Alaska earthquakes

M5.1 earthquake 76 km S of Adak, Alaska

A magnitude 5.1 earthquake struck 76 km S of Adak, Alaska on Sun, Dec 18, 1977, 11:52 PM GMT-11 (10:52 UTC), 53 km (33 mi) below the surface.

A larger quake followed: M5.3 44 km ESE of Adak, Alaska. This one was a foreshock.

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The earthquake

Magnitude
5.1 (mb), moderate
Local time
UTC
1977-12-19 10:52:38 UTC
Depth
53.0 km (32.9 mi), shallow
Epicenter
51.194° N, 176.437° 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.

Depth from
CONSTRAINED_BY_DEPTH_PHASES
Stations used
145

Nearby

Within 100 km, magnitude 2.1 and up: 5 in the 60 days after this one and 2 in the 30 days before it.

After

  1. 4.661 km SSE of Adak, Alaska · 17809 days ago · 54 km deep · 17 km away
  2. 4.065 km S of Adak, Alaska · 17809 days ago · 56 km deep · 12 km away
  3. 4.166 km SSE of Adak, Alaska · 17809 days ago · 53 km deep · 18 km away
  4. 5.344 km ESE of Adak, Alaska · 17792 days ago · 63 km deep · 71 km away
  5. 3.947 km SW of Adak, Alaska · 17788 days ago · 121 km deep · 69 km away

Before

  1. 4.281 km SSE of Adak, Alaska · 17809 days ago · 44 km deep · 11 km away
  2. 4.368 km SSE of Adak, Alaska · 17811 days ago · 50 km deep · 17 km away

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Sources

From the USGS Earthquake Hazards Program and its partner networks, event usp0000s50 (also filed as gcmtb121977a, gcmt19771219105238, iscgem689273). Read Tue, Sep 22, 2026, 8:42 PM UTC.