QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8ml

Earthquake near Arlington, WA

No earthquake was likely felt in Arlington in the 24 hours to 7:19 pm PST (03:19 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 1.8 earthquake was recorded 13 km (8 mi) north-northeast of Arlington, WA, at 6:31 am PDT on 29 June 2017 (13:31 UTC), 8.1 km deep. 3 people have reported feeling it to USGS.

USGS: 4 km WSW of Lake Cavanaugh, Washington

79 km (49 mi) NNE of Seattle, WA · 26 km (16 mi) NNE of Marysville, WA

6:31 am PDT, Jun 29, 2017 · · 8.1 km deep · released about 16 lb of TNT

10 km30 km60 km120 km N Skagit County 28 kmSnohomish County 37 kmIsland County 47 kmWhatcom County 62 kmSan Juan County 79 kmKitsap County 86 kmKing County 93 kmChelan 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
6:31 am PDT on 29 June 2017 ()
Where
13 km (8 mi) north-northeast of Arlington, WA · earthquakes near Arlington
Magnitude
M 1.8 (ml)
Depth
8.1 km below the surface
Felt
3 reports · strongest reported intensity III
Nearest
Skagit County, 28 km NE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 3415 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, 13 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: Bryant, Arlington Heights, Big Lake, Smokey Point, Clear Lake, Sisco Heights.

How big was it?

This earthquake released about 16 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 5.8 930,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 660,000× the energy of this one
  3. Around the size people start to feel M 3.0 59× the energy of this one
  4. This earthquake M 1.8 about 16 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 · 35 km S of this epicentre
  2. 5.0 6 km W of Conway, Washington · 26 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 48.3098, -122.0782. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Skagit County, WA 28 km (17 mi) NE earthquakes near Skagit County
Snohomish County, WA 37 km (23 mi) SE earthquakes near Snohomish County
Island County, WA 47 km (29 mi) WSW earthquakes near Island County
Whatcom County, WA 62 km (38 mi) NNE earthquakes near Whatcom County
San Juan County, WA 79 km (49 mi) WNW earthquakes near San Juan County
Kitsap County, WA 86 km (53 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 10 km SW of Swede Heaven, Washington
  2. 2.0 3 km E of Granite Falls, Washington
  3. 1.8 12 km S of Darrington, Washington
  4. 1.5 12 km S of Darrington, Washington
  5. 1.6 3 km SE of Warm Beach, Washington
  6. 1.7 4 km N of Weallup Lake, Washington
  7. 1.8 3 km ENE of Granite Falls, Washington
  8. 1.7 6 km SSE of Acme, Washington
  9. 1.5 1 km ENE of Bay View, Washington
  10. 2.0 4 km WSW of Darrington, Washington
  11. 1.8 3 km ENE of Granite Falls, Washington
  12. 1.8 5 km NE of Granite Falls, Washington
  13. 1.8 3 km E of Granite Falls, Washington
  14. 1.6 2 km ENE of Oak Harbor, Washington
  15. 2.0 4 km ENE 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.

On USGS

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