Four Earthquakes Hit the Same Area in California — Details from USGS

A series of earthquakes struck the same area in California in one day, with geological authorities providing details on the tremors.

Four earthquakes struck near Hayward, California, on Thursday, February 13, 2025, according to the U.S. Geological Survey (USGS). The quakes, ranging from magnitude 2.7 to 3.6, occurred within a small area 2 kilometers east of Hayward at depths between 3.3 and 3.9 miles.

The first earthquake of the day, a magnitude 2.7, occurred at 13:03 UTC (5:03 a.m. PST). Another two quakes, a 3.3 magnitude at 19:52 UTC (11:52 a.m. PST) and a 3.2 magnitude at 19:54 UTC (11:54 a.m. PST), struck just two minutes apart.

Meanwhile, the USGS reported that the strongest quake, a magnitude 3.6, was recorded at 21:59 UTC (1:59 p.m. PST) at a depth of 3.6 miles.

All four quakes were centered close to each other, with coordinates ranging from 37.645°N to 37.648°N latitude and 122.052°W to 122.059°W longitude.

While the earthquakes appear minor, their location is a stark reminder of the region's seismic vulnerability.

According to the USGS, Hayward sits on the Hayward Fault, a right-lateral, strike-slip fault that runs from San Pablo Bay to Fremont, passing through Berkeley, Oakland, and Fremont.

It moves gradually, creeping at about 5 millimeters (1/5 inch) per year, but some of this movement is uneven. Roughly 4 millimeters (1/6 inch) per year gets stuck, building up stress that eventually releases in earthquakes.

Studies estimate the fault's total movement at 9 millimeters (1/3 inch) per year, combining steady creep with sudden shifts. South of Fremont, it branches into a network of surface faults that connects to the Calaveras Fault. At depths greater than 5 kilometers (3 miles), scientists believe the two faults may merge, potentially influencing seismic activity.

Experts at the University of California, Berkeley Seismology Lab report that the last major earthquake on this fault occurred on October 21, 1868, at 15:53 UTC (7:53 a.m. local time). Known as the 1868 San Francisco earthquake, it struck the Bay Area with an estimated magnitude of 7.0.

The quake ruptured the southern segment of the Hayward Fault, from Berkeley to Fremont, shifting the ground 1.9 meters (6.2 feet) sideways.

The earthquake reportedly caused significant damage. At least five people were killed, and 30 others were injured. Property losses exceeded $300,000, which was a massive sum at the time.

Seismologists have long studied the recurring pattern of earthquakes along the Hayward Fault. USGS stated major quakes on this fault tend to occur every 140 to 170 years. With more than 150 years having passed since the last major rupture, experts warn that the fault is overdue for another powerful earthquake.

In 2003, the Working Group for California Earthquake Probability reportedly estimated a 27% probability of a magnitude 6.7 or larger earthquake striking the Hayward-Rodgers Creek Fault system within 30 years. Given this risk, the USGS and other geological agencies continue to monitor seismic activity in the region.