Alaska earthquakes

M3.5 earthquake 131 km W of Adak, Alaska

A magnitude 3.5 earthquake struck 131 km W of Adak, Alaska on Fri, Mar 16, 2018, 4:38 AM HADT (13:38 UTC), 19 km (12 mi) below the surface.

A larger quake followed: M4.5 208 km W 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: 3.5 (ML, local (Richter)), minor
Magnitude from: USGS National Earthquake Information Center
Local time: Fri, Mar 16, 2018, 4:38 AM HADT
UTC: 2018-03-16 13:38:44 UTC
Depth: 19.4 km (12.1 mi), shallow
Epicenter: 51.675° N, 178.519° 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
3.5	ML, local (Richter)	USGS National Earthquake Information Center	Preferred · Reviewed
3.5	ML, local (Richter)	Alaska Earthquake Center	Preliminary
3.49	ML, local (Richter)	AV	Final · ±0.282 · 10 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, 5.4 km in depth
Depth from: From location
Station coverage gap: 180°
Stations used: 24

Nearby

Within 100 km, magnitude 1.5 and up: 97 in the 60 days after this one and 75 in the 30 days before it.

After

The first 60 of 97.

Before

Earthquakes today Alaska earthquakes Live radar here

Sources

From the USGS Earthquake Hazards Program and its partner networks, event us1000d8pj (also filed as ak18700602, av61685706, ak0183g99wib). Read Fri, Oct 2, 2026, 4:11 AM UTC.