A quake with a magnitude as large as 7.1 has jolted much of California, cracking buildings, setting fires, breaking roads and causing several injuries, authorities and residents say.

The quake – preceded by Thursday’s 6.4-magnitude tremor in the Mojave Desert – was the largest Southern California tremor in at least 20 years and was followed by a series of large and small aftershocks.

It was centred 18 km from Ridgecrest in the same areas where the previous quake hit. But it was felt as far north as Sacramento, as far east as Las Vegas and as far south as Mexico.

Early magnitude estimates from the US Geological Survey wavered between 6.9 and 7.1.

The area in and around Ridgecrest, already trying to recover from the previous tremor, took the brunt of damage.

Megan Person, director of communications for the Kern County Fire Department, said there were reports of multiple injuries and multiple fires, but she didn’t have details.

The county opened an emergency shelter. Meanwhile, a rockslide closed State Route 178 in Kern River Canyon, where photos from witnesses also showed that a stretch of roadway had sunk.

San Bernardino County firefighters reported cracked buildings and one minor injury.

In downtown Los Angeles, 241 km away, offices in skyscrapers rolled and rocked for at least 30 seconds.

Andrew Lippman, who lives in suburban South Pasadena, was sitting outside and reading the paper when Friday’s quake hit.

“It just started getting stronger and stronger, and I looked into my house and the lamp started to sway. I could see power lines swaying,” he said. “This one seemed 45 (seconds) … I’m still straightening pictures.”

Gov. Gavin Newsom activated the state Office of Emergency Services operations centre “to its highest level.”

“The state is coordinating mutual aid to local first responders,” he said.

Lucy Jones, a seismologist at the California Institute of Technology and a former science adviser at the Geological Survey, tweeted that Thursday’s earthquake was a “foreshock” and that Friday’s quake was on the same fault system as the earlier quake.

Cracks appeared in roads during the 6.4 magnitude quake. Photo: Getty

“You know we say we have a 1 in 20 chance that an earthquake will be followed by something bigger? This is that 1 in 20 time,” she tweeted.

Firefighters around Southern California were mobilised to check for damage.

An NBA Summer League game in Las Vegas was stopped after the quake. Speakers over the court at the Thomas & Mack Centre continued swaying more than 10 minutes after the quake.

In Los Angeles, the quake rattled Dodger Stadium in the fourth inning of the team’s game against the San Diego Padres.

A fissure opens up in the ground following the 6.4 magnitude quake. Photo: Getty

Disneyland had evacuated rides as the park conducted safety checks, the Hollywood Reporter wrote. The park’s mobile app had marked all rides as “temporarily closed” on Friday night.

The quake came as communities in the Mojave Desert tallied damage and made emergency repairs to cracked roads and broken pipes from the earlier quake.

Hours earlier, seismologists had said that quake had been followed by more than 1,700 aftershocks and that they might continue for years.

California is partnering with the federal government to build the statewide earthquake warning system, with the goal of turning it on by June 2021. The state has already spent at least $25 million building it, including installing hundreds of seismic stations throughout the state.

quake is the largest in southern California since a 1994 magnitude 6.6 earthquake struck a heavily populated area of Los Angeles, killing 57 people and causing billions of dollars of damage.

-AAP