QuakeIndex

explosion · reviewed by a seismologist

M 1.6ml

4 km NNE of Oso, Washington

· -0.8 km deep · released about 6.6 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Skagit County 21 kmSnohomish County 30 kmWhatcom County 59 kmIsland County 59 kmSan Juan County 91 kmKing County 91 kmKitsap County 93 kmChelan County 108 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 1.6 (ml)
Depth
-0.8 km below the surface
Felt
no reports yet
Nearest
Skagit County, 21 km NNE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1199 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 6.6 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.6 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 2,300,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,600,000× the energy of this one
  3. Around the size people start to feel M 3.0 140× the energy of this one
  4. This earthquake M 1.6 about 6.6 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 48.3117, -121.9025. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Skagit County, WA 21 km (13 mi) SSW of here earthquakes near Skagit County
Snohomish County, WA 30 km (19 mi) NNW of here earthquakes near Snohomish County
Whatcom County, WA 59 km (37 mi) S of here earthquakes near Whatcom County
Island County, WA 59 km (37 mi) ENE of here earthquakes near Island County
San Juan County, WA 91 km (57 mi) ESE of here earthquakes near San Juan County
King County, WA 91 km (57 mi) N of here earthquakes near King 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. 1.6 4 km WSW of Darrington, Washington
  2. 1.7 2 km ENE of Granite Falls, Washington
  3. 1.7 5 km W of Weallup Lake, Washington
  4. 2.7 8 km NNW of Swede Heaven, Washington
  5. 1.9 5 km WSW of Stanwood, Washington
  6. 1.6 15 km NNE of Lyman, Washington
  7. 2.3 1 km SW of West Lake Stevens, Washington
  8. 1.6 2 km NE of Granite Falls, Washington
  9. 1.8 7 km ENE of Lake Roesiger, Washington
  10. 1.7 2 km N of Bryant, Washington
  11. 1.9 3 km ESE of Lake Roesiger, Washington
  12. 2.2 3 km SW of Roosevelt, Washington
  13. 1.7 2 km E of Granite Falls, Washington
  14. 1.9 3 km W of Mount Vernon, Washington
  15. 2.0 10 km NNE of Hamilton, 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 34,000 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.