A magnitude-5.1 earthquake hit north of Los Angeles on Sunday, rocking much of southern California as residents braced for heavy rain brought by Tropical Storm Hilary.
There were no immediate reports of damage or injuries from the quake, which struck at 2.41pm local time, about seven kilometres south-east of Ojai in Ventura County. It was followed by several smaller aftershocks.
Ventura County's information website said the earthquake was “felt extensively” throughout area.
The US Tsunami Warning System said there was no threat of a tsunami from the earthquake.
As of Sunday afternoon, Hilary's centre was in California with maximum sustained winds of 95kph, after moving up the Baja California Peninsula in Mexico.
The National Hurricane Centre said the storm, a rare event for southern California, was moving at 37kph.
By Sunday night, the NHC warned of “potentially historic” rainfall overnight that was expected to cause “life-threatening to locally catastrophic flash, urban, and arroyo flooding” in parts of the state.
Hilary earlier reached category 4, the second-most powerful on the five-step Saffir-Simpson hurricane scale, but was downgraded to a tropical storm as it headed towards the densely populated Mexican city of Tijuana, on the border with US.