Feds: Strong Quake Will Hit California in Next 30 Years
USGS warns of 'vast, interconnected fault system'
By Rob Quinn,  Newser Staff
Posted Mar 11, 2015 4:24 AM CDT
In this Oct. 17, 1989, photo, a California Highway Patrol officer checks the damage to cars that fell when the Bay Bridge's upper deck collapsed after the Loma Prieta earthquake in San Francisco.   (AP Photo/George Nikitin, File)
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(Newser) – The latest US Geological Survey forecast for California doesn't contain much that will reassure people worried about earthquakes—unless they find fatalism reassuring. The report says there is not only a 99% chance of a 6.7 magnitude or greater quake like the 1994 Northridge one hitting the state in the next 30 years, the chances of a mega-quake of 8 magnitude or greater are significantly higher than earlier thought, the AP reports. "California is earthquake country, and residents should live every day like it could be the day of a big one," says lead author Ned Field, a USGS geophysicist. He says that out of the state's hundreds of faults, the "locked and loaded" San Andreas Fault is still the biggest threat.

Field says the odds of a mega-quake in the next three decades have risen to 7% from 4.7% since the 2008 forecast because scientists now have a better understanding of the fault system and how quakes can jump from fault to fault, the Los Angeles Times reports. In California, "it has become increasingly apparent that we are not dealing with a few [well-separated] faults, but with a vast interconnected fault system," he says. The USGS still can't predict exactly when an earthquake will hit, but it's testing an early warning system that will give authorities vital seconds to do things like shut off gas lines and slow down trains, the AP reports. (Another federal study warns that small, fracking-linked quakes in Oklahoma and Kansas are making a big one more likely.)