M6.5 earthquake – Nikolski, Alaska

A magnitude 6.5 earthquake struck in the Nikolski, Alaska region at 14:19 UTC on 17 Sept 2026, at a depth of 98 km, according to USGS.

8 reports to USGS “Did You Feel It?”

Data: USGS · updated 2026-09-28 14:30 UTC · reviewed

Magnitude: 6.5strong
moment magnitude (W phase) (mww)
Depth: 98 km
Status: Reviewed
Origin time: 2026-09-17 14:19:52 UTC
Epicentre: 52.956° N, 171.503° W

Circles show this event and others within 224 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. Likely felt out to about 636 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.

Agency	Magnitude	Depth	Epicentre	Time offset	Status
USGSheadlineUSGS NEIC via U.S. Geological Survey	6.5 mww	98 km	52.96° N, 171.50° W	–	Reviewed

How big was it?

Can cause damage over tens of kilometres, depending on depth, local ground and how buildings are built.

It released roughly the energy of 85 kt 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 98 km this was a intermediate-depth earthquake, which spreads shaking over a wider area but less intensely.

Compare M6.5 with M5.5

M6.5 releases about 32× the energy of M5.5, and its waves are about 10× taller on a seismogram. Energy: 85 kt of TNT vs 2.7 kt of TNT.

Each square is the energy of one M5.5. Energy from log₁₀E = 1.5M + 4.8.

Aftershocks and nearby activity

193 later earthquakes within 224 km; the largest was M4.7 28 days ago. 29 in the 7 days before. Aftershock rates usually fall off roughly in proportion to 1/time.

Aftershocks

Mainshock M6.5

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

Aftershocks
Time after mainshock (hours)	Magnitude	Depth (km)
0.24	3.5	95
0.33	4.1	104
0.45	3.8	100
1.75	2.9	115
2.23	3.0	108
2.23	2.8	100
2.43	3.4	100
4.79	2.9	87
9.59	2.5	61
10.80	3.8	10
15.40	3.8	105
16.40	2.8	102
19.07	3.6	35
22.99	3.2	45
26.61	3.6	68
32.79	3.0	100
42.47	3.8	55
46.40	4.0	38
60.97	3.2	95
62.71	3.8	106
63.62	2.9	23
63.68	2.9	10
67.93	3.0	10
71.60	4.5	92
72.90	2.7	10
74.44	2.7	197
76.93	3.3	106
79.47	2.9	97
81.39	3.1	51
84.31	3.5	35
91.67	3.5	110
92.61	3.0	103
99.75	0.7	-1
99.76	0.6	7
102.23	0.6	2
106.41	3.8	99
106.81	0.7	1
107.00	1.0	8
107.08	0.6	5
107.77	1.2	9
107.79	0.7	8
108.04	0.6	10
108.04	1.0	9
108.63	1.4	8
109.51	0.6	11
109.62	0.5	-2
114.22	3.9	225
117.25	0.3	6
119.55	0.7	8
119.88	2.5	5
126.68	3.1	14
126.85	2.9	10
128.07	2.6	35
128.32	2.7	14
129.76	2.5	6
135.04	-0.5	1
136.29	0.0	2
143.78	3.2	190
147.92	3.3	34
170.55	3.5	10
190.29	3.5	46
194.75	1.1	4
219.08	1.8	8
219.99	1.4	7
223.19	4.0	35
223.98	1.2	8
239.42	1.6	15
242.85	0.4	0
243.73	3.1	10
245.59	1.3	13
247.73	2.9	50
259.82	1.0	5
261.81	1.6	9
264.17	2.5	16
267.00	2.9	214
272.56	2.5	21
274.76	2.7	8
275.31	2.8	7
291.34	2.7	185
293.46	2.6	3
294.87	2.8	208
298.48	0.3	1
302.42	2.8	10
302.61	2.8	10
309.90	2.5	10
310.81	0.5	4
312.52	3.1	183
325.30	3.1	10
349.86	2.7	90
371.74	0.7	12
373.13	0.9	0
377.44	0.5	2
377.83	0.8	8
379.58	0.6	13
385.05	0.9	8
386.60	3.4	55
386.76	3.1	35
391.09	3.5	35
418.15	2.7	35
449.72	0.9	9
453.56	3.0	85
460.56	2.5	74
462.22	3.1	10
464.41	1.2	-1
467.73	2.7	26
467.89	3.1	35
468.64	0.7	13
469.43	2.9	24
470.29	0.8	9
476.79	0.6	1
485.19	3.0	35
487.02	3.0	10
487.09	1.1	8
490.10	2.4	2
491.82	0.8	11
502.92	3.5	35
527.73	2.5	10
528.94	3.5	10
531.91	2.8	10
540.41	2.5	41
542.76	3.0	13
543.25	1.2	7
544.65	1.0	8
545.94	1.3	17
546.31	1.4	14
551.88	1.2	9
551.89	1.2	9
552.24	1.8	9
552.27	1.1	11
554.74	1.2	11
554.83	1.5	3
555.14	1.1	8
555.15	0.8	1
555.47	1.7	8
558.20	1.1	0
582.93	1.0	9
583.67	1.1	9
584.52	1.0	10
586.81	1.2	7
587.37	0.8	-1
589.09	1.5	9
589.17	1.2	7
589.43	0.9	11
590.64	1.3	9
595.98	2.6	12
598.25	0.2	5
612.99	1.2	9
613.28	2.8	35
613.34	2.5	8
613.50	1.3	10
613.52	1.3	8
615.47	2.6	18
619.69	1.2	8
619.75	1.2	9
619.78	1.3	9
619.81	2.5	7
620.11	1.2	8
620.73	1.1	9
620.99	0.9	8
621.05	1.0	10
622.96	3.0	11
624.92	2.7	17
627.36	2.0	10
628.17	2.5	3
628.48	1.9	9
628.57	1.0	5
628.91	0.8	9
629.33	1.8	6
629.52	1.1	5
631.20	1.4	5
632.90	0.9	8
633.67	0.7	4
640.60	1.1	9
640.97	0.5	9
646.00	4.0	193
656.13	1.7	9
662.38	1.2	1
663.05	1.6	5
663.18	0.9	0
670.31	1.4	8
670.94	4.7	10
676.88	2.9	68
684.97	2.2	10
684.99	1.2	7
684.99	1.0	12
686.37	1.5	9
689.46	2.8	71
691.54	3.0	10
705.08	3.0	25
710.38	0.6	2
717.24	0.9	14
717.35	0.6	11
717.48	0.7	5

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.

USGS “Did You Feel It?” has 8 reports: add yours at USGS.

Event id us7000ti1p. First recorded here 28 Sept 2026, 17:32:11 UTC. Solutions: USGS (usgs:us7000ti1p). Cite as: SeismoAtlas, “M6.5 earthquake – Nikolski, Alaska”, https://seismoatlas.com/earthquake/us7000ti1p-m6-5-earthquake-nikolski-alaska, data from USGS.

JSON: /api/v1/events/us7000ti1p. SeismoAtlas is not an official warning service.