M3.3 earthquake 61 km SE of Ugashik, Alaska

A magnitude 3.3 earthquake struck 61 km SE of Ugashik, Alaska on Wed, Aug 4, 2021, 5:45 PM AKDT (01:45 UTC), 5 km (3 mi) below the surface.

A larger quake followed: M4.0 81 km ENE of Chignik, Alaska. 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
3.3	ML, local (Richter)	Alaska Earthquake Center	Preferred · Preliminary
3.5	ML, local (Richter)	USGS National Earthquake Information Center	Reviewed · ±0.048 · 58 stations

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: 124 in the 60 days after this one and 63 in the 30 days before it.

The first 60 of 124.

From the USGS Earthquake Hazards Program and its partner networks, event ak0219ywhi49 (also filed as us6000f2bi). Read Fri, Oct 2, 2026, 1:35 AM UTC.