CONTRA COSTA COUNTY, CA - the U.S. Geological Survey reported that a preliminary 2.7 magnitude quake rattled near San Ramon at midnight on Tuesday.

In California's East Bay, a recent swarm of small earthquakes has pushed long-standing seismic risks back into public view. Since early November 2025, at least 90 minor quakes have been recorded around San Ramon,

California's seismic risk is increasing with supershear earthquakes, which are faster and more destructive than typical earthquakes.

SAN RAMON — A cluster of earthquakes struck the San Ramon area Friday night, continuing a pattern of seismic activity in recent weeks, according to the U.S. Geological Survey. Things kicked off at 7:41 p.m. with a magnitude 2.5 centered 3.1 miles southeast of the city.

The U.S. Geological Survey reports the small earthquake struck just before 3 p.m. about 1 mile west of Piedmont in Alameda County.

A minor, 3.1-magnitude earthquake struck in Southern California on Thursday, according to the United States Geological Survey. The temblor happened at 10:27 a.m. Pacific time about 8 miles northwest of Fillmore, Calif., data from the agency shows.

The quake came only eight days after three earthquakes shook the area in the course of about 100 minutes. More than 30 quakes also were recorded between midnight and 10:15 a.m. on Dec. 8, according to CalTech’s California Earthquake Center.

A preliminary 4.0-magnitude earthquake struck California’s Sonoma County on Sunday afternoon, according to the US Geological Survey. The tremor hit at about 15:30 local time and was centred near the town of Glen Ellen. Residents in nearby Santa Rosa reported feeling light shaking.