. You can use a variable resistor for the adjustments, but don't use it for the final construction, too noisy. Ted Blank in sub-freezing Portsmouth _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: resistive damping From: jmhannon@.................... Date: Fri, 12 Nov 1999 07:21:19 -0600 Marchal van Lare on 11/12/99 06:03:17 AM Hi all, I placed a resistance parallel with the coil, but the damping does not seem to occur. The problem is, the pendulum keeps swinging (sometimes even visibly!) and for now it did not had any plans to cease its motion. Thanks in advance. Best regards, Marchal van Lare Marchal, Have you tried just shorting the coil terminals to see how much damping you get with zero ohms of resistance? If you don't get any damping effect with the coil shorted you do not have enough coupling between the coil and the magnet. You will have to try decreasing the gap between the coil and magnet and/or increasing the strength of the magnet. Jim Hannon _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Golitsyn pendulum From: "Michael McCarty" mmccarty@.......... Date: Fri, 12 Nov 1999 08:16:54 -0700 >As best I can determine, Lehman in the late 1970's >described a particular two vertical strut instrument that he made. >Somehow his name stuck to the generic "garden gate" or >" Golitsyn" type instruments ever since. I believe that it is >mostly PSN folks that use the term I believe when the name Golitsyn is used it refers to the combination of the swinging gate type pendulum and the electromagnetic pickup. There were earlier varieties of the swinging gate pendulum. Modern Global Seismology by Lay and Wallace refers to an early "Omori" horizontal pendulum that etched the seismogram on smoked paper around a rotating drum. It says it was developed by a student of John Milne in Japan from 1899 to 1905. The picture shows the typical garden-gate style boom but without the magnet/coil we are accustomed to. I think the term "swinging-gate horizontal pendulum" aptly describes the style without too much confusion and history. Of course all mailing list references to this style should now become SGHP to add to the confusion. :) -Mac _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: resistive damping From: Marchal van Lare vanlare@.............. Date: Fri, 12 Nov 1999 11:14:58 -0500 Hi, Thank you for your input, it looks like I can control the damping now, so its time to experiment! Best regards, Marchal van Lare _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: LARGE QUAKE IN PROGRESS NOW From: "Giovanni Rotta" rottag@.......... Date: Fri, 12 Nov 1999 18:08:45 +0100 Large quake in progress now ! Giovanni... sorry for the virus... Giovanni Rotta Via F. Pizzigoni, 10 33010 Resia (Udine) I Lat. 46.373 N Long. 13.305 E rottag@.......... http://www.resianet.org
Large quake in progress now !
Giovanni... sorry for the virus...
 
 
Giovanni Rotta
Via F. Pizzigoni, 10
33010 = Resia=20 (Udine) I
Lat. 46.373 N  Long. 13.305 E
rottag@..........
http://www.resianet.org
= Subject: TURKEY Ml. 6.3 From: "Giovanni Rotta" rottag@.......... Date: Fri, 12 Nov 1999 18:13:43 +0100 ING reports a large quake in Turkey (Ml.6.3) at 16:56:39 UTC Giovanni Giovanni Rotta Via F. Pizzigoni, 10 33010 Resia (Udine) I Lat. 46.373 N Long. 13.305 E rottag@.......... http://www.resianet.org
ING reports a large quake in Turkey (Ml.6.3) at = 16:56:39=20 UTC
Giovanni
Giovanni Rotta
Via F. Pizzigoni, 10
33010 = Resia=20 (Udine) I
Lat. 46.373 N  Long. 13.305 E
rottag@..........
http://www.resianet.org
= Subject: R: LARGE QUAKE IN PROGRESS NOW From: "Francesco" franuc@...... Date: Fri, 12 Nov 1999 17:43:15 +0100 Same registration at Osimo (Italy) Very large S Another great aftershock from Turkey, after yestarday. M~6.5 ? Francesco Subject: TURKEY'S BIG QUAKE From: "Francesco" franuc@...... Date: Fri, 12 Nov 1999 18:44:23 +0100 16.57.11 Mw 7.2 Loc.: 40.8N 30.2E TURKEY -Izmit Saturation on all sensors of italian station's !!!!! Until now no report of victims or material damnages in the same region = of September main shock. Today's event is probabily located about 50 km western from Izmit, in = another portion of north-anatolic fault, not interested by 17/9/99 Francesco I.E.S.N. PSN-ITALY
16.57.11
Mw  7.2
Loc.: 40.8N  30.2E  = TURKEY =20 -Izmit
 
Saturation on all sensors of italian = station's=20 !!!!!
 
Until now no report of victims or = material damnages=20 in the same region of September main shock.
 
Today's event is probabily located = about 50 km=20 western from Izmit, in another portion of north-anatolic fault, not = interested=20 by 17/9/99
 
Francesco  I.E.S.N. =20 PSN-ITALY
Subject: LARGE QUAKE IN PROGRESS NOW From: "Danie Overbeek" danieo@............ Date: Sat, 13 Nov 1999 09:14:37 +0000 ------- Forwarded Message Follows ------- From: "Giovanni Rotta" To: "PSN-L Mailing List" Subject: LARGE QUAKE IN PROGRESS NOW Date: Fri, 12 Nov 1999 18:08:45 +0100 Organization: Reply-to: PSN-L Mailing List Large quake in progress now ! Giovanni... sorry for the virus... Giovanni Rotta Via F. Pizzigoni, 10 33010 Resia (Udine) I Lat. 46.373 N Long. 13.305 E rottag@.......... http://www.resianet.org Recording it loud and clear at: E28d 8' 20" S26d 9' 15" Cheers Danie Overbeek. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: EMON-7 From: RADIOTEL@....... Date: Sat, 13 Nov 1999 15:30:37 EST Ted, et.al Is it possible to monitor two (2) seismometers at the same time with EMON-7 with two data traces on the screen? If so, could someone please tell me how to do it. I am using a ComputerBoards A/D with several channels (CIODAS8JR). Thanks Jim Allen Cerritos, California, USA _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: amplitude for magnitude/distance From: S-T Morrissey sean@........... Date: Sat, 13 Nov 1999 14:58:25 -0600 (CST) Re: Expected seismograph output: For the benefit of estimating what amplitude a PSN seismograph should expect to detect from an earthquake at a given distance, we use the generic magnitude formula: Ms = log(A/T) + 1.66*log(distance) - 0.18 where A is the peak-to-peak ground amplitude at the seismograph in nanometers (10^-9 meters), T is the period in seconds, the distance is in degrees ( 1 deg = 111 km, and the constant -0.18 is an attenuation adjustment. which is solved for the amplitude: A = T * 10^[Ms -1.66*log(dist) + 0.18] Then selected combinations of Magnitude and distance are used to determine the seismograph amplitude in nanometers (m * 10^9), which are converted to peak velocity by multiplying by w (omega) = 2*pi*f, where f = 1/T. The possibilities are fortunately limited by the effect of dispersion of the seismic wave, namely that the wave period increases with distance, so a close quake will have periods of less than 1 second, while a distant event will arrive with periods in excess of 20 seconds. While the possibilities are endless, typical distance-period combinations are selected. Other limitations are presented by the expectations of the seismograph or seismometer-digitizer. Since these are velocity-recording systems, we will assume a constant VBB output of 1000 volts/meter/second (v*sec/m) for all periods/frequencies. THis then presents dynamic limits of a maximum voltage of 10 volts and a background noise level of 1 millivolt. Of course for a reasonable signal-to-noise ratio of 100 to 1,. the system noise floor must be 10 microvolts or less. Your particular seismograph parameters may be different, but the generalities here can be scaled appropriately. Also, the generic magnitude formula is not exactly applicable for nearby ( 100 to 200 km) quakes; special formulas will expect up to twice the amplitude since the attenuation is a fractional power of the distance. In the table below, the velocity in microns/second has the same value as the seismometer output in millivolts if the sensitivity is 1000 volts/meter/second. A "*" indicates a clipped output over 10 V. Magnitude Amplitude Velocity/output acceleration Ms microns u/sec = millivolts percent of g Distance: 0.1 degree (11 km), period: 0.25 seconds (4 hz). 3 17 435 0.11 4 173 4347 (ie 4.3volts) 1.11 5 1729 43469* 11.14 Distance: 1.0 degree (110 km), period: 0.50 seconds (2 hz). 3 0.76 9.5 0.0012 4 7.6 95 0.012 5 76 951 0.12 6 760 9510 1.12 Distance: 3 degrees (330km), period: 0.7 second (1.43hz). 3 0.17 1.5 0.0001 4 1.7 15 0.0014 5 17 154 0.014 6 171 1535 0.1406 Distance: 9 degrees (999 km), period 1.0 second (1.0hz). 3 0.039 0.247 4 0.39 2.478 5 3.9 24.78 0.0016 6 39.4 247.8 0.016 7 394.4 2478 0.1589 Distance: 30 degrees (3330km), period 15 seconds 4 0.8 0.336 5 8.0 3.36 6 80 33.6 7 802 335.9 0.00143 Distance: 45 degrees (4995 km), period 15 seconds 4 0.4 0.17 5 4.1 1.71 6 40.9 17.1 7 409 171.3 0.00073 Distance: 90 degrees (9990km), period 25 seconds 5 2.16 0.542 6 21.6 5.42 7 215.7 54.22 8 2157 542.17 0.00139 Distance: 135 degrees (14985 km), period 25 seconds 5 1.1 0.27 6 11.0 2.76 7 110.0 27.65 8 1100.5 276.58 For example, if the quakes in Turkey are about 90 degrees from St. Louis, I would estimate that a Ms 7.0 would have a peak-peak amplitude at 25 seconds of about 54 microns/second. Since the recording sensitivity here is 5290 Volts/meter/second (5.29mv/micron/sec), the digitizer should see 285 millivolts (peak voltage), which means that it clips on the 200mv scale, which it did for the 7.2 yesterday 12 Nov. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: EMON-7 From: ted@.......... Date: Sat, 13 Nov 1999 16:44:03 -0500 Hi, EMON lets you monitor up to 3 separate A/D cards (or 3 channels on one card, or any combination) but only one of them can be displayed on the screen at a time. The F7 key lets you swap among the inputs and display them one by one, to make sure everything is going OK. Sorry. Regards, Ted _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: amplitude for magnitude/distance From: barry lotz gbl@....... Date: Sun, 14 Nov 1999 09:13:55 -0800 Sean Thomas et al I graphed the equation of velocity vs distance for different magnitudes. I used log-log scales. The plots are nice straight lines (one line for each magnitude 3.0,3.5,4.0 etc). I tried ploting voltage output on the vertical scale but found counts better. I am now going to try ploting the events I've recorded as individual data points to see how regular the data is. Regards Barry PS STM- thanks for the equation. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Station Details requested by Greg From: "Danie Overbeek" danieo@............ Date: Sun, 14 Nov 1999 19:11:11 +0000 THE EDENVALE SEISMOGRAPHS The station at Edenvale, South Africa, E28d 8' 20", S26d 09' 15" has sensors to detect the vertical velocity of the Earth's surface and its velocity in an East-West direction. The sensors are firmly mounted on a concrete floor which in turn rests on a rocky outcrop. Even so, the floor flexes appreciably when one stands within one metre of the sensors. When surrounding ground is saturated with rain water, the floor tilts far enough to bring the horizontal detector to a limit stop. Microseisms are continually recorded. These are related to weather conditions. Microseisms are a fertile ground for study by persons interested in atmospheric as well as ground movement. The station has been in continuous operation with short inter- ruptions for adjustments and modifications since 1989. Numerous distant earthquakes and many hundreds, perhaps thousands of local earth tremors have been recorded in this period. A number of mining operations within 200 km of my station cause these tremors. The horizontal instrument consists of a Golytsin (Swinging gate) pendulum. Its lower bearing is a steel ball rolling on a hardened and polished vertical steel plate. The upper bearing is a thin wire under tension. At the free end of the pendulum sits a lead seismic mass and a transducer consisting of a pancake shaped coil moving between the poles of a magnet. The coil consists of 2000 turns of thin (48 SWG?) copper wire salvaged from an automobile high tension ignition coil. The coil is wound on a former which has aluminium sides in order to provide eddy current damping. The pendulum is definitely underdamped. The coil's output is approximately a microvolt per micron per second, which is representative of ordinary seismic motion. The pendulum's natural frequency is 0.07 Hz. The horizontal instrument is most useful for detecting distant events. It also responds to local tremors but these register more strongly on the vertical instrument, which has a higher frequency. The vertical instrument consists of a seismic mass sitting on the end of a semi-rigid beam which is attached to a 12" steel rule, the other end of which is firmly attached to the steel base of the instrument. Its natural frequency is 1 Hz. The mass is linked to a moving coil electromagnetic transducer without introducing friction. The transducer has a magnet from a large moving coil speaker, with the annular gap widened to accommodate the moving coil, which also consists of 2000 turns of fine copper wire. The coil is wound on a brass former to provide eddy current damping. A copper former would have made a much more effective damper, due to the lower resistivity of copper. I find it necessary to provide oil damping as well. Both instruments feed into DC amplifiers with appropriate filtering. The outputs of these amplifiers operate side by side penmotors which cause ink stylii to register the traces on a single rotating drum. The drum speed was originally 1000 mm per hour but I have recently changed it to 500 mm per hour in order to conserve paper and pens. I have no intention of converting to digital recording, which would be the way to go if one reported events to a scientific body. My scientific reporting is confined to lunar and planetary occultation timings and as well as a large number of variable star observations. I do not report magnetic and seismic data because South Africa has two agencies, each with a number of outstations, so my reports would simply duplicate theirs. The geologically quiet astronomical complex at Sutherland is host to overseas seismic organisations which use using state of the art detectors such as (I think) a rock strain guage seismograph and a cryogenic superconducting microgravimeter. There is much room for improvement. The amplifiers do not have common mode rejection and are consequently unstable and inefficient. At my age (79) I do not enjoy building electronic circuits and feel that it would be unfair to ask associates to help me with what is essentially a recreational activity. I also need active filters to define the passband frequency more sharply. The writing stylii are ordinary fine fibre tipped pens which are very robust but give an unacceptably wide trace. Originally, I used India ink in ultrafine draftman's tubular pens. The traces were very fine but the wires in the pens tended to stick, requiring more maintenance than I was prepared to give. The sticking can be avoided by lifting the pens periodically to exercise the wires but this would add a complication. I would like to convert the horizontal instrument to a displacement sensor, using light dependent resistors but in a displacement instrument, pendulum drift can be a problem. Drift can be overcome but that would again be a complication. The whole station except for electronic components and fasteners is built from discarded material. Even the penmotors would have been home made, had suitable units not been found in scrap boxes. If colleagues on PSN wants more information, I'll be glad to supply it but I leave for Australia in two days time for a 1-2 week visit and will not be on PSNet for that period. An ASCII based diagram of the vertical sensor is attached. Cheers all, Danie Overbeek Tel 27+ 11 453 6918 The following section of this message contains a file attachment prepared for transmission using the Internet MIME message format. If you are using Pegasus Mail, or any another MIME-compliant system, you should be able to save it or view it from within your mailer. If you cannot, please ask your system administrator for assistance. ---- File information ----------- File: 991113.sei Date: 14 Nov 1999, 17:25 Size: 820 bytes. Type: Unknown Subject: Re: SETI From: twleiper@........ Date: Sun, 14 Nov 1999 13:27:30 -0500 Forgot the "t" ... http://setiathome.ssl.berkeley.edu/ Now go forth and multiply _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Station Details requested by Greg From: Greg ghost@............. Date: Sun, 14 Nov 1999 12:12:46 -0700 Danie Overbeek wrote: > THE EDENVALE SEISMOGRAPHS Neat! Thanks! ,Greg _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: resistive damping From: Marchal van Lare vanlare@.............. Date: Sun, 14 Nov 1999 16:29:22 -0500 Hi all, The last couple of days I have been experimenting with resisitive damping. I am getting a little confused about the damping. A little while ago I read somewhere the boom (with damping) should stop = swinging in 2 1/2 - 3 1/2 cycles, others suggest the boom should stop = swinging as rapid as possible with minimal overshoot. What is correct? Marchal _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Seismograph amplifier on e-bay From: "Raul J. Alvarez" ralvarez@........ Date: Sun, 14 Nov 1999 15:10:10 -0700 Hi All, Seismo amp on ebay. Check it out if interested. http://cgi.ebay.com/aw-cgi/eBayISAPI.dll?ViewItem&item=200548268 Raul _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Seismograph amplifier on e-bay From: Doug Crice dcrice@............ Date: Sun, 14 Nov 1999 16:01:09 -0800 The Bison 1580 is an exploration seismograph, not an earthquake seismograph. It's generally used with a sledgehammer energy source to do shallow refraction surveys like depth-to-bedrock and such. It's a member of the class called "signal enhancement" seismographs because it can store the data from a hammer impact in a digital memory, and then add the signals from subsequent hammer blows to give you more range without resorting to explosives. It wasn't ever a commercial success because of logistic considerations related to the number of channels. It doesn't contain much in the way of components useful for earthquake recording but would be useful for checking out your foundation if it works. The schematics were never public knowledge and Bison went bankrupt just last year. There is a group in Minnapolis alegedly provding service. "Raul J. Alvarez" wrote: > > Hi All, > > Seismo amp on ebay. Check it out if interested. > http://cgi.ebay.com/aw-cgi/eBayISAPI.dll?ViewItem&item=200548268 > -- Doug Crice web site http://www.georadar.com GeoRadar Inc. e-mail dcrice@............ 19623 Via Escuela Drive phone 408-867-3792 Saratoga, CA 95070 USA fax 408-867-4900 _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Seismograph amplifier on e-bay From: "Raul J. Alvarez" ralvarez@........ Date: Sun, 14 Nov 1999 18:21:28 -0700 Hi Doug, Thanks for the reply and information on the Bison unit. I was aware of the type of device it was, but not it's method of operation. Thanks for that info. I put it on ebay in hopes some exploration company may be interested in it. Maybe someone in PSN also. Raul Doug Crice wrote: > The Bison 1580 is an exploration seismograph, not an earthquake > seismograph. It's generally used with a sledgehammer energy source to > do shallow refraction surveys like depth-to-bedrock and such. It's a > member of the class called "signal enhancement" seismographs because it > can store the data from a hammer impact in a digital memory, and then > add the signals from subsequent hammer blows to give you more range > without resorting to explosives. It wasn't ever a commercial success > because of logistic considerations related to the number of channels. It > doesn't contain much in the way of components useful for earthquake > recording but would be useful for checking out your foundation if it > works. The schematics were never public knowledge and Bison went > bankrupt just last year. There is a group in Minnapolis alegedly > provding service. > > "Raul J. Alvarez" wrote: > > > > Hi All, > > > > Seismo amp on ebay. Check it out if interested. > > http://cgi.ebay.com/aw-cgi/eBayISAPI.dll?ViewItem&item=200548268 > > > -- > Doug Crice web site http://www.georadar.com > GeoRadar Inc. e-mail dcrice@............ > 19623 Via Escuela Drive phone 408-867-3792 > Saratoga, CA 95070 USA fax 408-867-4900 > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L Hi Doug,

Thanks for the reply and information on the Bison unit.  I was aware of the type of device it was, but not it's method of operation.  Thanks for that info.  I put it on ebay in hopes some exploration company may be interested in it.  Maybe someone in PSN also.

Raul

Doug Crice wrote:

The Bison 1580 is an exploration seismograph, not an earthquake
seismograph.  It's generally used with a sledgehammer energy source to
do shallow refraction surveys like depth-to-bedrock and such.  It's a
member of the class called "signal enhancement" seismographs because it
can store the data from a hammer impact in a digital memory, and then
add the signals from subsequent hammer blows to give you more range
without resorting to explosives. It wasn't ever a commercial success
because of logistic considerations related to the number of channels. It
doesn't contain much in the way of components useful for earthquake
recording but would be useful for checking out your foundation if it
works.  The schematics were never public knowledge and Bison went
bankrupt just last year.  There is a group in Minnapolis alegedly
provding service.

"Raul J. Alvarez" wrote:
>
> Hi All,
>
> Seismo amp on ebay.  Check it out if interested.
> http://cgi.ebay.com/aw-cgi/eBayISAPI.dll?ViewI tem&item=200548268
>
--
Doug Crice          web site http://www.georadar.com
GeoRadar Inc.             e-mail dcrice@............
19623 Via Escuela Drive           phone 408-867-3792
Saratoga, CA 95070 USA              fax 408-867-4900

_____________________________________________________________________

Public Seismic Network Mailing List (PSN-L)

To leave this list email listserver@.............. with the body of the
message: leave PSN-L

Subject: Large Sth Indian Ocean event From: "David A. Nelson" davenn@........ Date: Mon, 15 Nov 1999 20:55:02 +1300 Red Puma gives Ms6.8 - 7.0 15Nov1999 05:42:43.3 1.4S 89.0E 10 MS=7.0 M*NEI SOUTH INDIAN OCEAN 0740 15Nov1999 05:42:44.5 1.6S 89.1E 33 MS=6.8 M*GSR SOUTH INDIAN OCEAN 0728 15Nov1999 05:42:13.2 5.2S 96.1E 33 mb=6.5 M*MAD SOUTHWEST OF SUMATERA, IND0644 15Nov1999 05:42:22.2 6.0S 93.0E 33 mb=6.0 M*MAD SOUTH INDIAN OCEAN 0622 Dave Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 23 Duncan St., Dunedin, South Is.. New Zealand. http://www.seismicnet.com/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: PSN station operators please read; PSN map update From: Larry Cochrane cochrane@.............. Date: Mon, 15 Nov 1999 00:15:48 -0800 All, While Dave Nelson was gone I made some changes to the PSN map station database files. Unfortunately I forgot to tell Dave and he recently overwrote the changes I made. If you have a record in the PSN Station database please review it and give Dave (davenn@......... any changes needed. Your database record should be in one of two files: http://www.seismicnet.com/dave/people.htm and http://www.seismicnet.com/dave/people1.htm. One thing I did with my database record is have the channel info point to a web page that I maintain. This way Dave doesn't need to change my database record each time I change something on my system. I would suggest other stations operators do the same thing if you have your own web page and change things often like I do. Regards, Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: More on Happy99 From: Nick & Sophie Caporossi nickcap@............. Date: Mon, 15 Nov 1999 08:37:03 -0500 Dave Nelson and psn members: Thanks for bringing to my attention that I was infected with the "Happy99 Virus" It wasn't that hard to remove it. See the web site: http://www.symantec.com/avcenter/venc/data/happy99.worm.html Sorry for any inconvenience that I may have caused. Nick _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: new quake From: EK kerls@...... Date: Tue, 16 Nov 1999 23:01:51 -0600 it looks like the Indian Ocean Maj. Kerls _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: new quake From: "J. D. Cooley" cooleyj@............ Date: Tue, 16 Nov 1999 21:06:46 -0800 At 09:01 PM 11/16/99 , you wrote: >it looks like the Indian Ocean >Maj. Kerls > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L > RedPuma: 17Nov1999 03:27:40.5 6.0S 148.8E 33 MS=6.7 M*NEI NEW BRITAIN REGION, P.N.G. "JD" _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: new quake From: EK kerls@...... Date: Tue, 16 Nov 1999 23:14:17 -0600 Thank you J.D. My satellite system is not that pinpoint yet. "J. D. Cooley" wrote: > At 09:01 PM 11/16/99 , you wrote: > >it looks like the Indian Ocean > >Maj. Kerls > > > > > >_____________________________________________________________________ > > > >Public Seismic Network Mailing List (PSN-L) > > > >To leave this list email listserver@.............. with the body of the > >message: leave PSN-L > > > > RedPuma: > > 17Nov1999 03:27:40.5 6.0S 148.8E 33 MS=6.7 M*NEI NEW BRITAIN REGION, P.N.G. > > "JD" > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: P.N.G. quake upgraded to M7.0 From: "J. D. Cooley" cooleyj@............ Date: Wed, 17 Nov 1999 00:07:12 -0800 99/11/17 03:27:40 5.95S 148.85E 7.0Ms NEW BRITAIN REGION, P.N.G. "JD" _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Planchets From: John Lahr lahr@................... Date: Wed, 17 Nov 1999 13:13:28 -0700 (MST) Hi Meredith, I think I'll order 10 planchets from Ted Pella, #16510, for $8. Who knows how they will work, but it's worth a try. JCLahr _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: WinQuake From: RADIOTEL@....... Date: Thu, 18 Nov 1999 20:04:31 EST In the program WinQuake, is the component labeled "Diff" on the last line when you print out earthquake results the area that indicates the period of the instrument? If so are there variables that change the period from one quake to another? Jim Allen _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: WinQuake From: Larry Cochrane cochrane@.............. Date: Thu, 18 Nov 1999 22:44:25 -0800 Jim, The Diff: number is the S marker time minus the P marker time. This number is used to calculate the distance from the station to the event. -Larry Cochrane Redwood City, PSN At 08:04 PM 11/18/99 EST, you wrote: >In the program WinQuake, is the component labeled "Diff" on the last line >when you print out earthquake results the area that indicates the period of >the instrument? If so are there variables that change the period from one >quake to another? >Jim Allen > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: PSN Meeting From: Larry Cochrane cochrane@.............. Date: Thu, 18 Nov 1999 23:40:40 -0800 At 12:23 AM 11/18/99 -0800, Karl Cunningham wrote: >Hi Larry -- > >Is the PSN meeting still on track for the weekend of Dec 17th? Is there a >schedule? > >My wife and I plan to come up and make a weekend of it in SF, but we are >running out of time to get the good plane fares. Actually, probably I'll >drive and she'll fly, but we need to decide what day to travel and get the >tickets. > >Do you have any more info? >Thanks, >Karl > > Hi Karl, Good question! I'm CCing the list as a second reminder. So far I have you, Edward Cranswick if he can make it, Jan Froom and Steve Hammond who have signed up so far. I think the best time would be on Sat. the 18th. at lets say 10:00 am. I think we need a few more people interested in coming before we should have the meeting. So for the other PSN members please let me know ASAP if you interested in attend the meeting. -Larry Cochrane Redwood City, PSN My original email announcing the meeting... > All, > I got this from Lind Gee the other day. She is a seismologist at the > Berkeley Seismo Lab (BSL) and involved with the IRIS (www.iris.edu) > Education and Outreach program. I had a meeting with her and other IRIS > members a few weeks ago. > >>Regarding the PSN meeting in December, the > >BSL would be happy to host the meeting at >> >our facilities on the UC Berkeley campus. Before >> >AGU is a little troublesome (people will be >> >working on their presentations), but either one >> >evening during AGU or the following Friday (12/17) >> >or Saturday (12/18) would be fine. My preference >> >would be for either Friday or Saturday, but Thursday >> >might be possible. It seems as if Catherine will >> >be able to attend. > > Catherine is from IRIS and is also part of the E & O program. I thought it > would be a nice change of pace if we have the next meeting at another > location. The last two meetings have been at the USGS in Menlo Park around > the time of the AGU in December. > > So who's interested, and what day and time should we have it? Maybe Sat. > would be best for most people? If people from IRIS, and maybe PEPP, are > there, the meeting should be geared around setting up and supporting system > in schools. I'm sure after the meeting we can have a tour of their lab. > > Regards, > Larry Cochrane > Redwood City, PSN > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: PSN Meeting From: Edward Cranswick cranswick@........ Date: Fri, 19 Nov 1999 01:01:46 -0700 Larry- I am planning to attend the PSN meeting with you'all on 17 Dec and am mainly wondering how I am going to get back from Turkey in time and with half a mind to show up for Bob Phinney's PEPP convocation on 12 Dec: > Although many are not coming, I am still taking advantage of AGU to have a brief > meeting of > PEPP network operators and others in the community involved with educational seismology. > -Edward Larry Cochrane wrote: > At 12:23 AM 11/18/99 -0800, Karl Cunningham wrote: > >Hi Larry -- > > > >Is the PSN meeting still on track for the weekend of Dec 17th? Is there a > >schedule? > > > >My wife and I plan to come up and make a weekend of it in SF, but we are > >running out of time to get the good plane fares. Actually, probably I'll > >drive and she'll fly, but we need to decide what day to travel and get the > >tickets. > > > >Do you have any more info? > >Thanks, > >Karl > > > > > > Hi Karl, > > Good question! I'm CCing the list as a second reminder. So far I have you, > Edward Cranswick if he can make it, Jan Froom and Steve Hammond who have > signed up so far. I think the best time would be on Sat. the 18th. at lets > say 10:00 am. I think we need a few more people interested in coming before > we should have the meeting. So for the other PSN members please let me know > ASAP if you interested in attend the meeting. > > -Larry Cochrane > Redwood City, PSN > > My original email announcing the meeting... > > > All, > > I got this from Lind Gee the other day. She is a seismologist at the > > Berkeley Seismo Lab (BSL) and involved with the IRIS (www.iris.edu) > > Education and Outreach program. I had a meeting with her and other IRIS > > members a few weeks ago. > > > >>Regarding the PSN meeting in December, the > > >BSL would be happy to host the meeting at > >> >our facilities on the UC Berkeley campus. Before > >> >AGU is a little troublesome (people will be > >> >working on their presentations), but either one > >> >evening during AGU or the following Friday (12/17) > >> >or Saturday (12/18) would be fine. My preference > >> >would be for either Friday or Saturday, but Thursday > >> >might be possible. It seems as if Catherine will > >> >be able to attend. > > > > Catherine is from IRIS and is also part of the E & O program. I thought it > > would be a nice change of pace if we have the next meeting at another > > location. The last two meetings have been at the USGS in Menlo Park around > > the time of the AGU in December. > > > > So who's interested, and what day and time should we have it? Maybe Sat. > > would be best for most people? If people from IRIS, and maybe PEPP, are > > there, the meeting should be geared around setting up and supporting system > > in schools. I'm sure after the meeting we can have a tour of their lab. > > > > Regards, > > Larry Cochrane > > Redwood City, PSN > > > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". Larry-
    I am planning to attend the PSN meeting with you'all on 17 Dec and am mainly wondering how I am going to get back from Turkey <http://groundmotion.cr.usgs.gov/koc/> in time and with half a mind to show up for Bob Phinney's PEPP convocation on 12 Dec: 
Although many are not coming,  I am still taking advantage of AGU to have a brief
meeting of
PEPP network operators and others in the community involved with educational seismology.


-Edward

Larry Cochrane wrote:

At 12:23 AM 11/18/99 -0800, Karl Cunningham wrote:
>Hi Larry --
>
>Is the PSN meeting still on track for the weekend of Dec 17th?  Is there a
>schedule?
>
>My wife and I plan to come up and make a weekend of it in SF, but we are
>running out of time to get the good plane fares.  Actually, probably I'll
>drive and she'll fly, but we need to decide what day to travel and get the
>tickets.
>
>Do you have any more info?
>Thanks,
>Karl
>
>

Hi Karl,

Good question! I'm CCing the list as a second reminder. So far I have you,
Edward Cranswick if he can make it, Jan Froom and Steve Hammond who have
signed up so far. I think the best time would be on Sat. the 18th. at lets
say 10:00 am. I think we need a few more people interested in coming before
we should have the meeting. So for the other PSN members please let me know
ASAP if you interested in attend the meeting.

-Larry Cochrane
Redwood City, PSN

My original email announcing the meeting...

> All,
> I got this from Lind Gee the other day. She is a seismologist at the
> Berkeley Seismo Lab (BSL) and involved with the IRIS (www.iris.edu)
> Education and Outreach program. I had a meeting with her and other IRIS
> members a few weeks ago.
>
>>Regarding the PSN meeting in December, the
> >BSL would be happy to host the meeting at
>> >our facilities on the UC Berkeley campus.  Before
>> >AGU is a little troublesome (people will be
>> >working on their presentations), but either one
>> >evening during AGU or the following Friday (12/17)
>> >or Saturday (12/18) would be fine.  My preference
>> >would be for either Friday or Saturday, but Thursday
>> >might be possible.  It seems as if Catherine will
>> >be able to attend.
>
> Catherine is from IRIS and is also part of the E & O program. I thought it
> would be a nice change of pace if we have the next meeting at another
> location. The last two meetings have been at the USGS in Menlo Park around
> the time of the AGU in December.
>
> So who's interested, and what day and time should we have it? Maybe Sat.
> would be best for most people? If people from IRIS, and maybe PEPP, are
> there, the meeting should be geared around setting up and supporting system
> in schools. I'm sure after the meeting we can have a tour of their lab.
>
> Regards,
> Larry Cochrane
> Redwood City, PSN
>

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--
Edward Cranswick                Tel: 303-273-8609
US Geological Survey, MS 966    Fax: 303-273-8600
PO Box 25046, Federal Center    cranswick@........
Denver, CO 80225-0046  USA      E.M. Forster said, "Only connect".
  Subject: Selected broadband data from liss.org now available on my From: Larry Cochrane cochrane@.............. Date: Fri, 19 Nov 1999 00:48:37 -0800 All, For some time now I have been receiving data from several of the broadband sensors available using the USGS Live Internet Seismic Server (www.liss.org). I finally resolved some random crashes in my TCP/IP receiving program so I can now receive data without restarting the program every day or two. Last weekend I created a web page and CGI script so that the data I receive can be access using the Web. The URL to the data request page is http://www.seismicnet.com/bbrequest.html and I've added a link to this page on my main web page. This page is a form that the users fills out with the station(s), channel , start date and time, and output format for the returned event files. I am currently monitoring 8 stations, each station produces 20 samples/second BHZ, BHN and BHE files and 1 sample/second LHZ, LHN and LHE files. The output file(s) can be in either PSN or SAC binary format. You can also view the event file(s) as a GIF image. I am currently receiving data from the following stations: HKT in Texas USA, KIP in Hawaii USA, ADK Alaska USA, KONO Norway, CTAO Australia, GUMO Guam, TATO Taiwan and GNI Armenia. I keep the data for 5 days, after that my system purges the data. Receiving this data only takes about 950 bytes per second or around 7600 bits per second. With my aDSL line I can get over 150 kbytes (~ 1.2 meg bit) download speeds, unfortunately for people accessing my web site the out going bandwidth is limited to 128 kbits, so the usage on my incoming data rate is less then 1%. The problem is the reliability of the connection to the LISS servers is so so and the LISS server gets its data from the world wide sensors using the Internet, so the data can have a lot of holes in it. For large events, using the data from your own sensor and a few of the LISS stations one should be able to locate the event using the new WinQuake location map feature available in the beta release. I was able to locate the 7.0Ms NEW BRITAIN REGION, P.N.G. event to with in 50 km using several of the LISS stations. I didn't get a clear P and S from my sensors so I only used the LISS stations to locate the event. Regards, Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: WinQuake From: ted@.......... Date: Fri, 19 Nov 1999 07:35:41 -0500 Jim, The period of the instrument is a kind of meta-data, similar to the location of the instrument, the maximum and minimum possible digital values for an instrument, etc. I had not left a lot of room for this stuff, but when Larry got interested we moved fields around in the PSN file header to make room for lots more meta-data. (Thus the "old" and "new" file formats.) However we did not define a field to store the period of the sensor. Theoretically, the three-character ID of the sensor should map to a particular set of characteristics, one of which would be period, but that's probably cutting it a bit fine for a basement operation. We already compute sampling rate directly from the data by knowing start and stop times, and the number of samples, so there's no need to store it in the header. I wonder - is it possible to figure out the fundamental period of a sensor from the recording of some interval of time when it was being energized by seismic waves? If so, then the period is already encoded in every data file, and it's just SMOP to get it out. (SMOP = Small Matter Of Programming. Term typically used by management, particularly Dilbert-type management.) Regards, Ted RADIOTEL@....... on 11/18/99 08:04:31 PM Please respond to PSN-L Mailing List To: psn-l@.............. cc: Subject: Re: WinQuake In the program WinQuake, is the component labeled "Diff" on the last line when you print out earthquake results the area that indicates the period of the instrument? If so are there variables that change the period from one quake to another? Jim Allen _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: SDR on W98 From: Karl Cunningham karlc@....... Date: Fri, 19 Nov 1999 13:25:49 -0800 Hi all -- I've been running SDR on a W95 system with a 540MB hard disk, and have been thinking about putting a larger hard disk in it. Does SDR work OK with W98 and a FAT32 partition? Karl Cunningham La Mesa, CA. PSN station #40 karlc@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: RE: SDR on W98 From: Jim Allen JAllen@............... Date: Fri, 19 Nov 1999 13:39:31 -0800 I have been having a hard time leaving the PSN Mailing list. This is my office mail box and my secretary is the one receiving my messages. My e-mail address is jallen@............ I hope one of you out there can remove my name -----Original Message----- From: Karl Cunningham [mailto:karlc@........ Sent: Friday, November 19, 1999 1:26 PM To: psn-l@.............. Subject: SDR on W98 Hi all -- I've been running SDR on a W95 system with a 540MB hard disk, and have been thinking about putting a larger hard disk in it. Does SDR work OK with W98 and a FAT32 partition? Karl Cunningham La Mesa, CA. PSN station #40 karlc@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) RE: SDR on W98

I have been having a hard time leaving the PSN = Mailing list.  This is my office mail box and my secretary is the = one receiving my messages.  My e-mail address is = jallen@............  I hope one of you out there can remove my = name

-----Original Message-----
From: Karl Cunningham [mailto:karlc@.......]
Sent: Friday, November 19, 1999 1:26 PM
To: psn-l@..............
Subject: SDR on W98


Hi all --

I've been running SDR on a W95 system with a 540MB = hard disk, and have been
thinking about putting a larger hard disk in = it.  Does SDR work OK with W98
and a FAT32 partition?


Karl Cunningham
La Mesa, CA.
PSN station #40
karlc@.......

_______________________________________________________________= ______

Public Seismic Network Mailing List (PSN-L)

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message: leave PSN-L

Subject: Re: PSN Meeting From: Tobin Fricke tobin@....... Date: Fri, 19 Nov 1999 16:59:19 -0800 (PST) >Is the PSN meeting still on track for the weekend of Dec 17th? Is there a >schedule? If you're going to have the PSN meeting on the weekend at Berkeley or elsewhere in the Bay Area, then I'd like to attend. I'm a sophomore Cal student (which makes the Berkeley meeting location quite convenient) in EE/CS. I have a bit of an interest in seismology just from living in California; I've wanted to build a seismometer for some time but I haven't yet, mostly because of non-familiarity with machine tools (that's my excuse anyway). This last summer I did an internship at the Geophysical Institude in Fairbanks, AK dealing with the realtime processing (eg, event detection) of data from the five seismic arrays in the state. I also spent two weeks deploying instruments (from IRIS) near Denali national park (the BEAAR project). I could talk about my project a little bit if anyone would find it interesting. So, hopefully I'll get to meet some of you folks at the PSN meeting, and maybe you can get me working on my own seismometer. (-: Tobin Fricke _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: PSN Meeting From: Doug Sutherland doug@............. Date: Fri, 19 Nov 1999 21:45:37 -0800 Larry wrote: > I think we need a few more people interested in coming before we should > have the meeting. So for the other PSN members please let me know ASAP Hi Larry. Count me in. -- Doug _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Pheraps OT From: "Antonio Cacosso" gidod@............. Date: Sat, 20 Nov 1999 16:14:20 +0100 Hail to all the participants to the newsgroup. I am a new element of the group and since I am taking a specialization in seismology I would need your collaboration for any information. I need, because of my studies, of a software for the casual generation of accelerogramm and, then, I want to acquire of the seismograph for measure the vibrations on bodies. You apologize are OT but I have urgent need of these information. There I beg answer Antonio Cacosso gidod@.............
Hail to all the participants to the = newsgroup. I am=20 a new element of the
group and since I am taking a specialization in=20 seismology I would need
your collaboration for any information. I = need,=20 because of my studies,
of a software for the casual generation of=20 accelerogramm and, then, I
want to acquire of the seismograph for = measure the=20 vibrations on bodies.
You apologize are OT but I have urgent need of = these=20 information. There
I beg answer Antonio Cacosso gidod@.............
 Subject: Re: Pheraps OT From: The Lahrs JohnJan@........ Date: Sat, 20 Nov 1999 16:47:52 -0700 Antonio, Welcome to the PSN list. Where are you studying seismology? I assume you have already seen Larry's web site at http://psn.quake.net/ . John At 04:14 PM 11/20/99 +0100, you wrote: >>>> Hail to all the participants to the newsgroup. I am a new element of the group and since I am taking a specialization in seismology I would need your collaboration for any information. I need, because of my studies, of a software for the casual generation of accelerogramm and, then, I want to acquire of the seismograph for measure the vibrations on bodies. You apologize are OT but I have urgent need of these information. There I beg answer Antonio Cacosso gidod@............. Arial6f6f,6d6d,3e3e Arial6f6f,6d6d,3e3e John C. Lahr 1925 Foothills Road Golden, CO 80402 (303) 215-9913 http://lahr.org/john-jan I am only one, But still I am one. I cannot do everything, and because I cannot do everything, I will not refuse to do the something that I can do. Edward Everette Hale _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: SDR on W98 From: Larry Cochrane cochrane@.............. Date: Sat, 20 Nov 1999 21:53:06 -0800 Karl, I'm not sure. If the DOS the comes with Win98 after booting to the pure DOS mode can read the disk,it should be OK. There may also be a problem with SDR and DOS with partitions greater then 2G so I would partition the drive so that no logical drive is greater the 2G. Let me know what happens.... -Larry Cochrane Redwood City, PSN At 01:25 PM 11/19/99 -0800, you wrote: >Hi all -- > >I've been running SDR on a W95 system with a 540MB hard disk, and have been >thinking about putting a larger hard disk in it. Does SDR work OK with W98 >and a FAT32 partition? > > >Karl Cunningham >La Mesa, CA. >PSN station #40 >karlc@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: quake coming in From: meredith lamb mlamb1@.......... Date: Sun, 21 Nov 1999 00:02:04 -0800 Hi all, Getting classic P-S signal here now. Could be relatively near by ~ afew thousand miles from Denver.....?? Starting to smear the SDR computer monitor screen somewhat. Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: quake coming in From: Canie canie@........... Date: Sat, 20 Nov 1999 23:41:03 -0800 How about this: The following is from the United States Geological Survey, National Earthquake Information Center: preliminary hypocenter for earthquake of 1999 nov 21, CHILE-BOLIVIA BORDER REGION, about 85 miles (140 km) NNE of Calama, Chile: latitude 21.3 degrees south longitude 68.6 degrees west origin time 03 51 15.3 utc depth 100, magnitude 6.1 mb. Canie At 12:02 AM 11/21/99 -0800, you wrote: >Hi all, > >Getting classic P-S signal here now. Could be relatively >near by ~ afew thousand miles from Denver.....?? Starting to >smear the SDR computer monitor screen somewhat. > >Meredith Lamb > > > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: quake coming in From: "David A. Nelson" davenn@........ Date: Sun, 21 Nov 1999 21:23:38 +1300 At 23:41 20/11/99 -0800, you wrote: >How about this: >The following is from the United States Geological Survey, National >Earthquake Information Center: preliminary hypocenter for >earthquake of 1999 nov 21, CHILE-BOLIVIA BORDER REGION, about 85 >miles (140 km) NNE of Calama, Chile: latitude 21.3 degrees south >longitude 68.6 degrees west origin time 03 51 15.3 utc depth 100, >magnitude 6.1 mb. >Canie later than that Carnie approx 06:30 odd as shown on the berkeley trace ummm its flatlining for that time on the 6.1 event u posted info on unless they screwed up their time ??? Dave Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 23 Duncan St., Dunedin, South Is.. New Zealand. http://www.seismicnet.com/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Earthquake Electronics Project From: Phil Schmidt pgschmidt@............... Date: Sun, 21 Nov 1999 23:16:29 +1000 G'day All I was going throught the Electronics section of the newsagent the other day and I came across this months Electronics Now magazine featuring an article on a seismic detector. The whole project is created around a 10Hz vibration sensor used in the oil industry. The sensor is coupled to a PIC microcontroler with an internal 8 bit ADC. The sample rate is 16 times a second and a serial FLASH memory chip is also included for storage of up to 1 minute of data. If you are interested the web site for the publishers is http://www.gernsback.com/ And the web page for this months edition is at the following address http://www.gernsback.com/noframe/en/current/ENcontents_nf.html Please let me know if this information is of any use to anybody. Yours Philip Schmidt Australia _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: R: Pheraps OT From: "Antonio Cacosso" gidod@............. Date: Sun, 21 Nov 1999 09:21:40 +0100 Hi, I study seismology in Italy, to the university of Basilicata with = center to Potenza. Could you help me to resolve the problem formulated = in precedence? Hi and still thank you. Antonio Cacosso gidod@............. ----- Original Message -----=20 From: The Lahrs=20 To: PSN-L Mailing List=20 Sent: Sunday, November 21, 1999 12:47 AM Subject: Re: Pheraps OT Antonio, Welcome to the PSN list. Where are you studying seismology? I assume you have already seen Larry's web site at http://psn.quake.net/ . John At 04:14 PM 11/20/99 +0100, you wrote:=20 >>>> Hail to all the participants to the newsgroup. I am a new element of = the group and since I am taking a specialization in seismology I would = need your collaboration for any information. I need, because of my = studies, of a software for the casual generation of accelerogramm and, then, = I want to acquire of the seismograph for measure the vibrations on = bodies. You apologize are OT but I have urgent need of these information. = There I beg answer Antonio Cacosso gidod@............. John C. Lahr 1925 Foothills Road Golden, CO 80402 (303) 215-9913 http://lahr.org/john-jan I am only one, But still I am one. I cannot do everything, and because I cannot=20 do everything, I will not refuse=20 to do the something that I can do. Edward Everette Hale _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of = the message: leave PSN-L
Hi, I study seismology in Italy, to = the university=20 of Basilicata with center to Potenza. Could you help me to resolve the = problem=20 formulated in precedence?
Hi and still thank you.
Antonio Cacosso=20 gidod@.............
----- Original Message -----
From:=20 The = Lahrs
Sent: Sunday, November 21, 1999 = 12:47=20 AM
Subject: Re: Pheraps OT

Antonio,

Welcome to the PSN list. Where are you = studying=20 seismology? I assume
you have already seen Larry's web site at http://psn.quake.net/ = ..

John

At=20 04:14 PM 11/20/99 +0100, you wrote:
>>>>
Hail to all the participants to the newsgroup. I = am a=20 new element of the
group and since I am taking a specialization = in=20 seismology I would need
your collaboration for any information. I = need,=20 because of my studies,
of a software for the casual generation of = accelerogramm and, then, I
want to acquire of the seismograph for = measure=20 the vibrations on bodies.
You apologize are OT but I have urgent = need of=20 these information. There
I beg answer Antonio Cacosso=20 gidod@.............




John=20 C. Lahr
1925 Foothills Road
Golden, CO 80402
(303)=20 215-9913
http://lahr.org/john-jan

I am only one, But still I = am=20 one.
I cannot do everything, and because I cannot
do = everything, I will=20 not refuse
to do the something that I can do.
Edward Everette=20 = Hale
_________________________________________________________________= ____
Public=20 Seismic Network Mailing List (PSN-L)
To leave this list email=20 listserver@.............. with the body of the message: leave=20 PSN-L Subject: Re: Earthquake Electronics Project From: The Lahrs JohnJan@........ Date: Sun, 21 Nov 1999 06:55:29 -0700 Philip, Thanks for the information on a seismic detector. I found a .zip file in the magazine's archive section ( ftp://ftp.gernsback.com/pub/EN/seismic.zip ) which I think may be the information on this system. It is a triggered system that one can set up via com port connection to a computer, then remove from the computer and set up in the field. Later the system is returned to the computer for downloading the triggered events into the computer, again via the com port. This may be an interesting device for looking at local earthquakes, but not teleseisms. I believe the author is Ron Newton of Carson City, NV.( sjnewt@....... ). Maybe he will join the PSN discussion group. John At 11:16 PM 11/21/99 +1000, you wrote: >G'day All > >I was going throught the Electronics section of the newsagent the other day >and I came across this months Electronics Now magazine featuring an article >on a seismic detector. The whole project is created around a 10Hz vibration >sensor used in the oil industry. The sensor is coupled to a PIC >microcontroler with an internal 8 bit ADC. The sample rate is 16 times a >second and a serial FLASH memory chip is also included for storage of up to >1 minute of data. If you are interested the web site for the publishers is > >http://www.gernsback.com/ > >And the web page for this months edition is at the following address > >http://www.gernsback.com/noframe/en/current/ENcontents_nf.html > >Please let me know if this information is of any use to anybody. > > >Yours > >Philip Schmidt >Australia > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) >See this web site for more information on the PSN: http://psn.quake.net/ > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L > John C. Lahr 1925 Foothills Road Golden, CO 80402 (303) 215-9913 http://lahr.org/john-jan I am only one, But still I am one. I cannot do everything, and because I cannot do everything, I will not refuse to do the something that I can do. Edward Everette Hale _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: R: Pheraps OT From: The Lahrs JohnJan@........ Date: Sun, 21 Nov 1999 07:11:35 -0700 At 09:21 AM 11/21/99 +0100, Antonio wrote: >>>> Hi, I study seismology in Italy, to the university of Basilicata with center to Potenza. Could you help me to resolve the problem formulated in precedence? Hi and still thank you. ***** Antonio, What you build depends on the earthquakes that you want to record and how much time and money you have to spend. Larry Cochrane's web site ( http://psn.quake.net/ ) has a lot of information on building seismometers and setting up the necessary AD within your computer to record and playback the data. Larry sells many of the necessary components at a good price. This type of system can be set up to record either local or teleseismic events, depending on the seismometer used. At the other extreme, I have a table-top demonstration of seismology that uses a very inexpensive ~10Hz exploration geophone and an AD with software sold by DaTaq for $100. This is good for demonstrating how seismology works and could even record local events. There is a description of the setup here: http://lahr.org/john-jan/handson/ I've also used this same AD with a home-build seismometer that can record teleseismic events. There is a description here: http://lahr.org/john-jan/psn/gldn_psn.html By the way, what does OT mean? Hope this helps a bit. John John C. Lahr 1925 Foothills Road Golden, CO 80402 (303) 215-9913 http://lahr.org/john-jan I am only one, But still I am one. I cannot do everything, and because I cannot do everything, I will not refuse to do the something that I can do. Edward Everette Hale _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: quake coming in From: Canie canie@........... Date: Sun, 21 Nov 1999 10:59:02 -0800 OK then - then here's one about that time: The following is from the United States Geological Survey, National Earthquake Information Center: preliminary hypocenter for earthquake of 1999 nov 21, OFF COAST OF JALISCO, MEXICO, about 180 miles (290 km) SW of Puerto Vallarta, Jalisco, Mexico: latitude 18.7 degrees north longitude 107.2 degrees west origin time 06 46 23.6 utc depth 60, magnitude 5.6 ms. At 09:23 PM 11/21/99 +1300, you wrote: >later than that Carnie approx 06:30 odd as shown on the berkeley trace > > ummm its flatlining for that time on the 6.1 event u posted info on unless >they screwed up their time ??? > >Dave >Co-ordinator: >New Zealand _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: quake coming in From: barry lotz gbl@....... Date: Sun, 21 Nov 1999 11:11:57 -0800 I like that time. I didn't see it posted on NEIS or Red Puma yet. Barry Canie wrote: > OK then - then here's one about that time: > The following is from the United States Geological Survey, National > Earthquake Information Center: preliminary hypocenter for > earthquake of 1999 nov 21, OFF COAST OF JALISCO, MEXICO, about 180 > miles (290 km) SW of Puerto Vallarta, Jalisco, Mexico: latitude > 18.7 degrees north longitude 107.2 degrees west origin time 06 46 > 23.6 utc depth 60, magnitude 5.6 ms. > > At 09:23 PM 11/21/99 +1300, you wrote: > > >later than that Carnie approx 06:30 odd as shown on the berkeley trace > > > > ummm its flatlining for that time on the 6.1 event u posted info on unless > >they screwed up their time ??? > > > >Dave > >Co-ordinator: > >New Zealand > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: R: Pheraps OT From: Greg ghost@............. Date: Sun, 21 Nov 1999 14:02:48 -0700 The Lahrs wrote: > By the way, what does OT mean? I think he's using it for "Off Topic." ,Greg _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Earthquake Electronics Project From: Edward Cranswick cranswick@........ Date: Sun, 21 Nov 1999 17:58:59 -0700 Philip & John & Ron- Philip, your post caught my eye, but John did a better job than I of spelunking through the website to find the pertinent data. A low-cost strong-motion sensor appropriate for mass deployments in seismogenic urban areas has been my Holy Grail for the past decade, and so this looks interesting. If you don't record the ground motions on both sides of the street, you can't explain why the building on one side fell down and the building on the other side did not: see Turkey . I did consider posting part of this message on the Poptronix forum but it became too complicated for me to figure out. -Edward The Lahrs wrote: > Philip, > Thanks for the information on a seismic detector. I found a .zip file > in the magazine's archive section > ( ftp://ftp.gernsback.com/pub/EN/seismic.zip ) which I think may > be the information on this system. It is a triggered system that > one can set up via com port connection to a computer, then remove > from the computer and set up in the field. Later the system is > returned to the computer for downloading the triggered events into > the computer, again via the com port. > > This may be an interesting device for looking at local earthquakes, > but not teleseisms. > > I believe the author is Ron Newton of Carson City, NV.( sjnewt@....... ). > Maybe he will join the PSN discussion group. > > John > > At 11:16 PM 11/21/99 +1000, you wrote: > >G'day All > > > >I was going throught the Electronics section of the newsagent the other day > >and I came across this months Electronics Now magazine featuring an article > >on a seismic detector. The whole project is created around a 10Hz vibration > >sensor used in the oil industry. The sensor is coupled to a PIC > >microcontroler with an internal 8 bit ADC. The sample rate is 16 times a > >second and a serial FLASH memory chip is also included for storage of up to > >1 minute of data. If you are interested the web site for the publishers is > > > >http://www.gernsback.com/ > > > >And the web page for this months edition is at the following address > > > >http://www.gernsback.com/noframe/en/current/ENcontents_nf.html > > > >Please let me know if this information is of any use to anybody. > > > > > >Yours > > > >Philip Schmidt > >Australia > > > > > >_____________________________________________________________________ > > > >Public Seismic Network Mailing List (PSN-L) > >See this web site for more information on the PSN: http://psn.quake.net/ > > > >To leave this list email listserver@.............. with the body of the > >message: leave PSN-L > > > John C. Lahr > 1925 Foothills Road > Golden, CO 80402 > (303) 215-9913 > http://lahr.org/john-jan > > I am only one, But still I am one. > I cannot do everything, and because I cannot > do everything, I will not refuse > to do the something that I can do. > Edward Everette Hale > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Meeting From: George Harris gjharris@............. Date: Sat, 20 Nov 1999 22:58:04 -0500 Larry, Count me in for the meeting on the 18th. George Harris _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Earthquake Electronics Project From: barry lotz gbl@....... Date: Sun, 21 Nov 1999 19:03:26 -0800 Ed et al It's based on the 10 hz geophone advertised by All Electronics. I have used one with other circuitry and it worked for me @ distances < ~200km. The article uses an 8 bit A/D and about 60 sec of storage at 16 s/sec. Barry Edward Cranswick wrote: > Philip & John & Ron- > Philip, your post caught my eye, but John did a better job than I of > spelunking through the website to find the pertinent data. A low-cost > strong-motion sensor appropriate for mass deployments in seismogenic urban areas > has been my Holy Grail for the past decade, and so this looks interesting. If > you don't record the ground motions on both sides of the street, you can't > explain why the building on one side fell down and the building on the other > side did not: see Turkey . > I did consider posting part of this message on the Poptronix forum > > but it became too complicated for me to figure out. > -Edward > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: MAKING A SHORT PERIOD SEISMO DETECT TELESICMIC EVENTS From: RADIOTEL@....... Date: Sun, 21 Nov 1999 22:50:19 EST ALL LIST MEMBERS If memory serves, I believe Jeff Batten once wrote that you could make a short period seismograph (6 sec.) detect teleseismic events by using a long period filter (20 seconds. I believe he also wrote that you could make it detect both teleseismic and local events by connecting the output simutaneously to a long period filter and a short period filter and summing the outputs of both using a summing amplifier. Does anyone know whether I got this right and has anyone tried it. Is Jeff still around - I have not seen a posting from him in a very long time? Is this a better (easier to make for someone not versed in electronics) approach than using an equalising circuit such as described by Roberts in BSSA? BTW, my seismograph is a velocity model of the STM-8 at a period of about 5.5 seconds. Jim Allen Cerritos, Calif. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: PSN Meeting From: Jim E ODonnell jimo17@........ Date: Mon, 22 Nov 1999 08:11:21 -0800 Larry- I would like to attend this year. UCB is my alma mater so that sounds like fun! Keep me posted. Jim O'Donnell 661 Del Prado Dr. Boulder City, NV 89005 702 293-5664 Registered Geologist No. 1240, State of California, 1970 Registered Geophysicist No.158, State of California, 1974 _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: [Fwd: Earthquake Electronics Project] From: Edward Cranswick cranswick@........ Date: Mon, 22 Nov 1999 16:50:40 -0700 Ron- You have to register with the PSN-L if you want to send email to the mailserver (see ). In the meantime, I have forwarded your email to the list. -Edward -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". Edward: I tried to foward this to your psn but it returned as blocked. This device may be what you are looking for as it is inexensive and will last about a year on a set of D cells. Greetings everyone. In answer to Johns Lahrs' E-mail, I was the one that wrote the article on building a seismic detector in Electronics Now. I am not a geologist or seismologist but am interested in many areas of science. I am a chemist and electronics engineer and having spent most of my life time in the medical field. You will have to educate me about teleseisms. I can also be reached during the day @ 800-627-4928 and evenings @ 775 885-8842. For those who can't get a copy of the article, give me an E-mail and I will try to scan it. I also have the files zipped that were on the Electronics Now Web site. Ron Newton 2230 Damon Rd. Carson City, NV 89701 Thanks, Ron Subject: FREE Filter design program From: Phil Schmidt pgschmidt@............... Date: Tue, 23 Nov 1999 12:28:33 +1000 G'day all In my travels over the various electronic company websites on the net, I came across this software on the Microchip Website. It is a software package called FILTER-LAB it is FREE and is used for designing active filters. I have not had a chance to look at it yet but for those interested take a look at the following net address http://www.microchip.com/10/Tools/analog/flab/index.htm Hope it is of interest to someone. Beware the file is 4.2 Mb Yours Philip Schmidt Australia _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Meeting From: Keith Payea kpayea@...................... Date: Mon, 22 Nov 1999 19:30:40 -0800 Count me in for the meeting. I'll probably need directions. Keith Payea _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: New WinQuake beta release. From: Larry Cochrane cochrane@.............. Date: Mon, 22 Nov 1999 23:05:40 -0800 All, I have a new WinQuake beta release available on my system at http://www.seismicnet.com/software.html. This release fixes a few bugs reported to me recently and several new features / improvements. The version number is 2.6.7 with a release date of 11/17/99. I fixed an old bug, there since I wrote the code that allows one to save the view only (cropping the event file). This bug would show up only if the event file spans a day and the start time of the new event file started after the new day. Example: if the event file started at 23:30 UTC and ended the next day at say 01:30, and if the start time of the cropped event file started at 00:30 the created event file would have bad date information in the header and WinQuake would not read the new event file in. I wasn't compensating for the date change. The other bug I fixed started with the new beta version and had to do with the colors of the P and S markers and the background color. Everything worked fine if the P and S markers had a darker color then the background. If the background was lighter then the markers they would not show up. I added, by request, a clear button in the Modify dialog box. This clears out any event report information. I added support in the GIF saving feature for 32k color video setting. Before WinQuake could only save GIF images with the proper colors if one had the video settings set to 256 or 65K (16 bit) color modes. I recently changed video cards that had 256, 32k and True Color modes. My old card had 256, 65k and True Color and when I saved an event file as a gif image it worked fine with the card set to 65k. With my new card set to 32k, the colors were off when I saved gif images. I figured out the problem but had problems with Windows in figuring out what mode the card was in so I added a check box in the GIF Settings dialog box. This dialog is accessible in the Save File dialog box when the Save Format is set to GIF Image. Unfortunately WinQuake still does not support saving files as a GIF image with True Color video mode selected. And in the View menu item I added a selection so that the new PSN Explorer can be started. If you use WinQuake please try out the new beta release and let me know if you run into any problems. I hope to make this the final beta release if no major problems are reported. Thanks, -Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: New WinQuake beta release. From: "J. D. Cooley" cooleyj@............ Date: Mon, 22 Nov 1999 23:35:14 -0800 At 11:05 PM 11/22/99 , you wrote: >All, > >I have a new WinQuake beta release available on my system at >http://www.seismicnet.com/software.html. This release fixes a few bugs >reported to me recently and several new features / improvements. The >version number is 2.6.7 with a release date of 11/17/99. Larry, I downloaded 2.6.7 this morning when I got home from work and used it. When I move the P and S markers they smear the screen. Do I need to change some settings somewhere? Thank you for all your hard work on WinQuake. It is GREAT. "JD" Cooley cooleyj@............ jdcooley@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: New WinQuake beta release. From: Larry Cochrane cochrane@.............. Date: Mon, 22 Nov 1999 23:58:26 -0800 At 11:35 PM 11/22/99 -0800, "JD" wrote: >Larry, > >I downloaded 2.6.7 this morning when I got home from work and used it. >When I move the P and S >markers they smear the screen. Do I need to change some settings somewhere? > >Thank you for all your hard work on WinQuake. It is GREAT. > >"JD" Cooley >cooleyj@............ >jdcooley@....... "JD", The only setting I can think of that might effect the drawing of the P and S markers is the "Quick Draw" option under the Options menu item. Let me know if it makes a difference if its on or off. If anyone is having problems with this option turned on please let me know. I think the default is off, so you might need to turn it on. It uses a little more memory but the drawing of the data in the window should be a little faster. I would like to remove this option and leave it in the on mode all of the time. -Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: New WinQuake beta release. From: "J. D. Cooley" jdcooley@....... Date: Tue, 23 Nov 1999 06:15:53 -0800 At 11:58 PM 11/22/99 -0800, you wrote: >At 11:35 PM 11/22/99 -0800, "JD" wrote: >>Larry, >> >>I downloaded 2.6.7 this morning when I got home from work and used it. >>When I move the P and S >>markers they smear the screen. Do I need to change some settings somewhere? >> >>Thank you for all your hard work on WinQuake. It is GREAT. >> >>"JD" Cooley >>cooleyj@............ >>jdcooley@....... > >"JD", > >The only setting I can think of that might effect the drawing of the P and >S markers is the "Quick Draw" option under the Options menu item. Let me >know if it makes a difference if its on or off. > >If anyone is having problems with this option turned on please let me know. >I think the default is off, so you might need to turn it on. It uses a >little more memory but the drawing of the data in the window should be a >little faster. I would like to remove this option and leave it in the on >mode all of the time. > >-Larry Cochrane >Redwood City, PSN Larry, I still have a smear no matter what I try. I have tried the re-draw on and off, changed the color on my monitor (16 bit, 32 bit, true color), and tried changing the speed of my mouse! I have not had any trouble with previous versions of WinQuake. My computer is an almost new Toshiba notebook. The display is a 13.3-inch, 1024 x 768 resolution, TFT active matrix color display. "JD" _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Gravity and quakes From: RLLaney@....... Date: Tue, 23 Nov 1999 10:33:26 EST Hi all: The exerpt below was sent by a friend of mine in Tucson. Thought the group might find it interesting. Bob Laney Herndon, VA ++++++++++++++++++++++++++++++++++++++++++++++++ "Dear Bob, I have a pretty good story to pass along to you. You may remember Gordon Wieduwilt who was a local geophysical contractor here in Tucson for many years. He is now mostly retired, works about 1/4 time out of a small office in his home. He was down in Mexico last week doing a gravity survey and at one station he had a terrible time getting the meter to stabilize so that he could take a reading. He turned it off and on several times and still the same peg-to-peg needle deflection. Finally he realized that a large earth quake was probably in progress somewhere. It turned out the be the one in Turkey last Thursday afternoon. It took the shock about 103 minutes to arrive in northern Mexico which works out to about 6,000 feet per second. I'd be curious to know if you detected that one as well. Maybe we don't need seismometers but only gravity meters." +++++++++++++++++++++++++++++++++++++++++++++++++++ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: New WinQuake beta release. From: Wayne Abraham J73WA abrahamw@........ Date: Tue, 23 Nov 1999 14:24:12 -0400 Larry I downloaded the new winquake and there is no smearing when I move the P and S markers. It makes no difference if Quick Redraw is off or on. I have mine set at the default - OFF. Wayne "J. D. Cooley" wrote: > At 11:58 PM 11/22/99 -0800, you wrote: > >At 11:35 PM 11/22/99 -0800, "JD" wrote: > >>Larry, > >> > >>I downloaded 2.6.7 this morning when I got home from work and used it. > >>When I move the P and S > >>markers they smear the screen. Do I need to change some settings somewhere? > >> > >>Thank you for all your hard work on WinQuake. It is GREAT. > >> > >>"JD" Cooley > >>cooleyj@............ > >>jdcooley@....... > > > >"JD", > > > >The only setting I can think of that might effect the drawing of the P and > >S markers is the "Quick Draw" option under the Options menu item. Let me > >know if it makes a difference if its on or off. > > > >If anyone is having problems with this option turned on please let me know. > >I think the default is off, so you might need to turn it on. It uses a > >little more memory but the drawing of the data in the window should be a > >little faster. I would like to remove this option and leave it in the on > >mode all of the time. > > > >-Larry Cochrane > >Redwood City, PSN > > Larry, > > I still have a smear no matter what I try. I have tried the re-draw on and > off, > changed the color on my monitor (16 bit, 32 bit, true color), and tried > changing > the speed of my mouse! I have not had any trouble with previous versions > of WinQuake. > > My computer is an almost new Toshiba notebook. The display is a 13.3-inch, > 1024 x 768 resolution, TFT active matrix color display. > > "JD" > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L -- Wayne Abraham 1430 Rodney Street Portsmouth, Dominica abrahamw@........ http://www.freeyellow.com/members6/dominicapsn/ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: New WinQuake beta release. From: "Mark Robinson" other@............... Date: Wed, 24 Nov 1999 08:06:02 +1300 do you have mouse trails switched on by any chance ? Mark ----- Original Message ----- From: J. D. Cooley To: PSN-L Mailing List Sent: Wednesday, 24 November 1999 03:15 Subject: Re: New WinQuake beta release. > At 11:58 PM 11/22/99 -0800, you wrote: > >At 11:35 PM 11/22/99 -0800, "JD" wrote: > >>Larry, > >> > >>I downloaded 2.6.7 this morning when I got home from work and used it. > >>When I move the P and S > >>markers they smear the screen. Do I need to change some settings somewhere? > >> > >>Thank you for all your hard work on WinQuake. It is GREAT. > >> > >>"JD" Cooley > >>cooleyj@............ > >>jdcooley@....... > > > >"JD", > > > >The only setting I can think of that might effect the drawing of the P and > >S markers is the "Quick Draw" option under the Options menu item. Let me > >know if it makes a difference if its on or off. > > > >If anyone is having problems with this option turned on please let me know. > >I think the default is off, so you might need to turn it on. It uses a > >little more memory but the drawing of the data in the window should be a > >little faster. I would like to remove this option and leave it in the on > >mode all of the time. > > > >-Larry Cochrane > >Redwood City, PSN > > Larry, > > I still have a smear no matter what I try. I have tried the re-draw on and > off, > changed the color on my monitor (16 bit, 32 bit, true color), and tried > changing > the speed of my mouse! I have not had any trouble with previous versions > of WinQuake. > > My computer is an almost new Toshiba notebook. The display is a 13.3-inch, > 1024 x 768 resolution, TFT active matrix color display. > > "JD" > > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: New WinQuake beta release. From: "J. D. Cooley" jdcooley@....... Date: Tue, 23 Nov 1999 14:01:20 -0800 At 08:06 AM 11/24/99 +1300, you wrote: >do you have mouse trails switched on by any chance ? > >Mark No. I checked that also. "JD" _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: New WinQuake beta release. From: ted@.......... Date: Tue, 23 Nov 1999 17:37:54 -0500 I am also getting "mouse trails" from the new beta release. When the P pointer is dragged, the point at the bottom of the P, and the bottom of the right part of the arrow head, leave black trails on the screen. It looks kind of like this: /|\ / | \ / | \ / | \ | * *.. * . . * .... * . * . . * * * In this picture I just moved the P pointer to the upper right, and the lines of asterisks can be seen trailing from the two points mentioned above. Regards, Ted Blank _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: New WinQuake beta release. From: Larry Cochrane cochrane@.............. Date: Tue, 23 Nov 1999 18:23:50 -0800 All, I am able to duplicate the problem on my test Win98 system. I will try and have a bug fix out in a few hours now that I can see the problem. -Larry At 02:01 PM 11/23/99 -0800, you wrote: >At 08:06 AM 11/24/99 +1300, you wrote: >>do you have mouse trails switched on by any chance ? >> >>Mark > >No. I checked that also. > >"JD" _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Thanksgiving Wishes to all... From: meredith lamb mlamb1@.......... Date: Wed, 24 Nov 1999 12:01:21 -0800 Hi all, If you observe the Thanksgiving holiday; I wish you and all those that don't, a very nice day; and of course a brighter future. Take care, Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Gravity and quakes From: Robert Avakian ravakian@............ Date: Wed, 24 Nov 1999 18:33:51 -0800 No surprise there since a meter is really just a mass humg on a spring. However, the spring are pretty amazing. The ones in the Lacoste portable instruments are made of fused quartz. As far as using one as a seismograph, the meters measure idsplace ment of the mass on the spring and, as such, detect the earth tides and must be corrected for this "diurnal" effect. One problem we do not deal with when measuring velocity or acceleration. One thing about the LaCoste meters of interest to those who enclose their seismographs. The the works of the meter are heated by an onboard battery to a temperature at least 5 degrees above the maximum expected ambient. The thermostats are sloid state, but were originally a mercury device. This , and the heating, required you keep the meter and carrier fairly upright and the batteries charged or you would suffer a thermal "tear" in your survey. Would be interesting to know what kind of meter he had. Bob Avakian ..RLLaney@....... wrote: > > Hi all: > > The exerpt below was sent by a friend of mine in Tucson. Thought the group > might find it interesting. > > Bob Laney > Herndon, VA > ++++++++++++++++++++++++++++++++++++++++++++++++ > "Dear Bob, > > I have a pretty good story to pass along to you. You may > remember Gordon Wieduwilt who was a local geophysical contractor here in > Tucson for many years. He is now mostly retired, works about 1/4 time > out of a small office in his home. He was down in Mexico last week doing > a gravity survey and at one station he had a terrible time getting the > meter to stabilize so that he could take a reading. He turned it off and > on several times and still the same peg-to-peg needle deflection. > > Finally he realized that a large earth quake was probably in > progress somewhere. It turned out the be the one in Turkey last Thursday > afternoon. It took the shock about 103 minutes to arrive in northern > Mexico which works out to about 6,000 feet per second. > > I'd be curious to know if you detected that one as well. Maybe > we don't need seismometers but only gravity meters." > > +++++++++++++++++++++++++++++++++++++++++++++++++++ > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: New WinQuake beta release From: Larry Cochrane cochrane@.............. Date: Wed, 24 Nov 1999 23:41:52 -0800 All WQ Beta testers, I hopefully fixed the P and S marker trails problem. The new beta release can be downloaded here: http://www.seismicnet.com/software.html. The release number is 2.6.8 with a release date of 11/24/99 I made an executive decision and decided to only release one version of the winqk32.exe program. The last few beta releases had two exes. One was for users running Win95 without Internet Explorer loaded on the system and the other for all of the other versions of Windows. It wasn't worth the extra hassle to maintain 2 versions of the program for a small gain in functionality. This beta version, like version 2.5 should run on all versions of Windows except 3.1. Since WQ is now a 32 bit program, I'm no longer maintaining the 16 bit version, it will only run on the newer operating systems. I also removed the "Quick Redraw" menu item under Options. Its now always on. This was something I need way back when for the 16 bit version. As always let me know if you see an more problems.... -Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: N. Cal PSN meeting Dec. 18th 10:00 am From: Larry Cochrane cochrane@.............. Date: Thu, 25 Nov 1999 00:10:22 -0800 Greetings, It looks like its a go for the meeting on Saturday Dec.18th at 10:00 am. We have about 15 members signed up. The location will be at the Berkeley Seismo Lab. I will post directions and more info later. We should try and carpool as much as possible since parking around the University can be a problem. Regards, Larry Cochrane _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Mid Willamette Valley Quake From: Eileen Clarke clarke@........ Date: Thu, 25 Nov 1999 07:13:38 -0800 Hi Just recorded a small earthquake about 6:30 am PST, this Thanksgiving morning. We are located approximately 45 miles south of Portland, Oregon, in the Willamette Valley. Steve _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: New WinQuake beta release From: ted@.......... Date: Thu, 25 Nov 1999 10:35:38 -0500 Problem with P- and S- marker trails appears to be fixed in 2.6.8 release. Thanks, Larry. Regards, Ted _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Mid Willamette Valley Quake From: Bob Fryer bfryer@............ Date: Thu, 25 Nov 1999 08:21:24 -0800 Hi Steve, I felt it -- woke up. I think! Was so sleepy that I thought clock said 5:52 -- but without putting on my glasses.... Interesting that I did not get an identifiable precursory ear tone for this PNW event; but not too surprising since my lead time is 21 - 24 hours, which means I probably slept through it. Note: Started getting precursory tones about two years ago. Take care, Bob Fryer >Hi > >Just recorded a small earthquake about 6:30 am PST, this Thanksgiving >morning. We are located approximately 45 miles south of Portland, Oregon, >in the Willamette Valley. >Steve ----- earthquake WARNING research ----- --- animals, people, scientific evidence --- --- http://www.teleport.com/~bfryer --- _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Mid Willamette Valley Quake From: Seisguy@....... Date: Thu, 25 Nov 1999 11:37:09 EST In a message dated 11/25/99 8:24:04 AM Pacific Standard Time, bfryer@............ writes: << I felt it -- woke up. I think! >> Happy Thanksgiving Bob and Steve! Here's the scoop from the NEIC: 99/11/25 14:46:16 45.11N 122.77W 29.0 3.5Md WASH-OREGON BDR REG Mike O'Bleness San Diego (but spending the holidays in Joshua Tree) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Mid Willamette Valley Quake From: Seisguy@....... Date: Thu, 25 Nov 1999 12:09:57 EST The following is from the United States Geological Survey, National Earthquake Information Center: Preliminary hypocenter for earthquake of 1999 Nov 25, WASHINGTON-OREGON BORDER REGION: latitude 45.1 degrees north, longitude 122.8 degrees west, origin time 14 46 16.0 utc, depth shallow, magnitude 3.5 MD. The earthquake was felt from Portland to Salem, Oregon and also at Brush Prairie, Washington. There have been no reports of damage. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: This is my way. From: EK kerls@...... Date: Thu, 25 Nov 1999 20:29:40 -0600 To see what I have been telling you about for the last sex months and the person that runs this lest keeps saying that my work is to much for the lest , or what ever . just see for yourself . what new hight-tech for detecting earthquakes will be. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: From: EK kerls@...... Date: Thu, 25 Nov 1999 20:31:32 -0600 Sorry I didn't give the site; www.jpl.nasa.gov/hectormine _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Interferometric map of the Hector Mine earthquake From: Larry Cochrane cochrane@.............. Date: Thu, 25 Nov 1999 18:44:41 -0800 Interesting site at: http://www.jpl.nasa.gov/hectormine/ Text from the page: The image is an interferometric map of the Hector Mine earthquake area showing the ground displacement along the radar line of sight. One full color cycle represents 10 cm of range displacement. Gray areas are zones of low phase coherence that have been masked before unwrapping. Dotted lines depict California faults, after Jennings (1975), and thick, solid lines the Landers , 1992 surface rupture, after Sieh et al. (1993). Thin, solid lines within zone of dense fringes are surface breaks inferred from azimuth and range disparities (offsets) between before and after images, and phase discontinuities. The topographic phase has been removed using a combination of the USGS 30 m and 90 m digital elevation maps. The rapid orbits from the ESA D-PAF were used to determine the interferometric baseline and to flatten the map. A small phase ramp was removed manually to minimize the far field displacement. Processing from RAW data to interferogram and geocoded map was done using the JPL/Caltech ROI_PAC software package. The radar data were acquired by the European Space Agency ERS-2 satellite on September 15 and October 20, 1999. The data used here cover frames 2907 and 2925 of descending track 127. The post-earthquake data were purchased from Eurimage and transfered from the Centre Canadien de Teledetection to JPL via FTP. -Larry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Vanuatu Isl event From: barry lotz gbl@....... Date: Fri, 26 Nov 1999 09:08:48 -0800 Well I must not have been that awake. My event longitude coordinate should be 168.18E not 168.18w. I was wondering why my time for the P arrival was 80 sec off :) Barry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: New WinQuake beta release From: RLLaney@....... Date: Fri, 26 Nov 1999 14:09:06 EST Hi Larry: I downloaded the version 2.6.8. You may recall that a month or so ago I could not get the New Event Files button on the tool bar to work, and could not get PSN Explorer to work. I how have a new computer with IE 5.0 as part of the included software. The New Event File button works fine, but under View, the PSN Explorer option is not highlighted. It works if I go to the Winquake directory and double click on the psnexplorer.exe file, but it is not available under the Veiw tab. Anyone else having a problem with this? Otherwise, WinQuake improves with every new version! Bob Laney Herndon, VA _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Guadeloupe From: Wayne Abraham J73WA abrahamw@........ Date: Fri, 26 Nov 1999 16:18:00 -0400 PSN It has been a few months now since I've heard rumours of heightened activity at the Soufri=E8re volcano in our neighbouring island of Guadeloupe but it was only confirmed this morning in a news item on a caribbean radio station stating that there is increased cooperation between the Montserrat Volcano Observatory and Guadeloupe as there is increased gas emission from the volcano. Does anybody on this list have links or information on that volcano and the scientific work being done there? This volcano is only 35 miles from my home. Wayne. -- Wayne Abraham 1430 Rodney Street Portsmouth, Dominica abrahamw@........ http://www.freeyellow.com/members6/dominicapsn/ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Guadeloupe From: Greg ghost@............. Date: Fri, 26 Nov 1999 15:42:12 -0700 Wayne Abraham J73WA wrote: > between the Montserrat Volcano Observatory and Guadeloupe as there is > increased gas emission from the volcano. Does anybody on this list have > links or information on that volcano and the scientific work being done > there? This volcano is only 35 miles from my home. You do have a 1000 HP Ferrari in the garage right? To get away in a hurry, I mean. ;) If it is close to Montserrat, it will probably act similar to it. I think Montserrat is/was composite or felsic? I know someone will correct me on that, if I'm wrong. :) Please do so. Watch for an increase in seismic activity, if you're worried it's going to go. I'm thinking volcanos are pretty hard to predict, but it might be a good idea to think about where to run now, before it blows. Really. Seriously. I'm not kidding. All joking around aside. Don't wait for the alarms to sound, take a vacation in an ugly, boring place. Get as far away from paradise as necessary. Good luck, Greg _______________________________