By Roland Pease
Jul. 13, 2020

A pair of earthquakes that struck the remote California desert 1 year ago have raised the risk of “the big one” hitting Southern California, according to a new study. The research finds that the 2019 Ridgecrest, California, quakes shifted underground stresses, making the San Andreas fault—the state’s longest and most dangerous fault—three times more likely to rupture.

“You would think an earthquake … out in the desert would have no impact on Los Angeles,” says Ross Stein, a seismologist and one of the authors of the new study. “But that is because we do not appreciate the way the network of fault lines connect across the state.”

In July 2019, two faults near the town of Ridgecrest ruptured in quick succession: a magnitude 6.4 on 4 July, followed by a substantial magnitude 7.1 a day and a half later. The temblors damaged buildings in the area, but residents in Los Angeles, nearly 200 kilometers away, felt little more than light shaking.

SNIP