The tremble was felt from Los Angeles to San Diego, and partially in Las Vegas.
Preliminary information from the U.S. Geological Survey estimated the quake at magnitude 5.8, centered 29 miles southeast of downtown Los Angeles near Chino Hills in San Bernardino County. Ten aftershocks occurred in the next dozen minutes, including three estimated at 3.8.
California is one of the world's most seismically active regions. More than 300 faults crisscross the state, which sits atop two of Earth's major tectonic plates, the Pacific and North American plates. About 10,000 quakes each year rattle Southern California alone, although most of them are too small to be felt.
