2.9 earthquake hits Berkeley, 3 in San Francisco Bay area in week

Sept. 15 (UPI) -- A third earthquake this week hit the San Francisco Bay Area on Thursday, shaking Berkeley with a 2.9-magnitude tremor, experts said.

The early morning quake's epicenter was a little less than two miles east-southeast of Berkeley at a depth of 5.5 miles, according to the U.S. Geological Survey.

Weak shaking was felt throughout East Bay and San Francisco, and more than 900 people told the survey they felt the shaking. Two days earlier, two earthquakes with magnitudes of 4.4 and 4.3 hit near Santa Rosa, Calif.

The earthquake happened along the Hayward Fault that runs from San Pablo Bay to the north and Fremont to the south, through some of the most populated areas of the San Francisco-Oakland region.

On June 28, a moderate earthquake struck Northern California near Cobb, which is located about 70 miles northwest of Sacramento. That quake measured 3.8, but scientists later revised it to 4.2.

Earthquakes are common in much of California due partly to the San Andreas Fault, which begins in far Northern California and runs down to near the San Diego area. There are also other geological fault lines that affect the San Francisco Bay Area, such as the Rodgers Creek and Hayward faults.