Alaska earthquakes

M1.8 earthquake 174 km W of Adak, Alaska

A magnitude 1.8 earthquake struck 174 km W of Adak, Alaska on Tue, Mar 20, 2018, 4:29 AM HADT (13:29 UTC), 10 km (6 mi) below the surface.

A larger quake followed: M4.5 208 km W of Adak, Alaska. This one was a foreshock.

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

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The earthquake

Magnitude: 1.8 (ML, local (Richter)), micro
Magnitude from: Alaska Earthquake Center
Local time: Tue, Mar 20, 2018, 4:29 AM HADT
UTC: 2018-03-20 13:29:45 UTC
Depth: 9.5 km (5.9 mi), shallow
Epicenter: 51.763° N, 179.163° 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
1.8	ML, local (Richter)	Alaska Earthquake Center	Preferred · Preliminary
1.35	ML, local (Richter)	AV	Final · ±0.243 · 7 stations

Did you feel it?

No one has reported feeling this quake to the USGS.

How well it is located

Reviewed by a seismologist.

Stations used: 11

Nearby

Within 100 km, magnitude 1.5 and up: 88 in the 60 days after this one and 76 in the 30 days before it.

After

The first 60 of 88.

Before

Earthquakes today Alaska earthquakes Live radar here

Sources

From the USGS Earthquake Hazards Program and its partner networks, event ak0183mvdd4h (also filed as ak18808529, av61687561). Read Fri, Oct 2, 2026, 12:06 AM UTC.