A magnitude 3.3 earthquake struck San Ramon late Sunday night at 11:21 p.m., followed by multiple smaller aftershocks ranging from 1.5 to 2.8 in magnitude. According to the U.S. Geological Survey, the tremor was centered about 2.5 miles southeast of San Ramon at a shallow depth of roughly 8.4 kilometers. No injuries or structural damage were immediately reported.
This latest quake is the newest chapter in San Ramon's seismic story. Since December 1, 2025, roughly 300 earthquakes have been recorded in the San Ramon area, according to USGS data. The region sits along the Calaveras Fault, a creeping fault that frequently releases stress through small-to-moderate quakes rather than storing it up for major events. This behavior explains why residents have grown accustomed to regular seismic activity in recent months.
At magnitude 3.3, this quake was strong enough for people across the Bay Area to feel it—especially those close to the epicenter. Light shaking was reported in nearby communities including Dublin, Blackhawk, and Diablo. The shallow depth made it more perceptible to residents compared to deeper quakes. Meteorologists monitoring the activity noted that the swarm wasn't finished, with several smaller tremors continuing after the initial shock. For more details on the broader pattern of seismic activity in the region, check out our coverage of the San Ramon earthquake swarm.