A swarm of earthquakes rattled the San Ramon area on Monday morning, with over 30 temblors reported by the U.S. Geological Survey (USGS). The strongest quake registered a magnitude of 4.2, centered in San Ramon and occurring at 7:01 a.m. This followed a slightly weaker earthquake of 3.8 magnitude that struck just before at 6:27 a.m.
The USGS indicated that the 4.2 magnitude quake occurred at a depth of approximately 9.4 kilometers. Additional seismic activity persisted throughout the afternoon, including a 2.5 magnitude quake at 2:06 p.m., followed by preliminary magnitudes of 3.1, 3.0, and 2.9 occurring shortly afterward.
Fortunately, there have been no reports of injuries or significant damage. Video footage taken from a San Ramon 7-Eleven captured items falling from shelves during one of the tremors, showcasing the quake’s impact.
Local residents expressed surprise at the frequency of the quakes, though many noted a familiarity with such seismic activity. One Dublin resident recalled similar swarms that happened in the past, suggesting a certain level of resilience among those living in the area. Rogelio Oropeza, an employee at a local café, recounted the shaking felt while preparing for the morning rush, describing a scene of chaos as items and equipment swayed.
The San Ramon Olympic Pool and Aquatic Park, which had around 45 people present during the initial quake, reported feeling the shake significantly, particularly as the largest tremor hit shortly after the smaller ones. The pool’s staff conducted safety checks, ultimately deeming the facility secure.
John Goodell from the California Earthquake Early Warning Program emphasized that while no larger earthquake seems imminent, earthquakes are a regular occurrence throughout the state, with hundreds happening annually. He noted that while some quakes may be felt more intensely, the swarm occurring now does not necessarily indicate a larger seismic event on the horizon.
Robert DeGroot of the USGS echoed this sentiment, suggesting that the series of small tremors could continue for months but calling it “not something that is necessarily significant of something bigger.” Mayor Mark Armstrong reiterated the importance of community preparedness and confirmed that city officials are actively monitoring the situation while maintaining robust emergency preparedness systems.
In response to the seismic activity, BART trains were temporarily slowed for inspections, a standard procedure during such events. As residents remain vigilant, the city continues to prioritize safety and readiness for any potential future occurrences.