Los Angeles - Southern California was rattled Friday by a 7.1-magnitude earthquake, the US Geological Survey (USGS) said, the strongest quake to hit the region in two decades.
The tremor, which surpassed a 6.4-magnitude quake on Thursday, struck at 8.19 pm (0319 GMT) near Ridgecrest around 180 kilometres north-east of Los Angeles.
The extent of the damage of Friday's quake in Ridgecrest - a desert city of about 30,000 people - was initially unclear.
David Witt, the Kern County fire chief, said that no major building collapses were known of but authorities were searching the area.
"There's so many calls for help that we have a backlog of calls," Witt told reporters.