QuakeIndex

explosion · reviewed by a seismologist

M 1.6ml

Earthquake near Shelton, WA

No earthquake was likely felt in Shelton in the 24 hours to 3:51 pm PST (23:51 UTC). The last one was M 4.2, 35 km (22 mi) NE, at 2:05 pm PDT on 29 September 2026, estimated intensity III (weak) in town; 9,329 felt reports to USGS. Every earthquake near Shelton

No: USGS classifies this as a explosion, not an earthquake. A magnitude 1.6 explosion was recorded 6 km (4 mi) south of Shelton, WA, at 10:40 am PST on 11 December 2025 (18:40 UTC), less than 1 km deep.

USGS: 5 km S of Shelton, Washington

76 km (47 mi) SW of Seattle, WA · 21 km (13 mi) NW of Olympia, WA

10:40 am PST, Dec 11, 2025 · · -0.2 km deep · released about 7.8 lb of TNT

10 km30 km60 km120 km N Mason County 22 kmThurston County 33 kmGrays Harbor County 55 kmKitsap County 63 kmPierce County 73 kmJefferson County 78 kmPacific County 85 kmLewis County 85 kmWahkiakum County 99 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
10:40 am PST on 11 December 2025 ()
Where
6 km (4 mi) south of Shelton, WA · earthquakes near Shelton
Magnitude
M 1.6 (ml)
Depth
-0.2 km below the surface
Felt
no reports yet
Nearest
Mason County, 22 km NNW
Nearest mapped fault
Olympia structure, 3 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 336 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

At this magnitude and depth, people at rest would likely notice it out to about 11 km (7 mi) from the epicentre. In Shelton, 6 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: Shelton 6 km, intensity II. Estimated for each town centre; each link is that town's own record.

USGS catalogues this as explosion, not an earthquake.

How big was it?

This earthquake released about 7.8 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.6 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 1,900,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,400,000× the energy of this one
  3. Around the size people start to feel M 3.0 120× the energy of this one
  4. This earthquake M 1.6 about 7.8 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 5,200 times the energy of this one.

Before 2016, the USGS record lists 7 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.8 The 2001 Nisqually, Washington Earthquake · 29 km E of this epicentre
  2. 6.7 4 km WNW of Roy, Washington · 42 km ESE of this epicentre
  3. 6.1 Puget Sound region, Washington · 38 km NE of this epicentre
  4. 5.8 Puget Sound area, Washington · 20 km NE of this epicentre
  5. 5.8 8 km N of Satsop, Washington · 29 km WSW 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 47.1620, -123.1037. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Mason County, WA 22 km (13 mi) NNW earthquakes near Mason County
Thurston County, WA 33 km (20 mi) SE earthquakes near Thurston County
Grays Harbor County, WA 55 km (34 mi) W earthquakes near Grays Harbor County
Kitsap County, WA 63 km (39 mi) NNE earthquakes near Kitsap County
Pierce County, WA 73 km (45 mi) E earthquakes near Pierce County
Jefferson County, WA 78 km (49 mi) NNW earthquakes near Jefferson County

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

Aftershocks so far

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

  1. 1.5 7 km W of Gorst, Washington
  2. 0.4 9 km ENE of Hoodsport, Washington
  3. 1.4 9 km ESE of McCleary, Washington
  4. 1.9 1 km SE of Belfair, Washington
  5. 0.9 5 km W of Fox Island, Washington
  6. 0.6 10 km SSW of Brinnon, Washington
  7. 1.5 3 km WSW of Hoodsport, Washington
  8. 1.3 4 km WNW of Wauna, Washington
  9. 1.1 11 km S of Shelton, Washington
  10. 1.6 5 km W of Burley, Washington
  11. 1.9 6 km WNW of Wauna, Washington
  12. 1.3 4 km WNW of Wauna, Washington
  13. 4.2 6 km WNW of Wauna, Washington
  14. 1.0 6 km SE of McCleary, Washington
  15. 0.4 11 km NE of Hoodsport, 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.