QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8ml

Earthquake near Anacortes, WA

No earthquake was likely felt in Anacortes in the 24 hours to 5:53 am PST (13:53 UTC). The last one was M 3.8, 25 km (15 mi) S, at 11:35 pm PDT on 1 July 2026, estimated intensity III (weak) in town; 2,030 felt reports to USGS. Every earthquake near Anacortes

This page: a magnitude 1.8 earthquake was recorded 8 km (5 mi) southwest of Anacortes, WA, at 8:51 am PDT on 1 October 2021 (15:51 UTC), 27 km deep.

USGS: 8 km SW of Anacortes, Washington

98 km (61 mi) NNW of Seattle, WA · 36 km (22 mi) SSW of Bellingham, WA

8:51 am PDT, Oct 1, 2021 · · 27 km deep · released about 14 lb of TNT

10 km30 km60 km120 km N San Juan County 30 kmIsland County 35 kmSkagit County 65 kmWhatcom County 76 kmSnohomish County 83 kmKitsap County 92 kmJefferson County 96 kmClallam County 97 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
8:51 am PDT on 1 October 2021 ()
Where
8 km (5 mi) southwest of Anacortes, WA · earthquakes near Anacortes
Magnitude
M 1.8 (ml)
Depth
27 km below the surface
Felt
no reports yet
Nearest
San Juan County, 30 km W
Nearest mapped fault
Utsalady Point fault, 15 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 1869 days ago

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

At this magnitude and depth it was probably too small to be felt, even directly above it. In Anacortes, 8 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: Ault Field, Oak Harbor, Friday Harbor, Mount Vernon, Burlington, Coupeville.

How big was it?

This earthquake released about 14 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 1,100,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 790,000× the energy of this one
  3. Around the size people start to feel M 3.0 70× the energy of this one
  4. This earthquake M 1.8 about 14 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 3 earthquakes of M5 or more within 50 km:

  1. 6.0 San Juan Islands, Washington · 27 km NNW of this epicentre
  2. 5.5 21 km SSE of Point Roberts, Washington · 43 km NNW of this epicentre
  3. 5.0 6 km W of Conway, Washington · 25 km SE 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 48.4687, -122.6998. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
San Juan County, WA 30 km (19 mi) W earthquakes near San Juan County
Island County, WA 35 km (21 mi) S earthquakes near Island County
Skagit County, WA 65 km (41 mi) E earthquakes near Skagit County
Whatcom County, WA 76 km (47 mi) ENE earthquakes near Whatcom County
Snohomish County, WA 83 km (52 mi) ESE earthquakes near Snohomish County
Kitsap County, WA 92 km (57 mi) S earthquakes near Kitsap County

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

Aftershocks so far

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

  1. 1.6 8 km WNW of Friday Harbor, Washington
  2. 1.8 9 km NW of Friday Harbor, Washington
  3. 2.0 13 km W of Ault Field, Washington
  4. 2.0 10 km E of Oak Bay, Canada
  5. 2.6 Washington-British Columbia border region
  6. 1.9 4 km ENE of La Conner, Washington
  7. 2.3 6 km WNW of Orcas, Washington
  8. 1.6 6 km W of Orcas, Washington
  9. 2.7 6 km WNW of Orcas, Washington
  10. 2.1 7 km SSW of Birch Bay, Washington
  11. 2.3 16 km SSE of Friday Harbor, Washington
  12. 1.6 8 km NE of Oak Bay, Canada
  13. 1.6 9 km NW of Orcas, Washington
  14. 1.9 5 km S of Acme, Washington
  15. 1.6 8 km NNW of Jamestown, 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.