M2.8 earthquake 245 km W of Adak, Alaska

A magnitude 2.8 earthquake struck 245 km W of Adak, Alaska on Sun, Aug 23, 2020, 4:43 AM GMT+12 (16:43 UTC), 72 km (45 mi) below the surface.

A larger quake followed: M4.8 193 km WSW of Adak, 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
2.8	ML, local (Richter)	USGS National Earthquake Information Center	Preferred · Reviewed · ±0.115 · 10 stations
2.3	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: 146 in the 60 days after this one and 69 in the 30 days before it.

The first 60 of 146.

From the USGS Earthquake Hazards Program and its partner networks, event us7000bm8r (also filed as ak020asx2pw1). Read Fri, Oct 2, 2026, 2:09 AM UTC.