M1.6 earthquake 26 km SSE of Yelm, Washington, United States
A magnitude 1.6 earthquake struck 26 km SSE of Yelm, Washington, United States at 09:34 local time (16:34 UTC) on 18 Oct 2026, at a depth of 25 km, according to USGS.
revised from M2.2
Data: USGS · updated 2026-10-18 16:42 UTC · reviewed
- Magnitude
- 1.6micro
local magnitude (Richter) (ml)
revised from 2.2 - Depth
- 25.1 km
- Status
- Reviewed
- Origin time
- 2026-10-18 16:34:55 UTC
- Local: 18 Oct 2026, 09:34:55 (America/Los Angeles)
- Epicentre
- 46.745° N, 122.431° 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
| Place | Distance | Est. shaking |
|---|---|---|
| YelmWashington, United States · pop. 8,434 | 26 km | INot felt |
| Elk PlainWashington, United States · pop. 14,205 | 34 km | INot felt |
| GrahamWashington, United States · pop. 23,491 | 36 km | INot felt |
| SpanawayWashington, United States · pop. 27,227 | 39 km | INot felt |
| LaceyWashington, United States · pop. 46,409 | 43 km | INot felt |
| South HillWashington, United States · pop. 52,431 | 46 km | INot felt |
| SeattleWashington, United States · pop. 780,995 | 96 km | INot felt |
| PortlandOregon, United States · pop. 652,503 | 138 km | INot 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 · UW, which has been reviewed by an analyst.
| Agency | Magnitude | Depth | Epicentre | Time offset | Status |
|---|---|---|---|---|---|
| USGS · UWheadlinePacific Northwest Seismic Network via U.S. Geological Survey | 1.6 mlwas 2.2 | 25.1 km | 46.75° N, 122.43° 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 4 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 25 km this was a shallow earthquake, which is felt more strongly at the surface than a deeper one of the same size.
M1.6 releases about 9.1× the energy of M1.0, and its waves are about 4.4× taller on a seismogram. Energy: 4 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
14 later earthquakes within 30 km; the largest was M1.8 5 days ago. 2 in the 7 days before. Aftershock rates usually fall off roughly in proportion to 1/time.
Mainshock M1.6
14 later earthquakes nearby. Aftershock rates typically fall off roughly as 1/time (Omori's law).
| Time after mainshock (hours) | Magnitude | Depth (km) |
|---|---|---|
| 147.35 | 0.6 | 6 |
| 249.64 | 0.8 | 6 |
| 288.78 | 0.8 | 3 |
| 288.96 | 1.6 | 4 |
| 293.19 | 1.3 | 0 |
| 412.67 | 0.6 | 5 |
| 429.41 | 0.7 | 4 |
| 483.38 | 1.8 | 6 |
| 488.55 | 1.6 | 6 |
| 510.78 | 1.0 | 22 |
| 536.32 | 0.7 | 4 |
| 539.25 | 0.8 | 6 |
| 577.78 | 0.7 | 8 |
| 596.63 | 1.0 | 4 |
- 1.840 km SSE of Graham, Washington, United States11-07 19:57
- 1.639 km SSE of Graham, Washington, United States10-30 17:32
- 1.639 km SSE of Graham, Washington, United States11-08 01:07
- 1.310 km SSE of Graham, Washington, United States10-30 21:46
- 1.040 km SSE of Graham, Washington, United States11-12 13:12
- 1.039 km ESE of Chehalis, Washington, United States11-08 23:21
- 0.840 km SSE of Graham, Washington, United States11-10 03:50
- 0.839 km SSE of Graham, Washington, United States10-30 17:21
- 0.840 km SSE of Graham, Washington, United States10-29 02:13
- 0.740 km SSE of Graham, Washington, United States11-05 13:59
- 0.739 km SSE of Graham, Washington, United States11-10 00:54
- 0.743 km ESE of Chehalis, Washington, United States11-11 18:21
- 0.639 km SSE of Graham, Washington, United States10-24 19:55
- 0.640 km SSE of Graham, Washington, United States11-04 21:15
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 uw714121692. First recorded here 18 Oct 2026, 16:38:52 UTC. Solutions: USGS · UW (usgs:uw714121692). Cite as: SeismoAtlas, “M1.6 earthquake 26 km SSE of Yelm, Washington, United States”, https://seismoatlas.com/earthquake/uw714121692-m1-6-earthquake-26-km-sse-of-yelm-washington-united-states, data from USGS.
JSON: /api/v1/events/uw714121692. SeismoAtlas is not an official warning service.