QuakeIndex

explosion · reviewed by a seismologist

M 1.8ml

9 km W of Napavine, Washington

· -0.3 km deep · released about 14 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Thurston County 42 kmWahkiakum County 44 kmLewis County 50 kmCowlitz County 51 kmPacific County 58 kmColumbia County 72 kmClatsop County 81 kmGrays Harbor County 84 kmPierce County 84 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
-0.3 km below the surface
Felt
1 report · strongest reported intensity III
Nearest
Thurston County, 42 km NNE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 418 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage. 1 person has reported feeling it to USGS.

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 46.5855, -123.0305. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Thurston County, WA 42 km (26 mi) SSW of here earthquakes near Thurston County
Wahkiakum County, WA 44 km (27 mi) NE of here earthquakes near Wahkiakum County
Lewis County, WA 50 km (31 mi) W of here earthquakes near Lewis County
Cowlitz County, WA 51 km (32 mi) NNW of here earthquakes near Cowlitz County
Pacific County, WA 58 km (36 mi) E of here earthquakes near Pacific County
Columbia County, OR 72 km (45 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

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

  1. 1.3 20 km E of Castle Rock, Washington
  2. 1.0 6 km SE of McCleary, Washington
  3. 1.2 12 km S of Rainier, Washington
  4. 0.7 21 km ESE of Castle Rock, Washington
  5. 0.9 20 km E of Castle Rock, Washington
  6. 0.6 21 km ESE of Castle Rock, Washington
  7. 1.7 20 km E of Castle Rock, Washington
  8. 1.7 6 km W of Mossyrock, Washington
  9. 3.8 20 km E of Castle Rock, Washington
  10. 1.6 6 km NE of Rochester, Washington
  11. 1.6 20 km E of Castle Rock, Washington
  12. 1.5 11 km ENE of East Cathlamet, Washington
  13. 1.6 9 km S of Mossyrock, Washington
  14. 1.5 6 km NW of Winlock, Washington
  15. 1.7 1 km E of Oakville, 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.