California earthquakes

M3.4 earthquake Central California

A magnitude 3.4 earthquake struck in Central California on Tue, Dec 27, 1977, 6:59 PM PST (02:59 UTC), 8 km (5 mi) below the surface.

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Map

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

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The earthquake

Magnitude: 3.4 (ML, local (Richter)), minor
Magnitude from: Northern California Seismic System
Local time: Tue, Dec 27, 1977, 6:59 PM PST
UTC: 1977-12-28 02:59:37 UTC
Depth: 8.1 km (5.0 mi), shallow
Epicenter: 35.811° N, 120.363° W
Region: California
Tsunami flag: No
Status: Reviewed by a seismologist

Magnitude estimates

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
3.4	ML, local (Richter)	Northern California Seismic System	Preferred · Final · 0 stations
3.5	ML, local (Richter)	USGS National Earthquake Information Center	Reviewed
3.89	ML, local (Richter)	Southern California Seismic Network	Final · ±0.099 · 6 stations

Did you feel it?

No one has reported feeling this quake to the USGS.

How well it is located

Reviewed by a seismologist.

Location uncertainty: About 0.7 km horizontally, 0.4 km in depth
Depth from: From location
Station coverage gap: 239°, poorly surrounded by stations
Stations used: 20

Nearest places

Distance and direction from each place to the epicenter, with its forecast.

Nearby

Within 100 km, magnitude 1.5 and up: 53 in the 60 days after this one and 38 in the 30 days before it.

After

Before

Earthquakes today California earthquakes Live radar here

Sources

From the USGS Earthquake Hazards Program and its partner networks, event nc1038288 (also filed as ci3337150, usp0000s8u). Read Sat, Oct 3, 2026, 7:50 PM UTC.