M3.8 earthquake 87 km W of Adak, Alaska

A magnitude 3.8 earthquake struck 87 km W of Adak, Alaska on Wed, Jan 22, 2020, 8:08 PM HAST (06:08 UTC), 10 km (6 mi) below the surface.

A larger quake followed: M4.7 133 km SW 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
3.8	mb, body-wave	USGS National Earthquake Information Center	Preferred · Reviewed · ±0.292 · 3 stations
3.5	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: at least 201 in the 60 days after this one and 120 in the 30 days before it.

The first 60 of at least 201.

From the USGS Earthquake Hazards Program and its partner networks, event us60007hq1 (also filed as ak020124ze4b). Read Thu, Oct 1, 2026, 2:58 AM UTC.