EL CENTRO, Calif., Aug. 26 (UPI) -- Southern California's Imperial County was shaken throughout the day Sunday by a swarm of about 300 earthquakes up to a 5.5-magnitude, seismologists said.
The equivalent of an "earthquake storm" caused cosmetic damage to at least three older buildings in downtown Brawley, Capt. Jesse Zendejas of the Brawley Fire Department said. No injuries were reported, the Los Angeles Times said.
Seismologist Rob Graves with the U.S. Geological Survey said such flurries of mostly minor temblors are not unprecedented in the region, with the last one also occurring in the Brawley area in 2005.
Graves said the cause of swarm earthquakes is not fully known, but he noted the Brawley area is situated between known active earthquake faults, including the Imperial and San Andreas faults.
Brawley resident Alfonso Alvarez, 28, said the multiple quakes led him and his family to leave their house.
"It's been pretty bad. Some of them are slow and then they get intense," he said. "We're so anxious right now we can't sit still."
USGS seismologist Lucy Jones said the swarm could last for days.