M3.1 earthquake 72 km SW of Unalaska, Alaska

A magnitude 3.1 earthquake struck 72 km SW of Unalaska, Alaska on Mon, Jul 17, 2023, 9:00 AM AKDT (17:00 UTC), 74 km (46 mi) below the surface.

A larger quake followed: M4.5 93 km S of Unalaska, 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 · ±0.115 · 10 stations
2.7	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: 136 in the 60 days after this one and 62 in the 30 days before it.

The first 60 of 136.

From the USGS Earthquake Hazards Program and its partner networks, event us7000ki19 (also filed as ak02393qj6ru). Read Fri, Oct 2, 2026, 1:25 PM UTC.