Media playback is unsupported on your device Media caption Shocked newsreaders react live on air as the earthquake hits

A 7.1 magnitude earthquake has rattled parts of Southern California, the biggest tremor to strike in 20 years.

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.

A 6.4-magnitude quake hit the same area on Thursday at a depth of nearly 11km.

Emergency officials say the damage is not as bad as they initially feared, with power restored to most who had lost it and food stores trading again.

All of the roads that were damaged by the quake have also now been reopened, they say, but add that crews are still assessing the aftermath.

It's thought about 3,000 people in Ridgecrest and the surrounding area were left without power.

California Governor Gavin Newsom offered his "heartfelt support" to all those affected, and requested a Presidential Emergency Declaration and federal aid to help.

He later added that there were a number of "minor to moderate level" injuries, and said there were "no reports of any fatalities, so I think we're very lucky there".

Image copyright Reuters Image caption A landslide after the quake shut a road near Ridgecrest, which has since been reopened

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, saying there was a 10% chance of a similar or even larger quake following in the next week.

However, Dr Jones said it was not likely the quake would trigger shocks on other fault lines.

The earthquake was felt as far away as Las Vegas in the neighbouring state of Nevada and over the border in Mexico.

What happened afterwards?

Fires broke out and emergency services were dispatched across the state to deal with calls after the quake.

"We've got fires, we've got gas leaks, we've got injuries, we've got people without power," Ridgecrest Mayor Peggy Breeden told Reuters news agency. "We're dealing with it as best we can."

Image copyright AFP Image caption This fire broke out in a mobile home park on Saturday

Image copyright AFP Image caption Shop owners were left with a great deal of cleaning to do

The San Bernardino County Fire Department said reports suggested "damage is more significant than yesterday's quake", referring to Thursday's earthquake, and said they were tackling blazes and gas leaks.

"It was bad. Man. It hasn't stopped yet," local resident Jeremiah Jones told the Los Angeles Times.

Thursday's event had already wrecked some homes in the region.

The Los Angeles Fire Department however said nobody had been killed or injured in that quake either. A statement after the latest quake said the authorities had seen "no major infrastructure damage" after a survey of the city.

Crowds at a Los Angeles Dodgers baseball game were seen leaving their seats when the quake struck, although the players themselves continued playing.

A US Navy weapons testing station near Ridgecrest was also affected.

NAWS China Lake - the Navy's single largest landholding, covering an area larger than the state of Rhode Island - announced on Facebook it is "not mission capable until further notice", without providing details.

In Las Vegas, a basketball match between the New York Knicks and the New Orleans Pelicans was abandoned because of the tremors.

LA Mayor Eric Garcetti said he was sending a task force to Kern County "to help with the damage closer to the epicenter".

What do we know about the new quake?

It hit at 20:19 local time on Friday (04:19 BST Saturday), the US Geological Survey (USGS) said.

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 would stop shaking briefly before "rolling again".

"I'm not comfortable inside," she said.

Media playback is unsupported on your device Media caption Thursday's quake wrecked homes and businesses

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.

But Dr Jones said this quake was in a distant fault system, and was unlikely to trigger a quake along the San Andreas Fault.

Quake raises fears of 'the Big One'

By Peter Bowes in Los Angeles

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 in Los Angeles would likely cause widespread death and destruction.