M3.8 earthquake 128 km WSW of Adak, Alaska

A magnitude 3.8 earthquake struck 128 km WSW of Adak, Alaska on Thu, Jul 28, 2022, 12:30 PM HADT (21:30 UTC), 35 km (22 mi) below the surface.

A larger quake followed: M4.8 145 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
3.8	ML, local (Richter)	USGS National Earthquake Information Center	Preferred · Reviewed · ±0.091 · 16 stations
3.4	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: 182 in the 60 days after this one and 126 in the 30 days before it.

The first 60 of 182.

From the USGS Earthquake Hazards Program and its partner networks, event us7000i7a0 (also filed as ak0229m003qd). Read Thu, Oct 1, 2026, 5:15 AM UTC.