M2.8 earthquake 6 km ESE of Sunol, California

A magnitude 2.8 earthquake struck 6 km ESE of Sunol, California on Fri, Apr 7, 1978, 4:13 PM PST (00:13 UTC), 11 km (7 mi) below the surface.

A larger quake followed: M3.1 9 km SSE of San Juan Bautista, California. This one was a foreshock.

Map

Where this earthquake was located, with the others nearby. Select one for its page.

No one has reported feeling this quake to the USGS.

Reviewed by a seismologist.

Distance and direction from each place to the epicenter, with its forecast.

Within 100 km, magnitude 1.5 and up: 88 in the 60 days after this one and 42 in the 30 days before it.

The first 60 of 88.

From the USGS Earthquake Hazards Program and its partner networks, event nc1039769. Read Tue, Sep 22, 2026, 9:28 PM UTC.