M4.0 earthquake 87 km W of Ferndale, California

A magnitude 4.0 earthquake struck 87 km W of Ferndale, California on Tue, Jun 23, 1981, 2:50 PM PDT (21:50 UTC), 5 km (3 mi) below the surface.

A larger quake followed: M4.6 23 km WSW of Weott, California. This one was a foreshock.

Map

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

Different scales measure different things and differ by a few tenths. The USGS marks one as preferred, and it is the one this page uses.

Mag.	Scale	Computed by	Notes
4.0	ML, local (Richter)	Northern California Seismic System	Preferred · Final · 0 stations
4.0	mb, body-wave	USGS National Earthquake Information Center	Reviewed · 2 stations

No one has reported feeling this quake to the USGS.

Reviewed by a seismologist.

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

Within 100 km, magnitude 1.5 and up: 126 in the 60 days after this one and 90 in the 30 days before it.

The first 60 of 126.

From the USGS Earthquake Hazards Program and its partner networks, event nc1064820 (also filed as usp0001eag). Read Sat, Oct 3, 2026, 11:42 AM UTC.