A powerful earthquake centered in Ventura County shook most of Southern California on Sunday on the same day the area was experiencing the effects of Tropical Storm Hilary.

The quake, with a magnitude of 5.1, struck at 2:41 p.m. in Ojai, according to the U.S. Geological Survey. It was quickly followed by a series of aftershocks.

There were no immediate reports of injuries or damage attributed to the quake. It was widely felt across the region, with shaking across Los Angeles County and into Riverside County.

Earthquake expert Lucy Jones wrote on X, formerly Twitter, that the shaker appeared to have been preceded by a series of foreshocks that began Saturday morning.

No tsunami threat was expected, according to officials.