M3.1 earthquake 4 km WSW of Dublin, California

A magnitude 3.1 earthquake struck 4 km WSW of Dublin, California on Wed, Sep 6, 1989, 2:45 AM PDT (09:45 UTC), 10 km (6 mi) below the surface.

A larger quake followed: M6.9 The 1989 Loma Prieta, California Earthquake. 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
3.09	Md, duration	Northern California Seismic System	Preferred · Final · ±0.1 · 100 stations
2.9	ML, local (Richter)	USGS National Earthquake Information Center	Reviewed

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

Felt at Castro Valley.

From the USGS event page for nc143665. 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: 182 in the 60 days after this one and 53 in the 30 days before it.

The first 60 of 182.

From the USGS Earthquake Hazards Program and its partner networks, event nc143665 (also filed as usp0003z9d). Read Sun, Oct 4, 2026, 9:01 PM UTC.