QuakeIndex

Earthquake · reviewed by a seismologist

M 1.5ml

Earthquake near Seattle, WA

No earthquake was likely felt in Seattle in the 24 hours to 4:09 am PST (12:09 UTC). The last one was M 4.2, 37 km (23 mi) SW, at 2:05 pm PDT on 29 September 2026, estimated intensity III (weak) in town; 9,329 felt reports to USGS. Every earthquake near Seattle

This page: a magnitude 1.5 earthquake was recorded 23 km (14 mi) west-northwest of Seattle, WA, at 4:35 am PDT on 30 August 2018 (11:35 UTC), 24 km deep.

USGS: 1 km SSE of Keyport, Washington

21 km (13 mi) WNW of Seattle, WA

4:35 am PDT, Aug 30, 2018 · · 24 km deep · released about 5.6 lb of TNT

10 km30 km60 km120 km N Kitsap County 6 kmIsland County 52 kmMason County 57 kmKing County 62 kmJefferson County 70 kmSnohomish County 75 kmPierce County 79 kmThurston County 86 kmSan Juan County 98 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
4:35 am PDT on 30 August 2018 ()
Where
23 km (14 mi) west-northwest of Seattle, WA · earthquakes near Seattle
Magnitude
M 1.5 (ml)
Depth
24 km below the surface
Felt
no reports yet
Nearest
Kitsap County, 6 km SSW
Nearest mapped fault
Seattle fault, 8 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 601 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 Seattle, 23 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: Poulsbo, Suquamish, Silverdale, Bangor Trident Base, Indianola, Tracyton.

How big was it?

This earthquake released about 5.6 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.5 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 2,700,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,900,000× the energy of this one
  3. Around the size people start to feel M 3.0 170× the energy of this one
  4. This earthquake M 1.5 about 5.6 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 4.1 on 2017-02-23 — about 7,400 times the energy of this one.

Before 2016, the USGS record lists 4 earthquakes of M5 or more within 50 km:

  1. 6.7 1 km ENE of Dash Point, Washington · 43 km SSE of this epicentre
  2. 6.1 Puget Sound region, Washington · 34 km SSW of this epicentre
  3. 5.3 Eastern Olympic Peninsula, Washington · 31 km WNW of this epicentre
  4. 5.0 3 km WSW of Des Moines, Washington · 39 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 47.6917, -122.6117. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Kitsap County, WA 6 km (4 mi) SSW earthquakes near Kitsap County
Island County, WA 52 km (32 mi) N earthquakes near Island County
Mason County, WA 57 km (35 mi) SW earthquakes near Mason County
King County, WA 62 km (39 mi) ESE earthquakes near King County
Jefferson County, WA 70 km (43 mi) W earthquakes near Jefferson County
Snohomish County, WA 75 km (47 mi) ENE earthquakes near Snohomish County

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

Aftershocks so far

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

  1. 1.7 5 km N of Belfair, Washington
  2. 2.0 7 km WSW of Grapeview, Washington
  3. 1.5 3 km SSW of Gorst, Washington
  4. 1.6 5 km NNE of Kingston, Washington
  5. 2.6 3 km WSW of Erlands Point-Kitsap Lake, Washington
  6. 1.9 1 km N of Enetai, Washington
  7. 2.0 0 km ESE of Erlands Point-Kitsap Lake, Washington
  8. 1.8 1 km NNE of Burley, Washington
  9. 1.7 2 km NW of Indianola, Washington
  10. 2.2 7 km W of Clinton, Washington
  11. 1.7 2 km SSE of Manchester, Washington
  12. 1.7 6 km SSE of Port Ludlow, Washington
  13. 2.5 0 km N of Woodway, Washington
  14. 1.7 2 km SE of Manchester, Washington
  15. 1.6 9 km NNE of Quilcene, 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.