QuakeIndex

explosion · reviewed by a seismologist

M 1.8ml

4 km SSW of Anacortes, Washington

· -0.1 km deep · released about 14 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N San Juan County 35 kmIsland County 35 kmSkagit County 61 kmWhatcom County 72 kmSnohomish County 80 kmKitsap County 93 kmJefferson County 99 kmClallam County 101 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
-0.1 km below the surface
Felt
no reports yet
Nearest
San Juan County, 35 km W
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 159 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 14 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 1,100,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 790,000× the energy of this one
  3. Around the size people start to feel M 3.0 70× the energy of this one
  4. This earthquake M 1.8 about 14 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 48.4722, -122.6383. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
San Juan County, WA 35 km (21 mi) E of here earthquakes near San Juan County
Island County, WA 35 km (22 mi) N of here earthquakes near Island County
Skagit County, WA 61 km (38 mi) W of here earthquakes near Skagit County
Whatcom County, WA 72 km (45 mi) SW of here earthquakes near Whatcom County
Snohomish County, WA 80 km (49 mi) NW of here earthquakes near Snohomish County
Kitsap County, WA 93 km (58 mi) N of here earthquakes near Kitsap County

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

Aftershocks so far

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

  1. 2.6 2 km ENE of Mount Vernon, Washington
  2. 1.6 2 km ESE of Oak Harbor, Washington
  3. 1.6 2 km E of Oak Harbor, Washington
  4. 2.1 3 km E of Oak Harbor, Washington
  5. 1.7 3 km E of Oak Harbor, Washington
  6. 2.1 3 km ESE of Oak Harbor, Washington
  7. 1.6 5 km N of Anacortes, Washington
  8. 2.1 3 km E of Oak Harbor, Washington
  9. 1.6 8 km WNW of Orcas, Washington
  10. 1.7 8 km WNW of Orcas, Washington
  11. 1.8 8 km WNW of Orcas, Washington
  12. 1.9 4 km E of Port Townsend, Washington
  13. 1.8 5 km E of Acme, Washington
  14. 1.8 2 km ESE of Oak Harbor, Washington
  15. 1.9 3 km E of Oak Harbor, 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 4.5 on 2025-03-03 — it released about 12,000 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.