QuakeIndex

explosion · reviewed by a seismologist

M 1.7ml

Earthquake near Tacoma, WA

No earthquake was likely felt in Tacoma in the 24 hours to 3:46 pm PST (23:46 UTC). The last one was M 4.2, 27 km (17 mi) NW, at 2:05 pm PDT on 29 September 2026, estimated intensity III (weak) in town; 9,329 felt reports to USGS. Every earthquake near Tacoma

No: USGS classifies this as a explosion, not an earthquake. A magnitude 1.7 explosion was recorded 43 km (26 mi) south of Tacoma, WA, at 11:38 am PDT on 10 October 2024 (18:38 UTC), less than 1 km deep.

USGS: 7 km SSE of McKenna, Washington

84 km (52 mi) S of Seattle, WA · 28 km (18 mi) SE of Lacey, WA

11:38 am PDT, Oct 10, 2024 · · -0.7 km deep · released about 11 lb of TNT

10 km30 km60 km120 km N Thurston County 24 kmPierce County 34 kmLewis County 34 kmMason County 72 kmCowlitz County 76 kmKitsap County 86 kmKing County 86 kmWahkiakum County 94 kmPacific 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
11:38 am PDT on 10 October 2024 ()
Where
43 km (26 mi) south of Tacoma, WA · earthquakes near Tacoma
Magnitude
M 1.7 (ml)
Depth
-0.7 km below the surface
Felt
no reports yet
Nearest
Thurston County, 24 km WNW
Nearest mapped fault
Olympia structure, 6 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 763 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 12 km (7 mi) from the epicentre. In Tacoma, 43 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: Yelm, North Yelm, Rainier, Eatonville, Elk Plain, Tenino.

USGS catalogues this as explosion, not an earthquake.

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 1,400,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 970,000× the energy of this one
  3. Around the size people start to feel M 3.0 86× 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 2 earthquakes of M5 or more within 50 km:

  1. 6.8 The 2001 Nisqually, Washington Earthquake · 34 km NNW of this epicentre
  2. 6.7 4 km WNW of Roy, Washington · 17 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 46.8738, -122.5213. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Thurston County, WA 24 km (15 mi) WNW earthquakes near Thurston County
Pierce County, WA 34 km (21 mi) NE earthquakes near Pierce County
Lewis County, WA 34 km (21 mi) SSE earthquakes near Lewis County
Mason County, WA 72 km (45 mi) NW earthquakes near Mason County
Cowlitz County, WA 76 km (47 mi) S earthquakes near Cowlitz County
Kitsap County, WA 86 km (53 mi) N earthquakes near Kitsap 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. 1.7 1 km SE of Kapowsin, Washington
  2. 1.6 6 km ESE of Mossyrock, Washington
  3. 2.2 2 km SE of Buckley, Washington
  4. 1.7 13 km N of Onalaska, Washington
  5. 1.5 1 km WSW of Kapowsin, Washington
  6. 2.8 3 km NE of Mineral, Washington
  7. 1.9 6 km NE of Mossyrock, Washington
  8. 1.6 6 km ESE of Mossyrock, Washington
  9. 1.8 17 km WSW of Alder, Washington
  10. 1.6 1 km SSE of Kapowsin, Washington
  11. 1.5 0 km SSW of Carbonado, Washington
  12. 1.7 8 km S of Mineral, Washington
  13. 1.8 1 km SE of Kapowsin, Washington
  14. 2.2 3 km NNE of Grand Mound, Washington
  15. 1.6 3 km NE of Wilkeson, 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.