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Swarm of earthquakes strike San Ramon, jolting residents
At least 17 moderate and smaller earthquakes hit San Ramon on Monday morning, jolting some residents awake.
SAN RAMON, Calif. - At least 21 moderate and smaller earthquakes hit San Ramon on Monday morning, jolting some residents awake.
By the numbers:
The largest one so far was an earthquake clocking in at a 4.2 magnitude, which struck about 7 a.m., and was felt throughout the Bay Area, from San Francisco to Santa Cruz.
The next largest quake clocked in at a 3.9 magnitude.
The rumbling began just about 6:30 a.m. with a pair of quakes with magnitudes of 3.7 and 3.3, according to the US Geological Survey. There were several other smaller ones at 2.0.
At least a dozen people living in San Ramon and Pleasant Hill called the KTVU newsroom to say they felt quite a big shake. The shaking was even felt at KTVU studios at Jack London Square in Oakland.
Evan Li, 16,of San Ramon sent in video of his paperclips and change on the table shaking during one of the quakes. He's loved earthquake science ever since the 2nd grade and created his own "Earthquake Cam" to capture situations just like this.
"I use something called Global Quake," he said. "And it was able to detect the quake as well, and tell me a prelimary magnitude before the USGS."
Miranda Harmon-Smith wrote on Facebook that her house in Brentwood creaked and the cat jumped. Tina Hernandez-Romo wrote that her bed shook in Cherryland near San Leandro. Others wrote in to say they felt the shaking in San Francisco, Livermore, Orinda and beyond.
To date, there have been no immediate reports of injury or damage.
Big picture view:
San Ramon has been a hotbed of moderate earthquakes in both Alameda and Contra Costa counties along the Calaveras Fault, known as a creeping fault.
Creeping faults move slowly and stress is released in lots of small-to-moderate quakes, which is textbook swarm behavior. Occasionally, stress stacks up just enough to release quakes in the 4.0-magnitude range.
Since Dec. 1, 2025, the USGS said there have been roughly 300 quakes in that same area.
Most recently, there were at least two reported on Friday, and another nearby in Dublin, according to the US Geological Survey.
To keep track of how many quakes struck Ramon on Monday, click here.