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SeismoAtlas

M1.9 earthquake – Petersville, Alaska

A magnitude 1.9 earthquake struck in the Petersville, Alaska region at 02:50 local time (10:50 UTC) on 18 Oct 2026, at a depth of 100 km, according to USGS.

revised from M1.7

Data: USGS · updated 2026-10-19 06:17 UTC · reviewed

Magnitude
1.9micro
local magnitude (Richter) (ml)
revised from 1.7
Depth
100.2 km
Status
Reviewed
Origin time
2026-10-18 10:50:10 UTC
Local: 18 Oct 2026, 02:50:10 (America/Anchorage)
Epicentre
62.881° N, 151.053° 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
AnchorageAlaska, United States · pop. 289,600194 kmINot felt

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 · AK, which has been reviewed by an analyst.

AgencyMagnitudeDepthEpicentreTime offsetStatus
USGS · AKheadlineAlaska Earthquake Center via U.S. Geological Survey1.9 mlwas 1.7100.2 km62.88° N, 151.05° W–Reviewed · 1 revision

How big was it?

Usually not felt. Recorded by nearby seismometers; thousands occur worldwide every day.

It released roughly the energy of 11 kg 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 100 km this was a intermediate-depth earthquake, which spreads shaking over a wider area but less intensely.

M1.9 releases about 22× the energy of M1.0, and its waves are about 7.9× taller on a seismogram. Energy: 11 kg of TNT vs 477 g of TNT.

Each square is the energy of one M1.0. Energy from log₁₀E = 1.5M + 4.8.

Aftershocks and nearby activity

31 later earthquakes within 30 km; the largest was M3.5 3 days ago. 11 in the 7 days before. Aftershock rates usually fall off roughly in proportion to 1/time.

Aftershocks

Mainshock M1.9

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

Aftershocks
Time after mainshock (hours)MagnitudeDepth (km)
16.071.785
22.891.5107
27.092.1113
34.981.990
36.203.1106
36.542.8118
61.412.1124
82.771.995
121.031.892
139.002.4106
150.412.1127
190.751.9134
195.141.9114
210.521.6107
260.042.396
297.412.7128
305.892.2117
356.492.387
360.302.086
375.112.1124
422.012.099
430.971.9121
437.372.192
476.292.6134
498.882.4138
501.362.1122
504.302.692
523.302.2104
523.551.45
525.643.5112
609.902.390
  1. 3.5Petersville, Alaska11-09 08:28
  2. 3.1Petersville, Alaska10-19 23:02
  3. 2.8Denali National Park, Alaska10-19 23:22
  4. 2.7Petersville, Alaska10-30 20:14
  5. 2.6Denali National Park, Alaska11-07 07:07
  6. 2.6Petersville, Alaska11-08 11:08
  7. 2.4Petersville, Alaska10-24 05:50
  8. 2.4Petersville, Alaska11-08 05:43
  9. 2.3Petersville, Alaska10-29 06:52
  10. 2.3145 km NNW of Meadow Lakes, Alaska, United States11-02 07:19
  11. 2.3141 km NW of Meadow Lakes, Alaska, United States11-12 20:44
  12. 2.2Denali National Park, Alaska10-31 04:43
  13. 2.2Petersville, Alaska11-09 06:08
  14. 2.1Petersville, Alaska10-19 13:55
  15. 2.1Denali National Park, Alaska10-21 00:14
  16. 2.1Petersville, Alaska10-24 17:14
  17. 2.1Petersville, Alaska11-03 01:56
  18. 2.1Petersville, Alaska11-05 16:12
  19. 2.1Denali National Park, Alaska11-08 08:11
  20. 2.0Petersville, Alaska11-02 11:07
  21. 2.0Petersville, Alaska11-05 00:50
  22. 1.9143 km NNW of Meadow Lakes, Alaska, United States10-19 21:48
  23. 1.9144 km NW of Meadow Lakes, Alaska, United States10-21 21:36
  24. 1.9Petersville, Alaska10-26 09:34
  25. 1.9Petersville, Alaska10-26 13:58

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 aka2026uqmavp. First recorded here 18 Oct 2026, 10:52:37 UTC. Solutions: USGS · AK (usgs:aka2026uqmavp). Cite as: SeismoAtlas, “M1.9 earthquake – Petersville, Alaska”, https://seismoatlas.com/earthquake/aka2026uqmavp-m1-9-earthquake-petersville-alaska, data from USGS.

JSON: /api/v1/events/aka2026uqmavp. SeismoAtlas is not an official warning service.