QuakeIndex

explosion · reviewed by a seismologist

M 1.6ml

Earthquake near Winlock, WA

No earthquake was likely felt in Winlock in the 24 hours to 9:41 pm PST (05:41 UTC). The last one was M 1.7, 3 km (2 mi) NNE, at 1:54 pm PDT on 2 October 2026, estimated intensity II (weak) in town. Every earthquake near Winlock

No: USGS classifies this as a explosion, not an earthquake. A magnitude 1.6 explosion was recorded 3 km (2 mi) west of Winlock, WA, at 12:48 pm PDT on 6 October 2025 (19:48 UTC), 4.5 km deep.

USGS: 3 km W of Winlock, Washington

12:48 pm PDT, Oct 6, 2025 · · 4.5 km deep · released about 7.6 lb of TNT

10 km30 km60 km120 km N Cowlitz County 40 kmWahkiakum County 41 kmLewis County 47 kmThurston County 50 kmPacific County 62 kmColumbia County 62 kmClatsop County 76 kmPierce County 88 kmClark County 89 km
Distance rings around the epicentre, with the nearest towns at their true direction and later quakes as coloured dots. Not a shaking map — see the USGS ShakeMap for that.
When
12:48 pm PDT on 6 October 2025 ()
Where
3 km (2 mi) west of Winlock, WA · earthquakes near Winlock
Magnitude
M 1.6 (ml)
Depth
4.5 km below the surface
Felt
no reports yet
Nearest
Cowlitz County, 40 km SE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 387 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

At this magnitude and depth, people at rest would likely notice it out to about 10 km (6 mi) from the epicentre. In Winlock, 3 km away, the estimate is intensity II (weak). Estimated from magnitude, depth and distance with the intensity equation USGS Did You Feel It? uses; felt reports, where there are any, are the measurement.

Earthquakes near other towns within 30 km: Napavine, Chehalis, Centralia, Castle Rock, Fords Prairie.

USGS catalogues this as explosion, not an earthquake.

How big was it?

This earthquake released about 7.6 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.6 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 2,000,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,400,000× the energy of this one
  3. Around the size people start to feel M 3.0 130× the energy of this one
  4. This earthquake M 1.6 about 7.6 lb of TNT

Energy from the Gutenberg–Richter relation (log10E = 1.5M + 4.8), rounded to two figures; bar length is magnitude, which is already a logarithm of energy. Magnitudes of past earthquakes from the USGS catalogue.

For this area

No earthquake of M4 or more has been recorded within 50 km since our catalogue begins in 2016.

Before 2016, the USGS record since 1900 lists no earthquake of M5 or more within 50 km.

Since 2016: the QuakeIndex catalogue (US, M1.5+), built from the USGS FDSN event service. Before 2016: USGS ComCat, M5+ from 1900. Distances are between epicentres. This is the record, not a forecast.

Where

Epicentre 46.4947, -122.9805. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Cowlitz County, WA 40 km (25 mi) SE earthquakes near Cowlitz County
Wahkiakum County, WA 41 km (25 mi) WSW earthquakes near Wahkiakum County
Lewis County, WA 47 km (29 mi) ENE earthquakes near Lewis County
Thurston County, WA 50 km (31 mi) NNE earthquakes near Thurston County
Pacific County, WA 62 km (38 mi) W earthquakes near Pacific County
Columbia County, OR 62 km (38 mi) S earthquakes near Columbia County

Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.

Aftershocks so far

55 earthquakes have been recorded within 50 km since this one.

  1. 0.3 22 km ESE of Castle Rock, Washington
  2. 0.6 20 km ESE of Castle Rock, Washington
  3. 0.5 20 km ESE of Castle Rock, Washington
  4. 1.1 10 km SSE of Toledo, Washington
  5. 0.1 22 km ESE of Castle Rock, Washington
  6. 1.6 10 km S of Toledo, Washington
  7. 1.3 6 km NNW of Clatskanie, Oregon
  8. 1.6 20 km E of Castle Rock, Washington
  9. 0.6 21 km ESE of Castle Rock, Washington
  10. 1.8 20 km E of Castle Rock, Washington
  11. 0.8 20 km E of Castle Rock, Washington
  12. 0.6 21 km ESE of Castle Rock, Washington
  13. 1.7 3 km NNE of Winlock, Washington
  14. 1.0 4 km E of Mossyrock, Washington
  15. 0.7 6 km SE of Mossyrock, Washington

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of . QuakeIndex does not forecast aftershocks. When USGS issues an operational aftershock forecast it appears on the USGS event page.

On USGS

QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.