California earthquakes

M3.9 earthquake 12 km W of Huron, California

A magnitude 3.9 earthquake struck 12 km W of Huron, California on Fri, Sep 9, 1983, 2:04 PM PDT (21:04 UTC), 8 km (5 mi) below the surface.

A larger quake followed: M4.8 11 km NNW of Coalinga, California. This one was a foreshock.

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Map

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

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The earthquake

Magnitude: 3.9 (Md, duration), minor
Magnitude from: Northern California Seismic System
Local time: Fri, Sep 9, 1983, 2:04 PM PDT
UTC: 1983-09-09 21:04:00 UTC
Depth: 7.5 km (4.7 mi), shallow
Epicenter: 36.221° N, 120.238° W
Region: California
Tsunami flag: No
Status: Reviewed by a seismologist

Magnitude estimates

Different scales measure different things and differ by a few tenths. The USGS marks one as preferred, and it is the one this page uses.

Mag.	Scale	Computed by	Notes
3.85	Md, duration	Northern California Seismic System	Preferred · Final · ±0.14 · 107 stations
3.5	ML, local (Richter)	USGS National Earthquake Information Center	Reviewed
3.73	ML, local (Richter)	Southern California Seismic Network	Final · ±0.107 · 12 stations

What happened

The USGS’s account of the effects of this earthquake.

Felt in the Coalinga area.

From the USGS event page for nc1102318. U.S. Geological Survey text and figures are in the public domain.

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 0.2 km horizontally, 0.4 km in depth
Magnitude uncertainty: ±0.14
Depth from: From location
Station coverage gap: 113°
Stations used: 46

Nearest places

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

Nearby

Within 100 km, magnitude 1.5 and up: 198 in the 60 days after this one and 199 in the 30 days before it.

After

The first 60 of 198.

Before

Earthquakes today California earthquakes Live radar here

Sources

From the USGS Earthquake Hazards Program and its partner networks, event nc1102318 (also filed as usp0001y81, ci21462). Read Fri, Oct 2, 2026, 12:59 PM UTC.