QuakeIndex

Earthquake · reviewed by a seismologist

M 2.2ml

Earthquake near Arlington, WA

No earthquake was likely felt in Arlington in the 24 hours to 3:43 pm PST (23:43 UTC). The last one was M 2.6, 18 km (11 mi) SE, at 2:29 pm PDT on 30 October 2026, estimated intensity II (weak) in town. Every earthquake near Arlington

This page: a magnitude 2.2 earthquake was recorded 5 km (3 mi) west of Arlington, WA, at 2:38 am PST on 16 December 2017 (10:38 UTC), 15 km deep. 9 people have reported feeling it to USGS.

USGS: 4 km E of Silvana, Washington

13 km (8 mi) NNW of Marysville, WA · 65 km (41 mi) N of Seattle, WA

2:38 am PST, Dec 16, 2017 · · 15 km deep · released about 67 lb of TNT

10 km30 km60 km120 km N Snohomish County 36 kmIsland County 36 kmSkagit County 43 kmKitsap County 71 kmSan Juan County 76 kmWhatcom County 76 kmKing County 83 kmJefferson County 108 kmMason 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
2:38 am PST on 16 December 2017 ()
Where
5 km (3 mi) west of Arlington, WA · earthquakes near Arlington
Magnitude
M 2.2 (ml)
Depth
15 km below the surface
Felt
9 reports · strongest reported intensity II
Nearest
Snohomish County, 36 km ESE
Nearest mapped fault
Utsalady Point fault, 22 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 3175 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 11 km (7 mi) from the epicentre. In Arlington, 5 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.

Likely felt in: Arlington 5 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 67 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.2 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 230,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 160,000× the energy of this one
  3. Around the size people start to feel M 3.0 14× the energy of this one
  4. This earthquake M 2.2 about 67 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 · 26 km SSE of this epicentre
  2. 5.0 6 km W of Conway, Washington · 23 km NW 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 48.1982, -122.1933. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Snohomish County, WA 36 km (22 mi) ESE earthquakes near Snohomish County
Island County, WA 36 km (22 mi) W earthquakes near Island County
Skagit County, WA 43 km (27 mi) NE earthquakes near Skagit County
Kitsap County, WA 71 km (44 mi) SSW earthquakes near Kitsap County
San Juan County, WA 76 km (47 mi) WNW earthquakes near San Juan County
Whatcom County, WA 76 km (47 mi) NNE earthquakes near Whatcom County

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

Aftershocks so far

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

  1. 1.9 6 km SE of Coupeville, Washington
  2. 1.8 4 km SW of Clinton, Washington
  3. 1.5 6 km W of Camano, Washington
  4. 2.3 2 km ENE of Granite Falls, Washington
  5. 1.6 2 km NE of Shoreline, Washington
  6. 1.9 4 km ESE of Camano, Washington
  7. 2.9 7 km NW of La Conner, Washington
  8. 1.9 2 km NE of Granite Falls, Washington
  9. 2.3 5 km ENE of Port Townsend, Washington
  10. 1.6 3 km NNW of Hamilton, Washington
  11. 1.9 6 km SSE of Port Ludlow, Washington
  12. 2.0 2 km ENE of Granite Falls, Washington
  13. 1.9 1 km WSW of Freeland, Washington
  14. 2.0 2 km NE of Granite Falls, Washington
  15. 1.6 6 km NE of Port Townsend, 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.