Southern California has been struck by a moderate earthquake of 6.4 magnitude, which has caused some fires.
The tremor’s epicentre was near the city of Ridgecrest, about 150 miles (240 km) northeast of Los Angeles.
People from the Mojave Desert to the Pacific coast are reported to have felt shaking as the US celebrated Independence Day.
Firefighters said they were providing medical assistance and dealing with fires in and around Ridgecrest.
It is the strongest earthquake to hit the region in more than two decades.
The city’s mayor, Peggy Breedon, told CNN that some people had been struck by objects falling from buildings and gas lines had been broken.
“We are used to earthquakes but we’re not used to this significance,” she said.
Stephen Sykes, who lives in Ridgecrest, was in the shower when his house started to shake.
“The whole house shook violently and we both ran out into the street. This went on for about ten to fifteen seconds, we were really scared,” he told the BBC.