Alaska earthquakes

M5.2 earthquake 196 km WSW of Adak, Alaska

A magnitude 5.2 earthquake struck 196 km WSW of Adak, Alaska on Mon, Aug 28, 1972, 5:21 AM GMT-10 (15:21 UTC), 37 km (23 mi) below the surface.

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The earthquake

Magnitude
5.2 (Mw, moment), moderate
Magnitude from
ISCGEMSUP
Local time
UTC
1972-08-28 15:21:02 UTC
Depth
37.2 km (23.1 mi), shallow
Epicenter
51.218° N, 179.266° 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
5.22Mw, momentISCGEMSUPPreferred · Final · ±0.2
5.5mb, body-waveUSGS historic United States catalogFinal

What happened

The USGS’s account of the effects of this earthquake.

Maximum observed Modified Mercalli Intensity (MMI) IV

From the USGS event page for iscgemsup771047. U.S. Geological Survey text and figures are in the public domain.

Did you feel it?

No one has reported feeling this quake to the USGS.

How well it is located

Reviewed by a seismologist.

Magnitude uncertainty
±0.20
Depth from
From location

Nearby

Within 100 km, magnitude 2.2 and up: 0 in the 60 days after this one and 3 in the 30 days before it.

Before

Earthquakes todayAlaska earthquakesLive radar here

Sources

From the USGS Earthquake Hazards Program and its partner networks, event iscgemsup771047 (also filed as ushis3203, iscgem771047). Read Sun, Oct 4, 2026, 8:35 AM UTC.