QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8ml

17 km WSW of Alder, Washington

· 19 km deep · released about 15 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Lewis County 19 kmThurston County 34 kmPierce County 44 kmCowlitz County 61 kmMason County 86 kmWahkiakum County 86 kmSkamania County 89 kmKing County 98 kmColumbia County 99 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
19 km below the surface
Felt
no reports yet
Nearest
Lewis County, 19 km SSE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 384 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

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 5.7 730,000× the energy of this one
  3. Around the size people start to feel M 3.0 65× 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 46.7312, -122.4918. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Lewis County, WA 19 km (12 mi) NNW of here earthquakes near Lewis County
Thurston County, WA 34 km (21 mi) SE of here earthquakes near Thurston County
Pierce County, WA 44 km (27 mi) SW of here earthquakes near Pierce County
Cowlitz County, WA 61 km (38 mi) NNE of here earthquakes near Cowlitz County
Mason County, WA 86 km (53 mi) SE of here earthquakes near Mason County
Wahkiakum County, WA 86 km (54 mi) NE of here earthquakes near Wahkiakum County

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

Aftershocks so far

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

  1. 1.5 5 km SSW of Morton, Washington
  2. 1.7 6 km W of Mossyrock, Washington
  3. 1.8 3 km SW of Kapowsin, Washington
  4. 1.5 0 km NNW of Eatonville, Washington
  5. 1.7 1 km SW of Kapowsin, Washington
  6. 1.6 9 km S of Mossyrock, Washington
  7. 1.5 6 km NW of Winlock, Washington
  8. 1.6 1 km SSE of Kapowsin, Washington
  9. 1.5 11 km NNE of Ashford, Washington
  10. 1.6 5 km W of Tumwater, Washington
  11. 2.0 3 km NNE of Winlock, Washington
  12. 1.5 2 km SSE of Kapowsin, Washington
  13. 2.0 5 km WSW of Crocker, Washington
  14. 1.8 4 km NW of Winlock, Washington
  15. 1.6 12 km SW 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

QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.