California earthquakes

M2.1 earthquake 7 km WSW of Cobb, California

A magnitude 2.1 earthquake struck 7 km WSW of Cobb, California on Sun, Oct 22, 1978, 1:07 AM PDT (08:07 UTC), 0 km (0 mi) below the surface.

A larger quake followed: M3.8 24 km NE of Potter Valley, California. This one was a foreshock.

Cobb forecastMore in California

Map

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

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The earthquake

Magnitude
2.1 (Md, duration), micro
Magnitude from
Northern California Seismic System
Local time
UTC
1978-10-22 08:07:34 UTC
Depth
0.0 km (0.0 mi), shallow
Epicenter
38.808° N, 122.802° 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 0.2 km horizontally, 0.5 km in depth
Magnitude uncertainty
±0.11
Depth from
From location
Station coverage gap
67°
Stations used
17

Nearest places

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

Nearby

Within 100 km, magnitude 1.5 and up: 81 in the 60 days after this one and 31 in the 30 days before it.

After

The first 60 of 81.

Before

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Sources

From the USGS Earthquake Hazards Program and its partner networks, event nc1042962. Read Thu, Oct 1, 2026, 4:28 PM UTC.