This is a podcast of Scripps Institution of Oceanography at UC San Diego.
To learn more about how you can support scripts, visit us online
at scripps.ucsd.edu. Scientists say there is a 99% chance
California will experience a magnitude 6.7 or greater
earthquake sometime within the next 30 years.
As the state braces for the inevitable, scientist
at Scripps Institution of Oceanography at UC San Diego
are making major improvements to one of the field's most fundamental tools:
the seismometer, and developing early warning systems they hope will save
lives when the expected finally happens.
Scripps researcher Yehuda Bock, director of the California Spatial
Reference Center,
installed the first real-time global positioning system stations
at Scripp's Pinyon Flats Earth Observation facility
in 2004. Today the system consists of
over eighty GPS stations throughout Southern California
offering a promising early warning system
that could outrun seismic waves giving cities precious seconds to prepare.
After we detect in advance
and
disseminate the event to first responders and they can use that information
to for example shut down critical facilities like gas lines
or slow down trains such as
has been demonstrated already in Japan.
The crucial step is to be able to find somebody to
accept this information and react basically in an predetermined
automatic fashion if such an event occurs.
We're now developing a
methodology to determine the
magnitude and the location of the event
within seconds and then set up a mechanism where this
this information could be assimilated. In addition.
Scripps researchers are giving seismometers a needed
face lift using the most modern technology. New sensors jointly designed
and built by Scripps researchers, Jose Otero,
Mark Zumberge, and Jon Berger, could offer seismologists an instrument capable of
producing clearer recordings of seismic movement
than current seismometers. They can also better withstand the extreme
environments that scientists must
access to listen to earth's rumblings.
The biggest motivation was there's a lot of seismometers on the
market,
but there's not very many broadband seismometers so we wanted to develop a
broadband seismometer
that's easily attainable because the current seismometer that everybody uses
is no longer being made and
that's the STS developed by Streckeisen.
There's very few of them available on the market and the few that are available in
the market are sharing the breakdown
and there's not very many people who can fix them, so don't really have
the tools we need to perform the science we want to do. We could deploy this into
boreholes
whereas most, like the STS one, which is you know, kind of
the instrument everyone wants to use, can't really easily go down the bore holes. One, because
you have these long electrical wires that connect the two and when you use start using really long
electrical wires, they start picking up noise from the environment. And more than
that
a lot of boreholes are encased in metal, so if you have a lightning strike in that
region,
lightening tends to ground to anything that's metal so if you have your instrument in there
your instruments going to get fried.
And you know if you have a hundred thirty thousand dollar instrument in a hole and it gets hit by
lightning and it's destroyed that's not a good day. This could get hit by lightning, it's not
going to hurt it.
The fiber optic carries the light into the interferometer.
There's two ways you can get light under the interferometer:
you can go directly and set the laser right up in front the
seismometer and
perfectly align everything, make sure there at the same heights,
but the problem with that is the laser has to be right next to the seismometer.
That won't work in a borehole.
But if you put the laser far away
you can imagine, fiber optic is like a hose, but
instead of carrying water, it carries light. Normally light scatters everywhere,
but in a fiber optic
the light will follow the fiber perfectly and come out the other end. So we
take the light from laser the through the fiber and to the seismometer
and it's as if the laser was right in front of the seismometer
when it's not really, it's really far away. we could place the seismometer, you know,
a couple kilometers away from the laser and the optics, which is nice cause then you could,
you know, use one laser to run a bunch of seismometers that are a few
kilometers apart from each other down boreholes. If there's a large earthquake,
like a magnitude eight or nine,
you're not going to detect that in San Diego. You're not going to feel that in San Diego. But surface
waves will come through San Diego
and a quiet instrument will detect those surface waves a few hours after the
earthquake here.
If you have a noisier instrument, it's not going to see them.
By understanding how the earth works around fault zones,
scientists can get even closer to pinpointing the causes,
strength, and locations of earthquakes. Information vital to save lives.
Scripps scientist continue to develop new earthquake monitoring systems
to better understand earthquake triggers and to quickly detect the direction
in which the destructive wave will travel.
In hopes it can be outpaced before arrives.
More looking at the structure of the earth, we're understanding how,
you know, seismic waves propagate through the Earth and what's down there
is kind of the goal of this instrument, but naturally a seismologist,
why is it important to monitor earthquakes well so we can get a better understanding and make
the public more aware of
the potential destruction it could create. I mean if we understand how the earthquake works more
then we can understand okay well we know the Earth might move this way so what could we
do to build a better building or something like
that.
This has been a presentation of Scripps
Institution of Oceanography at UC San Diego.