Bay Area shaken by 4.3-magnitude earthquake near Berkeley; no injuries reported yet

An earthquake measuring magnitude 4.3 rattled the San Francisco Bay Area early Monday, the United States Geological Survey said. The quake's epicenter was just east-southeast of Berkeley, California, and it struck shortly before 3 a.m. PDT, according to USGS data released in the agency's quick-look assessment. Residents across the region reported feeling a sharp shake, and many described phone alerts activating in the moments after the tremor began.

USGS said the tremor was detected by its network of seismic sensors and that preliminary information indicated the event occurred at a shallow depth beneath the surface. The agency stressed that data are evolving as scientists review recordings from dozens of stations across the region. The quake prompted widespread alerts on smartphones and other devices, with people reporting notifications in the immediate aftermath.

There were no immediate reports of injuries or significant damage, though authorities in several communities said they would monitor for possible aftershocks and inspect facilities where people woke to the shaking. Emergency managers urged residents to stay safe and be prepared for aftershocks, which can occur in the hours or days after a quake of this size. Local officials said they would provide updates as new information becomes available.

Across the Bay Area, witnesses described a range of shaking experiences depending on location. Some people in Berkeley and neighboring urban centers reported a brief but noticeable jolt, while others farther from the epicenter felt a lighter tremor. The event occurred in a highly populated region with substantial infrastructure, and officials urged residents to remain cautious until aftershocks could be ruled out and buildings could be inspected if needed. The shaking lasted only a few seconds in most areas, according to initial reports, but the memory of the sensation lingered for many who woke in the predawn hours.

Experts note that magnitude 4.3 is considered a light to moderate earthquake on the moment magnitude scale. Quakes of this size are usually felt over a wide area but rarely cause widespread structural damage, unless they strike near vulnerable buildings or critical infrastructure. The Bay Area sits near several major faults, including the San Andreas and Hayward faults, which have produced stronger earthquakes in the past. While this event did not appear to cause obvious widespread damage at the outset, officials stressed that even modest quakes can pose hazards indoors, such as falling objects, and urged residents to inspect surroundings if they notice any damage.

USGS and local authorities said they would release updates as they reviewed sensor data and any post-event inspections. The agency's early assessment can be refined in the coming hours as seismologists analyze more recordings. For residents, standard safety guidance remains: anticipate the possibility of aftershocks and check for hazards in homes and workplaces after any tremor. The Associated Press, citing USGS data, reported the event as it unfolded, with additional details expected as investigators continue to evaluate the tremor and its impacts.