A 90-minute earthquake swarm near San Ramon, CA, with a magnitude 4.2 quake, shook the Bay Area on Feb. 2, 2026, causing no damage or injuries.

A swarm of 13–17 small earthquakes struck San Ramon, California, on February 2, 2026, with the strongest measuring magnitude 4.2, about 2.5 miles southeast of downtown. The 90-minute series, centered near the Calaveras Fault, included several quakes above magnitude 3.0 and was felt across the Bay Area, including San Francisco, Oakland, and Richmond. No injuries or damage were reported, though BART faced brief delays for safety inspections. The activity is part of an ongoing swarm since November 2025, with 87 quakes of magnitude 2.0 or higher recorded in Contra Costa County. Scientists say such swarms do not necessarily indicate larger quakes.