M1.7 earthquake 20 km SW of Three Rocks, California

A magnitude 1.7 earthquake struck 20 km SW of Three Rocks, California on Tue, Jul 30, 1985, 10:36 AM PDT (17:36 UTC), 5 km (3 mi) below the surface.

A larger quake followed: M5.6 8 km SW of Huron, 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: at least 199 in the 60 days after this one and 93 in the 30 days before it.

The first 60 of at least 199.

From the USGS Earthquake Hazards Program and its partner networks, event nc51969. Read Mon, Sep 28, 2026, 8:34 PM UTC.