M3.9 earthquake 7 km NNE of Corralitos, California

A magnitude 3.9 earthquake struck 7 km NNE of Corralitos, California on Tue, Oct 17, 1989, 5:23 PM PDT (00:23 UTC), 7 km (4 mi) below the surface.

A larger quake followed: M5.1 7 km SW of Monte Sereno, 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
3.9	ML, local (Richter)	Northern California Seismic System	Preferred · Final · 7 stations
3.9	ML, local (Richter)	USGS National Earthquake Information Center	Reviewed

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: at least 200 in the 60 days after this one and 92 in the 30 days before it.

The first 60 of at least 200.

From the USGS Earthquake Hazards Program and its partner networks, event nc10090484 (also filed as usp00040t9). Read Fri, Oct 2, 2026, 4:29 PM UTC.