Residents in Los Angeles and Ventura counties reported feeling a magnitude-3.7 earthquake that struck in the mountains about 9 miles west of Castaic.
The temblor struck about 9:18 p.m. at a depth of 9 miles, the U.S. Geological Survey said. The epicenter was just north of Lake Piru.
There were no immediate reports of injuries or damages.
Several hundred residents in Los Angeles' Westside, the San Fernando Valley and Ventura County cities reported feeling the shaking on the USGS website.