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M5.5 earthquake 133 km NNW of Kodiak, Alaska, United States

A magnitude 5.5 earthquake struck 133 km NNW of Kodiak, Alaska, United States at 10:34 local time (18:34 UTC) on 6 Oct 2026, at a depth of 88 km, according to USGS and GFZ.

Reported by 2 agencies · revised from M5.4

Data: USGS, GFZ · updated 2026-10-06 18:39 UTC · reviewed

Magnitude
5.5moderate
local magnitude (Richter) (ml)
revised from 5.4
Depth
87.6 km
Status
Reviewed
Origin time
2026-10-06 18:34:31 UTC
Local: 6 Oct 2026, 10:34:31 (America/Anchorage)
Epicentre
58.802° N, 153.609° W

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Circles show this event and others within 71 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
KodiakAlaska, United States · pop. 6,253133 kmIIIWeak
HomerAlaska, United States · pop. 5,515150 kmIIIWeak
AnchorageAlaska, United States · pop. 289,600339 kmIIWeak

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 200 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 · AK, which has been reviewed by an analyst.

AgencyMagnitudeDepthEpicentreTime offsetStatus
USGS · AKheadlineAlaska Earthquake Center via U.S. Geological Survey5.5 mlwas 5.487.6 km58.80° N, 153.61° W–Reviewed · 3 revisions
GFZGFZ via GEOFON, GFZ Helmholtz Centre for Geosciences5.5 Mwwas 5.781.1 km59.02° N, 154.02° W−0.4 sAutomatic · 2 revisions

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How big was it?

Felt by most people over a wide area. Can damage poorly built structures close to the epicentre.

It released roughly the energy of 2.7 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 88 km this was a intermediate-depth earthquake, which spreads shaking over a wider area but less intensely.

M5.5 releases about 32× the energy of M4.5, and its waves are about 10× taller on a seismogram. Energy: 2.7 kt of TNT vs 85 t of TNT.

Each square is the energy of one M4.5. Energy from log₁₀E = 1.5M + 4.8.

Aftershocks and nearby activity

3 later earthquakes within 71 km; the largest was M1.9 2 h 28 min ago. 5 in the 7 days before. Aftershock rates usually fall off roughly in proportion to 1/time.

Aftershocks

Mainshock M5.5

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

Aftershocks
Time after mainshock (hours)MagnitudeDepth (km)
0.351.984
0.731.25
0.791.885
  1. 1.9139 km NW of Kodiak, Alaska, United States10-06 18:55
  2. 1.8135 km NNW of Kodiak, Alaska, United States10-06 19:21
  3. 1.2139 km NW of Kodiak, Alaska, United States10-06 19:18

Did you feel it?

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Reports on SeismoAtlas

No reports yet.

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Event id aka2026tuxgky. First recorded here 6 Oct 2026, 18:36:17 UTC. Solutions: USGS · AK (usgs:aka2026tuxgky); GFZ (geofon:gfz2026tpiq). Cite as: SeismoAtlas, “M5.5 earthquake 133 km NNW of Kodiak, Alaska, United States”, https://seismoatlas.com/earthquake/aka2026tuxgky-m5-5-earthquake-133-km-nnw-of-kodiak-alaska-united-states, data from USGS, GFZ.

JSON: /api/v1/events/aka2026tuxgky. SeismoAtlas is not an official warning service.