QuakeIndex

explosion · reviewed by a seismologist

M 1.8ml

4 km NW of West Longview, Washington

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

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Cowlitz County 28 kmColumbia County 28 kmWahkiakum County 32 kmClatsop County 55 kmClark County 64 kmLewis County 66 kmPacific County 70 kmWashington County 72 kmThurston 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
2 reports · strongest reported intensity III
Nearest
Cowlitz County, 28 km E
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2124 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage. 2 people have 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 5.7 790,000× 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 46.1962, -123.0370. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Cowlitz County, WA 28 km (17 mi) W of here earthquakes near Cowlitz County
Columbia County, OR 28 km (18 mi) N of here earthquakes near Columbia County
Wahkiakum County, WA 32 km (20 mi) ESE of here earthquakes near Wahkiakum County
Clatsop County, OR 55 km (34 mi) ENE of here earthquakes near Clatsop County
Clark County, WA 64 km (39 mi) NW of here earthquakes near Clark County
Lewis County, WA 66 km (41 mi) SW of here earthquakes near Lewis County

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

Aftershocks so far

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

  1. 1.7 10 km NE of Castle Rock, Washington
  2. 2.1 9 km ENE of Kalama, Washington
  3. 1.6 1 km W of Winlock, Washington
  4. 1.8 6 km NW of Winlock, Washington
  5. 1.8 10 km NE of Castle Rock, Washington
  6. 1.6 9 km NE of Castle Rock, Washington
  7. 1.6 2 km WNW of Saint Helens, Oregon
  8. 2.1 1 km WNW of Deer Island, Oregon
  9. 1.7 1 km SW of Columbia City, Oregon
  10. 1.9 3 km WNW of Winlock, Washington
  11. 1.8 2 km E of Saint Helens, Oregon
  12. 1.5 7 km ENE of Prescott, Oregon
  13. 2.1 11 km ENE of Prescott, Oregon
  14. 1.9 4 km SW of Cathlamet, Washington
  15. 1.5 3 km W of Winlock, 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.