M1.7 earthquake Central California

A magnitude 1.7 earthquake struck in Central California on Fri, Sep 23, 1977, 3:45 PM PDT (22:45 UTC), 12 km (7 mi) below the surface.

A larger quake followed: M1.9 8 km SSW of Ridgemark, 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: 146 in the 60 days after this one and 52 in the 30 days before it.

The first 60 of 146.

From the USGS Earthquake Hazards Program and its partner networks, event nc1036972. Read Tue, Sep 22, 2026, 8:45 PM UTC.