Strong aftershocks rock California
LOS ANGELES – Aftershocks from Southern California’s largest earthquake in 20 years rumbled beneath the Mojave Desert on Friday as authorities tallied damage in the sparsely populated region.
The strongest aftershock thus far hit shortly after 4 a.m., registering magnitude 5.4 and awakening people all the way to the coast.
Thursday’s 6.4 magnitude quake struck at midmorning about 150 miles northeast of Los Angeles, near the town of Ridgecrest and a sprawling Navy installation.
Multiple injuries and two house fires were reported in the town of 28,000. Emergency crews dealt with small vegetation fires, gas leaks and reports of cracked roads, said Kern County Fire Chief David Witt.
He said 15 patients were evacuated from the Ridgecrest Regional Hospital as a precaution.
Ridgecrest Mayor Peggy Breeden said that utility workers were assessing broken gas lines and turning off gas where necessary.
Naval Air Weapons Station China Lake said in a statement late Thursday that no injuries were reported and so far all buildings had been found to be intact but assessments were continuing across its 1,875 square miles. Its workforce was ordered to not report on Friday.
Gov. Gavin Newsom has declared a state of emergency for Kern County.
Breeden noted at a news conference that other nearby governments have offered to help the recovery effort.
Lucy Jones, a seismologist with the California Institute of Technology’s seismology lab, has said the earthquake was the strongest since a 7.1 quake struck another area of the Mojave Desert on Oct. 16, 1999.
“This has been an extremely quiet abnormal time,” Jones said. “This type of earthquake is much more normal … The long term average is probably once every five or 10 years somewhere in Southern California.”
Jones said that the 6.4 quake was preceded by a magnitude 4.2 temblor about a half hour earlier.
“This is an isolated enough location that that’s going to greatly reduce the damage,” she said.
There was little likelihood the quake raised the risk of a quake on the San Andreas Fault, the sleeping giant that runs through much of California and is expected to be the source of the feared “Big One,” the scientists said.
“We have never seen a foreshock more than 10 kilometers, 6 miles, away from its mainshock and this is substantially farther than that to the San Andreas,” Jones said.
The quake was detected by California’s new ShakeAlert system and it provided 48 seconds of warning to the seismology lab well before the shaking arrived at Caltech in the Los Angeles suburb of Pasadena but it did not trigger a public warning through an app recently made available in Los Angeles County.
USGS seismologist Robert Graves said the ShakeAlert system worked properly. He said it calculated an intensity level for the Los Angeles area that was below the threshold for a public alert. The limits are intended to avoid false alarms.