QuakeIndex

explosion · reviewed by a seismologist

M 1.8ml

5 km NNW of Winlock, Washington

· -0.4 km deep · released about 17 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Cowlitz County 43 kmWahkiakum County 44 kmLewis County 45 kmThurston County 46 kmPacific County 63 kmColumbia County 66 kmClatsop County 80 kmPierce County 84 kmGrays Harbor County 92 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
-0.4 km below the surface
Felt
no reports yet
Nearest
Cowlitz County, 43 km SSE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1395 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 17 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 5.8 900,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 640,000× the energy of this one
  3. Around the size people start to feel M 3.0 57× the energy of this one
  4. This earthquake M 1.8 about 17 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 46.5340, -122.9618. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Cowlitz County, WA 43 km (27 mi) NNW of here earthquakes near Cowlitz County
Wahkiakum County, WA 44 km (28 mi) NE of here earthquakes near Wahkiakum County
Lewis County, WA 45 km (28 mi) W of here earthquakes near Lewis County
Thurston County, WA 46 km (28 mi) SSW of here earthquakes near Thurston County
Pacific County, WA 63 km (39 mi) E of here earthquakes near Pacific County
Columbia County, OR 66 km (41 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

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

  1. 1.9 14 km WSW of Oakville, Washington
  2. 1.6 1 km N of Oakville, Washington
  3. 1.6 20 km NE of Onalaska, Washington
  4. 1.6 5 km SW of Napavine, Washington
  5. 2.0 19 km SE of Toledo, Washington
  6. 1.7 6 km WSW of Napavine, Washington
  7. 1.7 10 km SSE of Toledo, Washington
  8. 1.7 3 km S of Pe Ell, Washington
  9. 2.0 1 km N of Longview, Washington
  10. 2.1 20 km SSE of Mossyrock, Washington
  11. 1.5 5 km WSW of Napavine, Washington
  12. 2.2 5 km SW of Napavine, Washington
  13. 1.6 6 km ENE of Mossyrock, Washington
  14. 1.5 17 km NNW of Pe Ell, Washington
  15. 1.8 7 km SSE of McKenna, 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.