QuakeIndex

explosion · reviewed by a seismologist

M 1.8ml

10 km NE of Castle Rock, Washington

· -0.6 km deep · released about 13 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Cowlitz County 19 kmLewis County 42 kmWahkiakum County 48 kmColumbia County 49 kmThurston County 66 kmClark County 68 kmSkamania County 75 kmClatsop County 78 kmPacific County 78 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
-0.6 km below the surface
Felt
no reports yet
Nearest
Cowlitz County, 19 km SSE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2805 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 13 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 5.7 810,000× the energy of this one
  3. Around the size people start to feel M 3.0 72× the energy of this one
  4. This earthquake M 1.8 about 13 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 46.3443, -122.8073. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Cowlitz County, WA 19 km (12 mi) NNW of here earthquakes near Cowlitz County
Lewis County, WA 42 km (26 mi) SW of here earthquakes near Lewis County
Wahkiakum County, WA 48 km (30 mi) E of here earthquakes near Wahkiakum County
Columbia County, OR 49 km (31 mi) NNE of here earthquakes near Columbia County
Thurston County, WA 66 km (41 mi) S of here earthquakes near Thurston County
Clark County, WA 68 km (42 mi) NNW of here earthquakes near Clark 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. 1.6 14 km SE of Mossyrock, Washington
  2. 1.7 20 km N of Amboy, Washington
  3. 1.5 28 km NNW of Amboy, Washington
  4. 1.8 9 km NW of West Longview, Washington
  5. 1.8 4 km NW of West Longview, Washington
  6. 2.9 1 km WSW of Onalaska, Washington
  7. 2.1 10 km WSW of Chehalis, Washington
  8. 1.7 4 km SE of Kalama, Washington
  9. 1.6 2 km WNW of Kalama, Washington
  10. 2.5 16 km NE of Kalama, Washington
  11. 1.8 2 km NE of Deer Island, Oregon
  12. 1.5 3 km ENE of East Cathlamet, Washington
  13. 3.1 3 km NNE of Onalaska, Washington
  14. 1.6 14 km SSW of Morton, Washington
  15. 1.6 21 km SSE of Mossyrock, 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

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