Study suggests earthquake more likely on San Andreas Fault

A new study from the Bulletin of the Seismological Society of America has delivered some unfavorable news about the likelihood of an earthquake in Southern California. The study suggests that last year's earthquakes in Ridgecrest, California, increased the likelihood of a major earthquake.

In the next year, there is a 2.3% chance of a 7.5 or greater magnitude earthquake on the Garlock Fault, which runs along the north edge of the Mojave Desert. That's a big jump from the chances previously reported.

Study authors say that could trigger an earthquake on the San Andreas Fault, which would affect Los Angeles and the surrounding area.

"We estimate a 2.3% chance of a magnitude-7.7 Garlock Fault rupture in the next year — in other words, one chance in 43," the authors wrote. "This is 100 times higher than its annual chances in the ‘UCERF3’ benchmark model for California."

But the authors say that although this new information could be concerning, it is not reason to panic.

"A 1.15% chance of a great San Andreas rupture in the next year is low; it is the same as saying that there is a 98.9% chance it won’t rupture," the authors wrote. "So, no one should panic. But, as we have seen during the COVID-19 pandemic, low probability chain-reaction events do occur in nature, and when they do, their consequences can be great."