From: Arie Verveer Subject: New Zealand Epicentre location. A Journey Date: Wed, 01 Apr 1998 07:50:08 +0800 Hi, I thought it may be fun to identify the location of an event, so here is my journey. I selected David Nelson's recent M5.0 with a probable location SW of New Zealand. The files are 980331B22.DNN and 980331B22.DNZ. Then using the origin time (17:17:51.9) from these files, I loaded in the my data and performed a 1 hertz High pass filter. To my surprise I found many phases but was unable to identify them. Then using Dave's station location / time as a first approximation, I identified the "P" and "LQ" phases. No "S" phase was found but there was a large phase between the P and LQ phases that wasn't account for. That phases was eventually identified via the IDC data base as a "P" wave from Nepal. NEPAL Ml4.0 17:19:18.1 27.90N by 85.43East at 17:30:00 UTC The New Zealand "P" wave was located and the "S" marker was moved until the "LQ" wave was located. A first approximation location was found using the program "Mapit", via the new distance from my location and Dave's estimates of the location. The epicenter location was re-entered into my data and a new distance and time was extracted. The data was updated in both files and the "Mapit" program was run to identified the final epicenter. Though in Dave's files, I found that the time information was out. So entering a time correction of -70 seconds the phases were aligned. Both stations magnitude estimates were within 0.4 mag. the final epicenter ? 51.14South 170.81East at 17:17:52.0 UTC March 31/ 1998 File : 980331b.au3 The journey ends or maybe it should have never started. Arie _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: Re: New Zealand Epicentre location. A Journey Date: Wed, 01 Apr 1998 21:43:56 +1200 Though in Dave's >files, I found that the time information was out. So entering a time >correction of -70 seconds >the phases were aligned. Arie explain what u mean by that ????? my clock accuracy is better than 0.5 of a second Dave Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/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) From: Edward Cranswick Subject: PSN recordsection of the 29 Mar 98 M6.4 Fiji Earthquake Date: Wed, 01 Apr 1998 05:41:48 -0700 PSN- The 29 Mar 98 M6.4 Fiji Earthquake was recorded by several PSN stations world-wide (NOTE: in my haste to get this on the Web, I absent-mindedly forgot to include several other excellent PSN records of this event: I apologize for that, and I will try to do better next time) and by a portable autonomous digital seismograph (PADS) equipped with a Guralp CMG-40T broadband (0.03-20 Hz) three-component velocity sensor being tested in the basement of the USGS Geologic Hazards building in Golden, Colorado (i.e., the location of the NEIC). The raw, unfiltered timeseries of the P-waves of this event (77 s are displayed) as recorded by 6 PSN stations and by the USGS PADS are shown in the pseudo-recordsection. -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) From: Edward Cranswick Subject: Recordsection of the M6.4 Fiji Earthquake Date: Wed, 01 Apr 1998 05:48:41 -0700 PSN- Having forgotten to include the URL of the recordsection website http://groundmotion.cr.usgs.gov/PSN/M6_4Fiji/29mar98.htm I am posting this message again. The 29 Mar 98 M6.4 Fiji Earthquake was recorded by several PSN stations world-wide (NOTE: in my haste to get this on the Web, I absent-mindedly forgot to include several other excellent PSN records of this event: I apologize for that, and I will try to do better next time) and by a portable autonomous digital seismograph (PADS) equipped with a Guralp CMG-40T broadband (0.03-20 Hz) three-component velocity sensor being tested in the basement of the USGS Geologic Hazards building in Golden, Colorado (i.e., the location of the NEIC). The raw, unfiltered timeseries of the P-waves of this event (77 s are displayed) as recorded by 6 PSN stations and by the USGS PADS are shown in the pseudo-recordsection. -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) From: Arie Verveer Subject: Re: New Zealand. Apology Date: Wed, 01 Apr 1998 21:57:50 +0800 Hi Dave, Please accept my apology if I offended you. It was an attempt to locate an epicentre and my only solution to the problem was to change your timing to fit my interpretations. It fitted very well but I was totally incorrect. There is lesson to be learnt, and I've just learnt it. What happened, was I missed the true event that fitted my data. It was an event at 17:19:16.3 UTC 51.842S by 156.7557E that was just north of Macquarie Island plus the Nepal event. I didn't record your event and assumed they were the same. The posting was written as an explanation on how the results were derived and no bad interpretations were meant. So please again, accept my apology and if you ever see me walking across a road, don't hesitate to run me over in your red Ferrari. All the Best. Arie > Though in Dave's > >files, I found that the time information was out. So entering a time > >correction of -70 seconds > >the phases were aligned. > > Arie explain what u mean by that ????? > > my clock accuracy is better than 0.5 of a second > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Edward Cranswick Subject: Re: Hello from Daly City Date: Wed, 01 Apr 1998 10:51:25 -0700 Bob- I apologize for taking so long to get back to you. First of all, please check out the following site http://groundmotion.cr.usgs.gov/PSN/Ogburn/DalyCity.htm which is incomplete, but it gives you some idea of what I was trying to do. I decided to use the opportunity raised by your questions as an exercise in learning more about what is available on the PSN. I found out that there is alot that I didn't know. Larry's program WINQUAKE is really excellent at looking at teleseismic data, something I have had little experience with. I am used to studying events within about a source-depth of their epicenter. John Lahr is used to looking at regional distance records. WINQUAKE has alot of teleseismic phase and traveltime info that I did not recognize at first. Anyway, I then got lost in Web consciousness, and I have run out of time to finish my response to you because I am leaving for Australia for three weeks this evening. I am very interested in your attempt to record in such an urban environment as Daly City, and I will get back to you more about noise and gain levels. By the way, what happened to your vertical sensor? Good luck! -Edward bob ogburn wrote: > > Hi... > > Thanks again for the meeting at Menlo Park, and I believe that USGS has > decided to stay there... > > I have records of what I believe are these events: > 4.8 98/03/05 21:49:40 36.07N 117.65W 5.0 17 mi ENE of LITTLE LAKE > 5.2 98/03/05 21:47:40 36.08N 117.62W 0.7 20 mi SSW of PANAMINT > SPRING > > Since my S-G sensor is 'lightly coupled' through the condo structure, > the records do not look that good, but they have a time signature and > energy pattern that to my untrained eye indicate that the may be these > events. > > The sensor is positioned as an E-W device. > > If I send the records (Ted Blanks format) could you look at them and let > me know what you think? > > Thanks > > Bob Ogburn > (650) 594-9700 X19 > Satake Research Institute > San Carlos, CA -- 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) From: Edward Cranswick Subject: PS. Re: poster etc. Date: Wed, 01 Apr 1998 11:33:54 -0700 Sean- I wanted to say that I am very impressed with your seismometer. When you got on the PSN-L at Xmas, I was going through my winter solistice spiritual doldrums and could not keep up with the complex technical background to the device. I am not much sharper now, but I am feeling more confident about understanding the system after you went over it at John Lahr's last fortnight. As I said in my previous email, you should definitely take your machine to the IRIS meeting in Santa Cruz this July. -Edward S-T Morrissey wrote: > > Ed, > I want to thank you for your support and interest in the PSN/school > seismometer project. Its' taken me all week to get back to you > about it, but I came back here to about a dozen "by the end of > the month" things that weren't on my list when I left. > > I noticed some information about an April poster presentation, > which seemed to be an internal USGS affair if I read it correctly, > but I was wondering IF you wanted my poster material to contribute, > or if it was even appropriate. If you want to use it, let me know. > Or if you want to post it near your AGU poster there at the USGS, > let me know, and I will mail it. > > The university here is continuing to support the idea of getting > patent protection for the hardware store seismometer, so that we > can make sure it remains available to everyone. It has been > suggested that if we agree to let a commercial company make the > sensor, that for every unit they sell at a commercial price, they > must make one unit available at cost to the E&O and PSN programs. > How to draw the line may be problematic; some schools DO have > lots of "science" money. Any suggestions? > > So I have been writing up a 15-page or so "Patent Disclosure" about > the seis. One interesting aspect is the question of "witnessing" > the progress of an invention in time; it so happens that an > operating seismograph does it just by recording earthquakes, > which are always unique in time. So the first "witnessed" > existence of the seis is the VBB record of the M7.5 Santa > Cruse Isl. (SW Pacific) last April 20, the day after I made > the prototype, when it was operating on the wooden garage floor. > > I also never got around to asking you want research you were > involved in there other than the PSN support, which I assume > is not specifically supported by the USGS ... or is it? > If you get a minute, fill me in. > > Thanks, > Sean-Thomas -- 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) From: "Conti Claudio" Subject: TELESEISMIC RECORDING Date: Wed, 1 Apr 1998 20:55:32 +0200 I RECORDED A TELESEISMIC TRACE AT 18 09.50 UTC PKP a.t. 18 09 50 arr.2 SK s 18 19 20 UTC. Small Phase L . Regards Conti Claudio Syracuse (Sicily) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: meredith lamb Subject: The April 1st 1998 Seismograph Date: Wed, 01 Apr 1998 11:53:30 -0700 The April seismograph is finally nearing non-completion as of this date. The following is a description of the component parts of this magnificient machine. The base plate measures 3' X 6' and is 3" thick and is solid titanium. Machining of the plate was done with afew dozen diamond bits of various sizes. The urpright mast is of the same material for proper temperature co-efficient effects and was cast as one piece at a local refinery along with the base plate. The boom is made from a long extruded synthetic red ruby bole, of a diameter of 2" and 5' long. Proper cooling was done to alleviate minor 3" cracks across the diameter. The pickup and damping coils are made of solid gold #98 wire, with a thin teflon coating to prevent shorts. The coils themselves are 6" in diameter by 1" thick. The coils are encompassed by two 340 pound neodymium magnets spaced 1/2" apart. Its wise to not wear any kind of metal when servicing these units, and as a precaution food intake is severly watched for iron content. So far 346 seismologists have made the mistake of wearing steel belt buckles while checking out the magnets. The scrap iron is a visually distracting nuisance. One seismologist wore an opposing magnetic belt buckle, and some other physicists tried to spin and levitate the poor fellow over the magnets. The servicing technicians fondly call these magnets "the black holes", although they are gold plated to alleviate oxidation. Other sensors have been comtemplated but they are non-traditional. The leveling screws use rather large geared down motors which are coupled to a computer which has a program to instantly orientate the platform level. The screws rest on diamond squares. The pier is a solid block of optical grade quartz from Brazil and measured 20' X 40' X 10', and was polished by a collaboration of 459 companys in Redeye, California. The El Nino effects accelerated polishing work by the recent constant rains. The finished block measured 20' X 40' X 10', and took 24 years to complete. The polishing process was tedious and called for engineer correction calculations and surface grinding marks directly on the rough block. Subsequent correction erasures gradually polished the block over geological time. Work came to a halt when a child bumped into the optically clear block and threatened to sue them all as a public nuisance. The coil output is fed into a large computer using a 78 bit A to D card with room for 680 more inputs. The computer automatically configures all data and prints out earth maps with all depth features in 20 meg bits per inch clarity. The display continually shows on a giant screen, and with a hand held remote it is capable of displaying the instant location, magnitude and various other data relating to any earthquake in the world down to a magnitude -.00056 with a gain of one. Attenuation efforts are proceeding. Occasionally the women use the device to check out which shopping center is having a sale. The unit is so sensitive that distant supernovas will occasionally show up, due to the EMF aspects between here and there. More work needs to be done to filter out these frivilous solar system disturbances. Astronomers are not allowed into the control room. The housing for this unit emcompasses a two square mile outer shell building. Within the building are other progressively smaller building around the seismo...roughly 340 buildings or insulated "boxes" is a guess. The temperature is maintained to within ..00000023 of a degree by control electronics. Servicing is a open and shut case. Nevertheless, engineers are constantly at work upgrading the system...and hopefully next year we shall be able to report more significant and meaningful improvements. And then..............I woke up. Happy April Fools Day. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Edward Cranswick Subject: Re: Mark & Margaret (Re: NZ) Date: Wed, 01 Apr 1998 13:15:54 -0700 Dave- I have been paralyzed by not being able to find a suitable reference about the quantitative effect on noise and sensitivity of going downhole. These guys, Ralph Archuleta & Co., U.C. Santa Barbara Institute for Crustal Studies: http://www.crustal.ucsb.edu should have the info, but their website server is down. In the meantime, there is no question in my mind that going down about a meter will decrease the noise above a few Hz by a factor of two (sufficiently qualitative?). Even better is to plaster or cement the sensor to competent outcrop. I am glad you had a chance to meet Mark & Margaret and expose them to the antipodal PSN. I apologize for my belated reply. Have continued to be very busy preparing to leave for Australia for three weeks which I will tonight. Mostly I will be going to see my mother in Adelaide. Three years ago, I went with Anya & Olya and had to explain to my aged relatives why I had a Russian wife & stepdaughter -- now I have to explain to them why I don't. -Edward David A. Nelson wrote: > > At 08:36 AM 3/14/98 -0700, you wrote: > >Mark & Margaret & Dave - > > Good to hear from you. I should have left before you split, because > >everyone's questions to you have been redirected to me. I am really > >going to get started on Dave's poster today! So have a good time away > >from the orifice and enjoy NZ! > > Dave - I still haven't forgotten your question about the effect on > >seismic noise of going downhole; I haven't found any good info on the > >subject yet, perhaps, I'll hear something at the SSA meeting that starts > >Monday in Boulder. We are going to have a sort of small PSN dinner at > >Johh Lahr's house on Thursday because S-T. Morrissey will be in town for > >the SSA meeting. Good of you to be such a gracious host to M&M. > >-Edward > > Hi there, > Mark and Marg. left here 1/2 an hr after sending the mail. > they left Dunedin city the following morning heading south down the scenic > coast road. Unfortunately the weathere turned sour so they may have spent > more time in the car keeping dry than out sightseeing. > > ok on the seismometer burial Ed. i am still interested to see if it is > worth puttting the 3 - 4 ft down rather than virtually rite at the surface > as they are at present. > Hey no prob. having M&M here im pleased u let me know they were > coming this way. At least they know a bit more abt NZ tectonics and > seismology. He loved my wall maps of new zealand showing events over the > last 100 yrs or so. and quickly noted and commented on the seismic gap > along the central Alpine Fault in the South Island. This length of fault > ~300 km, is deemed likely to rupture in the next 30yrs odd if the avg > rupture time between events is upheld. > > take care hope u can visit one day u would be most welcome to stay a > few days at home here. can always find a spare bed. > > Cheers > Dave > > Co-ordinator: > New Zealand > Public Seismic Network > Dave A. Nelson ZL4TBN > 24 Jensen St., > Green Is., Dunedin, > South Is.. New Zealand. > > http://psn.quake.net/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 -- 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) From: Roger Baker Subject: Re: boom centering motor Date: Thu, 02 Apr 1998 12:25:01 -0600 At 06:53 PM 3/30/98 -0600, you wrote: >Meredith, > >The boom centering motor has to turn a fine thread (eg 8-32) screw >with an eccentric (so it won't turn) weight of 10 to 50 grams hanging >on it oriented along the axis of the boom. The Edmund Scientific >catalog has some nice miniature geared-down DC reversible motors >that weigh an ounce or two and draw less than 100 ma. In particular, >look at the motor part number J41331, a 2RPM, 31 inch-ounce laboratory- >grade (=$25) motor that runs on 8 milliamps at 12 V unloaded and is >1.75" dia x 1.75" long. > >THe motor can be mounted over the centerline of the hinges so as >to minimally affect the boom and the feedback coil/magnet. THere is >no problem with powering it via a pair of the fine coiled wires that >convey the signals over the hinges (I have two extra pair installed). >The fine #38 wire that I use can handle 2.5 amperes before it melts, >so a few hundred ma won't be a problem. > >The above motor can be controlled manually with a DPDT switch, and will >run quite nicely on a 9-volt battery; one could also set up an >auto-zeroing system using the integrator (= mass position) output >of the VBB feedback to control it via a meter relay (hard to find a >center-scale meter relay) or electronic comparators and cmos switches. > >I am also experimenting with electronic centering to extend the >operating temperature range. To do this, I integrate the mass position >output again with an extremely long (gt. 1000 seconds) time constant >and apply it through a limiting resistor to the auxillary 25-turn >coil above the main feedback coil. I am using a passive filter (ie >very large capacitors) to avoid adding noise. I have yet to evaluate >the change in the overall response. >regards, >Sean-Thomas Friends, If I understand the problem here correctly, it amounts to a minor trimming of the weight position to keep the horizontal beam of the seismo preperly centered and balanced. Since I think at least the leaf spring is magnetic, let me suggest a possible technique I have been using with some of my experiments. This is to use a ceramic magnet up to a foot away as a cheap and dirty and very easy to implement fine force trimmer. You position the magnet carefully back and forth until the chart output is within scale. In this way, I have been able to make external delicate beam adjustments on somewhat similar instruments mounted inside styrofoam coolers for purposes of temperature stabilization. Of course the magnetic fields involved are fairly linear at some distance and not necessarily much greater than the earth field, and so should not usually be expected to cause unexpected difficulties aside from slight temperature drift in the magnet or beam. Your motor could move the trimming magnet externally. And now my own question which is off topic for the PSN list, but likely to be known to somebody on this list, who can then respond to me privately: Does anybody know an easy way using my PC (and without spending $1000) to take a raw series of bytes representing a 256 step grey scale, like the scan lines of a TV picture and reconstruct an image? Or better yet by using my raw analog scan stream. Optical scanners do this all the time with lots of inscrutable code, but I am not a programmer and am generating the data stream at my own sweet slow rate with no coding attached except for the natural scan line breaks. Whats the simplest easy way for a relative cyber-klutz like me to turn this data into a picture -- for the purpose of my amateur friendly design for a scanning microscope? Or maybe there is just the right list to join, out there somewhere, and somebody here knows where it is. --Yours, Roger Baker _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: Re: boom centering motor Date: Thu, 2 Apr 1998 20:54:42 -0600 (CST) Roger, A known problem with ferro-magnetic (until we find a non-magnetic spring that is not a thermometer) leaf-spring vertical sensors is that at high gain they are sensitive to geomagnetic storms and have to be shielded in mu-metal enclosures. They have even been known to shift in output from other temporary ferro-magnetic disturbances like a large hunting knife, steel-shank boots, and analog multimetres. (also, BTW, geomagnetics is the reason we use moving COIL rather than a much simpler moving magnet design for velocity sensors). I would hope that refinement of the STM design will allow low noise operation and require magnetic shielding, so the internal center- of-mass trimming motor (which WILL cause a temporary transient when it is activated) will be needed. The current STM design with sliding trim masses on the boom requires about 5 grams/centimeter/deg C adjustment when it its near the center of the boom. I will use someting like 32 grams for the moving trim weight, so the 2 RPM motor and the 8-32 threaded rod will adjust for 1 deg C in about 1 minute. The 1 deg C figure is the current operating range for an integrator output voltage limit of 6 volts. (without any other thermal compensation). Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: RADIOTEL Subject: Re: SPIDER WIRE AND STAINLESS FISHING LEADER Date: Thu, 2 Apr 1998 22:47:32 EST TO: ANYONE I would like to purchase the boom suspension wire for a Lehman seismo that I am building. I have read some good things about a product called "Spider Wire" in the PSN archives. Has anyone had definitive experience with this product and if the experience was good what weight Spider wire should I purchase. According to the above referenced archives, this product, which is really not metal, does not stretch and is super strong. I also read about stainless steel fishing leader. Based on your experience what are its properties and what size(s) or weight and brands have be utilized for a boom suspension. Jim Allen Cerritos, Ca. U.S.A. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Francesco" Subject: ANOTHER BIG EVENT IN CENTRAL ITALY Date: Fri, 3 Apr 1998 12:00:30 +0200 7.27,16 UTC Mb 5.0 7.59.54 utc Mb 4.5 Located:=20 43.29N 12.67E =20 43.23N 12.58E =20 Francesco Nucera - Osimo, Italy
7.27,16 UTC  Mb = 5.0
7.59.54 utc     = Mb=20 4.5
 
 
Located:
43.29N   = 12.67E =20
43.23N   = 12.58E =20  
 
 
 
Francesco Nucera   - = Osimo, =20 Italy 
From: Arie Verveer Subject: FIJI Island Epicentre Date: Fri, 03 Apr 1998 21:03:08 +0800 Hi, After my last very poor effort in locating an epicentre, I thought that the FIJI Island quake might be a good event to study. I don't give up that easy. I used four stations each with very well defined "P" and "S" phase and plotted the information using the program "Mapit". Station .bue 10158km from event 30.112N .. 97.891W .lc3 8506km 37.496N 122.241W .ko1 4825km 19.723N 115.991W .au1 6638km 32.008S 116.135E The point where the lines crossed, was difficult to resolve given the large distance between the stations, but the answer was reasonably close. True Event 17.4S 178.2 West Mapit's Location 17.9S 178.6 West The results are not really that bad, considering the error box in locating the stations and difficulty in finding the point at which, the lines crossed. The answer would be a great deal better with close event and a better distribution of stations. Arie _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Darrell Collins Subject: Re: weather work Date: Fri, 03 Apr 1998 08:28:47 -0700 Is PSN going to be there?? Subject: Seismic Network April 2, 1998 PRESS RELEASE FIRST SEISMIC NETWORK FOR TORNADOES (SENETOR) WORKSHOP TO BE HELD 6 APRIL 1998 Seismologists and meteorologists will meet together for the first time at a workshop on 6 April at the Center for Earthquake Research and Information (CERI), University of Memphis to explore means of using existing seismic networks to detect tornadoes in real time. The workshop was organized by Dr. Frank B. Tatom of Engineering Analysis Inc., Huntsville, Alabama with CERI serving as host. Representatives from the U.S. Geologic Survey (USGS), the National Weather Service (NWS), the National Severe Storms Lab (NSSL), and the National Aeronautic and Atmospheric Administration (NASA) are expected to attend along with seismic network coordinators located in Tennessee, Alabama, Arkansas, Oklahoma and Missouri. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Charles R. Patton" Subject: Re: boom centering motor Date: Fri, 03 Apr 1998 09:25:44 -0800 Sean-Thomas, With the continuing discussion of temperature compensating the boom I have to ask: In the good old days they had temperature compensated pendulums for clocks. It consisted of brass and steel rods -- you've probably seen it and if you didn't know, would think it was for decoration -- as it was done typically in a grill pattern. I'm pretty sure the steel they used was standard magnetic, but today there are several non-magnetic materials you could use. For instance using brass at 20 ppmTCE and glass at 8.7 ppm TCE you could get positive or negative 12.3 ppm depending on construction. The question is, "Is this enough compensation range if one were using a phosphor-bronze spring?" Another fascinating number is magnesium with a TCE of 29.8 ppm. Invar is essentially zero, but I don't know is its magnetic or not, if not, this gives a combination possibility of almost 30 ppm. If I do my back of the napkin calculations right, for the current steel spring I estimate you are adjusting with an equivalent coefficient for the mass center of the boom of about 10 ppm/ degree C. So this would be in the ballpark. Left field or not, is a different question. Regards, Charles R. Patton _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: prewar Subject: Re: SPIDER WIRE AND STAINLESS FISHING LEADER Date: Fri, 03 Apr 1998 17:58:24 +0000 RADIOTEL wrote: > TO: ANYONE > I would like to purchase the boom suspension wire for a Lehman seismo that I > am building. I have read some good things about a product called "Spider > Wire" in the PSN archives. Has anyone had definitive experience with this > product and if the experience was good what weight Spider wire should I > purchase. ..........................snip.............. Hi, I was recommended spider wire, but was unable to find it over here (GB). Erich kindly sent me some USA wire (not spider),and I have since found that pike fishermen use multi stranded steel lines of various breaking strains. They all seem to consist of 7 strands of hard (piano wire?) wire with an outer nylon cover. I am using such a line (24 lbs breaking strain), altho I consider that a 100% nylon line to be more flexible (but it keeps on breaking!). This 24 lbs has 7 strands, each one .004" dia, so it's reasonably flexible, and strong enough. Here, ALL fishing tackle shops stock this pike wire, so you shouldn't have any trouble in USA. If you do, I will send you a some yards, (enough for a few seismos ), if you let me have your mail address, (privately of course). Incidentally, I use HEAVY galvanised wire for most of the suspension run, only using the flexible wire for the LAST 2 inches. In this way, any stretch is reduced to an absolute minimum. I have tried NON steel lines, in this way, in order to get minimum stretch. Regards Albert Noble (England) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: bob@................. (Bob Hammond (USGS-AVO Geophysicist)) Subject: Re: SPIDER WIRE AND STAINLESS FISHING LEADER Date: Fri, 3 Apr 1998 09:21:49 -0900 Spider Wire is THE best fishing product for fish with many sharp teeth. I don't doubt it will be very good for boom suspension! Here in Alaska, Spider Wire is available in most fishing isles of drug stores and super- markets. I might also suggest another product for boom suspension: Phillystran is a kevlar guy wire used for antenna tower guying. It is very flexible, very strong, and doesn't stretch too much. It is available from Texas Towers (www.texastowers.com/philstrn.html). Bob APSN Fairbanks _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: meredith lamb Subject: STM-8 Electronics Date: Fri, 03 Apr 1998 13:18:09 -0700 Sean-Thomas, >From my limited electronics experience viewpoint, personally I think it is a much bigger problem than the mechanical sensor building aspect. Of course, that angle of viewpoint will vary with the individuals experiences. Overall...either mechanical or electronics can stop the successful completion by interested parties. I do think it would be a shame for either problem to halt the individuals project; as the seismometer has great potential. The seismo is a prototype and therefore, both mechanical and electronics will see a possible ever changing composition, which is normal and desireable for progress. Anyway...as I gather it, the electronics are a composite of borrowed and "standard modules", and (?) therefore are not a part of the ongoing patent process, or are they? Question...would it be better from a homebrew approach, to build and test the individaul schematics boards, rather than a all in one approach? To supplement this; is there simple tests known for each schematic/board? What would be a minimum pre-requistite in regard to electronic test equipment...i.e., voltmeter and DC oscilloscope? With a specific schematic; the amp/demod/filter/DC amp....I do have questions regarding unspecified values. 1. On the right top side, is the unspecified resistor......160K? 2. A1 amp....the prior input + & -, R & C, are they different for the gain of 100? 3. A5 amp....the prior input + & -, R & C, are they different? 4. A6 amp....+ input, opt R range & C value? 5. Schematic has two opposing caps, one under A1, 2 X 10uf, and another of 2 X 47uf between A5 and A6. These are polarized caps I presume? 6. The MC14066B integrated circuit with its criss-cross lines, may need "connecting dots", for absolute clarity for dummys like myself-ha. I'am not real sure...but I don't want to blow the IC, or have a potential unrecognized problem. Right off, I don't see any other problems with interpreting the other schematics. Thanks, Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Norman Davis WB6SHI Subject: Re: SPIDER WIRE AND STAINLESS FISHING LEADER Date: Fri, 03 Apr 1998 12:17:56 I have read some good things about a product called "Spider >Wire" in the PSN archives. Has anyone had definitive experience with this >product and if the experience was good what weight Spider wire should I >purchase. I tried it and even used 3 strands of the 12*24 and it broke. I went back to a gatar string, G I beleave. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: CVW Subject: Where do I start (building a PSN station)? Date: Fri, 03 Apr 1998 17:07:10 -0500 Okay, I finally have the resources to pursue a dream of seismic proportions-- I have a budget of $1000 to spend on equipment to set up a seismograph. Here's what I already have: 1. A PC running Windows 3.1, with standard I/O and sound card, that can be 100% dedicated to this project. 2. Some potential sites on our lot where I can bury sensors. 3. Enough knowledge to be dangerous, based on the PSN FAQ's. Here's what I don't have: 1. A seismometer 2. An op amplifier 3. An A/D converter (but doesn't the sound card work on the same principle?) Here are my ideal requirements: 1. Measure on 3 axes. 2. Data captured in PSN usable format. 3. Durable and reliable sensors. 4. Ability to bury the sensors 50-100 feet away from recorder. So, how close can I come to creating a fully functional station for under $1000? Better to try making home-made seismometers, or buying commercial geophones? (I'm OK with DIY, but my main objective is good measurement.) Any comments would be greatly appreciated. Thanks, Charles van Wynbergen Atlanta, USA _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Terence Dowling Subject: Re: Where do I start (building a PSN station)? Date: Fri, 03 Apr 1998 14:08:13 -0800 CVW wrote: > > Okay, I finally have the resources to pursue a dream of seismic > proportions-- I have a budget of $1000 to spend on equipment to set up a > seismograph. I'm in essentially the same position. If you get any direct replies (not on the net) that you feel comfortable in sharing I'd appreciate it. -- Terence Dowling (408) 536-3856 Adobe Systems Inc. dowling@......... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Larry Cochrane Subject: Seismology Bibliography Date: Fri, 03 Apr 1998 16:18:02 -0800 Hi Everyone, A few days ago Bob Barns sent me a bibliography document he had put together. I went ahead and made a web page out of it and places it on my system. A link to the page can be found on: http://psn.quake.net/infoequip.html and a direct link to the document is: http://psn.quake.net/bibliography.html If anyone has a book or article they would like to add, please send me the info and I will add it to the list. Thanks Bob. Regards, Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Jim Hannon Subject: Re: Seismology Bibliography Date: Fri, 03 Apr 1998 19:29:32 -0600 Larry Cochrane wrote: > > > If anyone has a book or article they would like to add, please send me the > info and I will add it to the list. > > Thanks Bob. > > Regards, > Larry Cochrane > Redwood City, PSN > Here are a few books in my collection that I didn't see on the list. Elementary Seismology Charles F. Richter 1958 W.H. Freeman & Company Earthquake Interpretations A manual for reading seismograms Ruth B. Simon 1981 William Kaufmann Inc. Earthquakes G.A. Eiby 1980 Van Nostrand Reinhold Company -- Jim Hannon http://soli.inav.net/~jmhannon/ 42,11.90N 91,39.26W WB0TXL _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: VRDT amp/demod Date: Fri, 3 Apr 1998 21:09:12 -0600 (CST) Meredith, Answering your questions: 1: it is 160k, as the other switch driver. 2: The amp A1 gets gain two ways: the 40.2k/4.02k input circuit, and the 10k/1k divider in the feedback, for x 100. 3; The inputs to A5 are the same. 4: At A6, the optional low pass filter is 2meg with 0.1 uf (as in the feedback). 5: When opposing capacitors are used, they are electrolytics wired positive to positive. 6: The synchronous demodulator MC14066 (erroneously labeled 4088) is a quad cmos switch connected as drawn. The convention is that leads or wires that cross do not connect UNLESS there is a dot at the crossing point. I will update the schematic and re-post it on the web. It is a recent re-drawing of the 1982 version, so I have not actually made anything directly from it. It had been converted to a printed circuit that works; maybe I should put that artwork on the web? Or make it available by mail or FAX. The oscillator also exists as a PC board. If I put the PC artwork on the web, do you think that the home practitioner could retrieve it and rescale it to dimensions with enough accuracy that the IC sockets, etc, would fit? And would a photo-copied transparency of it be dense enough to print on a photo-resist PC board? Of course, the long term goal is to integrate all of it into one package. The oscillator will drive three VRDTs, but each needs its own amp/demod. But A6 could be re-configured as the integrator for the VBB feedback (with a different amplifier). BTW: none of the electronics is subject to any patent disclosure. Also, thanks for your thoughtful suggestions for the April 1 seismometer. I'm glad you avoided trying to use superconducting magnets; liquid helium would get expensive compared to the two 340 pound rare-earth magnets. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: meredith lamb Subject: Re: Where do I start (building a PSN station)? Date: Fri, 03 Apr 1998 20:46:59 -0700 CVW wrote: > Okay, I finally have the resources to pursue a dream of seismic > proportions-- I have a budget of $1000 to spend on equipment to set up a > seismograph. > > Here's what I already have: > 1. A PC running Windows 3.1, with standard I/O and sound card, that can > be 100% dedicated to this project. Opinion: Upgrade to Windows 95 for enhancements. Ditch the sound card if it is separate from the video card and you need a slot for the A/D card. > 2. Some potential sites on our lot where I can bury sensors. Sounds like a geophone preference. The Galitzin/Ewing/Columbia/ Lehman variety would give you the longer period phases OH's and AH's to check out and enjoy. > 3. Enough knowledge to be dangerous, based on the PSN FAQ's. > > Here's what I don't have: > 1. A seismometer > 2. An op amplifier Larry Cochrane has a 3 channel card. Beautifully made. > 3. An A/D converter (but doesn't the sound card work on the same > principle?) Larrys Cochranes A/D card seems to be in preference....via past email recommendations. Beautifully made again. People say they are a reliable item, which is very important. > Here are my ideal requirements: > 1. Measure on 3 axes. This is going to be the biggest time factor if you home brew, say a Lehman coil-magnet affair. The vertical will be the most difficult. > 2. Data captured in PSN usable format. Larrys programs again seen to be in preference. > 3. Durable and reliable sensors. The old and reliable coil-magnet affair is next to impossible to beat for simplicity and least cost factor. > 4. Ability to bury the sensors 50-100 feet away from recorder. Again, this sounds like a preference to geophones. A crawlspace or basement floor are much more accessible and weather protected. > > > So, how close can I come to creating a fully functional station for > under $1000? Realistically, it would give you a preamp and A/D card and maybe 500 for materials for the seismos. 2K$ over a period of time would probably be more appropriate. (I can hear the whistling spears being thrown now-ha.) I'am probably the cheapest person there ever was for this stuff....maybe 8K$ over some 34 years, but in many ways, the commercial stuff is ready made...and you don't have to STRUGGLE with acquiring every piece and part.... Personally I'd start with the Homebrew Lehman type first. Graduation with a STM-8 vertical may well be down the road of time. > > > Better to try making home-made seismometers, or buying commercial > geophones? (I'm OK with DIY, but my main objective is good measurement.) The reward with buying is a quicker result. The reward with building is learning, experience and ALOT of personal satisfaction. Being as you have the dream...you're already well on your way. Most important....have fun and enjoy it all...good and bad. Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: meredith lamb Subject: RE: VRDT amp/demod Date: Fri, 03 Apr 1998 23:22:20 -0700 Sean-Thomas, OK and thanks for the update on the schematic. A web or mail posting of the circuit board/s would indeed be a major step in accelerating home brew utilization. I for one, would certainly do the best I could in regard to rescaling etc. efforts. Circuit layout is a time intensive subject. I've never done transparencies, but I guess they have been around for years..... Obviously the total design is yours of course. I would think that with a possible OK from you that you maybe beseiged with willing minds toward more resolutions or possiblities. I suppose with multiple IC's available in one package, that the layout could be chopped down, although the accuracy could possibly suffer? Even the oscillator can be replaced from a 2 IC, to a one unit, I think. Anyway (even though I am no engineer), I would think it could be possible to reduce the specific IC's package units to maybe ~ 6 instead of the present ~ 10 or 11. Pure speculation. I think with time that your seismo will be a standard, and the circuit aspects can be enhanced to a degree of more managability for digital dummys like myself. P.S., perhaps next years April 1st seismograph may feature an anti-gravity mass that is stabilized in space and place. Such a device could be envisioned for cracking nuts during festivities with computer control upon command...besides serving as a seismometer?-ha. Hey...imagination knows no cost boundaries or practicality.... in the mind. Thanks, Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Frank Cooper" Subject: Re: MAKING A VISUALLY IMPRESSIVE SEISMOGRAM Date: Sat, 4 Apr 1998 01:17:04 -0600 ---------- From: Frank Cooper To: PSN-L@............. Subject: MAKING A VISUALLY IMPRESSIVE SEISMOGRAM Date: Saturday, April 04, 1998 12:47 AM I got my Lehman seismograph sensor up and running in January, 1997, using an Esterline-Angus chart recorder and home-brew amp. In april, 1997, I purchased Larry Cochrane's 16-bit A/D card with wwv correction and his amp/filter card. I also use Larry's SDR and Winquake programs in conjunction with his hardware and my 486 dedicated computer. The results have been extremely gratifying. It is pleasing to see earthquake events displayed on my crt and my chart recorder at the same time. Until a few days ago I felt I would never cease using the chart recorder because a three hour event could be displayed on a continuous sheet of chart paper while the computer seismogram was printed out on a single sheet of unimpressive 8 and 1/2 x 11 inch paper. I have been running the chart recorder at 12-inches per hour so a three-hour event would show three feet of continuous recording. This seemed to be a much more useful display than a single sheet of compressed data using winquake. This all changed a few days ago with the revelation that I can expand eq data from winquake and print it on more than one sheet of paper. Attaching the sheets of paper together makes a more readable seismogram as well as one that is very visually impressive --- even more visually impressive than events recorded with chart paper. On the chance that not everyone is familiar with this technique I am going to relate what I did. You will not want to read further if this is old hat to you. The recording part of my seismograph station can be seen at http://members.xoom.com/hatsatv/past.html --- look for Frank Cooper, W5VID. I used the compressed data from my 3/25/98, three hour BALLENY ISLANDS REGION (7.9 mag) event file (980325a.fc1) posted at Larry's PSN files site. I expanded the data, printed it and the result was a six-foot long very impressive record of the event. I then displayed it on the back wall of my seismograph room along with the many chart recordings. After displaying the Balleny file using Winquake, I changed the y-scale from -310 to -125 in order to increase the vertical amplitude for printing purposes. After the event was displayed with the new vertical scale I clicked on the 27:08 time marker on the far left dragging the vertical line to the next time marker 55:08. I unckecked TEXT under VIEW and then printed the expanded data. I closed the displayed event and then clicked on the file 980325a.fc1 again to re-display it. I again changed the y-scale from -310 to -125. I then clicked on the 55:08 time marker dragging the vertical line to 23:08. I again unchecked TEXT under VIEW and printed the expanded data display. I did the same thing for 23:08 to 51:08, 51:08 to 19:08, 19:08 to 47:08 and ended with 47:08 to 15:08. I now had six printed sheets. On the second printed sheet I cut closely along the first time line, matching it to the first sheet, and then taped the two sheet together with non-reflecting scotch tape. The event trace matched perfectly. I did the same for the other sheets. I ended up with a six foot long impressive display of the event that was easy to see changes in wave forms, etc. It is now possible to think about retiring my chart recorder. I displayed another of my event files, 12/05/97, 971205a.fc1, EAST COAST OF KAMACHATKA (7.7mag) on the well next to my BALLENY ISLANDS event and a three floot long display of my 3/29/98, FIJI ISLANDS REGION (6.4 mag). These expanded files from Winquake may eventually replace all of my displayed chart recordings. Larry, please don't tell me all this was in Winquake documentation. Regards, Frank Cooper W5VID Friendswood, Texas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Robert L Barns <75612.2635@..............> Subject: Where do I start (building a PSN station)? Date: Sat, 4 Apr 1998 10:17:31 -0500 Charles, Since you live in Atlanta, a seismic desert like here in New Jersey, geophones or other devices which can be buryed will be a waste of effort.= = You need something which will detect teleseismic events. This means something with a period longer than 10 secs. Verticals with the same period have a better signal-to-noise ratio but are more difficult. So go= for a horizontal. After you get your feet wet with a Lehman is the time to think about verticals and force feedback rigs. The Lehman (Scientific American, July 1979, pp152-16) is easy to understand and build. Mine has a 30" boom (1/2" dia. aluminum) but I thi= nk that 24" would be better in that it would req. a smaller housing. A "dog= house" to eliminate drafts is essential. This can be made from 2" thick Styrafoam (from a lumber yard) cemented together with Elmer's. Put a heater (say 15 watts) in the top to stagnate the air in the box. Mine usually operates with a 20-30 sec. period. The sens. to teleseisms is proportional to the square of the period. My coil has 15,000 turns. The suspension wire is piano wire and I can give you all that you will ever need. = A sensitive leveling device is a great convenience--either a leg under the base with a screw having 80 tpi or a lever driven by a micrometer hea= d. The meter-movement calibrator described on Larry's home page is also a convenience in checking performance daily. Mine sits (not bolted down) on the basement floor. There is a fair amount of spurious signals from foot traffic in the house but this is no problem because these events are easily distinguished from 'quakes. I get a good recording about every 2-3 days (a dedicated 286 computer running 24 hrs/day). The farthest 'quake I have recorded was from the Indian ocean-very nearly 180 deg. from here. So I can see 'quakes anywhe= re in the world with a magnitude of ~5.5 or greater. Two or three axes woul= d be nice but I miss only a few with only 1 seismometer. I think that buying Cochrane's A/D board (and his amplifier if you don'= t know how to handle op-amps) is the only way to go because it allows the u= se of his magnificent SDR program (free) for recording. This also allows th= e use of the even more magnificent Winquake (also free) program. I operate with a sampling rate of only 5 samples/sec. This is plenty wi= th a low-pass filter at 0.08 Hz and makes the hard disk storage space reasonable (about 2 megs/day). A sharp low-pass filter is necessary to reduce the noise from microseims which peak at about 0.16 Hz. $1,000 is way more than needed. Call (908-464-6785) if you need more details. Bob Barns _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: Re: MAKING A VISUALLY IMPRESSIVE SEISMOGRAM Date: Sat, 04 Apr 1998 10:51:14 -0800 Frank I like your idea. I have a tractor feed dot matrix printer. I wonder if one can suppress the formfeed to get the recording w/o the cutting? Barry Frank Cooper wrote: >..... > line, matching it to the first sheet, and then taped the two sheet > together > with non-reflecting scotch tape. The event trace matched perfectly. I > did > the same for the other sheets. I ended up with a six foot long impressive > display of the event that was easy to see changes in wave forms, etc. It > is now possible to think about retiring my chart recorder. > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Larry Cochrane Subject: Re: MAKING A VISUALLY IMPRESSIVE SEISMOGRAM Date: Sat, 04 Apr 1998 11:44:59 -0800 At 01:17 AM 4/4/98 -0600, Frank Cooper wrote: > [snip] > Larry, please don't tell me all this was in Winquake documentation. No, but it would be a nice feature to add.... -Larry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Frank Cooper" Subject: Re: MAKING A VISUALLY IMPRESSIVE SEISMOGRAM Date: Sat, 4 Apr 1998 13:48:28 -0600 Barry and others, I use a sheet fed laser printer so I don't know if you can use your dot matrix tractor fed printer as you indicated. Think it's worth a try. Perhaps someone else will know? Frank Cooper, Friendswood, Texas ---------- > From: barry lotz > To: PSN-L Mailing List > Subject: Re: MAKING A VISUALLY IMPRESSIVE SEISMOGRAM > Date: Saturday, April 04, 1998 12:51 PM > > Frank > I like your idea. I have a tractor feed dot matrix printer. I wonder > if one can suppress the formfeed to get the recording w/o the cutting? > Barry > > Frank Cooper wrote: > >..... > > > line, matching it to the first sheet, and then taped the two sheet > > together > > with non-reflecting scotch tape. The event trace matched perfectly. I > > did > > the same for the other sheets. I ended up with a six foot long impressive > > display of the event that was easy to see changes in wave forms, etc. It > > is now possible to think about retiring my chart recorder. > > > > _____________________________________________________________________ > > 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) From: S-T Morrissey Subject: printer seismograms Date: Sat, 4 Apr 1998 23:39:46 -0600 (CST) Frank, Barry, et. al. Re interesting seismograms: Having a paper copy of an interesting event is a real plus for the PSN practitioner. Since I am not using any of the current ADC hardware, SDR, or Winquake, etc, maybe my relatively primitive method might be of use to some in similar situations. I am using the Radio Shack RS-22-168 multimeter, mainly because I haven't had time to actually do something about the many other possibilities I have been evaluating. It provides one channel at 1 sample/second (teleseismic speed) data at 12-bits, with lots of verbiage written to a *.txt file. I use a simple C program to reformat the output into an array that Mathcad can feed on, and use Mathcad's rather flexible graphic capabilities to plot the data, either as a single line compressed time series, or a multiple line "seismogram" of between 1 and 4 hours of data, with 10 to 30 minutes per line. All these graphics print on a single page with any printer. These can be seen at the web site at: http://www.eas.slu.edu/People/STMorrissey/index.html look st the page showing recent data. For the future, I am trying to find or create a multiple channel ADC system that specifically addresses the output of a broadband sensor. Specifically, the output of a single VBB sensor would be digitized at a high sample rate (40 sps or greater) with event detection for logging short period data (1 to 20 hz), from which would be digitally derived (FIR filtered) a parallel 1 sample / second stream continuously recorded for teleseismic events, and even a 0.1 sps stream for VLP (very long period) data. Such digitizers are widely used in the University networks of broadband stations in conjunction with 24-bit digitizers, but are very expensive ($10K or more). I would hope that we can realize a similar capability for the PSN with broadband sensors. An alternate scheme would be to run parallel SDR processes on the output of the same sensor, but with different sample rates. Maybe Larry's ADC board and SDR and Winquake can support such. I am not familiar enough with it to know. If a PSN station wanted to share data with the professional scientific community, a three component broadband system would have channels (using the SEED (Standard for Exchange of Earthquake Data: the definitions/ nomenclature should be adopeted by the PSN) named: BHZ, BHN, BHE, LHZ, LHN, LHE, VHZ, VHN, VHE. Higher sample rates (80 sps) use the SHZ, SHN, SHE channels. There are definitions for almost any physical parameter and sample rate. Regards, Sean-Thomas. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: RE: VRDT amp/demod Date: Sun, 5 Apr 1998 00:05:48 -0600 (CST) Meredith, I should have thought of the PC artwork long ago. With it, making the VRDT electronics becomes a plug-and-play activity. Since I still have your SASE (and new film for the Polaroid), I will send you copies of the artwork; THe problem is that the original is black lines for circuitry, and I have always photo-reversed it since the PC photo-resists I have used need clear lines for conductors. I can try to photocopy the actual PC printing film to a transparency. Regarding suggestions for changing the circuits: the design is the end result of a long effort to achieve nano-radian stability for the tiltmeters they were designed for, so we might as well expect a similar best performance for our seismometers. IC chips are very cheap, so "simplifying" a circuit to reduce the number used is not worth considering. The individual amplifiers (LM308) actually become cheaper in quantity. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: shammon1@............. Subject: Update PSN San Jose Web site Date: Sun, 05 Apr 1998 00:35:25 -0800 I have updated the San Jose PSN WEB site. http://pw2.netcom.com/~shammon1/psnsj.htm There is a section with a number of photos of the new exhibt being dedicated on April 18th at the Randall Museum in San Franciso, Living with a restless earth. Sveral PSN members donated labor and parts to create a part of the technical features presented. If you are intersted in seeing an well developed display you might take a look. Regards, Steve Hammond PSN San Jose _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Norman Davis WB6SHI Subject: Re: MAKING A VISUALLY IMPRESSIVE SEISMOGRAM Date: Sun, 05 Apr 1998 09:22:01 At 01:48 PM 4/4/98 -0600, you wrote: >Barry and others, >I use a sheet fed laser printer so I don't know if you can use your dot >matrix tractor fed printer as you indicated. Think it's worth a try. >Perhaps someone else will know? >Frank Cooper, Friendswood, Texas A dot matrix printer with tractor feed will only sheet feed when told to. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: meredith lamb Subject: Re: Update PSN San Jose Web Site Date: Sun, 05 Apr 1998 11:04:51 -0600 Wow.......the pictures are a impressive graphic expression not only of the display and its educational awareness of earthquakes, but also too me of the larger hidden background of the big generiousity of the people involved in its creation. I for one would say that the PSN, has a great number of people whose contributions are evident and all over the various web sites......ranging from their pictures, programs, references and yes, a big live part is the continuing event and especially the e-mail ongoing educational process contributors. Thanks too ALL! Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Seisguy Subject: Another Quake Hits Central Italy Date: Sun, 5 Apr 1998 13:08:02 EDT Another Quake Hits Central Italy ..c The Associated Press ROME (AP) - Fans fled a soccer stadium in a small Umbrian town and tourists hurried out of St. Francis Basilica in Assisi on Sunday when another sharp earthquake struck central Italy. There were no immediate reports of injuries or damage. The quake has a preliminary magnitude of 4.5, making it weaker than the 5.0 quake that jolted the region on Friday and damaged 300 homes. Friday's quake was the strongest in several months of aftershocks following two killer quakes in September. Some 1,500 fans rushed from Gualdo Tadino's soccer stadium when the quake hit Sunday just two minutes before the end of a minor league match. Sunday's quake did no apparent damage to the Assisi basilica, whose lower- level church was filled with Palm Sunday visitors. The basilica's upper-level has been closed to the public since Sept. 26, when its ceiling collapsed during a quake. Thousands of people have been sleeping in tents or trailers since the first quakes in September punched the region, leaving 10 dead. Many have refused to go back to repaired homes for fear of the aftershocks. AP-NY-04-05-98 1302EDT _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Francesco" Subject: CENTRAL ITALY Date: Sun, 5 Apr 1998 19:31:38 +0200 Another medium quake occurred in Central Italy (Umbria-Marche border = region) 15.52.18 Utc Mb 5.1 Ml 4.7 Many material damnages I.E.S.N. PSN ITALY Francesco Nucera
Another medium quake occurred in = Central Italy=20 (Umbria-Marche border region)
15.52.18   = Utc
Mb 5.1  Ml 4.7
 
Many material damnages
 
I.E.S.N. PSN ITALY
Francesco = Nucera
From: S-T Morrissey Subject: highpass output Date: Sun, 5 Apr 1998 13:11:45 -0500 (CDT) Barry; Regarding accomodating the thermal drift caused by the leaf spring: the current operating range is about + - 1 degree C before the integrator output saturates. Here is a review of the highpass output discussion: (from previous postings) Also: the VBB output now contains the mass position component. To connect this to a recorder or digitizer (unless you have a 24-bit ADC), a long-period high-pass filter is needed, and usually an additional amplifier. I use 1000 uf, NP, into 1 megohm to an amplifier with a gain of 2 as a buffer to remove DC drift; it still passes periods of 10 minutes or more; you may want a shorter period corner with the horizontal. (see the curves of the step calibration on figure 10 of the figures page). With the unit here, the VBB output can range from + to - 6 volts (I have a +-9v regulated supply), which I monitor with a meter near the recorder so I know when the sensor needs to be recentered. It will also have a large drift anytime the covers have been removed for any length of time, and may take 4 to 6 hours to stabilize again. But the normal output from the high pass buffer is microseims of 1 to 10 mv, and the RS digitizer range is only +-200mv. So the high pass connection is a must. This near-DC response is because although the VBB output is flat to velocity from Tn up to the short period corner, it is flat to acceleration below Tn, so tilt, earth tides, acoustic gravity waves, etc, will be present in the output. From a later posting: I looked at the figure I posted of the electronics block diagram for the high-pass output configuration that is needed to remove DC drift and other ULP noise. It is conspicuously missing! oops and sorry about that. I will amend the drawing to show the large capacitor between the VBB output at the displacement detector and the buffer or "line driver" amplifier, which has a 1 megohm input resistor, which I should also show. (the drawing has been corrected to show the high pass output; the response to a calibratoin step also shows the effect of the high pass connection.) Hopefully you will be acquiring data by now. BTW: if your recorder and/or ADC has a very high input impedance (like 1 meg), you can forgo the buffer amplifier,and just install the capacitance. (I use two 2200uf capacitors connected + to + to get the 1100uf non-polarized; for trials, any large value will do) Regards, Sean-Thomas .. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: boom centering for STM-8 Date: Mon, 6 Apr 1998 00:25:50 -0500 (CDT) Re motor zeroing THe first boom centering motor has been installed on the Beta version of the STM vertical seis. It has been kept very simple: The Edmund Scientific motor part number J41331, is a 2RPM, 31 inch-ounce laboratory-grade (=$25) motor that runs on 8 milliamps max at 12 V ( 3ma with a 9-volt battery) and is 1.75" dia x 1.75" long. The centering motor shaft is coupled to a fine thread 6-32 SS rod about 8" long that simply protrudes out from the motor face. The motor is clamped to the outward end of the upper hinge angle by one if its mounting tabs. The weight of the motor is behind the hinge axis, and the threaded screw is on the boom side; they were set up so that they just about balance, so very little mechanical recentering of the boom is necessary when it is installed. The recentering weight is a small piece of aluminum angle (3/4" x 3/4" by 1/2" long, 1/16" material) with a 8-32 hole threaded into the upper half of the angle; the larger hole lets it turn freely, and also be easily relocated along the 6-32 threaded rod. The angle hangs below the rod. (so it won't turn), and the offset keeps the threads engaged; it has a weight of about 10 grams. THere is no problem with powering it via a pair of the fine coiled #38 wires that convey the signals over the hinges (I have two extra pair installed). The above motor is controlled manually with a DPDT switch and powered by a 9-volt battery. I am considering an automatic auto-zeroing system using the integrator (= mass position) output of the VBB feedback to control it via electronic comparators and cmos switches. The problem with this idea is that there has to be a long (electronic) time delay between the comparator (trigger) and the control switch to make sure it does not auto zero during an earthquake. In operating the motor while observing the integrator (mass position) output, one drives the voltage toward zero, but because of the VBB time constant, one has to stop the motor when the voltage has decreased to about half the starting value, and let the integrator catch up. Ie: if the voltage is 1 volt, run the motor until it approaches 0.5 volt, then wait. A more elaborate zeroing system would temporarily switch the integrator to a very short period during zeroing. Now we can proceed with enclosing the seismometer within a pressure tight containment to reduce barometric noise. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Larry Cochrane Subject: Looking for some help... Date: Sun, 05 Apr 1998 23:49:44 -0700 Hi Everyone, I'm slowly getting the next version of WinQuake together. One of the things I want to do with this release is add online help. To do this I will be adding Help buttons to most of the 30 some odd dialog boxes used by WinQuake. The online help will be in HTML rather then in the standard WinHelp format. Dealing with HTML is a lot easier then Microsoft's Help files. What I'm looking for is some help proofreading and editing the Web pages I come up with. You don't need to know HTML, I'll do that part of it. What I need help with is the content like spelling, grammar, suggestion etc. If you would like to help out please contact me at cochrane@............... Thanks, -Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: shammon1@............. Subject: Re: Update PSN San Jose Web Site Date: Mon, 06 Apr 1998 00:03:35 -0700 > > I for one would say that the PSN, has a great number of people > whose contributions are evident and all over the various web > sites......ranging from their pictures, programs, references > and yes, a big live part is the continuing event and especially > the e-mail ongoing educational process contributors. Thanks > too ALL! > > Meredith Lamb > I agree-- You may have noticed that I took John Lear's suggestion by adding a list of work PSN members have helped out to the web site. I started the list with things I remember. I'm sure there are a lot more. What I would like to do is have people send me one liners-- Who was helped and how. I just remembered a couple more. Ted Blank and I provide the amp and code to get two PSN stations going in a couple of middle schools in Russia. Ted traveled there and helped set them up. I also built part of a seismic system for a middle school in Wisconsin.The local science teacher built the seismograph. I also talked to Jan Froom last week, and he told me that he went back to the Jr. High school in Gilroy and spent two more days teaching seismology to 7th graders. Now there is real courage... And Ken N. ran the USGS BBS for more than a year. All stuff that should be added to the list. I need people to speak up. Please send me any info you have so I could add it to the list. Regards, Steve _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: shammon1@............. Subject: Re: Looking for some help... Date: Mon, 06 Apr 1998 00:05:14 -0700 Larry Cochrane wrote: > > Hi Everyone, > > I'm slowly getting the next version of WinQuake together. One of the things > I want to do with this release is add online help. To do this I will be > adding Help buttons to most of the 30 some odd dialog boxes used by > WinQuake. The online help will be in HTML rather then in the standard > WinHelp format. Dealing with HTML is a lot easier then Microsoft's Help files. > > What I'm looking for is some help proofreading and editing the Web pages I > come up with. You don't need to know HTML, I'll do that part of it. What I > need help with is the content like spelling, grammar, suggestion etc. > > If you would like to help out please contact me at cochrane@............... > Larry I'll help. Send me the HTML and I'll proof it. Regards, Steve _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Larry Cochrane Subject: Re: printer seismograms Date: Mon, 06 Apr 1998 01:51:37 -0700 At 11:39 PM 4/4/98 -0600, S-T Morrissey wrote: >An alternate scheme would be to run parallel SDR processes on >the output of the same sensor, but with different sample rates. >Maybe Larry's ADC board and SDR and Winquake can support such. >I am not familiar enough with it to know. SDR can record up to 6 channels at 100, 50, 25, 10, and 5 samples per second. Currently all channels have to be sampled at the same rate. SDR saves all data to disk creating daily record files in the ~6 meg per channel range at 50 SPS. It does have a trigger mode, automatically saving PSN formatted event files, but it uses the data saved to disk instead of data saved in RAM. When I designed SDR I decided to save all of the data to disk because I live near a freeway and I knew that I could not rely on triggered data. By saving everything to disk I could replay the data and see what I got. Since disk space is pretty cheep now a days, having a disk drive that can save 6 channels for several days is not that much of a problem. Regards, Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Kenneth J. De Nault" Subject: Re: Looking for some help... Date: Mon, 06 Apr 1998 07:40:09 -0500 Larry, I would be pleased to help but will not have time until May. Hope all is well. We have had some lovely weather following the blizzard you missed. Buck is fine and has been visiting more schools. We went to Charlotte, N.C. to race over Spring Break. I did well and finished 3rd. Ken _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: lahr@.................. Subject: http://pw2.netcom.com/~shammon1/psnsj.htm Date: Mon, 6 Apr 1998 08:38:43 -0600 (MDT) Steve, Your web site looks great! Is your section on "PSN outreach activities and link to other PSN web sites resources " available for others to add items or links? You need to add a link there to your pages on the Randall Museum. 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://www.aeic.alaska.edu/lahr http://www.lahr.org/john-jan _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: bob ogburn Subject: Re: Looking for some help... Date: Mon, 06 Apr 1998 07:52:56 -0700 Larry, Please place me in the reviewer pool, thanks Bob Ogburn Larry Cochrane wrote: > > Hi Everyone, > > I'm slowly getting the next version of WinQuake together. One of the things > I want to do with this release is add online help. To do this I will be > adding Help buttons to most of the 30 some odd dialog boxes used by > WinQuake. The online help will be in HTML rather then in the standard > WinHelp format. Dealing with HTML is a lot easier then Microsoft's Help files. > > What I'm looking for is some help proofreading and editing the Web pages I > come up with. You don't need to know HTML, I'll do that part of it. What I > need help with is the content like spelling, grammar, suggestion etc. > > If you would like to help out please contact me at cochrane@............... > > Thanks, > > -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) From: bob@................. (Bob Hammond (USGS-AVO Geophysicist)) Subject: Re: Update PSN San Jose Web Site Date: Mon, 6 Apr 1998 09:39:11 -0800 Steve, Here is a list of PSN-related outreach I have done and would be glad to see it on your webpage: -created a k-12 science and math education project based on in-school seismographs in urban and rural Alaska. Four schools are currently involved. Each school uses EMON and WINQUAKE software. Continue to guide students and teachers in the teaching of seismology as part of this project. -created and maintain the Alaska Public Seismic Network (APSN) webpage. -helped 3 individuals get their own seismograph stations up and running. My caveat is that I do this outreach as a USGS geophysicist as well as a PSN member. Maybe there is a distinction, maybe not. If I wasn't with the USGS, I'd be doing it anyhow. Hope this is want you want. regards, Bob Hammond APSN Fairbanks _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: meredith lamb Subject: Amateur Seismology Educational Contributors Date: Mon, 06 Apr 1998 13:16:42 -0600 Steve Hammon, or anyone interested in history..... The problem with time passing is that denotations of their specific contributions usually get more or less lost in various ways. This can be unfortunate for those presently interested in history roles of the subject. Yes....it would be wise to do it now, and hope that a list somehow survives longer than normal. Also involved seems to be the fact that historical figures usually would rather not be pointed out....they are givers and not preferential to basking in the spot light. Nature also finds a way to renew its human resource of contributors and is as it should be. I now wish I'd have kept alot of my earlier papers and references back to the 1960's....but I didn't. At that time there was a group of individuals who communicated via mail. Mail is a poor method of reaching out and communicating over the human population, unless the subject material is such that there is no other way. The web sites and email now, are a world apart from mail. The "tools" a contributor now can use is much better....uhh...perhaps with time, more drawings and etc., would enhance the present state of computer e-mail program technology. The only individuals I knew of that were contributors in the 1960's were: Elmer Rexin....amateur water well level indicators of strong world earthquakes. Deceased. Wisconsin. Worked as a maintenance engineer for a shoe company. Communication via Charles Cox at the time. Gerald Shea...a innovative and skilled seismograph user whose approaches were amazing creations of household materials. Indiana. Worked in a educational institution. Robert Barnard...instrumental innovation way beyond normal. Washington. Electronic engineer. Endless contributions. Charles Cox...A real educational promotion person, who devoted more effort to that than even developing his own seismograph. If I gave him equipment...he would give it away to another person for their use. Amazing. Deceased. Wisconsin. I miss him alot. Anyway....life goes on... However, your present group has great contributors all over the place. I've only been tapping into PSN for maybe 6 months...but your educators are in abundance. For example in the past week emails, information has been put forth by.....(do it in one breath-ha), Frank Cooper, Robert Barns, Steve Hammond, Larry Cochran, Sean-Thomas Morrissey, John Lahr, Bob Ogburn, Roger Griggs, Arie Verveer, David Nelson, Edward Cranswick, Roger Baker, Charles Patton, Albert Noble, Bob Hammond, Norman Davis, Barry Lotz......(whew!), besides all the gobs of event seismograms which are teaching tools, and any others I may have missed. My point is, that they are all conveying messages....information, and therefore education. If you were to go back further, you would expand the list a great deal. As a comparison to the 1960's mail and the present e-mail, your email in one week would cover perhaps a years worth of mail in the "old days". Each email alone will take the indivdual an amount of time to compose from their experiences or thoughts, and is really a contribution FOR others. Monster contributions like developing programs, teaching, traveling for such, or even maintaining a computer day in and day out, are really the ultimate in devotion heights probably. So....you have a rich wealth of people....whose contributions I appreciate very much. My problem is that I don't know the total history of the individuals efforts or accomplishments on PSN. It's been around for maybe some odd 3 years. I can read the email and see the programs, but I'am sure that alot was done before that time period. Getting those individauls to do their own versions would be very nice to see.....if they can be coherced or prodded enough-ha. Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: temperature compensation Date: Mon, 6 Apr 1998 21:55:44 -0500 (CDT) Charles; There are lots of available materials to try to make a zero temp. coefficient leaf spring. The STS units have such, made with two dissimilar metals; the remaining problem is that the temp. coefficient itself is temperature dependant; however, it does improve the stability by a factor of ten or more. For the homemade sensor, we have to keep focused on the less exotic stuff; I'm drawing the line at what I can find in the McMaster-Carr catalogue and Edmund Scientific. I still "cheat" a bit because I have the resources of my laboratory of the last 28 years, and I AM a packrat. Of course, everyone will make the best of their resources, and for the VBB instrument, temperature is a noise problem, and does not affect the response described by the transfer function at all. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: rayv Subject: Re: Looking for some help... Date: Mon, 06 Apr 1998 22:09:48 -0400 Larry Would be happy to assist. Ray Villemarette >Larry Cochrane wrote: >> >> Hi Everyone, >> >> I'm slowly getting the next version of WinQuake together. One of the things >> I want to do with this release is add online help. To do this I will be >> adding Help buttons to most of the 30 some odd dialog boxes used by >> WinQuake. The online help will be in HTML rather then in the standard >> WinHelp format. Dealing with HTML is a lot easier then Microsoft's Help files. >> >> What I'm looking for is some help proofreading and editing the Web pages I >> come up with. You don't need to know HTML, I'll do that part of it. What I >> need help with is the content like spelling, grammar, suggestion etc. >> >> If you would like to help out please contact me at cochrane@............... >> >> Thanks, >> >> -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) > >To leave this list email listserver@............. with the body of the >message: leave PSN-L > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: meredith lamb Subject: Long Period Horizontal Seismo Drift Date: Mon, 06 Apr 1998 21:25:45 -0600 Sean-Thomas, OK on the vrdt amp/demod circuit artwork. I'll give it a try. I'll be looking forward to results of your boom motor and pressure container info results. Actually...its irritating because for the moment,...I can't think of a question to ask (ha)...and you're going into a realm of instrumentation that very few people have entered, but it will be very interesting to hear about...and perhaps some day to follow. Perhaps...a tough question. With my horizontal Sprengether seis, (like a Ewing/Lehman etc.) they are capable of 20 second periods, and I've seen a period of 60 seconds once. Of course at some point with this they become grossly unstable naturallly, and drift all over the place, no matter how stable the pier or frame is constructed. Even a 20 second period will historically show need for a adjustment perhaps every couple weeks. I guess the real question is what is really necessary and would a shorter period like 15 seconds suffice? Big distant quakes will simply make the mass lag the subtle L wave tilt anyway....I think. Thanks, Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: shammon1@............. Subject: Re: Update PSN San Jose Web Site Date: Mon, 06 Apr 1998 21:32:31 -0700 Hi Bob-- got the not. I'll add it this week. Thanks for the input. Steve Bob Hammond (USGS-AVO Geophysicist) wrote: > > Steve, > > Here is a list of PSN-related outreach I have done and would be glad to > see it on your webpage: > > -created a k-12 science and math education project based on in-school seismographs > in urban and rural Alaska. Four schools are currently involved. Each school > uses EMON and WINQUAKE software. Continue to guide students and teachers in > the teaching of seismology as part of this project. > -created and maintain the Alaska Public Seismic Network (APSN) webpage. > -helped 3 individuals get their own seismograph stations up and running. > > My caveat is that I do this outreach as a USGS geophysicist as well as a PSN member. > Maybe there is a distinction, maybe not. If I wasn't with the USGS, I'd be doing > it anyhow. > > Hope this is want you want. > > regards, > > Bob Hammond > APSN > Fairbanks > > _____________________________________________________________________ > > 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) From: Larry Cochrane Subject: Re: new help files Date: Mon, 06 Apr 1998 23:18:33 -0700 Thanks John, I placed the documents I have so far on my PSN system. The following link can be used as a starting point: http://psn.quake.net/wqdocs/index.htm I now have 12 people offering to help, so I have plenty of help. -Larry At 09:00 AM 4/6/98 -0600, you wrote: >Larry, > >How about just putting the new help files on your web site with >a heading > 'Preliminary WinQuake help file under review' > 'Please forward suggestions or corrections to ...' >When the next version comes out, you can just change the >title and leave them there. > >Just a thought. > >JCLahr > >_____________________________________________________________________ > >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) From: Larry Cochrane Subject: Re: Where do I start (building a PSN station)? Date: Tue, 07 Apr 1998 00:32:48 -0700 Charles, Sorry for not responding sooner. I've been trying too concentrate on getting the next release of WinQuake ready...Some comments below. At 05:07 PM 4/3/98 -0500, Charles van Wynbergen wrote: >Okay, I finally have the resources to pursue a dream of seismic >proportions-- I have a budget of $1000 to spend on equipment to set up a >seismograph. > >Here's what I already have: >1. A PC running Windows 3.1, with standard I/O and sound card, that can >be 100% dedicated to this project. I recommend that people have two PC systems. One is dedicated too data logging, running SDR or EMON, and the other for general computer usage and WinQuake. The data logging system, if it is going to run SDR or EMON, only needs to have DOS running on it. Both program are DOS based so you won't need to have Windows on that system. The main system needs to have Windows, preferably Win95. If you want to get real fancy, you can network the two together so event files will show up on the Windows system's hard disk. This way you won't need to use a floppy to transfer event files between the two systems. >Here's what I don't have: >1. A seismometer You will need a long period sensor. A geophone is fine for local events, but you will need LP sensors to record teleseismic events. To stay under the 1K limit you will need to build one. Or get very lucking in finding a used one. >2. An op amplifier >3. An A/D converter (but doesn't the sound card work on the same >principle?) As you know I have both available. My Web site has the current price and other info about my boards. > >Here are my ideal requirements: >1. Measure on 3 axes. I'm not sure you can get 3 LP sensors going for around $1K. Maybe one or two horizontal. You can buy used 3 axis geophone for under a few hundred dollars, but they won't work very well in your location. >2. Data captured in PSN usable format. You will need to run SDR or EMON for this... >3. Durable and reliable sensors. Thats a hard one... depends on how well you can make your sensor. I find that my SG sensor is more reliable because I don't need to re center it as often. >4. Ability to bury the sensors 50-100 feet away from recorder. The problem with home built LP sensor is they need to need monitored and adjusted now and then. If you bury it, make sure you can get at it pretty easily. > >Better to try making home-made seismometers, or buying commercial >geophones? (I'm OK with DIY, but my main objective is good measurement.) Do too cost, I think you will need to go with the home-made sensor. Again, geophones are not going to work very well in your location. You will be able to see the P wave of large teleseismic events with them, I see then on the USGS geophone sensors I monitor, but all of the low frequency wave information will be missing from your event files. -Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: prewar Subject: Re: Long Period Horizontal Seismo Drift Date: Tue, 07 Apr 1998 13:04:25 +0100 meredith lamb wrote: > With my horizontal Sprengether > seis, (like a Ewing/Lehman etc.) they are capable of 20 second > periods, and I've seen a period of 60 seconds once. Of course > at some point with this they become grossly unstable naturallly, > and drift all over the place, no matter how stable the pier or frame > is constructed. .......................... Hi Meredith, I have been considering the possibility of increasing the period of my seismos, by electronic means. (2 hor. currently about 20secs and 1 vert about 1.5 secs). Erich sent me an article published by Seismological Soc. of America, dated Oct 89. Volume 79 Number 5. page 1607........ Article entitled ,'A vertical equalisation circuit for increasing seismometer velocity response below natural frequency'. This describes a cct using LP filter plus an inverter with a summer, in series with SAME again, to allow a 1sec period seismo to have an effective response down to 10 secs! Only 6 op amps required. I am no great electronics wizz kid , but it should be possible, by suitable changes to C in LP filter to extend ANY seismo period, by a useful factor, without too much effort. The article shows the response from a short period seismo, used in Jemez mountains. The response includes 10-20 sec noise which an unconverted seismo would have been transparent to. You will be able to get a copy of this article from SSA no doubt. Not sure if this article has been mentioned on PSN before. Regards Albert Noble (England). _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: lahr@.................. Subject: hand-held accelerometer Date: Tue, 7 Apr 1998 08:52:07 -0600 (MDT) Dear PSNers, Does anyone have any ideas re the question, below, raised by a San Francisco area teacher? I've never tried to measure acceleration while riding a wild ride, as I'm usually just holding on for dear life and laughing. (Hope this isn't too far off topic.) JCLahr > To: evans@.................... > Subject: home-built hand-held accelerometer > > Hi John, > > How is everything going in Menlo Park, and with your > accelerometer project(s)? > > I thought you might have some ideas for this teacher, > who wrote the question below to the pinhole listserver > of the Exploratorium. > > For Great America, I would think that measuring acceleration > to + or - 1 or 2 tenths would be sufficient. Electronic > means would be great, but may be overkill, unless you > have a hand held unit that they could borrow. > > Maybe just a clear plastic tube with two springs and a > weight? > > _______ > | S | > | P | - 1.g > | R | > | I | > | N | - 0.5g > | G | > | ^ | > | mass| > | v | > | S | > | P | + 0.5g > | R | > | I | > | N | + 1.0g > | G | > _______ > > > I think you can respond to pinhole@.................. > but if that fails, please cc me if you write to > Burt Kessler, as I'm curious too and will share your > response with the list. > > Thanks, > 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://www.aeic.alaska.edu/lahr > http://www.lahr.org/john-jan > > > > From john-jan@........ Tue Apr 7 07:43 MDT 1998 > > X-Sender: jlahr@................ > > Date: Tue, 07 Apr 1998 07:43:16 -0600 > > To: "John C Lahr, Lakewood, CO " > > From: The Lahrs > > Subject: accelerometer > > Mime-Version: 1.0 > > > > Date: 6 Apr 1998 20:49:54 U > > From: bcomet@.......... (Burt C. Kessler) > > Subject: accelerometer > > > > One of the new teachers at my school is looking for instructions for > > building some simple accelerometers in preparation for physics day at Great > > America. Can anyone help? > > > > Burt C. Kessler > > > > A decision is an action you must take when you have information so incomplete > > that the answer does not suggest itself. - Arthur Radford > > > > > > -- > > > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: grc@............ (Gary Chantler) Subject: Re: hand-held accelerometer Date: Tue, 7 Apr 1998 08:23:46 -0800 Hi, Paragliders use variometers all the time. they keep track of place, time of flight, distance, rate of climb, etc - and are light and small as weight is a consideration. They are not to expessive if you get one used...if this helps at all. GRC *********************************************************** ***************************************** Gary R. Chantler Instructional Tech. II Washington State University (509) 335-5353 Webster Rm 922 gchantler@....... *#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#* _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: lahr@.................. Subject: hand-held accelerometer Date: Tue, 7 Apr 1998 11:43:31 -0600 (MDT) I'll pass along John Evans' response on this. Also, Roger Baker suggested this as a good use for the "seismometer" that the Amateur Scientist column by Shawn Carlson in Scientific American carried a few years back. It wasn't sensitive enough to record any but the largest local earthquakes. JCLahr > From evans@.................... Tue Apr 7 10:59 MDT 1998 > Date: Tue, 7 Apr 98 10:01:07 PDT > From: evans@.................... (John Evans) > To: lahr@.................. > Subject: Re: home-built hand-held accelerometer > Cc: evans@.................... pinhole@.................. bcomet@.......... > > John, > > Finally solving the communications problems to get my prototypes into > the field. Took far longer than expected (doesn't it always?) and I > now know much more than I ever wanted to about TCP/IP/UDP and RS-232). > > I like your idea of the spring tube--very direct and visual and easily > built. Could be calibrated against gravity easily too. Might want to > use a chunk of scrap TEFLON for the mass so it will slide easily (add a > bolt through the center to secure the springs and increase the mass). > Teflon (R) works very easily (too easily), but NEVER get it really hot > (in other words, don't try to melt it)--LETHAL gasses result (envision > breathing through Teflon-coated lungs). A good plastics supplier or Si > Valley surplus house could supply bulk Teflon (R) for minor cost (or > free with a little talking?) in the small amounts needed. > > OSH has plenty of springs--you'll want sloppy ones. > > On the electronic side, I have one accel built for outreach--it could > be borrowed. It is nominally 1 V/g, but has a 0-g offset and has a > temperature dependent gain (and a temperature sensor to help). It is > VERY quiet (far quieter than they need on a roller coaster) but is a > bit tricky to use because of the offset and temperature dependence. > Also gets nonlinear somewhere between 2 and 3 g, so the wilder rides > might not measure accurately. > > For a more permanent (and less tricky) solution I suggest that they > talk to Analog Devices (contacts below) which I suspect would comp or > low-cost a few of their ADXL-05 or the newer ADXL-202 accelerometers. > These are 5-g devices. The latter may not be available yet--I have an > engineering sample sitting on my desk here. The -05 is a one-axis > accelerometer and the -202 a two-axis version, each with noise of a few > percent of g peak-to-peak over the frequencies of interest. Plenty > good enough for roller coaster physics demonstrations, and have been > used for that purpose. Would need power, a little wiring, and a > voltmeter to read the output. (Both my ICS-3028 box and the ADXLs are > micromachined silicon devices, and very tough--good for kids to use. > However, none would like being dropped onto concrete, since that type > of shock actually reaches thousands of gs, and these typically are > rated to 2000 g shock resistance (don't try this with an FBS-23!).) > > Analog Devices: > 804 Woburn St > Wilmington MA 01887-3462 > 617-937-1534 jim.doscher@.......... > 617-761-7436 christophe.lemaire@.......... > (You could tell either one that I sent you. My most recent contacts > are with LeMaire, who gave me this -202 sample.) > > Teflon (R): > Surplus house: HalTek Electronics, 1062 Linda Vista Av, Mtn. View > (650-969-0510) (101-->Shoreline-->toward mountains, away from > Bay--> left at first light-->down to Linda Vista Av-->left to > Haltek, which is on your left). They have scrap Teflon (R), > including some large chunks. Alternatively, try Commercial > Plastics and Supply Corp. in Santa Clara near 101 and De La Cruz > (408-988-6500). They might comp a scrap piece big enough (they > did comp part of the Teflon (R) I bought for the last Open > House--a urethane-foam fault model that needed a slippery > lower-crust and slide blocks). > > Good luck, > John > evans@................... > > Cc: Burt C. Kessler > pinhole@................. > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Walt Williams" Subject: SETI Fw: Aether Tectonics: Alert: Merging Black Hole Predicted Date: Tue, 7 Apr 1998 11:42:39 +0000 Hello All, I am a member of the SETI-L reflector. This interesting post is thought provoking. Best Regards Walt Williams, 98.04.07 dfheli@.............. == Cross Posted From seti@....... == ------- Forwarded Message Follows ------- Reply-to: "Ron Blue" From: "Ron Blue" To: Cc: "Ross Tessien" Subject: SETI Fw: Aether Tectonics: Alert: Merging Black Hole Prediction; Date: Tue, 7 Apr 1998 01:55:45 -0400 Ross Tessien has asked for help in monitoring the likely black hole merger estimated to occur April 31, 1998. Any reports should be forwarded to him. Naturally, data before, during, and after would be useful. Also as a intuitive guess, if the timing is good, radio signals from your favorite SETI source could be stronger around this time. Ron Blue >>>>>> -----Original Message----- From: Ross Tessien To: Ron Blue Date: Tuesday, April 07, 1998 12:09 AM Subject: Re: Aether Tectonics: Alert: Merging Black Hole Prediction; >>I wish you luck Ross. Action is a rarer event than the merger of two back >>holes at least you will be able to sleep at night knowing that >>you make an effort. >>Would changes in radio signals occur as two black holes merge. I belong >>to SETI and would be willing to encourage support from the group? >>Ron Blue > >Yes. You ought to encourage any observations possible. The amplitude of >the radio energy is modulating on the order of 18 hours I think it is. You >could get frequencies and directions from astronomy groups and catalogues. >The galaxy name was in the original post, (I don't have it right now), Seyfert galaxy IRAS 18325-5926 >and >you can look that up on the Skyview Virtual Telescope by just typing in the >name, and the coordinates will come up. But I imagine that the guys >pointing the radio antennae know how to locate a galaxy. > >Anyway, any observations ought to be encouraged. > >Personally, I would give it a slim chance (but not zero), that we will >observe something really dramatic. ie, the ejection of a quasar from the >galaxy core. This is because black holes, IMO and according to the >fundamental models of forces means of transferring action via solitonic >interactions, leads to the conclusion that a BH has a core inside, and not >a singularity. Thus, a BH merger interupts the inflow of aether, ramming the >cores, and one or the other ought to breach! > >In any case, I certainly expect that fireworks are to be expected. If one >or the other is simply swallowed, I am not going to cry. But if some >radical things happen that cannot be explained I will have a smile on my >face ;-) > >Ross Tessien > From: baez@............ (John Baez)Newsgroups: sci.physics.research Subject: Merging black holes?Date: 5 Apr 1998 20:31:01 GMT Organization: Department of Physics - Penn State Univ.Lines: 73 Approved: bunn@...................... (sci.physics.research) Message-ID: <6g8pm5$q2t$1@..................> NNTP-Posting-Host: pac2.berkeley.eduContent-Type: textOriginator: bunn@pac2 Xref: oronet sci.physics.research:7648 Is anyone here familiar with the recent observations of the Seyfert galaxy IRAS 18325-5926 which could be interpreted as indicating a massive black hole binary system that would merge on or before April31st? Apparently in December 1997 researchers observed X-ray emissions with a period of 11 hours, significantly shorter than those seen previously in March 1997, and this February they saw a periodicity of 7.8 hours. They regard it as a priori "very unlikely" to stumble like this upon in-spiralling black holes right before they collide, but they raise the possibility because it would be very interesting if true. (Unfortunately LIGO is not yet up, but I hear that some prototype interferometric gravitational wave detectors will be used to try to detect this possible collision.) For more information, see the telegram posted by the IAU: http://cfa-www.harvard.edu/iauc/06800/06835.htmlas well as the following papers: > >>Mike what does you model say about these events? How about your model >Jerry? Would a tide wave of Aether have significant effect on earth even >though the distance is huge? >Ron Blue A post of mine was rejected from spr. this is my retort. In response to your question, it has already been measured that the earth is exposed to incessant free oscillations. These are not of earthquake origin, and so are either due to wind, waves, or gravitational wave excitation. No other sources are known. Will the earth be damaged, I think not. Is it possible that sensitive instruments might be able to detect the signals? I think so. do we have those instruments in place now? probably not but we have some instruments that might be barely able to detect these waves. Later, Ross Tessien I include ****paper abstracts below*****, a Stanford web site, and logic pointing out that you should post the ideas because they are valid and have already been attempted. The researchers, and others, may not be aware of the potential BH merger. It may well be that the amplitude of the resulting waves are below the sensitivity limits of any of these schemes. I am not saying that a run of the mill, "seismograph", has the sensitivity to detect a gravitational wave. I am telling you that the global network of seismographs, when the data is processed collectively create an interference pattern which can detect, in principle, graviational waves. There are a number of experiments that have attempted to detect gravitational waves using seismometers and the earths motions. These are not your run of the mill earth quake monitors or tecniques. Also, there are other superconducting seismographs that are more sensitive than most and perhaps these might detect a signal. The point is, it is unlikely that a black hole merger would occur again in our lifetimes. Thus, it is prudent to act now and ask questions later. If the idea is stupid, then fine, blame it on an ignorant crackpot and you are home free. But the fact is, physicists have indeed attempted to detect gravitational waves using high tech seismometers and by using the motions of the entire earth. I include also a commentary on the earth's free oscillations at the end so that you can see that the geo physicists have a lot of experience subtracting earthquake generated noise. So much so that they can monitor the earths incessant free oscillations. Now gravitational waves, would show up as incessant free oscillations, if they were originating from celestial sources that are orbiting one another **assuming that the waves were sufficiently large to induce the earths motions**. However, remember that when you excite a bell with a frequency that the bell is sensitive to, you are dealing with an underdamped resonance. Therefore, if the frequency of the BH merger oscillations passes through a normal mode of ringing of the earth, then the earth will behave as an underdamped oscillator, and the signal will be amplified. Ross Tessien In the following document, the knowledge of the direction and or timing of the source signal would help in detecting it from the noise. And improvements in the timing accuracies of the seismometers used could further improve the potential for detecting a signal. http://sepwww.stanford.edu/public/docs/sep75/ray1/paper_html/index.ht ml Detecting gravitational waves using seismic data Ray Abma Author has no known email address ABSTRACT Several years of seismic data acquired by the international deployment of accelerometers (IDA) are used in an attempt to detect gravitational waves radiated from low-frequency astronomical binary sources. These data were preconditioned with various combinations of earthquake removal, gain, and tapering. Directionally weighted spectra were calculated for 0.012 to 0.556 milli-Hz (one day to one-half hour periods) in 84 directions, one year at a time, with correction for the earth's rotation. While patterns similar to the synthetic response from a gravitational-wave source were observed, these patterns showed no consistency when compared between years. This inconsistency suggests that the patterns are noise and not the result of gravitational wave excitation by binary sources. And also see: Progress on low-frequency active vibration isolation for gravitational wave detectors. S. J. Richman, J. A. Giaime, D. B. Newell, R. T. Stebbins, P. L. Bender, J. E. Faller (JILA, University of Colorado.) The preliminary stage of a three-stage active vibration isolation system now includes sensors that measure the position of the platform with respect to the ground. We have developed a control strategy in which these new sensors dominate the feedback signal at frequencies below 0.3 Hz, and seismometers mounted on the platform dominate above 0.3 Hz. The preliminary stage now achieves the same isolation performance as previously reported, and is also tilt-stabilized against the first main stage actuators. These new sensors and new flexure ends for the first main stage support springs have allowed all control loops on the preliminary and first main stages to be closed simultaneously. Forced vibration transfer function measurements show isolation factors of at least 3\times10^3 from 1-10 Hz in both vertical and horizontal directions. The results of these measurements show agreement with our computer model of the performance of the stacked system. [K11.04] Low-Frequency Signal Extraction from Interferometers Using Balanced Heterodyne Detection Scheme with Orthogonally-Polarized Signal and Local Oscillator Beams Ke-Xun Sun (Apollonics Technology, 632 Des Moines Place, San Jose, CA 95133) Balanced heterodyne signal extraction schemes are proposed and analyzed for both Michelson and Sagnac interferometers for gravitational wave detection. In these schemes, local oscillator and signal beams are introduced in orthogonal polarization states, and mixed after exiting the interferometers. The local oscillator freqeuncy can be shifted for heterodyne detection by phase modulators. Extended from a previous measurement at a high frequency (91.9 MHz), low frequency signal extraction is experimentally demonstrated with a zero-area Sagnac interferometer. The local oscillator was frequency-shifted by a post-interferometer phase modulator. At a heterodyne frequency of 96 MHz, signals generated by displacing interferometer arm mirrors were detected in the frequency range from 50 Hz to 10 kHz. Detection of signal was robust against laser amplitude and frequency noises. Low noise interferometric seismometer readouts in an active vibration isolation system for gravitational wave detectors. J. A. Giaime, S. J. Richman, R. T. Stebbins, P. L. Bender, J. E. Faller (JILA, University of Colorado.) Within the frequency range of significant servo gain, our actively controlled seismic isolation platform's noise floor is limited by seismometer readout noise. A new Michelson interferometer readout has been designed and tested which should allow a displacement noise spectral density of approximately 3\times 10^-15m/\sqrtHz. Light for 12 readouts is supplied from a quiet laser though optical fibers, and corner-cube interferometer mirrors allow simple alignment and signal stability. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: W6JRF Subject: Re: SETI Fw: Aether Tectonics: Alert: Merging Black Hole Predicted Date: Tue, 7 Apr 1998 15:01:24 EDT Let's see, as I remember, the old grade school mind jogger went something like... "thirty days hath september, april, june and november..........April 31 huh? _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Stephen & Kathy Subject: re SETI Date: Tue, 07 Apr 1998 13:28:58 -0700 If you drop the as off the end of the first link it works and the date there says april 21!!!!!!! If you add ml to the end of the second link it works and you go to the abstract!! SKM Pilot Hill _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Charles R. Patton" Subject: Re: hand-held accelerometer Date: Tue, 07 Apr 1998 13:03:58 -0700 John Lahr posted: > > > One of the new teachers at my school is looking for instructions for > > > building some simple accelerometers in preparation for physics day at Great > > > America. Can anyone help? > > > > > > Burt C. Kessler I'd like to suggest something very simple. Take a piece of plastic strip like a 1" wide piece of a plastic divider from a notebook, or a vertical slice from a plastic milk bottle or pop bottle. A "straw" the diameter of pencil lead from a plastic broom is still another possibility. In any case, use one of these as a horizontal spring. Take a small cardboard box and cut a square hole in it. Tape one end of the "spring" in the box, horizontally across the hole with the end of the spring adjacent to the edge of the hole on the other side. Now depending on the strength of the "spring" you can add weights, such as pennies, marbles, lengths of wire, etc. one unit of weight is so much deflection, and then is marked on the edge of the hole opposite the "spring". 10 units is so much more. If you leave the 10 units attached permanently, you have just marked a scale in 0.1's of a G. Turn upside down and calibrate in other direction. Now you have a plus and minus G meter. Refinements are to cover the hole with Saran wrap in order to prevent drafts from bothering it -- those 30+ MPH winds on the roller coaster can play havoc with the calibration. Cutting the hole with a radius to match the "spring" will improve accuracy. Use of a strip of plastic rather than a "straw" will confine its reaction primarily to be perpendicular to the plane of the "spring", or even better, two "straws" spreading apart to the attachment point -- a triangle when viewed from above. The side rigidity would be excellent this way so sine/cosine vector resolution of forces could be attempted. Cheap, fast, needs no machining, test equipment, electric power, simle to calibrate, and uses materials found around the house. -------------------------------------- | box | | --------------------------- | | | | | | | | | | S | plastic | | | C | "spring" | tape| | A |==X========================XXXX| | L | X | | | E | weight(s) | | | | | | | | | | | --------------------------- | | | | | -------------------------------------- Regards Charles R. Patton _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Pinhole Listserv" Subject: Re: Re: hand-held accelerometer Date: Tue, 7 Apr 1998 15:31:18 -0700 (PDT) No action was taken on your mail by this listserver. This listserver supports the following commands. These commands should be the text in the SUBJECT field of your mail message. Make sure they are in the SUBJECT field!!! subscribe Your address will be added to the list of subscribers. You will then be able to send messages to this list that will be forwarded to all other list subscribers. subscribe digest Your address will be added to the list of subscribers who receive a digest instead of each forwarded message. You will be able to send messages to this list, and will receive a digest of accumulated messages once a day. digests A list of available digests will be returned to you. This command will only work if you are already subscribed to the list. unsubscribe Your address will be removed from the list of subscribers. You will no longer be able to send messages to the members of the list. This command will only work if you are already subscribed to the list. help This help message will be returned. -------------------- Original Message Follows -------------------- John Lahr posted: > > > One of the new teachers at my school is looking for instructions for > > > building some simple accelerometers in preparation for physics day at Great > > > America. Can anyone help? > > > > > > Burt C. Kessler I'd like to suggest something very simple. Take a piece of plastic strip like a 1" wide piece of a plastic divider from a notebook, or a vertical slice from a plastic milk bottle or pop bottle. A "straw" the diameter of pencil lead from a plastic broom is still another possibility. In any case, use one of these as a horizontal spring. Take a small cardboard box and cut a square hole in it. Tape one end of the "spring" in the box, horizontally across the hole with the end of the spring adjacent to the edge of the hole on the other side. Now depending on the strength of the "spring" you can add weights, such as pennies, marbles, lengths of wire, etc. one unit of weight is so much deflection, and then is marked on the edge of the hole opposite the "spring". 10 units is so much more. If you leave the 10 units attached permanently, you have just marked a scale in 0.1's of a G. Turn upside down and calibrate in other direction. Now you have a plus and minus G meter. Refinements are to cover the hole with Saran wrap in order to prevent drafts from bothering it -- those 30+ MPH winds on the roller coaster can play havoc with the calibration. Cutting the hole with a radius to match the "spring" will improve accuracy. Use of a strip of plastic rather than a "straw" will confine its reaction primarily to be perpendicular to the plane of the "spring", or even better, two "straws" spreading apart to the attachment point -- a triangle when viewed from above. The side rigidity would be excellent this way so sine/cosine vector resolution of forces could be attempted. Cheap, fast, needs no machining, test equipment, electric power, simle to calibrate, and uses materials found around the house. -------------------------------------- | box | | --------------------------- | | | | | | | | | | S | plastic | | | C | "spring" | tape| | A |==X========================XXXX| | L | X | | | E | weight(s) | | | | | | | | | | | --------------------------- | | | | | -------------------------------------- Regards Charles R. Patton _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: lahr@.................. Subject: Re: Re: hand-held accelerometer Date: Tue, 7 Apr 1998 17:44:13 -0600 (MDT) "From: "Pinhole Listserv" " "No action was taken on your mail by this listserver." Woops, looks like the pinhole list requires subscription. I'll send the psn suggestions in from my home account, which is subscribed. Thanks for the help! JCLahr _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: VRDT osc ICs Date: Tue, 7 Apr 1998 19:25:54 -0500 (CDT) Meredith, I just checked the Newark catalog re the ICs: (800 463 9275; www.newark,com) On page 812; Harris Semiconductor.: CD4047BE Cmos oscillator $0.87 ea CD4066BE Quad switch 0.72 CD4018BE Counter/divider 0.97 Also: from Motorola: (look in price list) MC14018BCP $1.00 MC14066BCP 0.75. The Statek quartz oscillator was needed for the long-term (weeks to months) stability of the tiltmeters in Alaska, and is probably over-kill for the seismometer; use the 4047; I do believe that mechanical thermal noise will far ourweigh thermal drift of the cmos oscillator (but DO use 1% resistors and a polystyrene capacitor at pin 1 of the 4047.) Also, the last time I needed LM308As, Newark had them even though they were not listed. I will try to see if one of the Analog Devices "OP" series would be an affordable replacement (with FET inputs). regards Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Charles R. Patton" Subject: Re: hand-held accelerometer Date: Tue, 07 Apr 1998 17:46:14 -0700 (My apologies if this went twice, but I received no response from the psn-l@............. address, so I'm re-sending to the webtronics address) John Lahr posted: > > > One of the new teachers at my school is looking for instructions for > > > building some simple accelerometers in preparation for physics day at Great > > > America. Can anyone help? > > > > > > Burt C. Kessler I'd like to suggest something very simple. Take a piece of plastic strip like a 1" wide piece of a plastic divider from a notebook, or a vertical slice from a plastic milk bottle or pop bottle. A "straw" the diameter of pencil lead from a plastic broom is still another possibility. In any case, use one of these as a horizontal spring. Take a small cardboard box and cut a square hole in it. Tape one end of the "spring" in the box, horizontally across the hole with the end of the spring adjacent to the edge of the hole on the other side. Now depending on the strength of the "spring" you can add weights, such as pennies, marbles, lengths of wire, etc. one unit of weight is so much deflection, and then is marked on the edge of the hole opposite the "spring". 10 units is so much more. If you leave the 10 units attached permanently, you have just marked a scale in 0.1's of a G. Turn upside down and calibrate in other direction. Now you have a plus and minus G meter. Refinements are to cover the hole with Saran wrap in order to prevent drafts from bothering it -- those 30+ MPH winds on the roller coaster can play havoc with the calibration. Cutting the hole with a radius to match the "spring" will improve accuracy. Use of a strip of plastic rather than a "straw" will confine its reaction primarily to be perpendicular to the plane of the "spring", or even better, two "straws" spreading apart to the attachment point -- a triangle when viewed from above. The side rigidity would be excellent this way so sine/cosine vector resolution of forces could be attempted. Cheap, fast, needs no machining, test equipment, electric power, simple to calibrate, and uses materials found around the house. -------------------------------------- | box | |