Stephen, Sounds like an interesting project. My first suggestion would be to join the PSN mailing list so there can be a full discussion. See: http://psn.quake.net/maillist.html to subscribe. Some needed details of your project include: purpose time available to complete rough budget limit size of field what other activity is going on in the field at the same time Cheers, John At 09:23 PM 5/25/00 , Larry Cochrane wrote: >Stephen, > >Sounds like an interesting project. Unfortunately I can't help you much. I >would think three geophone would do the job if the sensors can pick up the >impact offer the local ground noise. > >I'm CC'ing this message to the Public Seismic Network mailing list. Maybe >someone on the list can help you. > >PSN'ers please send any info directly to Stephen Hertig at >shertig@........... and CC the list, since he is not on this mailing list. > >Regards, >Larry Cochrane >Redwood City, PSN > >At 10:02 AM 5/25/00 -0500, Stephen Hertig wrote: > > > >Dear Mr. Cochrane > > > >I am researching how to calculate low-mass (like baseballs), impact surface > >locations on a grass field (2D only, X & Y's) in a relatively small area >(100 x > >300 m) using vibration sensors or geophones and PC-based, real-time data > >recording. > > > >The software and programming is very much in the public domain and I'm >assuming > >it can be worked out, but it's the general hardware parameters that have me > >perplexed (out of my field) at this stage. > > > >I'm not sure how many geophones I'll need or what fequency response would >best > >be suited for these measurements. As the area is small the low-mass, >hense low > >energy impacts may not be a problem, but the signal to noise ratio is a >concern. > >However, I've got no feel if this is assumption is close to reality or > >equivalent to the energy (db) distance ratios of earthquakes, but that > is the > >current analog I'm using to try to build a prototype system to record >these xy, > >impact locations. Although I suspect as all I need are s-wave, first >arrivals I > >may be able to detect and calculate the "epicenter" (+/- about 1/m???) >from at > >least 3 senors and hopefully be well above any noise. If more than 3 >senors are > >needed to record the events in this area (e.g., sensor has to be closer to >the > >impact than about 100 yds to see signal above noise) then I suspect things >get > >really complicated/expensive in terms of the A/D device and new modified > >multi-channel (3+) software needed. > > > >Do you think this can be done with only 3 sensors (i.e. Channels)? > > > >If so what type/parameters of senors would you suggest? (i.e. geophone >frequency > >response, vertical or horizontal spring orientations. Is horizontal better >for > >just s waves?) > > > >If not any comments on a alternate system setup? or others to ask these > >questions? > > > > > >You can blame your great web page(s) for this request, and thank you very >much > >for taking time > >for any consideration or comments. > > > >Sincerely, > >Steve Hertig, geologist > >shertig@.......... > > > > > > > > > > >__________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email PSN-L-REQUEST@.............. with >the body of the message (first line only): unsubscribe >See http://www.seismicnet.com/maillist.html for more information. John C. Lahr 1925 Foothills Road Golden, CO 80402 (303) 215-9913 http://lahr.org/john-jan/science.html __________________________________________________________ Public Seismic Network Mailing List (PSN-L)
Larry Cochrane <cochrane@..............>