QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8ml

Earthquake near Port Townsend, WA

No earthquake was likely felt in Port Townsend in the 24 hours to 9:26 am PST (17:26 UTC). The last one was M 4.2, 80 km (50 mi) S, at 2:05 pm PDT on 29 September 2026, estimated intensity II (weak) in town; 9,329 felt reports to USGS. Every earthquake near Port Townsend

This page: a magnitude 1.8 earthquake was recorded 4 km (3 mi) north-northwest of Port Townsend, WA, at 6:58 am PDT on 19 October 2024 (13:58 UTC), 24 km deep.

USGS: 4 km NNW of Port Townsend, Washington

67 km (42 mi) NNW of Seattle, WA · 47 km (29 mi) W of Marysville, WA

6:58 am PDT, Oct 19, 2024 · · 24 km deep · released about 14 lb of TNT

10 km30 km60 km120 km N Island County 8 kmSan Juan County 46 kmKitsap County 58 kmJefferson County 67 kmSnohomish County 76 kmSkagit County 81 kmClallam County 82 kmMason County 94 kmKing County 102 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
6:58 am PDT on 19 October 2024 ()
Where
4 km (3 mi) north-northwest of Port Townsend, WA · earthquakes near Port Townsend
Magnitude
M 1.8 (ml)
Depth
24 km below the surface
Felt
no reports yet
Nearest
Island County, 8 km E
Nearest mapped fault
Southern Whidbey Island fault, under 1 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 755 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 Port Townsend, 4 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: Coupeville, Port Hadlock-Irondale, Oak Harbor, Camano, Ault Field, Freeland.

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 5.7 760,000× the energy of this one
  3. Around the size people start to feel M 3.0 68× 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

The largest earthquake within 50 km since 2016 was M 4.3 on 2023-10-09 — about 6,200 times the energy of this one.

Before 2016, the USGS record lists 2 earthquakes of M5 or more within 50 km:

  1. 5.3 Eastern Olympic Peninsula, Washington · 42 km SSW of this epicentre
  2. 5.0 6 km W of Conway, Washington · 33 km NE 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 48.1512, -122.7822. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Island County, WA 8 km (5 mi) E earthquakes near Island County
San Juan County, WA 46 km (29 mi) NNW earthquakes near San Juan County
Kitsap County, WA 58 km (36 mi) S earthquakes near Kitsap County
Jefferson County, WA 67 km (42 mi) SW earthquakes near Jefferson County
Snohomish County, WA 76 km (47 mi) E earthquakes near Snohomish County
Skagit County, WA 81 km (50 mi) ENE earthquakes near Skagit 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. 1.6 24 km SSW of River Road, Washington
  2. 1.7 6 km SE of Port Ludlow, Washington
  3. 2.8 16 km SSW of River Road, Washington
  4. 1.5 11 km WNW of Ault Field, Washington
  5. 2.3 3 km SW of Oak Harbor, Washington
  6. 1.9 14 km N of Jamestown, Washington
  7. 1.6 5 km SE of Port Ludlow, Washington
  8. 1.5 3 km S of Port Ludlow, Washington
  9. 2.1 8 km E of Port Townsend, Washington
  10. 2.5 6 km SE of Coupeville, Washington
  11. 1.5 8 km WNW of La Conner, Washington
  12. 1.8 5 km SE of Oak Bay, Canada
  13. 1.7 4 km W of Mount Vernon, Washington
  14. 1.9 4 km W of Mount Vernon, Washington
  15. 2.8 4 km W of Mount Vernon, 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.