QuakeIndex

Earthquake · reviewed by a seismologist

M 1.7ml

Earthquake near Sequim, WA

No earthquake was likely felt in Sequim in the 24 hours to 3:01 pm PST (23:01 UTC). The last one was M 4.2, 81 km (50 mi) SSE, at 2:05 pm PDT on 29 September 2026, estimated intensity II (weak) in town; 9,329 felt reports to USGS. Every earthquake near Sequim

This page: a magnitude 1.7 earthquake was recorded in Sequim, WA, at 12:43 pm PDT on 20 October 2017 (19:43 UTC), 45 km deep.

USGS: 1 km NNW of Sequim, Washington

77 km (48 mi) NW of Seattle, WA

12:43 pm PDT, Oct 20, 2017 · · 45 km deep · released about 11 lb of TNT

10 km30 km60 km120 km N Island County 33 kmJefferson County 45 kmSan Juan County 46 kmClallam County 58 kmKitsap County 61 kmMason County 83 kmSnohomish County 100 kmSkagit County 106 kmKing County 117 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
12:43 pm PDT on 20 October 2017 ()
Where
in Sequim, WA · earthquakes near Sequim
Magnitude
M 1.7 (ml)
Depth
45 km below the surface
Felt
no reports yet
Nearest
Island County, 33 km ENE
Nearest mapped fault
Lake Creek-Boundary Creek fault, 16 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 3310 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. 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: Port Angeles East, Port Angeles, Port Hadlock-Irondale, Port Townsend.

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 1,300,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 930,000× the energy of this one
  3. Around the size people start to feel M 3.0 83× 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 one earthquake of M5 or more within 50 km:

  1. 5.3 Eastern Olympic Peninsula, Washington · 34 km SSE 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 48.0937, -123.1105. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Island County, WA 33 km (21 mi) ENE earthquakes near Island County
Jefferson County, WA 45 km (28 mi) SW earthquakes near Jefferson County
San Juan County, WA 46 km (29 mi) N earthquakes near San Juan County
Clallam County, WA 58 km (36 mi) W earthquakes near Clallam County
Kitsap County, WA 61 km (38 mi) SE earthquakes near Kitsap County
Mason County, WA 83 km (51 mi) S earthquakes near Mason County

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

Aftershocks so far

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

  1. 1.8 12 km NNE of Port Angeles East, Washington
  2. 1.6 9 km NNE of Quilcene, Washington
  3. 1.7 5 km SW of Hansville, Washington
  4. 1.7 7 km N of Ault Field, Washington
  5. 1.6 11 km NW of Jamestown, Washington
  6. 1.7 8 km W of Ault Field, Washington
  7. 2.5 8 km SE of Friday Harbor, Washington
  8. 1.6 1 km NNE of Six Mile, Canada
  9. 1.8 7 km ESE of Quilcene, Washington
  10. 2.8 8 km WNW of Carlsborg, WA
  11. 2.2 6 km NNE of Oak Bay, Canada
  12. 1.7 6 km W of Lofall, Washington
  13. 1.9 3 km SSE of Port Ludlow, Washington
  14. 1.6 2 km N of Port Townsend, Washington
  15. 2.3 15 km SW of River Road, 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.