California earthquakes

M4.7 earthquake 42 km SW of Ferndale, California

A magnitude 4.7 earthquake struck 42 km SW of Ferndale, California on Sat, Aug 4, 1984, 2:45 PM PDT (21:45 UTC), 20 km (12 mi) below the surface.

A larger quake followed: M4.8 101 km W of Ferndale, California. This one was a foreshock.

Ferndale forecast More in California

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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: 4.7 (ml), light
Local time: Sat, Aug 4, 1984, 2:45 PM PDT
UTC: 1984-08-04 21:45:54 UTC
Depth: 19.9 km (12.4 mi), shallow
Epicenter: 40.329° N, 124.649° 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 0.9 km horizontally, 0.3 km in depth
Depth from: From location
Station coverage gap: 233°, poorly surrounded by stations
Stations used: 52

Nearest places

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

Nearby

Within 100 km, magnitude 1.7 and up: 74 in the 60 days after this one and 15 in the 30 days before it.

After

The first 60 of 74.

Before

Earthquakes today California earthquakes Live radar here

Sources

From the USGS Earthquake Hazards Program and its partner networks, event nc24939 (also filed as gcmtb080484c, ushis3852, usp000267f, gcmt19840804214552, iscgem545874). Read Tue, Sep 22, 2026, 9:34 PM UTC.