QuakeIndex

Earthquake · reviewed by a seismologist

M 3.1ml

6 km SSE of Black Diamond, Washington

· 22 km deep · released about 1,200 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Pierce County 27 kmKing County 28 kmKitsap County 66 kmThurston County 74 kmLewis County 82 kmSnohomish County 90 kmMason County 91 kmKittitas County 99 kmIsland County 113 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 3.1 (ml)
Depth
22 km below the surface
Felt
259 reports · strongest reported intensity IV
Measured shaking
intensity III (ShakeMap)
Nearest
Pierce County, 27 km SSW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1447 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage. 259 people have reported feeling it to USGS.

How big was it?

This earthquake released about 1,200 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.1 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 290,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 13,000× the energy of this one
  3. Magna, Utah 2020 M 5.7 9,100× the energy of this one
  4. This earthquake M 3.1 about 1,200 lb of TNT
  5. Around the size people start to feel M 3.0 this one released 1.2× more

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 47.2587, -121.9718. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Pierce County, WA 27 km (17 mi) NNE of here earthquakes near Pierce County
King County, WA 28 km (17 mi) SSW of here earthquakes near King County
Kitsap County, WA 66 km (41 mi) SE of here earthquakes near Kitsap County
Thurston County, WA 74 km (46 mi) ENE of here earthquakes near Thurston County
Lewis County, WA 82 km (51 mi) NNE of here earthquakes near Lewis County
Snohomish County, WA 90 km (56 mi) S of here earthquakes near Snohomish County

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

Aftershocks so far

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

  1. 1.9 3 km NNE of White Center, Washington
  2. 2.4 21 km NE of Ashford, Washington
  3. 1.7 6 km ESE of Tanner, Washington
  4. 1.5 0 km WNW of Pacific, Washington
  5. 1.8 1 km ESE of Union Hill-Novelty Hill, Washington
  6. 1.6 0 km NNE of Lake Marcel-Stillwater, Washington
  7. 1.6 Washington
  8. 1.6 22 km ENE of Ashford, Washington
  9. 1.6 0 km N of Lake Marcel-Stillwater, Washington
  10. 1.6 11 km W of Greenwater, Washington
  11. 2.0 3 km N of White Center, Washington
  12. 2.3 3 km W of Hobart, Washington
  13. 2.8 2 km SW of Wilderness Rim, Washington
  14. 1.7 8 km ENE of Snoqualmie, Washington
  15. 1.8 1 km ESE of Kapowsin, 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.