California earthquakes

M2.5 earthquake 8km N of Cabazon, CA

A magnitude 2.5 earthquake struck 8km N of Cabazon, CA on Fri, Jul 21, 1978, 4:40 AM PDT (11:40 UTC), 9 km (6 mi) below the surface.

A larger quake followed: M3.9 6km N of Fontana, CA. 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
2.5 (ML, local (Richter)), micro
Magnitude from
Southern California Seismic Network
Local time
UTC
1978-07-21 11:40:07 UTC
Depth
9.3 km (5.8 mi), shallow
Epicenter
33.987° N, 116.775° 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 0.3 km horizontally, 0.8 km in depth
Magnitude uncertainty
±0.16
Depth from
From location
Station coverage gap
35°
Stations used
47

Nearest places

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

Nearby

Within 100 km, magnitude 1.5 and up: 147 in the 60 days after this one and 102 in the 30 days before it.

After

The first 60 of 147.

Before

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Sources

From the USGS Earthquake Hazards Program and its partner networks, event ci3340842. Read Thu, Oct 1, 2026, 2:59 AM UTC.