M3.3 earthquake 143 km SE of Perryville, Alaska

A magnitude 3.3 earthquake struck 143 km SE of Perryville, Alaska on Thu, Jul 29, 2021, 1:07 AM AKDT (09:07 UTC), 28 km (17 mi) below the surface.

A larger quake followed: M6.9 125 km SE of Perryville, 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
3.6	ML, local (Richter)	USGS National Earthquake Information Center	Reviewed · ±0.091 · 16 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: at least 201 in the 60 days after this one and 87 in the 30 days before it.

The first 60 of at least 201.

From the USGS Earthquake Hazards Program and its partner networks, event ak0219ng9dzz (also filed as us6000f78v). Read Thu, Oct 1, 2026, 8:16 PM UTC.