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M4.2 earthquake 12 km W of Maplewood, Washington, United States

A magnitude 4.2 earthquake struck 12 km W of Maplewood, Washington, United States at 14:05 local time (21:05 UTC) on 29 Sept 2026, at a depth of 28 km, according to USGS.

revised from M4.0 · 9571 reports to USGS “Did You Feel It?”

Data: USGS · updated 2026-10-26 20:54 UTC · reviewed

Magnitude
4.2light
local magnitude (Richter) (ml)
revised from 4.0
Depth
27.9 km
Status
Reviewed
Origin time
2026-09-29 21:05:56 UTC
Local: 29 Sept 2026, 14:05:56 (America/Los Angeles)
Epicentre
47.400° N, 122.722° 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
MaplewoodWashington, United States · pop. 5,13812 kmIIIWeak
Gig HarborWashington, United States · pop. 8,75313 kmIIIWeak
BremertonWashington, United States · pop. 39,52020 kmIIIWeak
University PlaceWashington, United States · pop. 32,84222 kmIIIWeak
TacomaWashington, United States · pop. 222,90627 kmIIIWeak
BurienWashington, United States · pop. 50,46729 kmIIIWeak
SeattleWashington, United States · pop. 780,99538 kmIIIWeak
VictoriaBritish Columbia, Canada · pop. 289,625125 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. Likely felt out to about 43 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 · UW, which has been reviewed by an analyst.

AgencyMagnitudeDepthEpicentreTime offsetStatus
USGS · UWheadlinePacific Northwest Seismic Network via U.S. Geological Survey4.2 mlwas 4.227.9 km47.40° N, 122.72° W–Reviewed · 5 revisions

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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 26 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.

M4.2 releases about 28× the energy of M3.2, and its waves are about 9.1× taller on a seismogram. Energy: 26 t of TNT vs 951 kg of TNT.

Each square is the energy of one M3.2. Energy from log₁₀E = 1.5M + 4.8.

Aftershocks and nearby activity

22 later earthquakes within 30 km; the largest was M2.0 38 days ago. 3 in the 7 days before. Aftershock rates usually fall off roughly in proportion to 1/time.

Aftershocks

Mainshock M4.2

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

Aftershocks
Time after mainshock (hours)MagnitudeDepth (km)
1.971.325
6.181.932
17.421.627
41.211.327
55.381.02
144.640.619
155.511.825
161.232.023
162.240.922
171.102.024
172.221.124
272.930.714
275.130.813
277.721.113
313.690.923
358.750.713
360.001.930
385.740.619
496.161.328
670.830.4-1
674.871.518
686.821.022
  1. 2.0Near Tracyton, Washington, United States10-07 00:11
  2. 2.0Near Tracyton, Washington, United States10-06 14:19
  3. 1.912 km W of Maplewood, Washington, United States09-30 03:16
  4. 1.917 km WSW of East Port Orchard, Washington, United States10-14 21:06
  5. 1.8Near Tracyton, Washington, United States10-06 08:36
  6. 1.611 km W of Maplewood, Washington, United States09-30 14:30
  7. 1.513 km W of Port Orchard, Washington, United States10-27 23:58
  8. 1.37 km SE of Manchester, Washington, United States10-20 13:15
  9. 1.310 km W of Maplewood, Washington, United States09-29 23:04
  10. 1.311 km W of Maplewood, Washington, United States10-01 14:18
  11. 1.17 km SW of Silverdale, Washington, United States10-11 10:48
  12. 1.13 km E of Tracyton, Washington, United States10-07 01:19
  13. 1.07 km WNW of Federal Way, Washington, United States10-28 11:55
  14. 1.03 km SE of East Port Orchard, Washington, United States10-02 04:28
  15. 0.99 km SW of Artondale, Washington, United States10-12 22:47
  16. 0.94 km E of Tracyton, Washington, United States10-06 15:20
  17. 0.85 km WSW of Tracyton, Washington, United States10-11 08:13
  18. 0.76 km WSW of Tracyton, Washington, United States10-11 06:01
  19. 0.74 km W of Tracyton, Washington, United States10-14 19:50
  20. 0.64 km SSW of Bainbridge Island, Washington, United States10-15 22:50
  21. 0.622 km WSW of Silverdale, Washington, United States10-05 21:44
  22. 0.424 km NNE of Shelton, Washington, United States10-27 19:56

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 9571 reports: add yours at USGS.

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Event id ew1790715960. First recorded here 29 Sept 2026, 21:08:07 UTC. Solutions: USGS · UW (usgs:uw714111952). Cite as: SeismoAtlas, “M4.2 earthquake 12 km W of Maplewood, Washington, United States”, https://seismoatlas.com/earthquake/ew1790715960-m4-2-earthquake-12-km-w-of-maplewood-washington-united-states, data from USGS.

JSON: /api/v1/events/ew1790715960. SeismoAtlas is not an official warning service.