No damage or injuries were reported after a strong earthquake struck about 80 miles south of San Francisco on a branch of the San Andreas Fault. The quake woke some people in a wide area of Northern California and knocked objects off store shelves. Police in the Monterey area and the state Office of Emergency Services said strong motion was reported in the quake at 12:39 a.m. Saturday, centered seven miles southeast of Hollister. The seismographic station at UC Berkeley assigned the temblor a preliminary Richter scale reading of 5.1, later reported as 4.6 by the National Earthquake Information Center at Golden, Colo. The quake was also felt in San Francisco, Alameda, Santa Clara, Santa Cruz and Monterey counties.