California earthquakes

M3.3 earthquake 37km WSW of Lompoc, CA

A magnitude 3.3 earthquake struck 37km WSW of Lompoc, CA on Tue, Oct 17, 1939, 11:21 AM GMT-8 (19:21 UTC), 6 km (4 mi) below the surface.

A larger quake followed: M4.2 49km WSW of Vandenberg Air Force Base, CA. This one was a foreshock.

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The earthquake

Magnitude
3.3 (ml), minor
Local time
UTC
1939-10-17 19:21:41 UTC
Depth
6.0 km (3.7 mi), shallow
Epicenter
34.554° N, 120.845° 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 50.6 km horizontally, 31.6 km in depth
Magnitude uncertainty
±0.10
Depth from
Operator assigned
Station coverage gap
359°, poorly surrounded by stations
Stations used
2

Nearest places

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

Nearby

Within 100 km, magnitude 1.5 and up: 1 in the 60 days after this one and 0 in the 30 days before it.

After

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Sources

From the USGS Earthquake Hazards Program and its partner networks, event ci3365126. Read Wed, Sep 30, 2026, 9:53 PM UTC.