San Francisco, Jul 6 : A 7.1 magnitude earthquake rattled a desert area of Southern California on Saturday.
The US meteorologists say it was the biggest tremor in two decades.
It struck at the shallow depth of 0.9km (0.6 miles) and its epicentre was near the city of Ridgecrest, about 240km north-east of Los Angeles, said a BBC News report.
A 6.4 magnitude quake hit the same region on Thursday at a depth of nearly 11km.
Seismologist Dr Lucy Jones said the quakes could continue.
"This is an earthquake sequence," she said at a press conference. "It will be ongoing."
"Every earthquake makes another earthquake more likely," she added.
As yet, there have been no reports of deaths or of a major damage.
The Los Angeles Fire Department said nobody had been killed or injured. A statement after the latest quake said the authorities had seen "no major infrastructure damage" after a survey of the city.
There were however reports of local power outages and damage after the new quake. A spokeswoman for the Kern County Fire Department said there had received multiple reports of injuries and fires.
Officials said it was still unclear how much damage had been caused and how many people had been injured in the state.
"It was bad. Man. It hasn't stopped yet," local resident Jeremiah Jones told the Los Angeles Times.
It hit at 20:19 local time on Friday (03:19 GMT Saturday), the US Geological Survey (USGS) said.
There are reports of fires and other damage in Ridgecrest, the Los Angeles Times reports, quoting local emergency officials.
After Thursday's event, seismologists had been warning that aftershocks could continue for a prolonged period of time.
Ridgecrest resident Jessica Kormelink told AFP news agency the ground stops shaking briefly "and then it starts rolling again".
"I'm not comfortable inside," she said.
California is prone to earthquakes as it lies on a number of faults - regions where tectonic plates come together.
Dr Jones told the Los Angeles Times this fault could be up to 30 miles long.
"The fault is growing," she said. "We ruptured a piece in the first earthquake... and we've ruptured more now."
The San Andreas Fault is the largest, extending about 1,200km through the state.
Californians are on permanent alert for the 'Big One', a catastrophic earthquake that seismologists say is well overdue.
This latest series of quakes has caused relatively minor damage - that we are currently aware of - but they have rattled nerves, big time.
The latest was felt as far afield as Las Vegas in Nevada, Palm Springs to the east of Los Angeles, and Beverly Hills.
With a baseball game in progress at Dodger Stadium, in downtown LA, people fled from their seats as the building started to shake - although the players, apparently oblivious to what was happening, continued with the game.
This event serves as a wakeup call to residents of densely populated areas, like Los Angeles, that it is only a matter of time before the mighty San Andreas fault blows. A magnitude of 7.0 or higher would likely cause widespread death and destruction. (UNI)