QuakeIndex

Earthquake · reviewed by a seismologist

M 1.7ml

Earthquake near Mount Vernon, WA

No earthquake was likely felt in Mount Vernon in the 24 hours to 10:03 pm PST (06:03 UTC). The last one was M 2.6, 2 km (1 mi) ENE, at 9:17 pm PDT on 11 September 2026, estimated intensity II (weak) in town; 10 felt reports to USGS. Every earthquake near Mount Vernon

This page: a magnitude 1.7 earthquake was recorded 10 km (6 mi) south of Mount Vernon, WA, at 9:31 am PDT on 4 August 2017 (16:31 UTC), 11 km deep.

USGS: 2 km ESE of Conway, Washington

79 km (49 mi) N of Seattle, WA · 31 km (19 mi) NNW of Marysville, WA

9:31 am PDT, Aug 4, 2017 · · 11 km deep · released about 11 lb of TNT

10 km30 km60 km120 km N Island County 33 kmSkagit County 41 kmSnohomish County 51 kmSan Juan County 61 kmWhatcom County 67 kmKitsap County 81 kmKing County 100 kmJefferson County 107 kmClallam County 119 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
9:31 am PDT on 4 August 2017 ()
Where
10 km (6 mi) south of Mount Vernon, WA · earthquakes near Mount Vernon
Magnitude
M 1.7 (ml)
Depth
11 km below the surface
Felt
no reports yet
Nearest
Island County, 33 km SW
Nearest mapped fault
Utsalady Point fault, 14 km from its surface trace — near is not the same as on
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 3388 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

At this magnitude and depth, people at rest would likely notice it out to about 5 km (3 mi) from the epicentre. In Mount Vernon, 10 km away, the estimate is intensity II (weak). Estimated from magnitude, depth and distance with the intensity equation USGS Did You Feel It? uses; felt reports, where there are any, are the measurement.

Earthquakes near other towns within 30 km: Big Lake, Stanwood, Bryant, Clear Lake, Burlington, Warm Beach.

How big was it?

This earthquake released about 11 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.7 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 1,400,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 970,000× the energy of this one
  3. Around the size people start to feel M 3.0 86× the energy of this one
  4. This earthquake M 1.7 about 11 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.

For this area

No earthquake of M4 or more has been recorded within 50 km since our catalogue begins in 2016.

Before 2016, the USGS record lists 2 earthquakes of M5 or more within 50 km:

  1. 5.0 4 km ENE of Machias, Washington · 44 km SSE of this epicentre
  2. 5.0 6 km W of Conway, Washington · 9 km W of this epicentre

Since 2016: the QuakeIndex catalogue (US, M1.5+), built from the USGS FDSN event service. Before 2016: USGS ComCat, M5+ from 1900. Distances are between epicentres. This is the record, not a forecast.

Where

Epicentre 48.3325, -122.3167. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Island County, WA 33 km (20 mi) SW earthquakes near Island County
Skagit County, WA 41 km (26 mi) ENE earthquakes near Skagit County
Snohomish County, WA 51 km (32 mi) SE earthquakes near Snohomish County
San Juan County, WA 61 km (38 mi) WNW earthquakes near San Juan County
Whatcom County, WA 67 km (42 mi) NNE earthquakes near Whatcom County
Kitsap County, WA 81 km (50 mi) SSW earthquakes near Kitsap 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. 2.1 6 km SSE of Acme, Washington
  2. 2.0 2 km NE of Granite Falls, Washington
  3. 1.6 6 km NE of Port Townsend, Washington
  4. 1.7 6 km NE of Port Townsend, Washington
  5. 1.6 4 km SW of Geneva, Washington
  6. 1.6 7 km SSW of Geneva, Washington
  7. 2.1 10 km SW of Swede Heaven, Washington
  8. 2.0 3 km E of Granite Falls, Washington
  9. 1.6 3 km SE of Warm Beach, Washington
  10. 1.6 5 km NNW of Ault Field, Washington
  11. 1.7 4 km N of Weallup Lake, Washington
  12. 1.8 3 km ENE of Granite Falls, Washington
  13. 1.8 6 km NE of Port Townsend, Washington
  14. 1.7 6 km SSE of Acme, Washington
  15. 1.5 1 km ENE of Bay View, 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.

On USGS

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