ALAMEDA, Calif. (KRON) – A sizable earthquake jolted the San Francisco Bay Area shortly before 3 a.m. Monday.

The quake, a magnitude 4.3, had its epicenter about a mile east of Berkeley. It was felt across the East Bay in Walnut Creek, Martinez, and Alameda, and across the Bay in San Francisco and Sausalito. Northward, it was detected in Santa Rosa, while southward, it was felt in Santa Cruz, according to the United States Geological Survey’s Did You Feel It? reporting system.

Around 23,000 people reported feeling the jolt as of 6:30 a.m. Pacific time, according to the system.

The United States Geological Survey (USGS) said the earthquake struck at a depth of 4.34 miles. Initially, the USGS deemed the quake a 4.6 before revising it down to 4.3.

There were no preliminary reports of damage or injuries. The Bay Area Rapid Transit District (BART) said it is running its trains at reduced speeds as track inspections are made. San Francisco Mayor Daniel Lurie said the Department of Emergency Management, along with first responders, will be assessing the city for impacts.

According to the USGS’s aftershock forecast, there is a 24% chance of an aftershock between a magnitude of 3.0 and 4.0 within the next week.