Skepticism greets California quake forecast system

KENNETH REICH AND USHA LEE MCFARLING LOS ANGELES TIMES

LOS ANGELES -- University of Colorado scientists say they might have found a way to forecast Southern California earthquakes -- but the method cannot be verified until the end of the decade.

The system, developed primarily by John B. Rundle and Kristy F. Tiampo of Colorado's Cooperative Institute for Research in Environmental Sciences, uses past patterns of small quakes to evaluate which areas are most likely to have quakes of 5.0 magnitude or larger.

The scientists have provided a color-coded map showing areas where the bigger quakes may occur through 2010.

But three Southern California earthquake scientists -- David Jackson of the University of California, Los Angeles, Egill Hauksson of the California Institute of Technology and Lucy Jones of the U.S. Geological Survey -- cautioned that they believe the system is subject to considerable doubt.

Rundle acknowledged that success is far from certain, but said the map, produced by a team including scientists at the Jet Propulsion Laboratory in California and the Los Alamos National Laboratory in New Mexico, will let researchers test the theory.

"There's going to be a great deal of skepticism about this, and there should be," Rundle said. "We don't know whether it will work or not."

The map was developed early last year, but not released until publication in an article that appeared Feb. 19 in the Proceedings of the National Academy of Sciences.

In the last year there have been two quakes of 5.1 or larger in Southern California. One, near Big Bear Lake on Feb. 10, 2001, was inside an area marked as susceptible to large quakes. Another, near Anza last Oct. 31, was about 10 miles outside one. A third quake, the 5.7 that occurred Feb. 22 about 30 miles inside Baja California, Mexico, was within another area designated as susceptible.

But Jones said "one year and three events is not enough to say" whether Rundle and Tiampo's system works.

Jones noted that most of the areas marked as being at risk on the Colorado scientists' map are in the state's most active seismic areas anyway.

The Olympian Copyright 2002

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