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[wxsig] Array of X1W-4 sensors to detrime direction and distance ?

VA7OTC JD Erskine VA7OTC at rac.ca
Sat Feb 16 23:21:35 UTC 2008


Stanley Reynolds wrote:
> Thank you both Gerry and Joe , I see I have some reading to do. I would love to say cost is no problem but I do need to keep cost in the hobby range which will effect how large a network and how much labor this project will get. This will mean I need to start small and once I get some results maybe request more help then. If I start small and it turns out I must have a large base line then I can expand to more sites. I'm located in Alabama and would be able to set up several sites in Birmingham,Cullman, and Arley (near smith lake) measured in Google earth that would be 23, 47, and 46 miles apart with Cullman to Arley the shorter distance. For just the feasibility part I could ignore linking the sites and review data by retrieving it physically after the fact. 
> 
> My idea would be to have a PC with hard drive record data in two ways, one the stock sensor and GPS time of start and length, the other would be some record of amplitude or wave form via a modified sensor during the same time.
> 
> I will post my progress and check for comments here.
snip

Neat thread. The only partial contribution I may make is that much was 
done over the years with tele-seismic data collection which had similar 
issues. This means there should be a great body of knowledge 'out there' 
to mine.

Initially it involved calculations of system delay to correct errors in 
delivery of data to a central recording centre, then on-site timing 
using CHU/WWV and such off-air sources and now accurised GPS date/time 
stamping of data such that it not matter as much when it arrives at a 
central location.

http://gsc.nrcan.gc.ca/org/sidney/index_e.php
http://earthquakescanada.nrcan.gc.ca/gen_info/seismos/seismograph_e.php
http://earthquakescanada.nrcan.gc.ca/stnsdata/netdc/index_e.php

http://www.polarisnet.ca/   see About.

http://earthquakescanada.nrcan.gc.ca/stnsdata/nwfa/formats/seed_def_e.php
http://www.iris.washington.edu/manuals/SEED_chpt1.htm

Sorry I can't help with more technical info, my primary role was as a 
land schmoozer for many of the POLARIS sites that went in on Vancouver 
Island and area or the Lower Mainland (around Vancouver BC).

I went looking around for material in a similar vein and found these:
This uses SMPTE code for date/time stamping, rather interesting
http://www.geology.smu.edu/~dpa-www/gps_video/index.html

Seismic data stamping info under patents
http://www.freepatentsonline.com/7269095.html

Digital Geophones
http://www.wipo.int/pctdb/en/wo.jsp?wo=2003032010&IA=WO2003032010&DISPLAY=DESC

Internet based near-real time seismic observation
http://findarticles.com/p/articles/mi_qa4089/is_200403/ai_n9366643/pg_4

Low cost high performance seismic a/d converter
http://mariottim.interfree.it/doc04_e.htm

Cheers, John
VA7OTC/VE0JD mm




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