Alaska earthquakes

M4.7 earthquake 133 km SW of Adak, Alaska

A magnitude 4.7 earthquake struck 133 km SW of Adak, Alaska on Sun, Feb 16, 2020, 5:33 PM HAST (03:33 UTC), 35 km (22 mi) below the surface.

A larger quake followed: M5.3 216 km WSW 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: 4.7 (mwr), light
Local time: Sun, Feb 16, 2020, 5:33 PM HAST
UTC: 2020-02-17 03:33:14 UTC
Depth: 35.0 km (21.7 mi), shallow
Epicenter: 51.142° N, 178.161° W
Region: Alaska
Tsunami flag: No
Status: Reviewed by a seismologist

Did you feel it?

No one has reported feeling this quake to the USGS.

Fault motion and ground failure

How the rock slipped, from the moment tensor, and the USGS estimate of landslides and liquefaction.

Faulting: Reverse (thrust)
Moment magnitude: 4.7 Mwr
Nodal plane 1: Strike 59°, dip 77°, rake 87°
Nodal plane 2: Strike 251°, dip 13°, rake 101°

How well it is located

Reviewed by a seismologist.

Location uncertainty: About 4.2 km horizontally, 1.9 km in depth
Magnitude uncertainty: ±0.09
Depth from: Operator assigned
Station coverage gap: 122°
Stations used: 215

Nearby

Within 100 km, magnitude 1.7 and up: 165 in the 60 days after this one and at least 200 in the 30 days before it.

After

The first 60 of 165.

Before

Earthquakes today Alaska earthquakes Live radar here

Sources

From the USGS Earthquake Hazards Program and its partner networks, event us70007rm3 (also filed as ak02027fs28j). Read Wed, Sep 30, 2026, 10:34 AM UTC.