Alaska earthquakes

M3.9 earthquake 77 km WSW of False Pass, Alaska

A magnitude 3.9 earthquake struck 77 km WSW of False Pass, Alaska on Thu, Oct 20, 2016, 7:40 AM AKDT (15:40 UTC), 10 km (6 mi) below the surface.

A larger quake followed: M4.1 120 km ESE of Akutan, Alaska. This one was a foreshock.

Akutan forecast More in Alaska

Map

Where this earthquake was located, with the others nearby. Select one for its page.

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The earthquake

Magnitude: 3.9 (ML, local (Richter)), minor
Magnitude from: USGS National Earthquake Information Center
Local time: Thu, Oct 20, 2016, 7:40 AM AKDT
UTC: 2016-10-20 15:40:43 UTC
Depth: 10.0 km (6.2 mi), shallow
Epicenter: 54.559° N, 164.502° W
Region: Alaska
Tsunami flag: No
Status: Reviewed by a seismologist

Magnitude estimates

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	ML, local (Richter)	USGS National Earthquake Information Center	Preferred · Reviewed · ±0.105 · 12 stations
3.4	ML, local (Richter)	Alaska Earthquake Center	Preliminary

Did you feel it?

No one has reported feeling this quake to the USGS.

How well it is located

Reviewed by a seismologist.

Location uncertainty: About 5.3 km horizontally, 2.0 km in depth
Magnitude uncertainty: ±0.10
Depth from: Operator assigned
Station coverage gap: 157°
Stations used: 47

Nearest places

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

Akutan, AlaskaPopulation 1,040. Forecast95 kmENE

Nearby

Within 100 km, magnitude 1.5 and up: 72 in the 60 days after this one and 23 in the 30 days before it.

After

The first 60 of 72.

Before

Earthquakes today Alaska earthquakes Live radar here

Sources

From the USGS Earthquake Hazards Program and its partner networks, event us20007gpk (also filed as ak016dih676d, ak14250356). Read Sun, Oct 4, 2026, 3:13 AM UTC.