QuakeIndex

Earthquake · reviewed by a seismologist

M 2.5ml

Earthquake near Snoqualmie, WA

No earthquake was likely felt in Snoqualmie in the 24 hours to 11:28 am PST (19:28 UTC). The last one was M 2.6, 12 km (8 mi) S, at 6:09 pm PDT on 14 October 2026, estimated intensity II (weak) in town; 46 felt reports to USGS. Every earthquake near Snoqualmie

This page: a magnitude 2.5 earthquake was recorded 10 km (6 mi) north-northeast of Snoqualmie, WA, at 12:08 am PDT on 17 September 2023 (07:08 UTC), 16 km deep. 32 people have reported feeling it to USGS.

USGS: 9 km NNE of Snoqualmie, Washington

44 km (28 mi) E of Seattle, WA · 21 km (13 mi) E of Sammamish, WA

12:08 am PDT, Sep 17, 2023 · · 16 km deep · released about 170 lb of TNT

10 km30 km60 km120 km N King County 14 kmSnohomish County 50 kmKitsap County 67 kmPierce County 68 kmChelan County 90 kmIsland County 92 kmKittitas County 97 kmSkagit County 99 kmThurston County 110 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
12:08 am PDT on 17 September 2023 ()
Where
10 km (6 mi) north-northeast of Snoqualmie, WA · earthquakes near Snoqualmie
Magnitude
M 2.5 (ml)
Depth
16 km below the surface
Felt
32 reports · strongest reported intensity IV
Nearest
King County, 14 km SSW
Nearest mapped fault
Rattlesnake Mountain fault, 9 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 893 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage.

At this magnitude and depth, people at rest would likely notice it out to about 16 km (10 mi) from the epicentre. In Snoqualmie, 10 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.

Likely felt in: Snoqualmie 10 km, intensity II · Fall City 10 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 170 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.5 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 89,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 63,000× the energy of this one
  3. Around the size people start to feel M 3.0 5.6× the energy of this one
  4. This earthquake M 2.5 about 170 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 4.6 on 2019-07-12 — about 1,300 times the energy of this one.

Before 2016, the USGS record lists 3 earthquakes of M5 or more within 50 km:

  1. 5.4 8 km NNE of Lake Marcel-Stillwater, Washington · 20 km NNW of this epicentre
  2. 5.2 9 km NE of Lake Marcel-Stillwater, Washington · 17 km NNW of this epicentre
  3. 5.0 4 km ENE of Machias, Washington · 48 km NNW 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 47.6032, -121.7608. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
King County, WA 14 km (8 mi) SSW earthquakes near King County
Snohomish County, WA 50 km (31 mi) N earthquakes near Snohomish County
Kitsap County, WA 67 km (41 mi) W earthquakes near Kitsap County
Pierce County, WA 68 km (42 mi) SSW earthquakes near Pierce County
Chelan County, WA 90 km (56 mi) ENE earthquakes near Chelan County
Island County, WA 92 km (57 mi) NW earthquakes near Island County

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

Aftershocks so far

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

  1. 2.1 3 km SSE of Issaquah, Washington
  2. 1.6 3 km SSE of Issaquah, Washington
  3. 1.7 6 km NNE of Lake Marcel-Stillwater, Washington
  4. 1.5 3 km SSE of Issaquah, Washington
  5. 1.6 12 km ESE of Enumclaw, Washington
  6. 2.6 7 km NE of Fall City, Washington
  7. 1.5 2 km W of Woods Creek, Washington
  8. 1.6 2 km W of Kirkland, Washington
  9. 1.5 1 km ESE of Three Lakes, Washington
  10. 1.9 5 km E of Enumclaw, Washington
  11. 1.6 10 km NNE of Snoqualmie, Washington
  12. 2.5 10 km NE of Snoqualmie, Washington
  13. 1.7 3 km N of Woods Creek, Washington
  14. 1.9 11 km NE of Snoqualmie, Washington
  15. 1.5 5 km WSW of Black Diamond, 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.