QuakeIndex

explosion · reviewed by a seismologist

M 1.8ml

1 km E of Granite Falls, Washington

· -0.4 km deep · released about 15 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Snohomish County 14 kmSkagit County 46 kmIsland County 54 kmKing County 67 kmKitsap County 72 kmWhatcom County 85 kmSan Juan County 98 kmChelan County 102 kmPierce County 116 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
-0.4 km below the surface
Felt
2 reports · strongest reported intensity II
Nearest
Snohomish County, 14 km ESE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 569 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 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 48.0847, -121.9463. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Snohomish County, WA 14 km (9 mi) WNW of here earthquakes near Snohomish County
Skagit County, WA 46 km (29 mi) SSW of here earthquakes near Skagit County
Island County, WA 54 km (34 mi) E of here earthquakes near Island County
King County, WA 67 km (41 mi) N of here earthquakes near King County
Kitsap County, WA 72 km (45 mi) NE of here earthquakes near Kitsap County
Whatcom County, WA 85 km (53 mi) S of here earthquakes near Whatcom County

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

Aftershocks so far

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

  1. 1.5 4 km N of Woods Creek, Washington
  2. 2.3 4 km SW of Darrington, Washington
  3. 1.5 1 km NE of Ames Lake, Washington
  4. 1.7 3 km ENE of Granite Falls, Washington
  5. 1.9 3 km SSE of Sultan, Washington
  6. 1.7 1 km N of Kingsgate, Washington
  7. 1.7 4 km ENE of Granite Falls, Washington
  8. 1.6 0 km S of Big Lake, Washington
  9. 1.9 5 km NNW of North Sultan, Washington
  10. 1.7 5 km ENE of Lake Roesiger, Washington
  11. 1.7 3 km WSW of Lake Cavanaugh, Washington
  12. 1.5 5 km NNW of North Sultan, Washington
  13. 1.7 3 km E of Granite Falls, Washington
  14. 1.6 6 km SSE of Oso, Washington
  15. 1.9 4 km WSW of Lake Marcel-Stillwater, 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.

For this area

The largest earthquake within 50 km in our catalogue was M 4.6 on 2019-07-12 — it released about 15,000 times the energy of this one.

From the QuakeIndex catalogue, built from the USGS FDSN event service.

On USGS

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