Alaska earthquakes

M5.2 earthquake 120 km SSW of Nikolski, Alaska

A magnitude 5.2 earthquake struck 120 km SSW of Nikolski, Alaska on Sun, Sep 27, 2020, 6:44 PM AKDT (02:44 UTC), 15 km (10 mi) below the surface.

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Map

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

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The earthquake

Magnitude: 5.2 (Mww, W-phase moment), moderate
Magnitude from: USGS National Earthquake Information Center
Local time: Sun, Sep 27, 2020, 6:44 PM AKDT
UTC: 2020-09-28 02:44:20 UTC
Depth: 15.5 km (9.6 mi), shallow
Epicenter: 51.953° N, 169.608° 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
5.2	Mww, W-phase moment	USGS National Earthquake Information Center	Preferred · Reviewed · ±0.058 · 29 stations
5.18	Mw, moment	ISC-GEM global catalog	Final · ±0.1
5.2	Mww, W-phase moment	Alaska Earthquake Center	Preliminary

Did you feel it?

No one has reported feeling this quake to the USGS.

Fault motion and ground failure

How the rock slipped, from the moment tensor, and the USGS estimate of landslides and liquefaction.

Faulting: Reverse (thrust)
Moment magnitude: 5.2 Mww
Nodal plane 1: Strike 252°, dip 40°, rake 94°
Nodal plane 2: Strike 67°, dip 50°, rake 87°

How well it is located

Reviewed by a seismologist.

Location uncertainty: About 5.5 km horizontally, 3.3 km in depth
Magnitude uncertainty: ±0.06
Depth from: From location
Station coverage gap: 55°
Stations used: 172

Nearest places

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

Unalaska, AlaskaPopulation 4,491. Forecast297 kmSW

Nearby

Within 100 km, magnitude 2.2 and up: 15 in the 60 days after this one and 15 in the 30 days before it.

After

Before

Earthquakes today Alaska earthquakes Live radar here

Sources

From the USGS Earthquake Hazards Program and its partner networks, event us6000c20q (also filed as ak020chvmqxk, iscgem619394861). Read Mon, Oct 5, 2026, 2:56 AM UTC.