Alaska earthquakes

M5.5 earthquake 73 km S of Nikolski, Alaska

A magnitude 5.5 earthquake struck 73 km S of Nikolski, Alaska on Mon, Mar 28, 2016, 9:14 AM AKDT (17:14 UTC), 11 km (7 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: 5.5 (Mww, W-phase moment), moderate
Magnitude from: USGS National Earthquake Information Center
Local time: Mon, Mar 28, 2016, 9:14 AM AKDT
UTC: 2016-03-28 17:14:55 UTC
Depth: 11.2 km (7.0 mi), shallow
Epicenter: 52.290° N, 168.693° W
Region: Alaska
Strongest shaking: IV, light shaking
PAGER alert: Green
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
5.5	Mww, W-phase moment	USGS National Earthquake Information Center	Preferred · Reviewed
5.6	Mw, moment	ISC-GEM global catalog	Final · ±0.1
5.6	Mw, moment	Alaska Earthquake Center	Preliminary
5.6	Mwb, body-wave moment	USGS National Earthquake Information Center	Moment tensor · Reviewed

Shaking

The USGS ShakeMap: shaking estimated from seismic stations and the quake’s size, on the Modified Mercalli intensity scale.

Strongest estimated: IV, light shaking
Map: Automatic

USGS ShakeMap: estimated shaking intensity around the epicenter — Estimated shaking intensity. Map: USGS ShakeMap.

Did you feel it?

No one has reported feeling this quake to the USGS.

Estimated impact

The USGS PAGER system estimates deaths and economic losses from the shaking and the population and buildings exposed to it.

Alert level: Green: little or no damage or loss of life expected

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: 5.5 Mww
Nodal plane 1: Strike 67°, dip 75°, rake 93°
Nodal plane 2: Strike 236°, dip 15°, rake 79°

How well it is located

Reviewed by a seismologist.

Location uncertainty: About 4.6 km horizontally, 3.3 km in depth
Depth from: From location
Station coverage gap: 64°
Stations used: 759

Nearest places

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

Unalaska, AlaskaPopulation 4,491. Forecast228 kmSW

Nearby

Within 100 km, magnitude 2.5 and up: 64 in the 60 days after this one and 54 in the 30 days before it.

After

The first 60 of 64.

Before

Earthquakes today Alaska earthquakes Live radar here

Sources

From the USGS Earthquake Hazards Program and its partner networks, event us20005cx1 (also filed as ak13124412, gcmt20160328171455, ak01641ti11p, iscgem608505866). Read Mon, Oct 5, 2026, 10:41 AM UTC.