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SeismoAtlas

M4.0 earthquake – Nikolski, Alaska

A magnitude 4.0 earthquake struck in the Nikolski, Alaska region at 19:27 UTC on 3 Sept 2026, at a depth of 37 km, according to USGS.

Data: USGS · updated 2026-09-13 21:35 UTC · reviewed

Magnitude
4.0light
body-wave magnitude (mb)
Depth
37.4 km
Status
Reviewed
Origin time
2026-09-03 19:27:43 UTC
Epicentre
52.409° N, 169.328° 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 23 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 Survey4.0 mb37.4 km52.41° N, 169.33° W–Reviewed

How big was it?

Widely felt near the epicentre: rattling windows and objects. Significant damage is unlikely.

It released roughly the energy of 15 t 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 37 km this was a shallow earthquake, which is felt more strongly at the surface than a deeper one of the same size.

M4.0 releases about 32× the energy of M3.0, and its waves are about 10× taller on a seismogram. Energy: 15 t of TNT vs 477 kg of TNT.

Each square is the energy of one M3.0. Energy from log₁₀E = 1.5M + 4.8.

Aftershocks and nearby activity

54 later earthquakes within 30 km; the largest was M5.0 25 days ago. 49 in the 7 days before. Aftershock rates usually fall off roughly in proportion to 1/time.

Aftershocks

Mainshock M4.0

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

Aftershocks
Time after mainshock (hours)MagnitudeDepth (km)
0.683.035
0.793.725
0.915.033
1.063.838
1.214.410
1.432.615
1.492.812
3.243.310
3.562.535
3.912.723
8.222.824
9.642.812
11.402.81
11.962.810
12.852.75
13.072.635
13.272.711
13.532.722
13.963.512
14.933.215
16.592.635
19.413.135
22.032.625
32.702.535
37.692.714
43.373.07
44.702.75
46.544.929
46.732.820
60.362.821
63.652.814
73.782.711
79.852.612
90.842.735
107.393.015
108.822.95
118.543.410
118.992.610
122.652.914
123.584.046
124.002.713
124.922.712
124.933.650
125.722.524
129.492.53
164.872.735
178.892.98
190.953.135
214.813.335
219.802.539
241.222.716
241.582.935
377.274.041
554.064.035
  1. 5.0Nikolski, Alaska09-03 20:22
  2. 4.9Nikolski, Alaska09-05 18:00
  3. 4.4Nikolski, Alaska09-03 20:40
  4. 4.0Nikolski, Alaska09-08 23:02
  5. 4.0Nikolski, Alaska09-19 12:44
  6. 4.0Fox Islands, Aleutian Islands09-26 21:31
  7. 3.8Nikolski, Alaska09-03 20:31
  8. 3.7Nikolski, Alaska09-03 20:14
  9. 3.6Nikolski, Alaska09-09 00:23
  10. 3.5Nikolski, Alaska09-04 09:25
  11. 3.4Nikolski, Alaska09-08 18:00
  12. 3.3Nikolski, Alaska09-03 22:42
  13. 3.3Nikolski, Alaska09-12 18:16
  14. 3.2Nikolski, Alaska09-04 10:23
  15. 3.1Nikolski, Alaska09-04 14:52
  16. 3.1Nikolski, Alaska09-11 18:24
  17. 3.0Nikolski, Alaska09-03 20:08
  18. 3.0Nikolski, Alaska09-05 14:49
  19. 3.0Nikolski, Alaska09-08 06:50
  20. 2.9Nikolski, Alaska09-08 08:16
  21. 2.9Nikolski, Alaska09-08 22:06
  22. 2.9Nikolski, Alaska09-11 06:21
  23. 2.9Nikolski, Alaska09-13 21:02
  24. 2.8Nikolski, Alaska09-03 20:56
  25. 2.8Nikolski, Alaska09-04 03:41

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 us7000te5z. First recorded here 28 Sept 2026, 17:32:13 UTC. Solutions: USGS (usgs:us7000te5z). Cite as: SeismoAtlas, “M4.0 earthquake – Nikolski, Alaska”, https://seismoatlas.com/earthquake/us7000te5z-m4-0-earthquake-nikolski-alaska, data from USGS.

JSON: /api/v1/events/us7000te5z. SeismoAtlas is not an official warning service.