Alaska earthquakes

M4.0 earthquake 173 km SSW of Adak, Alaska

A magnitude 4.0 earthquake struck 173 km SSW of Adak, Alaska on Sun, Aug 20, 2023, 5:26 AM HADT (14:26 UTC), 10 km (6 mi) below the surface.

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

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The earthquake

Magnitude
4.0 (mb, body-wave), light
Magnitude from
USGS National Earthquake Information Center
Local time
UTC
2023-08-20 14:26:11 UTC
Depth
10.0 km (6.2 mi), shallow
Epicenter
50.359° N, 177.238° 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
4.0mb, body-waveUSGS National Earthquake Information CenterPreferred · Reviewed · ±0.064 · 65 stations
4.0mb, body-waveAlaska Earthquake CenterPreliminary

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 4.9 km horizontally, 1.9 km in depth
Magnitude uncertainty
±0.06
Depth from
Operator assigned
Station coverage gap
140°
Stations used
46

Nearby

Within 100 km, magnitude 1.5 and up: 13 in the 60 days after this one and 19 in the 30 days before it.

After

  1. 2.6175 km S of Adak, Alaska · 1137 days ago · 10 km deep · 55 km away
  2. 2.6139 km S of Adak, Alaska · 1135 days ago · 10 km deep · 45 km away
  3. 1.9190 km SW of Adak, Alaska · 1133 days ago · 5 km deep · 70 km away
  4. 2.0138 km SW of Adak, Alaska · 1132 days ago · 26 km deep · 72 km away
  5. 1.993 km S of Adak, Alaska · 1121 days ago · 26 km deep · 82 km away
  6. 1.5103 km SW of Adak, Alaska · 1121 days ago · 20 km deep · 90 km away
  7. 2.6112 km SW of Adak, Alaska · 1116 days ago · 35 km deep · 98 km away
  8. 2.1Andreanof Islands, Aleutian Islands, Alaska · 1116 days ago · 8 km deep · 27 km away
  9. 2.4163 km SW of Adak, Alaska · 1109 days ago · 13 km deep · 94 km away
  10. 2.7131 km SW of Adak, Alaska · 1108 days ago · 35 km deep · 82 km away
  11. 2.7Andreanof Islands, Aleutian Islands, Alaska · 1106 days ago · 35 km deep · 86 km away
  12. 2.8Andreanof Islands, Aleutian Islands, Alaska · 1105 days ago · 26 km deep · 92 km away
  13. 1.898 km SW of Adak, Alaska · 1095 days ago · 22 km deep · 99 km away

Before

  1. 2.4244 km SSW of Adak, Alaska · 1138 days ago · 10 km deep · 87 km away
  2. 2.1195 km SSW of Adak, Alaska · 1139 days ago · 1 km deep · 44 km away
  3. 1.8151 km S of Adak, Alaska · 1140 days ago · 7 km deep · 46 km away
  4. 1.9141 km SW of Adak, Alaska · 1142 days ago · 11 km deep · 97 km away
  5. 2.9142 km SW of Adak, Alaska · 1142 days ago · 17 km deep · 94 km away
  6. 1.6139 km SW of Adak, Alaska · 1142 days ago · 17 km deep · 88 km away
  7. 1.6143 km SW of Adak, Alaska · 1142 days ago · 5 km deep · 76 km away
  8. 2.0143 km SW of Adak, Alaska · 1142 days ago · 17 km deep · 95 km away
  9. 1.7Andreanof Islands, Aleutian Islands, Alaska · 1142 days ago · 25 km deep · 89 km away
  10. 1.7144 km SW of Adak, Alaska · 1142 days ago · 18 km deep · 94 km away
  11. 1.9133 km SW of Adak, Alaska · 1142 days ago · 26 km deep · 98 km away
  12. 4.7149 km SW of Adak, Alaska · 1142 days ago · 10 km deep · 86 km away
  13. 3.1Andreanof Islands, Aleutian Islands, Alaska · 1147 days ago · 10 km deep · 94 km away
  14. 2.5241 km SSW of Adak, Alaska · 1147 days ago · 10 km deep · 76 km away
  15. 2.3192 km S of Adak, Alaska · 1150 days ago · 12 km deep · 75 km away
  16. 3.2150 km SSW of Adak, Alaska · 1152 days ago · 10 km deep · 23 km away
  17. 1.6101 km SSW of Adak, Alaska · 1160 days ago · 25 km deep · 79 km away
  18. 1.5Andreanof Islands, Aleutian Islands, Alaska · 1161 days ago · 16 km deep · 81 km away
  19. 2.1222 km S of Adak, Alaska · 1161 days ago · 12 km deep · 58 km away

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Sources

From the USGS Earthquake Hazards Program and its partner networks, event us7000kpml (also filed as ak023anx66i5). Read Thu, Oct 1, 2026, 2:57 AM UTC.