California rocked by earthquakes

SAN DIEGO — Dozens of small to moderate earthquakes rattled Southern California on Sunday, shaking an area from rural Imperial County to the San Diego coast and north into the Coachella Valley.

The largest quake, magnitude 5.3, struck at 12:31 p.m. about five kilometres north-northwest of the small town of Brawley, according to Paul Caruso, a geophysicist with the U.S. Geological Survey. It was followed minutes later by a magnitude-4.9 quake. The first quake had a magnitude of 3.9 and hit at 10:02 a.m. It was followed by a smaller quake about 90 seconds later in the same area near the southern end of the Salton Sea, and other smaller quakes followed within six minutes of the first shock.

A Brawley Police Department dispatcher said several downtown buildings sustained minor damage. No injuries were reported.

The USGS said more than 100 aftershocks struck the same approximate epicentre, about 26 kilometres north of El Centro. Some shaking was felt along the San Diego County coast in Del Mar, some 193 km from the epicentre, as well as in the Coachella Valley, southern Orange County and parts of northern Mexico.

USGS seismologist Lucy Jones said earthquake swarms are characteristic of the region, known as the Brawley Seismic Zone.

“The area sees lots of events at once, with many close to the largest magnitude, rather than one main shock with several much smaller aftershocks,” Jones said.

The last major swarm was in 2005, following a magnitude-5.1 quake, she said. Scientists weren’t yet sure what fault Sunday’s quake cluster was on, but it was near the 1,300-km San Andreas Fault, Caruso said.