M3.3 earthquake 87 km SE of Atka, Alaska

A magnitude 3.3 earthquake struck 87 km SE of Atka, Alaska on Mon, Jul 27, 2020, 8:52 AM HADT (17:52 UTC), 22 km (13 mi) below the surface.

A larger quake followed: M3.9 30 km ESE of Atka, 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)	USGS National Earthquake Information Center	Preferred · Reviewed · ±0.097 · 14 stations
2.8	ML, local (Richter)	Alaska Earthquake Center	Preliminary

No one has reported feeling this quake to the USGS.

Reviewed by a seismologist.

Within 100 km, magnitude 1.5 and up: 76 in the 60 days after this one and 47 in the 30 days before it.

The first 60 of 76.

From the USGS Earthquake Hazards Program and its partner networks, event us6000b9s0 (also filed as ak0209lxr4tq). Read Thu, Oct 1, 2026, 4:55 PM UTC.