The US Geological Survey has said a moderate earthquake measuring 5.4 on the Richter Scale hit the southern California desert region overnight.
No serious damage or injuries were reported.
The quake was centred about 200km east of Los Angeles.
It caused tall buildings in downtown Los Angeles to sway and tremors were felt as far away as San Diego to the south.
A series of aftershocks followed. This is the latest in a flurry of small to moderate temblors to hit southern California in the months since a magnitude 7.2 shock erupted along the US-Mexico border on Easter Sunday.
Geologists have been studying whether the Easter quake made seismic activity along more dangerous fault lines - such as the Whittier and San Andreas faults - more or less likely.
