On Thursday, the largest earthquake to hit Southern California in roughly 20 years rumbled from 125 miles northeast of Los Angeles.
The 6.4 magnitude earthquake, the biggest in Southern California since the magnitude 7.1 Hector Mine quake hit the Mojave Desert in 1999, struck at roughly 10:30 a.m. and was felt as far away as Las Vegas, Nevada, Reno, Nevada, Phoenix, Arizona, and Ensenada and Mexicali in Mexico. As The Los Angeles Times noted, a 5.4 magnitude aftershock awakened many people Friday morning.
Ridgecrest, California, Mayor Peggy Breeden said she was contacted by various politicians as well as the White House. The Washington Post reported on Friday, “There have been over 1,000 earthquakes in the remote Searles Valley region in the past day, according to U.S. Geological Survey data, though fewer than 200 registered over the 2.5 magnitude at which earthquakes can usually be felt.”
The Desert Sun added, “Abhijit Ghosh, a professor of geophysics at the University of California, Riverside, said the quake isn’t likely to have a significant impact on seismic activity in the Coachella Valley, which sits on the San Andreas Fault. ‘In general, the earthquake hazard is high in the Coachella Valley, but this particular earthquake is not a cause of additional concern for people in the Palm Springs area,’ Ghosh said.”
But CBS News quoted Caltech seismologist Lucy Jones saying that the earthquake could portend more serious ones, asserting, “There is about a 1 in 20 chance that this location will be having an even bigger earthquake within the next few days.” Jones noted on Twitter, “M6.4 on a strikeslip fault about 10 miles from Ridgecrest. Not the San Andreas fault. It is an area with a lot of little faults but no long fault.”
Jones explained further, “The aftershocks to the #SearlesValley earthquake show that two faults are involved. One strikes northwest and the other northeast.”
Laist reported, “Thursday morning’s earthquake was on the Little Lake fault. The last time there was major activity on that fault was a swarm in 1982, with the largest being a 5.2 quake. Today’s earthquake was likely powerful enough to break the earth’s surface.”
The Los Angeles Times explained that just because the Southern California area had an earthquake does not mean that stress was relieved underground that would postpone the major earthquake everyone fears:
One part of California, west of the San Andreas, is constantly moving northwest, toward Alaska, relative to the other side of the Golden State, which is headed toward Mexico. These immense forces are what generated the state’s mountains, from the ranges seen in the Los Angeles Basin to the hills lining the ridges of the Bay Area. There’s a reason why earthquake faults are often alongside hills and mountains … There is no avoiding, eventually, big earthquakes being unleashed on faults somewhere in this state. We just don’t know exactly when or where it’ll happen. But just as it’s happened before in centuries and millennia past, it will happen again.