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SeismoAtlas

M4.1 earthquake – Adak, Alaska

A magnitude 4.1 earthquake struck in the Adak, Alaska region at 10:52 UTC on 11 Sept 2026, at a depth of 28 km, according to USGS.

revised from M4.3

Data: USGS · updated 2026-10-08 14:24 UTC · reviewed

Magnitude
4.1light
body-wave magnitude (mb)
revised from 4.3
Depth
28.1 km
Status
Reviewed
Origin time
2026-09-11 10:52:51 UTC
Epicentre
51.117° N, 178.473° W

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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 39 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 Survey4.1 mbwas 4.328.1 km51.12° N, 178.47° W–Reviewed · 1 revision

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How big was it?

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

It released roughly the energy of 21 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 28 km this was a shallow earthquake, which is felt more strongly at the surface than a deeper one of the same size.

M4.1 releases about 32× the energy of M3.1, and its waves are about 10× taller on a seismogram. Energy: 21 t of TNT vs 674 kg of TNT.

Each square is the energy of one M3.1. Energy from log₁₀E = 1.5M + 4.8.

Aftershocks and nearby activity

21 later earthquakes within 30 km; the largest was M3.9 25 days ago. 6 in the 7 days before. Aftershock rates usually fall off roughly in proportion to 1/time.

Aftershocks

Mainshock M4.1

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

Aftershocks
Time after mainshock (hours)MagnitudeDepth (km)
0.063.035
0.242.720
0.312.524
0.352.530
0.802.517
1.232.535
3.352.535
7.282.521
10.802.615
16.843.335
39.263.929
47.163.335
81.642.542
127.953.036
128.802.520
129.662.911
258.943.50
281.872.862
330.303.514
410.762.229
437.212.822
  1. 3.9Adak, Alaska09-13 02:08
  2. 3.5Adak, Alaska09-22 05:49
  3. 3.5Adak, Alaska09-25 05:10
  4. 3.3Adak, Alaska09-12 03:43
  5. 3.3Adak, Alaska09-13 10:02
  6. 3.0Adak, Alaska09-11 10:56
  7. 3.0Adak, Alaska09-16 18:49
  8. 2.9Adak, Alaska09-16 20:32
  9. 2.8Adak, Alaska09-23 04:44
  10. 2.8Adak, Alaska09-29 16:05
  11. 2.7Adak, Alaska09-11 11:07
  12. 2.6Adak, Alaska09-11 21:41
  13. 2.5Adak, Alaska09-11 11:11
  14. 2.5Adak, Alaska09-11 11:13
  15. 2.5Adak, Alaska09-11 11:40
  16. 2.5Adak, Alaska09-11 12:06
  17. 2.5Adak, Alaska09-11 14:14
  18. 2.5Adak, Alaska09-11 18:09
  19. 2.5Adak, Alaska09-14 20:31
  20. 2.5Adak, Alaska09-16 19:40
  21. 2.2Adak, Alaska09-28 13:38

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.

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Event id aka2026sadhvu. First recorded here 28 Sept 2026, 17:32:12 UTC. Solutions: USGS (usgs:us7000tgpi). Cite as: SeismoAtlas, “M4.1 earthquake – Adak, Alaska”, https://seismoatlas.com/earthquake/aka2026sadhvu-m4-1-earthquake-adak-alaska, data from USGS.

JSON: /api/v1/events/aka2026sadhvu. SeismoAtlas is not an official warning service.