Alaska earthquakes

M5.8 earthquake 146 km WSW of Adak, Alaska

A magnitude 5.8 earthquake struck 146 km WSW of Adak, Alaska on Wed, May 20, 1970, 10:30 AM GMT-10 (20:30 UTC), 35 km (22 mi) below the surface.

A larger quake followed: M6.1 141 km WSW of Adak, Alaska. This one was a foreshock.

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The earthquake

Magnitude
5.8 (mw), moderate
Local time
UTC
1970-05-20 20:30:54 UTC
Depth
35.0 km (21.7 mi), shallow
Epicenter
51.409° N, 178.611° 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.

How well it is located

Reviewed by a seismologist.

Magnitude uncertainty
±0.70
Depth from
From location

Nearby

Within 100 km, magnitude 2.5 and up: 2 in the 60 days after this one and 0 in the 30 days before it.

After

  1. 5.5125 km WSW of Adak, Alaska · 20555 days ago · 44 km deep · 20 km away
  2. 6.1141 km WSW of Adak, Alaska · 20520 days ago · 31 km deep · 10 km away

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Sources

From the USGS Earthquake Hazards Program and its partner networks, event iscgem795833 (also filed as ushis3104, iscgemsup795833). Read Tue, Sep 22, 2026, 10:57 AM UTC.