[time-nuts] USGS: GPS for seismic work

Magnus Danielson magnus at rubidium.dyndns.org
Sun May 20 02:56:28 UTC 2012


On 05/20/2012 03:09 AM, Hal Murray wrote:
> It wasn't hard to find the right people at the Open House.
>
> GPS is interesting for big quakes.
>
> Most seismometers measure acceleration.  It's a double integration to get
> displacement which is what they are used to working with.  Big quakes last
> longer which leads normal seismometers to get into troubles with drift.  GPS
> doesn't have any drift problems.  The cross over is somewhere in the mag 7-8
> range.
>
> Japan has a large earthquake warning system.  On the big tsunami of last
> year, they weren't looking for long enough.  They estimated 7.9.  In
> hindsight, they probably could have gotten better data sooner by using GPS.
>
> This news story says that they can see the disturbance in the ionosphere.
>    http://www.cbc.ca/news/technology/story/2012/04/23/f-tsunami-research.html
>

Thanks for the report Hal!

I would love to find the papers where they really show that it is the 
ionsphere which was affected. Measures could be bias as the old fix 
becomes invalid as things move about.

Cheers,
Magnus





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