QuakeIndex

explosion · reviewed by a seismologist

M 1.8md

4 km WSW of Yacolt, Washington

· -0.5 km deep · released about 15 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Clark County 10 kmMultnomah County 35 kmCowlitz County 41 kmSkamania County 43 kmColumbia County 49 kmWashington County 60 kmHood River County 73 kmClackamas County 80 kmLewis County 81 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 (md)
Depth
-0.5 km below the surface
Felt
no reports yet
Nearest
Clark County, 10 km SSW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 25 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 15 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 1,000,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 710,000× the energy of this one
  3. Around the size people start to feel M 3.0 63× the energy of this one
  4. This earthquake M 1.8 about 15 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 45.8570, -122.4583. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Clark County, WA 10 km (6 mi) NNE of here earthquakes near Clark County
Multnomah County, OR 35 km (21 mi) N of here earthquakes near Multnomah County
Cowlitz County, WA 41 km (26 mi) SSE of here earthquakes near Cowlitz County
Skamania County, WA 43 km (27 mi) WSW of here earthquakes near Skamania County
Columbia County, OR 49 km (31 mi) E of here earthquakes near Columbia County
Washington County, OR 60 km (37 mi) NE of here earthquakes near Washington County

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

Aftershocks so far

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

  1. 1.3 20 km E of Castle Rock, Washington
  2. 0.2 37 km NNE of Amboy, Washington
  3. 0.5 38 km NNE of Amboy, Washington
  4. 1.5 5 km NNW of Venersborg, Washington
  5. 0.6 38 km NNE of Amboy, Washington
  6. 1.7 18 km N of Amboy, Washington
  7. 0.3 32 km NE of Amboy, Washington
  8. 0.7 21 km ESE of Castle Rock, Washington
  9. 1.3 38 km NNE of Amboy, Washington
  10. 1.0 32 km NNE of Amboy, Washington
  11. 0.9 20 km E of Castle Rock, Washington
  12. 0.6 21 km ESE of Castle Rock, Washington
  13. 0.0 38 km NE of Amboy, Washington
  14. 1.5 37 km NNE of Amboy, Washington
  15. 1.5 31 km E of Kelso, 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.