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SeismoAtlas

M2.5 earthquake – Nikolski, Alaska

A magnitude 2.5 earthquake struck in the Nikolski, Alaska region at 02:19 UTC on 4 Sept 2026, at a depth of 10 km, according to USGS.

Data: USGS · updated 2026-09-28 02:02 UTC · reviewed

Magnitude
2.5micro
local magnitude (Richter) (ml)
Depth
10 km
Status
Reviewed
Origin time
2026-09-04 02:19:09 UTC
Epicentre
51.989° N, 169.264° 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.

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 Survey2.5 ml10 km51.99° N, 169.26° W–Reviewed

How big was it?

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

It released roughly the energy of 85 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 10 km this was a shallow earthquake, which is felt more strongly at the surface than a deeper one of the same size.

M2.5 releases about 32× the energy of M1.5, and its waves are about 10× taller on a seismogram. Energy: 85 kg of TNT vs 3 kg of TNT.

Each square is the energy of one M1.5. Energy from log₁₀E = 1.5M + 4.8.

Aftershocks and nearby activity

91 later earthquakes within 30 km; the largest was M4.9 23 days ago. 137 in the 7 days before. Aftershock rates usually fall off roughly in proportion to 1/time.

Aftershocks

Mainshock M2.5

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

Aftershocks
Time after mainshock (hours)MagnitudeDepth (km)
0.042.610
0.092.88
0.343.010
0.533.019
1.222.824
1.263.79
1.912.830
2.333.54
2.862.710
3.162.610
3.312.511
3.882.610
4.542.81
4.802.716
5.102.810
5.622.710
6.222.635
6.412.711
7.103.512
8.083.215
9.302.711
11.832.810
12.354.035
13.242.910
23.693.129
24.643.217
24.963.010
25.402.810
26.002.727
27.982.710
30.832.714
31.662.720
34.132.810
34.602.87
37.923.020
39.684.929
46.802.88
50.053.825
50.122.922
50.852.810
53.502.821
54.742.91
56.982.917
58.192.818
60.663.110
61.153.910
66.922.711
68.352.711
69.372.76
69.552.813
72.153.210
73.002.612
78.932.711
80.462.85
81.973.218
82.772.713
82.932.722
83.982.735
100.533.015
101.903.28
101.962.95
111.613.210
112.132.610
112.562.710
115.802.914
116.753.38
116.832.77
116.983.09
117.142.713
118.062.712
122.212.611
144.182.511
168.573.411
172.042.98
173.082.718
173.182.719
181.862.614
184.103.135
207.963.335
215.462.73
229.602.85
234.362.716
260.552.710
270.402.98
279.442.952
279.702.818
318.882.714
334.813.825
347.003.245
387.633.211
387.692.910
  1. 4.9Nikolski, Alaska09-05 18:00
  2. 4.0Nikolski, Alaska09-04 14:39
  3. 3.9Nikolski, Alaska09-06 15:28
  4. 3.8Nikolski, Alaska09-06 04:22
  5. 3.8Nikolski, Alaska09-18 01:07
  6. 3.7Nikolski, Alaska09-04 03:34
  7. 3.5Nikolski, Alaska09-04 04:38
  8. 3.5Nikolski, Alaska09-04 09:25
  9. 3.4Nikolski, Alaska09-11 02:53
  10. 3.3Nikolski, Alaska09-08 23:04
  11. 3.3Nikolski, Alaska09-12 18:16
  12. 3.2Nikolski, Alaska09-04 10:23
  13. 3.2Nikolski, Alaska09-05 02:57
  14. 3.2Nikolski, Alaska09-07 02:28
  15. 3.2Nikolski, Alaska09-07 12:17
  16. 3.2Nikolski, Alaska09-08 08:13
  17. 3.2Nikolski, Alaska09-08 17:55
  18. 3.2Nikolski, Alaska09-18 13:19
  19. 3.2Nikolski, Alaska09-20 05:57
  20. 3.1Nikolski, Alaska09-05 02:00
  21. 3.1Nikolski, Alaska09-06 14:58
  22. 3.1Nikolski, Alaska09-11 18:24
  23. 3.0Nikolski, Alaska09-04 02:39
  24. 3.0Nikolski, Alaska09-04 02:50
  25. 3.0Nikolski, Alaska09-05 03:16

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 us7000ted4. First recorded here 28 Sept 2026, 17:32:13 UTC. Solutions: USGS (usgs:us7000ted4). Cite as: SeismoAtlas, “M2.5 earthquake – Nikolski, Alaska”, https://seismoatlas.com/earthquake/us7000ted4-m2-5-earthquake-nikolski-alaska, data from USGS.

JSON: /api/v1/events/us7000ted4. SeismoAtlas is not an official warning service.