San Ramon Valley Earthquakes Felt Across Bay Area

SAN RAMON VALLEY, CA — A series of four earthquakes struck in the San Ramon Valley shortly before noon on Wednesday, according to the United States Geological Survey. The magnitudes, which have been adjusted by the USGS, were 3.9, 3.2, 2.6 and 3.0. An initial alert about the first earthquake pegged it higher, at 4.2.

The quake was centered in the area of the Danville-San Ramon border.

However, the earthquake app QuakeFeed, calibrated to report earthquakes down to 2.0, has reported a total of 10 earthquakes, continuing through the afternoon until 4:01 p.m.

The first earthquake was described as "notable" by the USGS on Twitter. A Patch family member called it "scary" while another guessed the magnitude as much higher than the final determination.

On Twitter, residents reported "two massive jolts" and "a lot of shaking."

The USGS describes earthquake aftershocks as "creaking" as the earth settles into a relaxed state after the main earthquake. "The Earth wants to get back to some type of equilibrium, and that is the process that produces aftershocks," the USGS wrote in 2020. "If an event larger than the first strong quake occurs as part of the sequence, that then becomes the main shock and all prior events become foreshocks."

An earthquake swarm does not have a main shock.

There haven't been any reports of injuries or damage due to Wednesday's earthquakes.

The earthquakes were felt from the Santa Rosa area to the north, south to Santa Cruz, west to San Francisco and east to Modesto.

Did you feel them?

You may report your experience to the USGS for tracking purposes.

Report your response to USGS Did You Feel It.

Also see: Earthquake Preparedness: Must-Have List

Read more from the USGS about earthquake swarms and aftershocks.