Think quakes can be predicted? Think again, say quake experts
Think quakes can be predicted? Think again, say quake experts
Maggie Fox, Reuters/Washington
Think scientists are close to being able to predict earthquakes?
Think again, U.S. quake experts said on Sunday.
The magnitude-9 quake off the Indonesian island of Sumatra
that triggered December's devastating tsunami was a potent
reminder that while it is easy to say where big quakes will
happen, pinning it down to a day, a week or even a decade has
proved impossible, they said.
That quake apparently gave no warning whatsoever, researchers
told a meeting of the American Association for the Advancement of
Science.
Quake experts do not even agree how to measure a quake's
magnitude to see if an experiment for predicting quake activity
has worked, said Thomas Jordan of the Southern California
Earthquake Center.
"Most seismologists, including myself, are pessimistic that in
the next five years or 10 years that we will ever be able to come
up with a silver bullet earthquake solution," Jordan told a news
conference, but, "Never say never."
There are some suggestions that very low-frequency seismic
activity might predict some quakes.
U.S. Geological Survey (USGS) researchers have measured low-
pitched rumbles from deep under California's San Andreas fault,
about 22 km southeast of Parkfield. They resemble measurements
made at subduction zones in Japan and the Pacific Northwest.
A subduction zone is where one of the Earth's tectonic plates
is slipping under another and the Sumatra quake occurred at one
such subduction zone.
"We just don't understand what those signals mean," Jordan
said. "As best we can tell, there are no reliable short-term
precursors to earthquakes."
David Applegate of the USGS said Parkfield, which has been
covered with instruments for 20 years in the hope of catching a
quake in the act, is providing useful information, but nothing
that can be used to begin predicting a quake in a useful way.
More important will be finding out the highest risk areas so
building codes can be brought up to date and emergency services
told where the ground will shake the most, so they can respond
quickly when a quake does occur.
REUTERS
GetRTR 3.00 -- FEB 21, 2005 08:01:01