Magnitude 4.2 Quake Strikes Near San Ramon, Bay Area

A series of earthquakes, including a magnitude 4.2 tremor, struck near San Ramon in California's San Francisco Bay Area on Monday morning, shaking residents across a wide region but causing no reports of injuries or significant damage.

The strongest quake hit at approximately 7:01 a.m. local time, centered about 2.5 miles southeast of downtown San Ramon at a depth of around six miles, according to the U.S. Geological Survey. It was preceded by smaller tremors starting around 6:27 a.m., with at least 19 earthquakes recorded in the following hour to 90 minutes. Magnitudes ranged from 2.5 to 4.2, all at shallow depths of five miles or less. Shaking extended more than 30 miles to San Francisco and across East Bay cities including Oakland, Richmond and Concord, with some reports of sensation as far as the Peninsula and toward Sacramento, Stockton and Modesto.

Bay Area Rapid Transit reported systemwide delays of about 20 minutes as trains operated at reduced speeds during routine track safety inspections prompted by the activity. No tsunami warnings were issued, though one automated alert was briefly triggered before officials confirmed no risk. More than 4,000 people reported feeling...