The quake hit at about 8:18 p.m.
It was originally measured at a magnitude 5.5, but it was downgraded to 5.1 an hour later.
Shaking could be felt from San Diego to Los Angeles. Resident reported feeling the quake in Palmdale, Lake Elsinore, Fontana, Glendale, San Bernardino and Las Vegas.
The U.S. Geological Survey says the temblor struck just outside Ludlow on Interstate 40, about 120 miles east of Los Angeles.
USGS geophysicist Rafael Abreu said the closest fault is the Lavic Lake Fault, in the Calico-Hidalgo fault zone, which is part of the San Andreas Fault region.
He said the movement is related to the gradual movement of the Pacific plate against the North American plate along a strike slip fault that crosses California.
So far, there are no reports of damage or injury.
Southern California Edison says they have no reports of outages or damage to any equipment due to the earthquake.
Fontana had a small and brief power outage, but Edison says it was not related to the earthquake.
The quake was just a few miles away from where the 7.1 magnitude Hector Mine quake hit in 1999. USGS seismologist Lucy Jones said it was probably an aftershock of that shake. She said it's not uncommon for big earthquakes to spawn aftershocks years later.
Latest from the Earthquake Center
The Associated Press contributed to this report.
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