M3.1 earthquake 123 km SE of Old Harbor, Alaska

A magnitude 3.1 earthquake struck 123 km SE of Old Harbor, Alaska on Mon, Sep 1, 2025, 3:15 AM AKDT (11:15 UTC), 12 km (7 mi) below the surface.

A larger quake followed: M4.9 128 km SE of Old Harbor, 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)	Alaska Earthquake Center	Preferred · Preliminary
3.3	ML, local (Richter)	USGS National Earthquake Information Center	Reviewed · ±0.056 · 42 stations

No one has reported feeling this quake to the USGS.

Reviewed by a seismologist.

Distance and direction from each place to the epicenter, with its forecast.

Within 100 km, magnitude 1.5 and up: 43 in the 60 days after this one and 4 in the 30 days before it.

From the USGS Earthquake Hazards Program and its partner networks, event ak025b7prp9m (also filed as us6000rjcp). Read Sat, Oct 3, 2026, 5:50 PM UTC.