Alaska earthquakes

M4.2 earthquake 76 km W of Adak, Alaska

A magnitude 4.2 earthquake struck 76 km W of Adak, Alaska on Thu, Jan 23, 2020, 2:46 PM HAST (00:46 UTC), 10 km (6 mi) below the surface.

A larger quake followed: M5.0 71 km WNW 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: 4.2 (mb, body-wave), light
Magnitude from: USGS National Earthquake Information Center
Local time: Thu, Jan 23, 2020, 2:46 PM HAST
UTC: 2020-01-24 00:46:38 UTC
Depth: 10.0 km (6.2 mi), shallow
Epicenter: 51.766° N, 177.726° 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
4.2	mb, body-wave	USGS National Earthquake Information Center	Preferred · Reviewed · ±0.047 · 126 stations
3.8	ML, local (Richter)	Alaska Earthquake Center	Preliminary
3.82	ML, local (Richter)	AV	Final · ±0.23 · 17 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 6.0 km horizontally, 1.9 km in depth
Magnitude uncertainty: ±0.05
Depth from: Operator assigned
Station coverage gap: 93°
Stations used: 173

Nearby

Within 100 km, magnitude 1.5 and up: at least 201 in the 60 days after this one and at least 200 in the 30 days before it.

After

The first 60 of at least 201.

Before

Earthquakes today Alaska earthquakes Live radar here

Sources

From the USGS Earthquake Hazards Program and its partner networks, event us60007ebe (also filed as av62128381, ak02013p69r8). Read Thu, Oct 1, 2026, 2:45 AM UTC.