QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8ml

Earthquake near Friday Harbor, WA

No earthquake was likely felt in Friday Harbor in the 24 hours to 7:24 pm PST (03:24 UTC). The last one was M 3.8, 41 km (25 mi) SE, at 11:35 pm PDT on 1 July 2026, estimated intensity II (weak) in town; 2,030 felt reports to USGS. Every earthquake near Friday Harbor

This page: a magnitude 1.8 earthquake was recorded 14 km (9 mi) south-southwest of Friday Harbor, WA, at 1:58 pm PDT on 30 September 2017 (20:58 UTC), 51 km deep.

USGS: 13 km SSW of Friday Harbor, Washington

57 km (36 mi) SW of Bellingham, WA · 103 km (64 mi) NNW of Seattle, WA

1:58 pm PDT, Sep 30, 2017 · · 51 km deep · released about 16 lb of TNT

Every earthquake near Friday Harbor Felt it? Tell USGS Check my area
10 km30 km60 km120 km N San Juan County 11 kmIsland County 40 kmClallam County 70 kmJefferson County 76 kmKitsap County 91 kmSkagit County 92 kmWhatcom County 102 kmSnohomish County 104 kmMason County 118 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
1:58 pm PDT on 30 September 2017 ()
Where
14 km (9 mi) south-southwest of Friday Harbor, WA · earthquakes near Friday Harbor
Magnitude
M 1.8 (ml)
Depth
51 km below the surface
Felt
no reports yet
Nearest
San Juan County, 11 km NNW
Nearest mapped fault
Utsalady Point fault, 5 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 3328 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 Friday Harbor, 14 km away, the estimate is intensity I (not felt). 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.

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 4 earthquakes of M5 or more within 50 km:

  1. 6.0 San Juan Islands, Washington · 37 km NNE of this epicentre
  2. 5.5 21 km SSE of Point Roberts, Washington · 43 km N of this epicentre
  3. 5.1 10 km ESE of Salt Spring Island, Canada · 48 km NNW of this epicentre
  4. 5.0 6 km W of Conway, Washington · 47 km E 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 48.4123, -123.0568. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
San Juan County, WA 11 km (7 mi) NNW earthquakes near San Juan County
Island County, WA 40 km (25 mi) SE earthquakes near Island County
Clallam County, WA 70 km (44 mi) WSW earthquakes near Clallam County
Jefferson County, WA 76 km (47 mi) SSW earthquakes near Jefferson County
Kitsap County, WA 91 km (57 mi) SSE earthquakes near Kitsap County
Skagit County, WA 92 km (57 mi) E earthquakes near Skagit County

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

Aftershocks so far

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

  1. 2.1 8 km NW of Friday Harbor, Washington
  2. 1.7 8 km NNW of Friday Harbor, Washington
  3. 2.5 8 km NNW of Friday Harbor, Washington
  4. 2.2 8 km NNW of Friday Harbor, Washington
  5. 1.7 8 km NNW of Friday Harbor, Washington
  6. 1.7 6 km NNW of Friday Harbor, Washington
  7. 2.4 6 km SW of Bay View, Washington
  8. 2.3 6 km SW of Bay View, Washington
  9. 1.7 7 km N of Ault Field, Washington
  10. 1.6 11 km NW of Jamestown, Washington
  11. 2.4 13 km WNW of Orcas, Washington
  12. 1.7 8 km W of Ault Field, Washington
  13. 2.5 8 km SE of Friday Harbor, Washington
  14. 1.6 1 km NNE of Six Mile, Canada
  15. 2.8 8 km WNW of Carlsborg, WA

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.