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SeismoAtlas

M4.0 earthquake – Nikolski, Alaska

A magnitude 4.0 earthquake struck in the Nikolski, Alaska region at 23:02 UTC on 8 Sept 2026, at a depth of 35 km, according to USGS.

Data: USGS · updated 2026-10-06 21:25 UTC · reviewed

Magnitude
4.0light
body-wave magnitude (mb)
Depth
35 km
Status
Reviewed
Origin time
2026-09-08 23:02:33 UTC
Epicentre
52.263° N, 169.399° 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 26 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 mb35 km52.26° N, 169.40° W–Reviewed · 2 revisions

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 35 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

33 later earthquakes within 30 km; the largest was M4.0 54 days ago. 167 in the 7 days before. Aftershock rates usually fall off roughly in proportion to 1/time.

Aftershocks

Mainshock M4.0

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

Aftershocks
Time after mainshock (hours)MagnitudeDepth (km)
0.023.110
0.102.77
0.262.710
0.412.713
1.342.712
1.353.740
5.912.53
41.292.735
51.853.310
55.312.810
56.462.719
65.142.614
67.373.135
91.233.335
96.222.539
117.642.716
118.002.935
153.672.710
162.722.952
202.162.714
218.083.810
230.283.245
253.694.038
270.912.923
270.972.910
333.973.114
355.203.334
430.484.035
479.842.521
500.752.63
594.043.135
675.022.726
675.183.135
  1. 4.0Nikolski, Alaska09-19 12:44
  2. 4.0Fox Islands, Aleutian Islands09-26 21:31
  3. 3.8Nikolski, Alaska09-18 01:07
  4. 3.7Nikolski, Alaska09-09 00:23
  5. 3.3Nikolski, Alaska09-11 02:53
  6. 3.3Nikolski, Alaska09-12 18:16
  7. 3.3Nikolski, Alaska09-23 18:14
  8. 3.2Nikolski, Alaska09-18 13:19
  9. 3.1Nikolski, Alaska09-08 23:04
  10. 3.1Nikolski, Alaska09-11 18:24
  11. 3.1Nikolski, Alaska09-22 21:00
  12. 3.1Nikolski, Alaska10-03 17:05
  13. 3.1Nikolski, Alaska10-07 02:13
  14. 2.9Nikolski, Alaska09-13 21:02
  15. 2.9Nikolski, Alaska09-15 17:45
  16. 2.9Nikolski, Alaska09-20 05:57
  17. 2.9Nikolski, Alaska09-20 06:00
  18. 2.8Nikolski, Alaska09-11 06:21
  19. 2.7Nikolski, Alaska09-08 23:08
  20. 2.7Nikolski, Alaska09-08 23:17
  21. 2.7Nikolski, Alaska09-08 23:27
  22. 2.7Nikolski, Alaska09-09 00:22
  23. 2.7Nikolski, Alaska09-10 16:19
  24. 2.7Nikolski, Alaska09-11 07:29
  25. 2.7Nikolski, Alaska09-13 20:40

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 us7000tfy4. First recorded here 28 Sept 2026, 17:32:12 UTC. Solutions: USGS (usgs:us7000tfy4). Cite as: SeismoAtlas, “M4.0 earthquake – Nikolski, Alaska”, https://seismoatlas.com/earthquake/us7000tfy4-m4-0-earthquake-nikolski-alaska, data from USGS.

JSON: /api/v1/events/us7000tfy4. SeismoAtlas is not an official warning service.

M4.0 earthquake – Nikolski, Alaska · SeismoAtlas