SAN FRANCISCO (KRON) -- Many San Francisco Bay Area residents were jolted awake by a sizable earthquake early Thursday morning. The quake, with a magnitude of 4.6, according to the U.S. Geological Survey, struck at 1:41 a.m. The quake's epicenter was Boulder Creek in the Santa Cruz Mountains, near San Jose. However, it was felt across the Bay Area with reports of significant shaking in Walnut Creek, Alameda, San Francisco and even up in the North Bay. An earthquake intensity map from USGS indicated it was most heavily felt across the South Bay, the SF Peninsula and Santa Cruz County. Earthquake intensity map (USGS) There were no preliminary reports of damage or injuries related to the quake. ...read more read less