M4.6 earthquake 71 km SSE of Adak, Alaska

A magnitude 4.6 earthquake struck 71 km SSE of Adak, Alaska on Thu, Mar 20, 2025, 8:29 PM HADT (05:29 UTC), 37 km (23 mi) below the surface.

A larger quake followed: M6.2 88 km SSE 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
4.6	mb, body-wave	USGS National Earthquake Information Center	Preferred · Reviewed · ±0.044 · 156 stations
4.6	mb, body-wave	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 1.6 and up: at least 199 in the 60 days after this one and at least 200 in the 30 days before it.

The first 60 of at least 199.

From the USGS Earthquake Hazards Program and its partner networks, event us7000pli7 (also filed as ak0253oe581y). Read Fri, Oct 2, 2026, 7:12 PM UTC.