An earthquake that struck Thursday morning (local time) in the Mojave Desert rattling a large swath of Southern California was also felt in neighbouring Nevada.

There have been reports of minor cracks in buildings, power lines down, broken water mains, rock slides and fires in some areas. And at least one major highway in San Bernardino County has a four inch crack, according to local fire department spokesman Jeremy Kern.

The quake measured with a preliminary magnitude of 6.4 struck near the town of Ridgecrest, California, about 240 kilometres northeast of Los Angeles.

The quake was the largest in Southern California since the 7.1 Hector Mine quake struck the Twentynine Palms Marine Corps Base in 1999. The National Weather Service tweeted that the earthquake was felt in Las Vegas, adding, "so far no significant damage reports".


Mark Leach, an engineer who lives in LA, was in his garage about to drive to a July 4 barbecue in Los Angeles when the shaking started. He told the LA Times that it "felt like it went on for 30 seconds".

"About halfway through it I dashed out into the road completely freaking out," he said. "You can see some cracking in the seams of the drywall and stuff was knocked off the shelves — books and CDs and stuff."

People from Las Vegas to the Pacific Coast reported feeling a rolling motion that shook shower doors and made hanging dining room lights sway.

Local emergency agencies also took to social media to ask people to only call 911 for emergencies.

"We are very much aware of the significant earthquake that just occurred in Southern California. Please DO NOT call 9-1-1 unless there are injuries or other dangerous conditions. Don't call for questions please," the LAPD said in a statement published on Twitter.

Ashleigh Chandler, a helicopter rescue medic at Fort Irwin, California, told the Hollywood Reporter the quake happened as she was getting ready for a July 4th party.

"I was just in the living room getting everything ready, we start to feel the shaking, so then I look up and then the wine bottles start rattling and I thought, 'They're going to fall.'

"My sister was in the house and my dog, so we just got everyone outside and then it ended. It was like 15, 20 seconds, maybe. It was pretty good shaking, so I'm out of breath.

"Everyone's OK."

People from the desert to the Pacific coast in Southern California reported feeling the tremor, including several Hollywood figures including Dwayne 'The Rock' Johnson, talk show host Trevor Noah and film director Ava DuVernary.

"Been living in Los Angeles all my life. That was the longest earthquake I've ever experienced. Not jerky. Smooth and rolling. But it was loooong. It was so long I thought for the first time ever 'Is this the big one?'" DuVernay tweeted. "Damn. Respect Mother Nature. She's the boss."

Added Noah on Twitter, "That earthquake was not fun …"

Johnson also commented on the strength of the quake: "6.6 is strong. We felt a lil' movement here in the valley, but all good. Prayers to those in D valley, Bakersfield, S Valley, Kern etc. Be safe, stay prepared. #mothernature"

"I've lived in Los Angeles for 7+ years and that's the first time an earthquake actually made me quake," wrote film producer Matt Dentler.

NBC News anchor Lester Holt was in the beachside neighbourhood of Santa Monica, where he described how the earthquake felt in a TV report.

"I was sitting in my living room and felt the shaking," he said. "Now, as a New Yorker, there was a moment of processing, 'Is there a subway beneath me?'

"Because there are buildings that shake a little bit because of a subway. But I quickly processed that out and realised what was happening, got up away from near the glass door where I was sitting, got up and called out to my family and the craziest thing about this one is it kept rolling and rolling and rolling and rolling."

Additional reporting: