Alaska earthquakes

M3.4 earthquake 25 km SE of Unalaska, Alaska

A magnitude 3.4 earthquake struck 25 km SE of Unalaska, Alaska on Sat, Mar 17, 2018, 12:01 PM AKDT (20:01 UTC), 12 km (7 mi) below the surface.

A larger quake followed: M4.5 96 km SSE of Akutan, Alaska. This one was a foreshock.

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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: 3.4 (mb, body-wave), minor
Magnitude from: USGS National Earthquake Information Center
Local time: Sat, Mar 17, 2018, 12:01 PM AKDT
UTC: 2018-03-17 20:01:39 UTC
Depth: 12.0 km (7.5 mi), shallow
Epicenter: 53.720° N, 166.257° 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
3.4	mb, body-wave	USGS National Earthquake Information Center	Preferred · Reviewed · ±0.2 · 6 stations
3.5	ML, local (Richter)	Alaska Earthquake Center	Preliminary
3.56	ML, local (Richter)	AV	Final · ±0.235 · 20 stations

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 3.4 km horizontally, 8.3 km in depth
Magnitude uncertainty: ±0.20
Depth from: From location
Station coverage gap: 174°
Stations used: 70

Nearest places

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

Unalaska, AlaskaPopulation 4,491. Forecast25 kmSE

Nearby

Within 100 km, magnitude 1.5 and up: 112 in the 60 days after this one and 41 in the 30 days before it.

After

The first 60 of 112.

Before

Earthquakes today Alaska earthquakes Live radar here

Sources

From the USGS Earthquake Hazards Program and its partner networks, event us1000d8gq (also filed as ak0183i0rcdu, ak18704280, av61686381). Read Thu, Oct 1, 2026, 11:23 AM UTC.