A 6.9-magnitude earthquake rattled Southern California on Friday night, one day after the strongest recorded quake in 20 years struck the state, and seismologists warned to expect further episodes.
The United States Geological Survey reported that the latest earthquake’s epicenter was between Bakersfield and the Mojave Desert. It followed a 5.4-magnitude aftershock that roused Californians on Friday morning.
“This is an earthquake sequence,” the seismologist Lucy Jones said during a briefing Friday night. “It is clearly an energetic system.”
Tom Heaton, an earthquake expert at the California Institute of Technology, said the earthquake Friday evening appeared to have taken place northwest of Thursday’s earthquake. He estimated the magnitude at around 7 but said a final calculation would be made later. The rupture was about 10 to 15 miles long and the duration of the earthquake was around 7 seconds. Friday’s earthquake was much larger than Thursday’s: the total energy released was about 8 times greater.
For now the earthquakes appear to be localized. There is “no plausible connection” between these earthquakes and the San Andreas, the larger and more potentially destructive fault that runs from the Gulf of California to well north of San Francisco, Dr. Heaton said.
“But in this business I don’t like to ever say things can never happen,” Dr. Heaton said.
The region where both Thursday’s and Friday’s earthquake struck is characterized by a complex set of faults that have helped form geological features called basin and ranges.
“I like to tell people that earthquakes are very social in the basin and range; they don’t like being alone,” Dr. Heaton said. “I would be surprised if this thing just stopped.”
The largest known earthquake in the area occurred in 1872 and was a magnitude 8, one of the largest in California.
Tim Dorcey of Santa Monica noticed something was amiss when the wine bottles in his home began rattling on Friday night. “That happened and I thought, ‘Oh aftershock,’” Mr. Dorcey said by phone. “And then it stopped. Fifteen seconds later it started going again. I hopped up and got away from my windows.”
Mr. Dorcey said the shaking began again and went on for a minute. “It kept getting stronger and stronger,” he said.
Giovanna Gomez of Bakersfield said Friday’s earthquake felt like the 6.4-magnitude quake that hit the same region on Thursday.
“I was in my living room with my parents, and all of a sudden we started feeling the earth slowly moving,” Ms. Gomez said. “And then it started getting bigger, just rocking back and forth.” She said the family promptly went outside and reported no damage and complained of dogs barking.