M1.5 earthquake 18 km S of Three Rocks, California

A magnitude 1.5 earthquake struck 18 km S of Three Rocks, California on Thu, Aug 18, 1983, 1:07 AM PDT (08:07 UTC), 9 km (6 mi) below the surface.

A larger quake followed: M5.5 11 km NE of Coalinga, 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: 200 in the 60 days after this one and at least 200 in the 30 days before it.

The first 60 of 200.

From the USGS Earthquake Hazards Program and its partner networks, event nc1100617 (also filed as ci20081). Read Fri, Oct 2, 2026, 1:05 PM UTC.