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