Alaska earthquakes

M4.0 earthquake 158 km SW of Nikolski, Alaska

A magnitude 4.0 earthquake struck 158 km SW of Nikolski, Alaska on Sun, Dec 20, 2020, 12:59 PM HAST (22:59 UTC), 41 km (25 mi) below the surface.

A larger quake followed: M4.4 174 km SW of Nikolski, Alaska. This one was a foreshock.

More in Alaska

Map

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

Open the live map with earthquakes

The earthquake

Magnitude
4.0 (mb, body-wave), light
Magnitude from
USGS National Earthquake Information Center
Local time
UTC
2020-12-20 22:59:14 UTC
Depth
40.9 km (25.4 mi), shallow
Epicenter
51.873° N, 170.407° 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 · ±0.081 · 41 stations
3.6ML, local (Richter)Alaska 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 4.3 km horizontally, 7.0 km in depth
Magnitude uncertainty
±0.08
Depth from
From location
Station coverage gap
136°
Stations used
112

Nearby

Within 100 km, magnitude 1.5 and up: 24 in the 60 days after this one and 14 in the 30 days before it.

After

  1. 3.6129 km SSW of Nikolski, Alaska · 2111 days ago · 10 km deep · 70 km away
  2. 2.993 km WSW of Nikolski, Alaska · 2108 days ago · 35 km deep · 72 km away
  3. 4.270 km SW of Nikolski, Alaska · 2108 days ago · 46 km deep · 88 km away · felt by 1
  4. 2.870 km SW of Nikolski, Alaska · 2103 days ago · 35 km deep · 89 km away
  5. 4.4174 km SW of Nikolski, Alaska · 2095 days ago · 28 km deep · 26 km away
  6. 2.4113 km SSW of Nikolski, Alaska · 2090 days ago · 32 km deep · 70 km away
  7. 3.2171 km SW of Nikolski, Alaska · 2088 days ago · 35 km deep · 40 km away
  8. 2.697 km WSW of Nikolski, Alaska · 2078 days ago · 102 km deep · 97 km away
  9. 3.3246 km ESE of Atka, Alaska · 2077 days ago · 10 km deep · 94 km away
  10. 3.8113 km SW of Nikolski, Alaska · 2077 days ago · 49 km deep · 50 km away
  11. 3.281 km WSW of Nikolski, Alaska · 2076 days ago · 70 km deep · 86 km away
  12. 4.2116 km WSW of Nikolski, Alaska · 2075 days ago · 44 km deep · 57 km away
  13. 3.1132 km SW of Nikolski, Alaska · 2073 days ago · 27 km deep · 32 km away
  14. 2.7178 km WSW of Nikolski, Alaska · 2071 days ago · 35 km deep · 61 km away
  15. 4.0220 km SSW of Nikolski, Alaska · 2071 days ago · 10 km deep · 91 km away
  16. 2.2113 km SW of Nikolski, Alaska · 2070 days ago · 36 km deep · 45 km away
  17. 3.087 km SSW of Nikolski, Alaska · 2066 days ago · 35 km deep · 80 km away
  18. 3.3153 km SW of Nikolski, Alaska · 2059 days ago · 35 km deep · 35 km away
  19. 3.8111 km SSW of Nikolski, Alaska · 2059 days ago · 30 km deep · 75 km away
  20. 3.5113 km SW of Nikolski, Alaska · 2059 days ago · 50 km deep · 48 km away
  21. 2.595 km WSW of Nikolski, Alaska · 2058 days ago · 43 km deep · 78 km away
  22. 3.5160 km SW of Nikolski, Alaska · 2057 days ago · 35 km deep · 3 km away
  23. 2.973 km SW of Nikolski, Alaska · 2057 days ago · 39 km deep · 85 km away
  24. 2.476 km SSW of Nikolski, Alaska · 2056 days ago · 9 km deep · 85 km away

Before

  1. 2.485 km SW of Nikolski, Alaska · 2114 days ago · 24 km deep · 73 km away
  2. 2.767 km SSW of Nikolski, Alaska · 2114 days ago · 35 km deep · 96 km away
  3. 3.6213 km ESE of Atka, Alaska · 2115 days ago · 25 km deep · 61 km away
  4. 4.2127 km WSW of Nikolski, Alaska · 2115 days ago · 53 km deep · 56 km away
  5. 3.098 km SSW of Nikolski, Alaska · 2123 days ago · 31 km deep · 80 km away
  6. 3.4111 km SW of Nikolski, Alaska · 2127 days ago · 35 km deep · 49 km away
  7. 3.7178 km SW of Nikolski, Alaska · 2128 days ago · 40 km deep · 40 km away
  8. 3.6169 km WSW of Nikolski, Alaska · 2128 days ago · 40 km deep · 47 km away
  9. 4.2172 km SW of Nikolski, Alaska · 2128 days ago · 44 km deep · 41 km away
  10. 3.1149 km WSW of Nikolski, Alaska · 2132 days ago · 35 km deep · 43 km away
  11. 3.2132 km WSW of Nikolski, Alaska · 2133 days ago · 28 km deep · 47 km away
  12. 2.380 km SSW of Nikolski, Alaska · 2136 days ago · 10 km deep · 98 km away
  13. 4.5104 km SSW of Nikolski, Alaska · 2136 days ago · 40 km deep · 66 km away
  14. 4.4177 km SW of Nikolski, Alaska · 2139 days ago · 35 km deep · 44 km away

Earthquakes todayAlaska earthquakesLive radar here

Sources

From the USGS Earthquake Hazards Program and its partner networks, event us7000cst3 (also filed as ak020gbh8h6s). Read Mon, Oct 5, 2026, 3:50 AM UTC.