San Ramon, CA

Magnitude 3.8 Earthquake Strikes San Ramon, Moderate Shaking Felt, Light Damage Possible

Thomas Smith
Original photo by the author

On the morning of November 17, 2021 at approximately 11:45 AM, a magnitude 4.0 earthquake struck San Ramon, California. Initially, the earthquake was estimated to be a 4.1 magnitude, but this was later revised down to 3.8

According to the United States Geological Survey, the quake struck the region at a depth of about 10.9 kilometers. The epicenter was listed as being just North of the Crow Canyon Country Club. Light shaking was reported in the immediate area, and the earthquake rippled outwards around the region, being felt in nearby areas like Oakland and Lamorinda.

Personally, I was in Lafayette, California at the time, about 10 miles North of the epicenter. I experienced the quake as light shaking in my home, which appeared to last for about 5 seconds. Generally, the length of a quake corresponds with its intensity, so it was reassuring that the quake was relatively short-lived, even if experiencing it was surprising.

Light shaking generally does not result in damage to structures, and a magnitude 3.8 earthquake is generally considered mild by the USGS. In the San Ramon area, however, moderate shaking was reported, scoring a ranking of five on the USGS' scale.

This corresponds to the potential for "very light" damage, according to the USGS. If you live in San Ramon, you might notice damage such as glasses breaking in drawers, pictures falling from the walls, and other related minor damage. If you smell gas or experience other signs of more intense damage, call authorities and exit your home or business.

Several San Ramon citizens took to Twitter to share their experiences of the quake. One user wrote "I thought someone had broke in my place. It was loud and a big jolt. I’m on my balcony and looked up thinking something is going to drop." Another said "Yeah, it was quick and lasted about 1 second. It was like a swoosh/shake."

The quake was felt as far away as downtown San Francisco and in the Oakland Hills. One user on Twitter reported minor shaking in the Oakland Hills region, calling it a "very mild jolt." Another user reported being in Alameda that the earthquake startled them by rattling their shower door.

Although the quake was relatively minor, it was still the largest quake felt in the region for at least the last three weeks. San Francisco and the Bay Area always have a baseline level of seismic activity, but most quakes aren't felt. Larger quakes are possible, however. It's important to follow guidelines from local authorities on quake preparedness and to always have an emergency "go bag" ready just in case.

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Award-winning entrepreneur, and the co-founder and CEO of Gado Images. Thomas writes, speaks and consults about artificial intelligence, privacy, food, photography, tech, and the San Francisco Bay Area. As a professional photographer, Thomas' photographic work regularly appears in publications worldwide. Pitches/news tips:

Lafayette, CA

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