California earthquakes

M2.8 earthquake 22 km NE of Potter Valley, California

A magnitude 2.8 earthquake struck 22 km NE of Potter Valley, California on Sun, Sep 13, 1987, 6:11 AM PDT (13:11 UTC), 12 km (7 mi) below the surface.

A larger quake followed: M3.4 4 km W of Cobb, California. This one was a foreshock.

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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: 2.8 (md), micro
Local time: Sun, Sep 13, 1987, 6:11 AM PDT
UTC: 1987-09-13 13:11:41 UTC
Depth: 12.0 km (7.5 mi), shallow
Epicenter: 39.463° N, 122.926° 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, 0.5 km in depth
Magnitude uncertainty: ±0.11
Depth from: From location
Station coverage gap: 45°
Stations used: 34

Nearest places

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

Nearby

Within 100 km, magnitude 1.5 and up: 160 in the 60 days after this one and 103 in the 30 days before it.

After

The first 60 of 160.

Before

Earthquakes today California earthquakes Live radar here

Sources

From the USGS Earthquake Hazards Program and its partner networks, event nc105708. Read Sun, Sep 27, 2026, 12:41 PM UTC.