A light, 4.7-magnitude earthquake struck in Northern California on Wednesday, according to the United States Geological Survey. The temblor happened at 6:34 p.m. Pacific time about 2 miles northwest of Cobb, Calif., or about 70 miles north of San Francisco, data from the agency shows.

The quake epicenter was 2 miles north-northwest of Cobb, a small community in the hills south of Clear Lake. The epicenter was 70 miles west of Sacramento and 27 miles north of Santa Rosa. A ShakeAlert was issued to cellphone users in portions of Lake, Sonoma, Napa and Mendocino counties, according to the USGS.

A magnitude 5.5 earthquake that struck in a remote area of Nevada on Monday afternoon sent shaking throughout Central California, including the Sacramento area.

The temblor was initially rated at 4.5 magnitude, then revised to 4.7 roughly a half hour later. Magnitude measures the energy released at the source of the earthquake, the U.S. Geological Survey says.

A magnitude 4.7 earthquake struck in California's Lake County on Wednesday afternoon, the U.S. Geological Survey said. The quake hit at 6:34 p.m. about 2 miles northwest of Cobb at a depth of 0.68 of a mile,