[Dews] USGS: ShakeAlert

[Hal Murray <hmurray@megapathdsl.net>]

In Apr, 2012, the monthly public lecture at the USGS Menlo Park campus 
described their work in this area:

 ShakeAlert!
 --building an earthquake early warning system for California
 by Doug Given, USGS Earthquake Early Warning Coordinator
   * Millions of Japanese citizens received advance warning of the 2011
magnitude 9.0 Tohoku earthquake -- can such a system be built for use in
California?
   * University researchers and government agencies are working together to
create an Earthquake Early Warning system in California to reduce earthquake
losses
   * April is Earthquake Awareness Month in California -- how could you and
your family best prepare for severe ground shaking using 30 seconds of
advance warning?

The video of the talk is online.  It's an hour and a half.
 http://online.wr.usgs.gov/calendar/2012/apr12.html

It's pretty good.  I think anybody interested in this topic should watch it.
If nothing else, it will give us a common reference.


Numbers and such from my memory:

 P waves travel at 3 miles/second.  S waves (the destructive ones) travel at 
2 miles/second.

 It takes about 10 seconds to verify that a quake exists and estimate how
big it is.

 They think they can get a 20-30 second warning.  That's for a big enough
quake, and far enough away but not too far.  If it isn't big, nobody cares.
If it's too far away nobody cares.  If it's too close, you don't get enough
warning time to be useful.  Quakes on the San Andreas Fault near Los Angeles
are likely to fit.  (The USGS people doing the work are located in Pasadena.)

Half (or more) of the work is making contact with the people who want to
know that a quake is coming.  BART wants to stop their trains.  (BART trains 
can carry 1000 people.A serious wreck would overload the emergency response 
system even without any other earthquake damage.)

He had lots of info from Japan.  They have a lot more/denser sensors than we 
do.

The USGS is looking for $50-100 million over 5 years to install more sensors 
and $5-10 million/year for operations.

--------

The Moore foundation gave $6 million to CalTech, Berkeley, and Univ of
Washington for work in this area.
 http://www.usgs.gov/newsroom/article_pf.asp?ID=3041
They are cooperating with the USGS.


-- 
These are my opinions.  I hate spam.