USGS Questions Study’s Claim of 99.9% Chance of Large L.A. Earthquake in the Next 3 Years

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A couple survey the damage to their Parkfield home after a magnitude 6 earthquake hit southern Monterey County in 2004. (Credit: Stephen Osman / Los Angeles Times)

The U.S. Geological Survey is raising serious doubts about a recent study that calculates a 99.9 percent chance of a large earthquake in the Los Angeles area in the next three years.

The USGS took the rare step of issuing a statement raising questions about the study, recently published in the journal Earth and Space Science and coauthored by a research scientist at NASA’s Jet Propulsion Laboratory in La Cañada Flintridge.

“I have serious doubts that the conclusions of the paper are supported by the analysis that’s presented there,” Robert Graves, a USGS seismologist and Southern California coordinator for earthquake hazards, said in an interview Wednesday. The study lists Graves as a consultant who helped with calculations for the study, but Graves says he has deep concerns about the study.

The USGS said in a statement that the study’s forecast “has not yet been examined by the long-established committees that evaluate earthquake forecasts and predictions made by scientists.”

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