Alaska earthquakes

M5.1 earthquake 94 km SW of Adak, Alaska

A magnitude 5.1 earthquake struck 94 km SW of Adak, Alaska on Sat, Sep 1, 2018, 5:23 AM HADT (14:23 UTC), 35 km (22 mi) below the surface.

Map

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

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The earthquake

Magnitude: 5.1 (Mww, W-phase moment), moderate
Magnitude from: USGS National Earthquake Information Center
Local time: Sat, Sep 1, 2018, 5:23 AM HADT
UTC: 2018-09-01 14:23:23 UTC
Depth: 35.0 km (21.7 mi), shallow
Epicenter: 51.331° N, 177.682° 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
5.1	Mww, W-phase moment	USGS National Earthquake Information Center	Preferred · Reviewed · ±0.059 · 28 stations
5.09	Mw, moment	ISC-GEM global catalog	Final · ±0.1
5.1	Mw, moment	Alaska Earthquake Center	Preliminary

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: 5.1 Mww
Nodal plane 1: Strike 263°, dip 31°, rake 116°
Nodal plane 2: Strike 53°, dip 62°, rake 75°

How well it is located

Reviewed by a seismologist.

Location uncertainty: About 5.8 km horizontally, 1.9 km in depth
Magnitude uncertainty: ±0.06
Depth from: Operator assigned
Station coverage gap: 91°
Stations used: 103

Nearby

Within 100 km, magnitude 2.1 and up: 102 in the 60 days after this one and 150 in the 30 days before it.

After

The first 60 of 102.

Before

Earthquakes today Alaska earthquakes Live radar here

Sources

From the USGS Earthquake Hazards Program and its partner networks, event us2000h6hg (also filed as ak20239135, ak018b7rlq02, iscgem612678103). Read Thu, Oct 1, 2026, 11:22 PM UTC.