California residents would be well advised to check their insurance policies following the latest predictions from the US Geological Survey (click the picture for a full size map).
A snazzy new model which, for the first time, allows statewide earthquake probability forecasts says a 6.7 or above magnitude quake is “more than 99%” likely over the next 30 years (press release).
“The sobering thing to me is we’ve never seen anything like a 99 percent probability before. That’s not a number we throw around a lot,” says Tom Parsons, a seismologist with the USGS (San Jose Mercury).
Over the same 30 year period, a 7.5 or above quake is 46% likely. SoCal is more likely to get hit than NoCal by such a quake, according to the model.
The LA Times notes:
The scientists acknowledged that talk of a “Big One” has been going on for decades, with references to how the San Andreas fault was in the 10th month of its pregnancy.
“You have to realize this is a long pregnancy,” Jordan said. “It’s been 300 years since the southern San Andreas has ruptured. We expect ruptures to occur on the order of every 150 years. So that makes it a high probability location for a future rupture.”
Reuters notes that a 7.5 quake would be capable of “inflicting catastrophic damage” on LA or San Francisco. “Magnitude 7.5, that’s a really big earthquake,” says Tom Jordan, director of the Southern California Earthquake Center. “…If that were to take place in say, the Los Angeles region, then you would have a big problem.”
The model combines past data on seismology, earthquake geology, and geodesy. Although it hasn’t been peer reviewed it has been looked over by an independent review panel. Localised estimates from the new model tally with previous estimates.
“What we’re presenting is the most comprehensive earthquake forecast ever developed of the entire state of California,” said Ned Field, a USGS geophysicist (LA Times).
USGS hopes it will be used to help in emergency planning and zoning. Unfortunately for Californians it will also likely be used to set insurance rates…
Image: USGS