M3.6 earthquake 4 km W of Cobb, California

A magnitude 3.6 earthquake struck 4 km W of Cobb, California on Fri, Jun 8, 1990, 5:04 PM PDT (00:04 UTC), 2 km (1 mi) below the surface.

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
3.6	ML, local (Richter)	Northern California Seismic System	Preferred · Final · 0 stations
4.1	mb, body-wave	USGS National Earthquake Information Center	Reviewed · 1 stations

The USGS’s account of the effects of this earthquake.

Felt (V) at Angwin; (IV) at Cobb and Santa Rosa; (III) at Finley and Guerneville.

From the USGS event page for nc20091518. U.S. Geological Survey text and figures are in the public domain.

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: 181 in the 60 days after this one and 88 in the 30 days before it.

The first 60 of 181.

From the USGS Earthquake Hazards Program and its partner networks, event nc20091518 (also filed as usp0004a9s). Read Mon, Oct 5, 2026, 7:08 AM UTC.