Alaska earthquakes

M2.6 earthquake 162 km W of Adak, Alaska

A magnitude 2.6 earthquake struck 162 km W of Adak, Alaska on Fri, Oct 20, 2017, 2:20 PM HADT (23:20 UTC), 106 km (66 mi) below the surface.

A larger quake followed: M4.8 131 km WSW of Adak, Alaska. This one was a foreshock.

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The earthquake

Magnitude
2.6 (ML, local (Richter)), micro
Magnitude from
USGS National Earthquake Information Center
Local time
UTC
2017-10-20 23:20:11 UTC
Depth
106.5 km (66.2 mi), intermediate-depth
Epicenter
51.769° N, 178.984° 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.ScaleComputed byNotes
2.6ML, local (Richter)USGS National Earthquake Information CenterPreferred · Reviewed
2.6ML, local (Richter)Alaska Earthquake CenterPreliminary

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 7.4 km horizontally, 6.5 km in depth
Depth from
From location
Station coverage gap
161°
Stations used
21

Nearby

Within 100 km, magnitude 1.5 and up: at least 199 in the 60 days after this one and 104 in the 30 days before it.

After

The first 60 of at least 199.

Before

Earthquakes todayAlaska earthquakesLive radar here

Sources

From the USGS Earthquake Hazards Program and its partner networks, event us1000aw5v (also filed as ak17093889, ak017dgy9yv2). Read Fri, Oct 2, 2026, 1:48 AM UTC.