M2.8 earthquake Central California

A magnitude 2.8 earthquake struck in Central California on Mon, Dec 18, 1989, 3:15 PM PST (23:15 UTC), 4 km (3 mi) below the surface.

A larger quake followed: M4.3 36 km WSW of Three Rocks, 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
2.82	Md, duration	Northern California Seismic System	Preferred · Final · ±0.1 · 70 stations
2.5	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: 189 in the 60 days after this one and 189 in the 30 days before it.

The first 60 of 189.

From the USGS Earthquake Hazards Program and its partner networks, event nc149183 (also filed as usp0004393). Read Sat, Oct 3, 2026, 11:39 PM UTC.