QuakeIndex

Earthquake · reviewed by a seismologist

M 2.9ml

4 km S of Monroe, Washington

· 26 km deep · released about 650 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Snohomish County 31 kmKing County 37 kmKitsap County 55 kmIsland County 65 kmSkagit County 76 kmPierce County 86 kmChelan County 101 kmMason County 104 kmSan Juan County 114 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
26 km below the surface
Felt
182 reports · strongest reported intensity IV
Measured shaking
intensity III (ShakeMap)
Nearest
Snohomish County, 31 km NNE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1939 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage. 182 people have reported feeling it to USGS.

How big was it?

This earthquake released about 650 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 23,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 16,000× 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 650 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 47.8132, -121.9667. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Snohomish County, WA 31 km (19 mi) SSW of here earthquakes near Snohomish County
King County, WA 37 km (23 mi) NNW of here earthquakes near King County
Kitsap County, WA 55 km (34 mi) ENE of here earthquakes near Kitsap County
Island County, WA 65 km (40 mi) SE of here earthquakes near Island County
Skagit County, WA 76 km (48 mi) S of here earthquakes near Skagit County
Pierce County, WA 86 km (53 mi) N of here earthquakes near Pierce 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. 1.8 1 km SW of Snoqualmie, Washington
  2. 1.7 2 km E of Lake Stevens, Washington
  3. 1.6 1 km ESE of Issaquah, Washington
  4. 1.6 2 km ENE of Granite Falls, Washington
  5. 1.5 1 km ENE of Bainbridge Island, Washington
  6. 1.9 2 km NNE of Esperance, Washington
  7. 2.3 0 km SSW of Boulevard Park, Washington
  8. 2.2 1 km NNE of Carnation, Washington
  9. 1.5 1 km N of Boulevard Park, Washington
  10. 1.7 3 km ENE of Granite Falls, Washington
  11. 1.7 6 km ENE of Lake Roesiger, Washington
  12. 1.7 1 km NNE of Woods Creek, Washington
  13. 1.6 0 km N of Boulevard Park, Washington
  14. 2.8 0 km S of Boulevard Park, Washington
  15. 2.1 0 km SSW of Boulevard Park, 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 340 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.