Swarm of more than 30 earthquakes rattles Southern California, geologists say
A swarm of more than 30 earthquakes reaching up to 4.0 magnitude have rattled Southern California since Sunday afternoon, the U.S. Geological Survey reported.
Other quakes in the swarm ranged from 0.2 to 3.0 magnitude, according to USGS.
Starting about 12:30 p.m. Sunday, several small earthquakes were measured near Anza, according to USGS. More quakes followed overnight and into Monday morning, with the most recent striking near Niland at about 10:45 a.m.
The most intense earthquake hit at about 10:05 a.m. near Niland, less than 20 miles from Brawley, according to USGS. The 4.0 quake was about 1.4 miles deep.
Magnitude measures the energy released at the source of the earthquake, the U.S. Geological Survey says. It replaces the old Richter scale.
Quakes between 2.5 and 5.4 magnitude are often felt but rarely cause much damage, according to Michigan Tech.
