In the early hours of Monday, the San Francisco Bay Area experienced a significant seismic event that rattled residents across the region. The earthquake, which was estimated at a magnitude of 4.3, struck at precisely 2:56 a.m. The epicenter was located in Berkeley, around the intersection of Dwight Way and Piedmont Avenue, just a short distance from the UC Berkeley campus.
This earthquake marks the strongest seismic activity to hit the Bay Area in three years, following a magnitude 5.1 quake that occurred on October 25, 2022, near Mt. Hamilton, east of San José. According to the U.S. Geological Survey (USGS), the shaking was classified as "light" on the Modified Mercalli Intensity Scale, affecting areas such as Berkeley, Oakland, and San Francisco. Other nearby regions that reported similar shaking included Albany, Alameda, San Leandro, Piedmont, Orinda, Lafayette, Walnut Creek, and Richmond.
While there were no immediate reports of significant damage, some effects were noted. A display window at a butcher shop in Berkeley shattered, and reports from residents in the Oakland Hills indicated that dishes were knocked off shelves. KGO-TV shared images of plastic bottles that had fallen from store shelves in Oakland's Montclair neighborhood. Additionally, a magnitude 2.6 aftershock occurred at 8:01 a.m. near Claremont and Ashby avenues, following an earlier magnitude 2.1 earthquake in the same vicinity.
As of early Monday morning, the USGS estimated a 4% chance of experiencing another earthquake of magnitude 4 or greater within the week. The likelihood of an aftershock of magnitude 5 or greater was reported to be less than 1%, although these probabilities decreased by midday. The earthquake's epicenter was situated near the Hayward Fault, a major fault line known for its historical seismic activity.
The Hayward Fault stretches approximately 74 miles through the East Bay, extending into San José. Its most notable earthquake in modern history occurred in 1868, with a magnitude of 7, impacting areas from Fremont's Warm Springs neighborhood to Berkeley. A USGS report cautions that a hypothetical magnitude 7 earthquake along this fault could result in at least 800 fatalities and 18,000 injuries, with thousands more affected by building collapses and trapped in elevators.
The earthquake was felt as far away as Santa Rosa and Santa Cruz. It also activated the MyShake earthquake early warning app, part of the USGS’s ShakeAlert system. Many users reported feeling the tremors concurrently with the app's alert notifications. For example, Alameda resident Laura Sonido described the experience, stating, “It was strong enough to where I could hear my windows rattling. Thankfully, nothing spilled out.”
If you felt the earthquake, consider reporting your experience to the USGS. Your observations can help enhance the understanding of seismic activity and improve early warning systems for future events.
