M1.8 earthquake 88 km W of Adak, Alaska

A magnitude 1.8 earthquake struck 88 km W of Adak, Alaska on Sun, Mar 12, 2023, 12:55 AM HAST (10:55 UTC), 5 km (3 mi) below the surface.

A larger quake followed: M4.1 150 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
1.8	ML, local (Richter)	Alaska Earthquake Center	Preferred · Preliminary
1.73	ML, local (Richter)	AV	Final · ±0.206012193230992 · 5 stations

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 at least 200 in the 30 days before it.

The first 60 of at least 201.

From the USGS Earthquake Hazards Program and its partner networks, event ak02339lfvm4 (also filed as av91800961). Read Sat, Oct 3, 2026, 2:56 AM UTC.