M4.1 earthquake 192 km WSW of Adak, Alaska

A magnitude 4.1 earthquake struck 192 km WSW of Adak, Alaska on Thu, Feb 23, 2023, 7:27 AM HAST (17:27 UTC), 35 km (22 mi) below the surface.

A larger quake followed: M5.0 121 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
4.1	mb, body-wave	USGS National Earthquake Information Center	Preferred · Reviewed · ±0.086 · 37 stations
4.0	ML, local (Richter)	Alaska Earthquake Center	Preliminary

The USGS ShakeMap: shaking estimated from seismic stations and the quake’s size, on the Modified Mercalli intensity scale.

No one has reported feeling this quake to the USGS.

Reviewed by a seismologist.

Within 100 km, magnitude 1.5 and up: 113 in the 60 days after this one and 54 in the 30 days before it.

The first 60 of 113.

From the USGS Earthquake Hazards Program and its partner networks, event us6000jr2i (also filed as ak0232hlaz0t). Read Fri, Oct 2, 2026, 9:36 AM UTC.