A 2.9 magnitude earthquake just east of Piedmont jolted Oakland and other East Bay cities shortly before 3 p.m. on Monday — the latest of dozens of small quakes to rattle the East Bay in a span of 15 hours, according to the U.S. Geological Survey.
Earlier, a 3.6 magnitude earthquake struck the East Bay’s Tri-Valley region. The 9:07 a.m. quake was the strongest of a cluster of jolts that popped in the San Ramon area throughout the morning. No damage was immediately reported, but the 3.6 quake, which was initially measured as a 3.7 and later revised downward, was felt as far as San Jose to the south and Hercules to the north.
USGS officials did not know whether the 3.6 quake would be the largest of the swarm, but they said such strings of seismic activity aren’t uncommon in the region and generally don’t get much stronger. Last month, a swarm in the same area lasted a couple of days, peaking with a 3.8 magnitude quake on Nov. 9…