Los Angeles May Survive the Worst of the “Big One,” According to a New Earthquake Simulation

The nightmare earthquake scenario described in an influential 2008 study may end up being less destructive than scientists thought, but Angelenos still shouldn't get too comfortable.

By Nick Keppler |
The San Andreas Faultline north of Los Angeles.
The San Andreas Faultline north of Los Angeles. / Lloyd Cluff/Corbis Documentary/Getty Images

For generations, denizens of Southern California have awaited “the Big One”—an earthquake that would decimate their sunbaked Babylon. Downtown Los Angeles is 30 miles from the San Andreas Faultline, where two tectonic plates scrape against each other. By some estimates, each of the faultline’s three segments should produce a high-magnitude earthquake every 200 to 300 years, and L.A. seems due [PDF]. According to a major 2008 paper from the California Geological Survey, a 7.8-magnitude quake in the southern segment of the fault would cause 1800 deaths, 50,000 injuries, and $200 billion in damage. 

In a less scientific assessment, things were pretty bad in that 2015 California earthquake disaster movie starring The Rock. But according to new research from a pair of geophysicists at San Diego State University, the Big One might not be as destructive as past geologists and screenwriters have thought. 

Their paper, published on an open-source website and not yet peer-reviewed, theorizes that the network of interconnected sedimentary basins around Los Angeles, acting as “waveguides,” would actually absorb earthquake movements and reduce the ground motion by possibly 50 percent. 

The two researchers, Kim Bak Olsen and Te-Yang Yeh, aimed to update a model from the 2008 study, which was prepared for the California Geological Survey for a massive earthquake preparedness project called the Great Southern California ShakeOut (a name surprisingly not already claimed by a high-priced music festival). The “ShakeOut model” incorporated Southern California as a simple flatland. Yeh told the website Live Science that computer modeling has improved since then, allowing them to incorporate more complex geological features.

The newer model presents good news for the inland region, which was the worst hit in the ShakeOut predictions. Yeh and Olsen write that the particularly deep San Bernardino and Chino basins would “substantially impact the long-period waves.”

Yeh told Live Science that, though their findings are “not as horrifying as what was previously predicted,” the ground motions in the new scenario “are still profound.”

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