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SeismoAtlas

M2.8 earthquake – Nikolski, Alaska

A magnitude 2.8 earthquake struck in the Nikolski, Alaska region at 02:39 UTC on 4 Sept 2026, at a depth of 9 km, according to USGS.

revised from M3.0

Data: USGS · updated 2026-09-29 01:04 UTC · reviewed

Magnitude
2.8micro
local magnitude (Richter) (ml)
revised from 3.0
Depth
9.2 km
Status
Reviewed
Origin time
2026-09-04 02:39:46 UTC
Epicentre
52.175° N, 169.133° W

Circles show this event and others within 30 km from 7 days before to 30 days after. Lines: plate boundaries and GEM active faults. Open on the live map

Nearby places

Distance and estimated shaking at nearby places
PlaceDistanceEst. shaking
No towns within 400 km. This is a remote area.

Shaking is an estimate from the intensity prediction equation of Allen, Wald & Worden (2012), not an observation. Local ground and buildings can change it by a level or more. Likely felt out to about 9 km.

Every agency's solution

Agencies locate earthquakes with their own stations and methods, so their numbers differ. We match reports of the same event by time, distance and magnitude and show them side by side. The headline uses USGS, which has been reviewed by an analyst.

AgencyMagnitudeDepthEpicentreTime offsetStatus
USGSheadlineUSGS NEIC via U.S. Geological Survey2.8 mlwas 3.09.2 km52.17° N, 169.13° W–Reviewed · 1 revision

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How big was it?

Usually not felt. Recorded by nearby seismometers; thousands occur worldwide every day.

It released roughly the energy of 239 kg of TNT. Magnitude is logarithmic: each whole step means about 32 times more energy and 10 times larger waves on a seismogram. Depth matters too: at 9 km this was a shallow earthquake, which is felt more strongly at the surface than a deeper one of the same size.

M2.8 releases about 32× the energy of M1.8, and its waves are about 10× taller on a seismogram. Energy: 239 kg of TNT vs 8 kg of TNT.

Each square is the energy of one M1.8. Energy from log₁₀E = 1.5M + 4.8.

Aftershocks and nearby activity

103 later earthquakes within 30 km; the largest was M4.9 23 days ago. 148 in the 7 days before. Aftershock rates usually fall off roughly in proportion to 1/time.

Aftershocks

Mainshock M2.8

103 later earthquakes nearby. Aftershock rates typically fall off roughly as 1/time (Omori's law).

Aftershocks
Time after mainshock (hours)MagnitudeDepth (km)
0.192.710
0.882.824
0.923.79
1.022.824
1.983.54
2.442.812
2.522.710
2.812.610
2.962.511
3.542.610
4.202.81
4.462.716
4.762.810
5.282.710
5.652.75
5.872.635
6.072.711
6.332.722
6.763.512
7.733.215
8.962.711
9.392.635
11.482.810
12.004.035
12.213.135
14.832.625
23.353.129
24.303.217
24.613.010
25.062.810
25.502.535
25.652.727
27.642.710
30.492.714
31.312.720
33.792.810
34.262.87
36.173.07
37.502.75
37.583.020
39.344.929
39.532.820
46.452.88
49.713.825
49.782.922
50.512.810
53.152.821
54.402.91
56.642.917
57.852.818
60.323.110
60.813.910
66.582.711
68.012.711
69.022.76
69.212.813
71.803.210
72.652.612
78.592.711
82.432.713
82.582.722
83.642.735
100.193.015
101.553.28
101.622.95
111.273.210
111.343.410
111.792.610
112.212.710
115.452.914
116.384.046
116.403.38
116.482.77
116.643.09
116.792.713
117.722.712
117.733.650
121.872.611
143.842.511
151.722.718
157.672.735
168.233.411
171.692.98
172.742.718
172.842.719
181.522.614
183.753.135
207.613.335
212.602.539
229.252.85
234.022.716
234.382.935
260.202.710
270.052.98
279.102.952
279.352.818
318.542.714
334.463.825
370.074.041
387.293.211
387.352.910
396.572.710
546.864.035
  1. 4.9Nikolski, Alaska09-05 18:00
  2. 4.0Nikolski, Alaska09-04 14:39
  3. 4.0Nikolski, Alaska09-08 23:02
  4. 4.0Nikolski, Alaska09-19 12:44
  5. 4.0Fox Islands, Aleutian Islands09-26 21:31
  6. 3.9Nikolski, Alaska09-06 15:28
  7. 3.8Nikolski, Alaska09-06 04:22
  8. 3.8Nikolski, Alaska09-18 01:07
  9. 3.7Nikolski, Alaska09-04 03:34
  10. 3.6Nikolski, Alaska09-09 00:23
  11. 3.5Nikolski, Alaska09-04 04:38
  12. 3.5Nikolski, Alaska09-04 09:25
  13. 3.4Nikolski, Alaska09-08 18:00
  14. 3.4Nikolski, Alaska09-11 02:53
  15. 3.3Nikolski, Alaska09-08 23:04
  16. 3.3Nikolski, Alaska09-12 18:16
  17. 3.2Nikolski, Alaska09-04 10:23
  18. 3.2Nikolski, Alaska09-05 02:57
  19. 3.2Nikolski, Alaska09-07 02:28
  20. 3.2Nikolski, Alaska09-08 08:13
  21. 3.2Nikolski, Alaska09-08 17:55
  22. 3.2Nikolski, Alaska09-20 05:57
  23. 3.1Nikolski, Alaska09-04 14:52
  24. 3.1Nikolski, Alaska09-05 02:00
  25. 3.1Nikolski, Alaska09-06 14:58

Did you feel it?

Reports from people help show where shaking was strong. They are anonymous and shown here in aggregate.

Reports close 14 days after an earthquake.

Reports on SeismoAtlas

No reports yet.

Event id aka2026rmosja. First recorded here 28 Sept 2026, 17:32:13 UTC. Solutions: USGS (usgs:us7000ted7). Cite as: SeismoAtlas, “M2.8 earthquake – Nikolski, Alaska”, https://seismoatlas.com/earthquake/aka2026rmosja-m2-8-earthquake-nikolski-alaska, data from USGS.

JSON: /api/v1/events/aka2026rmosja. SeismoAtlas is not an official warning service.