California earthquakes

M3.3 earthquake 15 km S of Three Rocks, California

A magnitude 3.3 earthquake struck 15 km S of Three Rocks, California on Thu, Jul 21, 1983, 9:27 PM PDT (04:27 UTC), 4 km (2 mi) below the surface.

A larger quake followed: M5.5 11 km NE of Coalinga, California. This one was a foreshock.

Coalinga forecast More in California

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Where this earthquake was located, with the others nearby. Select one for its page.

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The earthquake

Magnitude: 3.3 (md), minor
Local time: Thu, Jul 21, 1983, 9:27 PM PDT
UTC: 1983-07-22 04:27:40 UTC
Depth: 3.7 km (2.3 mi), shallow
Epicenter: 36.364° N, 120.360° W
Region: California
Tsunami flag: No
Status: Reviewed by a seismologist

Did you feel it?

No one has reported feeling this quake to the USGS.

How well it is located

Reviewed by a seismologist.

Location uncertainty: About 0.3 km horizontally, 1.1 km in depth
Magnitude uncertainty: ±0.12
Depth from: From location
Station coverage gap: 65°
Stations used: 69

Nearest places

Distance and direction from each place to the epicenter, with its forecast.

Nearby

Within 100 km, magnitude 1.5 and up: at least 201 in the 60 days after this one and at least 200 in the 30 days before it.

After

The first 60 of at least 201.

Before

Earthquakes today California earthquakes Live radar here

Sources

From the USGS Earthquake Hazards Program and its partner networks, event nc1099006 (also filed as usp0001x0v, ci14595). Read Wed, Sep 30, 2026, 5:50 PM UTC.