M3.9 earthquake 118 km S of Unalaska, Alaska

A magnitude 3.9 earthquake struck 118 km S of Unalaska, Alaska on Tue, Oct 22, 2019, 9:13 PM AKDT (05:13 UTC), 34 km (21 mi) below the surface.

A larger quake followed: M4.3 52 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
3.9	mb, body-wave	USGS National Earthquake Information Center	Preferred · Reviewed · ±0.121 · 18 stations
3.4	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: 59 in the 60 days after this one and 64 in the 30 days before it.

From the USGS Earthquake Hazards Program and its partner networks, event us70005xjj (also filed as ak019dlm4q5c). Read Sat, Oct 3, 2026, 6:17 AM UTC.