M3.3 earthquake 16km SSW of Olancha, CA

A magnitude 3.3 earthquake struck 16km SSW of Olancha, CA on Sun, Sep 5, 2021, 4:39 PM PDT (23:39 UTC), 3 km (2 mi) below the surface.

A larger quake followed: M4.0 15km ESE of Olancha, CA. 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
3.31	ML, local (Richter)	Southern California Seismic Network	Preferred · Final · ±0.153 · 84 stations
3.1	ML, local (Richter)	USGS National Earthquake Information Center	Reviewed · ±0.026 · 196 stations

2 people reported to the USGS what they felt; the strongest reported shaking was III, weak shaking.

Reviewed by a seismologist.

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

Within 100 km, magnitude 1.5 and up: 165 in the 60 days after this one and 83 in the 30 days before it.

The first 60 of 165.

From the USGS Earthquake Hazards Program and its partner networks, event ci40034008 (also filed as us7000f8dh). Read Sat, Oct 3, 2026, 8:49 PM UTC.