Bay Area Earthquake Flare-Up Persists Into Monday Afternoon, Residents Remain Alert

The Bay Area experienced a continued surge of small earthquakes into Monday afternoon, extending a pattern of seismic activity that started last month. The latest quake struck Oakland at 2:55 p.m. with a preliminary magnitude of 2.9 and an epicenter north of Montclair, according to the U.S. Geological Survey (USGS).

Earlier in the day, San Ramon saw multiple tremors, including two quakes at 1:50 p.m. and 1:59 p.m., registering magnitudes of 2.9 and 2.6 respectively. These events follow a morning series of at least seven smaller earthquakes. Residents in Alameda and Contra Costa counties reported feeling light shaking, according to USGS’s “Did You Feel It?” map.

Seismologist Roland Burgmann of UC Berkeley characterized Monday’s activity as a “flare-up” of a swarm from November, when about 90 minor earthquakes rattled the region. He explained that such swarms are common in San Ramon and Alamo, with roughly a dozen recorded over the last 20 to 25 years.

Unlike typical earthquake sequences that begin with a larger quake followed by smaller aftershocks, this swarm consists of many small tremors happening intermittently without growing stronger. These earthquakes cluster around the Calaveras Fault, which also produced a series of quakes in Gilroy late last month.

Burgmann noted that the probability of a stronger earthquake slightly increases for about a week following these swarms but advised calm. “People shouldn’t be scared, but just statistically, yes, the chances are so much higher,” he said, encouraging residents to review their earthquake preparedness.

The early Monday morning quakes ranged from magnitude 2.5 to 3.0 and were felt in several cities, including Concord, Berkeley, Oakland, San Francisco, Hayward, San Leandro, Livermore, Fremont, and San Jose. The consistent tremors at varying depths, from around 2.85 to over 5 miles, demonstrate ongoing seismic tension in the Bay Area.

This persistent earthquake activity highlights the importance of community awareness and readiness as the region remains geologically active. Residents are urged to stay informed through USGS updates and maintain preparedness measures for potential future shakes.