QuakeIndex

Earthquake · reviewed by a seismologist

M 2.9ml

3 km W of Mount Vernon, Washington

· 8.7 km deep · released about 630 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Island County 35 kmSkagit County 43 kmSan Juan County 54 kmSnohomish County 61 kmWhatcom County 62 kmKitsap County 88 kmJefferson County 108 kmKing County 111 kmClallam 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 2.9 (ml)
Depth
8.7 km below the surface
Felt
67 reports · strongest reported intensity III
Measured shaking
intensity III (ShakeMap)
Nearest
Island County, 35 km SW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 113 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage. 67 people have reported feeling it to USGS.

How big was it?

This earthquake released about 630 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.9 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 24,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 17,000× the energy of this one
  3. Around the size people start to feel M 3.0 1.5× the energy of this one
  4. This earthquake M 2.9 about 630 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 48.4145, -122.3868. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Island County, WA 35 km (22 mi) NE of here earthquakes near Island County
Skagit County, WA 43 km (27 mi) WSW of here earthquakes near Skagit County
San Juan County, WA 54 km (33 mi) E of here earthquakes near San Juan County
Snohomish County, WA 61 km (38 mi) NW of here earthquakes near Snohomish County
Whatcom County, WA 62 km (39 mi) SW of here earthquakes near Whatcom County
Kitsap County, WA 88 km (55 mi) NNE of here earthquakes near Kitsap County

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

Aftershocks so far

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

  1. 2.9 2 km ESE of Oak Harbor, Washington
  2. 2.1 5 km N of Anacortes, Washington
  3. 2.4 4 km SSW of Anacortes, Washington
  4. 2.0 5 km N of Anacortes, Washington
  5. 2.7 5 km N of Anacortes, Washington
  6. 1.5 2 km WNW of Arlington, Washington
  7. 1.8 4 km SSW of Anacortes, Washington
  8. 1.5 2 km ENE of Granite Falls, Washington
  9. 2.1 15 km ESE of Acme, Washington
  10. 1.6 2 km W of Port Townsend, Washington
  11. 1.6 3 km SE of Alger, Washington
  12. 1.5 4 km NW of Tulalip Bay, Washington
  13. 1.6 4 km SSE of Mount Vernon, Washington
  14. 2.7 12 km WSW of Anacortes, Washington
  15. 1.7 3 km E of Granite Falls, 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 270 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.