As SFGATE report:
An earthquake swarm continues to shake the San Ramon Valley with almost 200 temblors rippling through the region through Monday afternoon, when a 2.8 quake struck at 4:02 p.m followed by a 3.5 quake,the largest in the series, and a second 2.8 quake, both at 4:21.
The 4:21 quakes were widely felt in the East Bay.
Most of the 25 quakes, which started at 11:58 p.m. Saturday, were felt within the Tri-Valley region of Contra Costa and eastern Alameda counties. The swarm could last for days or weeks, then end without notice, say earthquake experts.
The swarm appears unlikely at this point to stop..