M3.1 earthquake 136 km W of Adak, Alaska

A magnitude 3.1 earthquake struck 136 km W of Adak, Alaska on Mon, Jun 26, 2023, 10:33 PM HADT (07:33 UTC), 189 km (117 mi) below the surface.

A larger quake followed: M4.0 229 km W 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
3.1	ML, local (Richter)	USGS National Earthquake Information Center	Preferred · Reviewed · ±0.081 · 20 stations
2.8	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 199 in the 60 days after this one and 156 in the 30 days before it.

The first 60 of at least 199.

From the USGS Earthquake Hazards Program and its partner networks, event us6000kp86 (also filed as ak02386i0wlh). Read Thu, Oct 1, 2026, 2:38 AM UTC.