A moderate earthquake has jolted part of central California's San Luis Obispo County.

County Sgt. Steve Himmelrich says several people called and reported alarms going off after the quake shook the area early Saturday.

But he said there were no reports of damage or injury.

The U.S. Geological Survey said preliminary reports estimated the quake at magnitude 4.6.

The USGS said the quake was centered about 15 miles west of the city of Paso Robles.