M1.7 earthquake 9 km SW of Ripon, California

A magnitude 1.7 earthquake struck 9 km SW of Ripon, California on Sat, Jan 31, 1981, 11:08 AM PST (19:08 UTC), 5 km (3 mi) below the surface.

A larger quake followed: M2.0 10 km SW of Brentwood, 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: 147 in the 60 days after this one and 9 in the 30 days before it.

The first 60 of 147.

From the USGS Earthquake Hazards Program and its partner networks, event nc1059814. Read Tue, Sep 22, 2026, 8:43 AM UTC.