QuakeIndex

explosion · reviewed by a seismologist

M 1.8ml

1 km S of Kapowsin, Washington

· -0.4 km deep · released about 14 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Pierce County 11 kmLewis County 45 kmThurston County 46 kmKing County 65 kmKitsap County 81 kmMason County 83 kmCowlitz County 93 kmSkamania County 107 kmWahkiakum County 118 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
Pierce County, 11 km NNE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 510 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 5.7 790,000× the energy of this one
  3. Around the size people start to feel M 3.0 70× 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 46.9700, -122.2242. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Pierce County, WA 11 km (7 mi) SSW of here earthquakes near Pierce County
Lewis County, WA 45 km (28 mi) NNE of here earthquakes near Lewis County
Thurston County, WA 46 km (29 mi) E of here earthquakes near Thurston County
King County, WA 65 km (40 mi) SSW of here earthquakes near King County
Kitsap County, WA 81 km (50 mi) SSE of here earthquakes near Kitsap County
Mason County, WA 83 km (52 mi) ESE of here earthquakes near Mason County

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

Aftershocks so far

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

  1. 2.2 2 km SE of Buckley, Washington
  2. 2.5 2 km SE of Buckley, Washington
  3. 1.8 2 km ESE of Buckley, Washington
  4. 1.7 13 km N of Onalaska, Washington
  5. 2.2 24 km ENE of Ashford, Washington
  6. 1.5 1 km WSW of Kapowsin, Washington
  7. 2.8 3 km NE of Mineral, Washington
  8. 1.9 6 km NE of Mossyrock, Washington
  9. 1.8 17 km WSW of Alder, Washington
  10. 2.2 4 km ESE of Enumclaw, Washington
  11. 1.6 1 km SSE of Kapowsin, Washington
  12. 1.5 0 km SSW of Carbonado, Washington
  13. 1.7 8 km S of Mineral, Washington
  14. 1.9 1 km NNW of Maple Valley, Washington
  15. 1.6 5 km SE of Enumclaw, 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.