California earthquakes

M1.8 earthquake 6 km NE of Ridgemark, California

A magnitude 1.8 earthquake struck 6 km NE of Ridgemark, California on Thu, May 7, 1981, 11:07 AM PDT (18:07 UTC), 7 km (5 mi) below the surface.

A larger quake followed: M2.2 23 km W of Three Rocks, 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
1.8 (md), micro
Local time
UTC
1981-05-07 18:07:51 UTC
Depth
7.3 km (4.5 mi), shallow
Epicenter
36.861° N, 121.321° W
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 0.1 km horizontally, 0.4 km in depth
Magnitude uncertainty
±0.19
Depth from
From location
Station coverage gap
43°
Stations used
45

Nearest places

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

Nearby

Within 100 km, magnitude 1.5 and up: 161 in the 60 days after this one and 8 in the 30 days before it.

After

The first 60 of 161.

Before

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Sources

From the USGS Earthquake Hazards Program and its partner networks, event nc1063384. Read Tue, Sep 22, 2026, 5:21 PM UTC.