A swarm of more than 350 earthquakes reaching up to magnitude 4.7 rattled Brawley in Southern California near the Salton Sea, the U.S. Geological Survey reported.
The other quakes in the Saturday evening swarm ranged from magnitude 1.3 to 4.5, according to the USGS.
The swarm began with a quake at 4:14 p.m., 2 miles southwest of Brawley in Imperial County, the USGS reported. More followed overnight with the most recent, a magnitude 1.3 quake, striking at 1:46 p.m. Sunday.
The 10-mile deep 4.7 quake hit at 10:21 p.m. Saturday, according to the USGS.
More than 175 people from as far away as Pacific Palisades and Los Alamitos reported feeling the tremors to the agency. A Shake Alert was sent on the earthquake.
Brawley is about 200 miles southeast of Los Angeles.
“The Imperial Valley has seen dozens if not hundreds of these sort of swarms over the century we have recorded,” said seismologist Lucy Jones on Blueskey. “A swarm is a group of quakes (dozens to thousands) where there are many quakes close in size and no obvious mainshock.”
Magnitude measures the energy released at the source of the earthquake, the U.S. Geological Survey says. It replaces the old Richter scale.
Earthquakes between magnitudes 2.5 and 5.4 are often felt but rarely cause much damage, according to Michigan Tech. Quakes below magnitude 2.5 are seldom felt by most people.
