Alaska earthquakes

M4.1 earthquake 30 km E of Atka, Alaska

A magnitude 4.1 earthquake struck 30 km E of Atka, Alaska on Mon, May 21, 2018, 2:50 AM HADT (11:50 UTC), 190 km (118 mi) below the surface.

A larger quake followed: M4.3 75 km NE of Atka, 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: 4.1 (mb, body-wave), light
Magnitude from: USGS National Earthquake Information Center
Local time: Mon, May 21, 2018, 2:50 AM HADT
UTC: 2018-05-21 11:50:00 UTC
Depth: 189.9 km (118.0 mi), intermediate-depth
Epicenter: 52.171° N, 173.763° 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
4.1	mb, body-wave	USGS National Earthquake Information Center	Preferred · Reviewed · ±0.076 · 47 stations
4.1	mb, body-wave	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 4.9 km horizontally, 5.4 km in depth
Magnitude uncertainty: ±0.08
Depth from: From location
Station coverage gap: 188°, poorly surrounded by stations
Stations used: 90

Nearby

Within 100 km, magnitude 1.5 and up: 63 in the 60 days after this one and 10 in the 30 days before it.

After

The first 60 of 63.

Before

Earthquakes today Alaska earthquakes Live radar here

Sources

From the USGS Earthquake Hazards Program and its partner networks, event us1000ebwb (also filed as ak19641534, ak0186hdmfb1). Read Thu, Oct 1, 2026, 4:18 PM UTC.