An earthquake rumbled early Saturday off the northern California coast and dozens of people in Humboldt County reported feeling it, the U.S. Geological Survey said.

The 4.6-magnitude temblor hit at 12:46 a.m. and was centered in the Pacific Ocean about 30 miles west of Ferndale.

USGS geophysicist Randy Baldwin said the temblor was lightly felt in area cities such as Eureka and Ferndale but wasn't strong enough to cause damage.