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.
The earthquake was reportedly felt as far as Las Vegas in Nevada. There have been several smaller aftershocks.
Lucy Jones, a seismologist with the US Geological Survey, told reporters the epicentre was in a relatively uninhabited area.
She said there would likely be a number of aftershocks, some powerful.