M1.8 earthquake 6 km SW of Cobb, California

A magnitude 1.8 earthquake struck 6 km SW of Cobb, California on Mon, Jun 20, 1983, 2:43 PM PDT (21:43 UTC), 1 km (1 mi) below the surface.

A larger quake followed: M3.6 2 km SSE of Point Arena, California. This one was a foreshock.

Map

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

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: 179 in the 60 days after this one and 90 in the 30 days before it.

The first 60 of 179.

From the USGS Earthquake Hazards Program and its partner networks, event nc1097254. Read Fri, Oct 2, 2026, 9:38 PM UTC.