M2.8 earthquake 79 km S of Unalaska, Alaska

A magnitude 2.8 earthquake struck 79 km S of Unalaska, Alaska on Mon, Oct 16, 2023, 6:22 PM AKDT (02:22 UTC), 35 km (22 mi) below the surface.

A larger quake followed: M5.6 122 km ESE of Nikolski, 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
2.8	ML, local (Richter)	USGS National Earthquake Information Center	Preferred · Reviewed · ±0.148 · 6 stations
2.5	ML, local (Richter)	Alaska Earthquake Center	Preliminary

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: 138 in the 60 days after this one and 61 in the 30 days before it.

The first 60 of 138.

From the USGS Earthquake Hazards Program and its partner networks, event us7000l8p8 (also filed as ak023dbn69bi). Read Fri, Oct 2, 2026, 4:29 AM UTC.