M3.8 earthquake 35km S of Tecopa, CA

A magnitude 3.8 earthquake struck 35km S of Tecopa, CA on Mon, Jul 17, 1978, 7:46 AM PDT (14:46 UTC), 13 km (8 mi) below the surface.

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
3.84	ML, local (Richter)	Southern California Seismic Network	Preferred · Final · ±0.141 · 7 stations
4.0	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: 7 in the 60 days after this one and 7 in the 30 days before it.

From the USGS Earthquake Hazards Program and its partner networks, event ci3340763 (also filed as usp0000vma). Read Sat, Oct 3, 2026, 1:41 AM UTC.