Overview
- At least six to seven small earthquakes struck south of San Ramon early Monday, capped by a magnitude 3.7 at 9:07 a.m., according to the U.S. Geological Survey.
- The sequence continued into the afternoon with additional tremors near San Ramon and a separate magnitude 2.9 quake in Oakland at 2:55 p.m.
- USGS “Did You Feel It?” reports logged weak to light shaking across Bay Area cities including Concord, Berkeley, Oakland, San Francisco, Hayward, San Leandro, Livermore, Fremont and San Jose.
- UC Berkeley’s Roland Burgmann described the activity as a flare-up of November’s swarm near the Calaveras Fault, a pattern that USGS seismologist Annemarie Baltay notes has recurred in the area for decades.
- No injuries or damage were reported, and seismologists say the chance of a larger quake is modestly elevated for about a week as monitoring continues and residents are urged to review preparedness.