QuakeIndex

explosion · reviewed by a seismologist

M 1.8ml

4 km NW of Winlock, Washington

· -0.2 km deep · released about 14 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Cowlitz County 42 kmWahkiakum County 43 kmLewis County 46 kmThurston County 48 kmPacific County 62 kmColumbia County 65 kmClatsop County 79 kmPierce County 86 kmClark County 91 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
Magnitude
M 1.8 (ml)
Depth
-0.2 km below the surface
Felt
no reports yet
Nearest
Cowlitz County, 42 km SSE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 913 days ago

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

USGS catalogues this as explosion, not an earthquake.

How big was it?

This earthquake released about 14 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.8 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 1,100,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 760,000× the energy of this one
  3. Around the size people start to feel M 3.0 68× the energy of this one
  4. This earthquake M 1.8 about 14 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.

Where

Epicentre 46.5175, -122.9735. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Cowlitz County, WA 42 km (26 mi) NNW of here earthquakes near Cowlitz County
Wahkiakum County, WA 43 km (26 mi) NE of here earthquakes near Wahkiakum County
Lewis County, WA 46 km (29 mi) W of here earthquakes near Lewis County
Thurston County, WA 48 km (30 mi) SSW of here earthquakes near Thurston County
Pacific County, WA 62 km (39 mi) E of here earthquakes near Pacific County
Columbia County, OR 65 km (40 mi) N of here earthquakes near Columbia County

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

Aftershocks so far

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

  1. 1.7 2 km N of Oakville, Washington
  2. 1.7 13 km N of Onalaska, Washington
  3. 1.7 18 km E of West Side Highway, Washington
  4. 1.6 3 km W of Winlock, Washington
  5. 1.9 6 km NE of Mossyrock, Washington
  6. 1.9 4 km WSW of Winlock, Washington
  7. 1.8 17 km WSW of Alder, Washington
  8. 2.2 3 km NNE of Grand Mound, Washington
  9. 1.5 17 km NNW of Pe Ell, Washington
  10. 1.8 9 km W of Napavine, Washington
  11. 1.6 12 km WSW of Alder, Washington
  12. 1.6 3 km ENE of East Cathlamet, Washington
  13. 1.7 5 km SW of Napavine, Washington
  14. 1.6 6 km WSW of Castle Rock, Washington
  15. 1.6 10 km NE of Castle Rock, 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.