M3.3 earthquake – Nikolski, Alaska

Name: M3.3 earthquake – Nikolski, Alaska
Start: 2026-09-04T09:25:23.409Z
End: 2026-09-04T09:25:23.409Z
Location: Nikolski, Alaska

A magnitude 3.3 earthquake struck in the Nikolski, Alaska region at 09:25 UTC on 4 Sept 2026, at a depth of 35 km, according to USGS.

revised from M3.5

Data: USGS · updated 2026-10-01 18:06 UTC · reviewed

Magnitude: 3.3minor
local magnitude (Richter) (ml)
revised from 3.5
Depth: 35 km
Status: Reviewed
Origin time: 2026-09-04 09:25:23 UTC
Epicentre: 52.258° N, 169.358° 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
Place	Distance	Est. 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.

Agency	Magnitude	Depth	Epicentre	Time offset	Status
USGSheadlineUSGS NEIC via U.S. Geological Survey	3.3 mlwas 3.5	35 km	52.26° N, 169.36° W	–	Reviewed · 1 revision

How big was it?

Often felt by people at rest close to the epicentre, rarely causes damage.

It released roughly the energy of 1.3 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.

Compare M3.3 with M2.3

M3.3 releases about 32× the energy of M2.3, and its waves are about 10× taller on a seismogram. Energy: 1.3 t of TNT vs 43 kg of TNT.

Each square is the energy of one M2.3. Energy from log₁₀E = 1.5M + 4.8.

Aftershocks and nearby activity

75 later earthquakes within 30 km; the largest was M4.9 26 days ago. 157 in the 7 days before. Aftershock rates usually fall off roughly in proportion to 1/time.

Aftershocks

Mainshock M3.3

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

Aftershocks
Time after mainshock (hours)	Magnitude	Depth (km)
0.97	3.2	28
2.20	2.7	11
2.63	2.6	35
4.72	2.8	10
5.24	4.0	35
5.45	3.1	35
8.07	2.6	25
16.59	3.1	29
17.54	3.2	17
17.85	3.0	10
18.30	2.8	10
18.74	2.5	35
18.89	2.7	27
20.88	2.7	10
23.73	2.7	14
24.55	2.7	20
27.03	2.8	10
29.41	3.0	35
30.74	2.7	5
32.58	4.9	29
32.77	2.8	20
39.69	2.8	8
43.02	2.9	22
43.75	2.8	10
46.39	2.8	21
47.64	2.7	10
49.68	2.8	14
49.88	2.9	17
54.05	3.9	10
59.82	2.7	11
61.25	2.7	11
62.45	2.8	13
65.04	3.2	10
65.89	2.6	12
71.83	2.7	11
75.67	2.7	13
75.82	2.7	22
76.88	2.7	35
93.42	3.2	10
94.79	2.9	10
94.86	2.7	10
104.51	3.2	10
104.58	3.4	10
105.03	2.6	10
105.45	2.7	10
108.69	2.8	40
109.62	4.0	45
109.64	3.1	10
109.72	2.7	7
109.88	2.7	43
110.03	2.7	13
110.95	2.7	12
110.97	3.7	43
150.91	2.7	35
161.47	3.4	11
164.93	2.9	8
166.08	2.7	19
174.76	2.6	14
176.99	3.1	35
200.85	3.3	35
205.84	2.5	39
227.26	2.7	16
227.62	2.9	35
263.29	2.9	8
272.34	2.9	52
311.78	2.7	14
327.70	3.8	25
339.90	3.2	45
363.31	4.0	38
380.53	2.9	23
380.59	2.9	10
443.59	3.1	12
443.76	3.1	16
540.10	4.0	35
589.46	2.5	21

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 aka2026rncfrf. First recorded here 28 Sept 2026, 17:32:13 UTC. Solutions: USGS (usgs:us7000teca). Cite as: SeismoAtlas, “M3.3 earthquake – Nikolski, Alaska”, https://seismoatlas.com/earthquake/aka2026rncfrf-m3-3-earthquake-nikolski-alaska, data from USGS.

JSON: /api/v1/events/aka2026rncfrf. SeismoAtlas is not an official warning service.