M1.8 earthquake 5 km NNE of Windsor, California

A magnitude 1.8 earthquake struck 5 km NNE of Windsor, California on Mon, Sep 23, 1985, 5:41 PM PDT (00:41 UTC), 5 km (3 mi) below the surface.

A larger quake followed: M4.1 5 km NW of Cobb, 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: 173 in the 60 days after this one and 139 in the 30 days before it.

The first 60 of 173.

From the USGS Earthquake Hazards Program and its partner networks, event nc1131638. Read Tue, Sep 29, 2026, 10:52 AM UTC.