Alaska earthquakes

M3.9 earthquake 52 km ESE of Adak, Alaska

A magnitude 3.9 earthquake struck 52 km ESE of Adak, Alaska on Wed, Mar 11, 2026, 3:31 AM HADT (12:31 UTC), 58 km (36 mi) below the surface.

A larger quake followed: M4.5 27 km S of Adak, Alaska. This one was a foreshock.

Map

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

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The earthquake

Magnitude: 3.9 (mb, body-wave), minor
Magnitude from: USGS National Earthquake Information Center
Local time: Wed, Mar 11, 2026, 3:31 AM HADT
UTC: 2026-03-11 12:31:42 UTC
Depth: 57.7 km (35.8 mi), shallow
Epicenter: 51.684° N, 175.943° W
Region: Alaska
Strongest shaking: IV, light shaking
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	mb, body-wave	USGS National Earthquake Information Center	Preferred · Reviewed · ±0.088 · 34 stations
4.5	ML, local (Richter)	Alaska Earthquake Center	Reviewed · ±0.2 · 44 stations

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
Peak ground acceleration: 2.4% of gravity
Peak ground velocity: 0.9 cm/s
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.

How well it is located

Reviewed by a seismologist.

Location uncertainty: About 6.9 km horizontally, 6.7 km in depth
Magnitude uncertainty: ±0.09
Depth from: From location
Station coverage gap: 180°
Stations used: 81

Nearby

Within 100 km, magnitude 1.5 and up: 151 in the 60 days after this one and 45 in the 30 days before it.

After

The first 60 of 151.

Before

Earthquakes today Alaska earthquakes Live radar here

Sources

From the USGS Earthquake Hazards Program and its partner networks, event us7000s3lp (also filed as aka2026exqamc). Read Sat, Oct 3, 2026, 2:47 AM UTC.