[time-nuts] GPS, USGS Early Earthquake Warning
Brooke Clarke
brooke at pacific.net
Mon Apr 30 21:15:31 UTC 2012
Hi Hal:
Thanks very much for that link.
I have a sensor on order.
http://www.prc68.com/I/Seismometer.shtml#QCN
Have Fun,
Brooke Clarke
http://www.PRC68.com
http://www.end2partygovernment.com/Clarke4Congress.html
Hal Murray wrote:
> tvb at LeapSecond.com said:
>> Related to that, are there any seismometer experts on the list? I've always
>> wondered why they don't augment the extremely sensitive detectors with less
>> sensitive detectors? Of course a really good detector will overload; so just
>> co-locate cheap detectors that are 40 and 80 dB less sensitive. That way you
>> get a clean signal no matter how close or far the epicenter is from the
>> detector.
> I'm not a seismometer expert, but I live/worked close to the USGS Menlo Park
> campus.
>
> A couple days after the 1989 Loma Prieta earthquake, I wandered over there to
> see if there was anything interesting for people like me to see. I was in a
> glass enclosed walkway between two buildings. They had a long (20 ft?)
> seismograph printout taped up high on one side. The first foot or two had
> obviously saturated. There was a guy next to me who looked like he might
> know something, so I asked, roughly, "Don't they have stations with the
> amplification turned down so it doesn't saturate?" He gave me a dirty look
> and said "That was the low gain channel."
>
> I think there are two issues with saturation. One is the electronics and
> communication channel. The other is the instrument itself.
>
> There is probably a seismic-nuts list someplace. There is a lot of good work
> going on in that area.
>
> My favorite seismic URL is:
> The Yosemite Rock Fall of July 10, 1996
> UC Berkeley Seismographic Station, Earthquake of the Week
> http://seismo.berkeley.edu/seismo/events_of_interest/yosemite/eoi_yos.html
>
> For only slightly-geeky amateur seismology, try
> QCN Quake-Catcher Network
> http://qcn.stanford.edu/
> For $50 you can get a USB connected seismometer. They provide software that
> will plug it into their data collection setup.
>
> Here is a good note:
> http://qcn.stanford.edu/qcn-detects-earthquake-in-seconds
>
>
> Some/many modern fancy cell phones include accelerometers. There is at least
> one app that turns your phone into a seismometer and displays a graph.
>
>
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