QuakeIndex

Earthquake · reviewed by a seismologist

M 1.5ml

21 km NE of Townsend, Montana

· 3.6 km deep · released about 5.7 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Broadwater County 19 kmMeagher County 34 kmJefferson County 68 kmCascade County 98 kmJudith Basin County 101 kmGallatin County 103 kmWheatland County 111 kmLewis and Clark County 112 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
Magnitude
M 1.5 (ml)
Depth
3.6 km below the surface
Felt
no reports yet
Nearest
Broadwater County, 19 km SW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1771 days ago

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

How big was it?

This earthquake released about 5.7 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 2,600,000× 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 5.7 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.

Where

Epicentre 46.4360, -111.3053. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Broadwater County, MT 19 km (12 mi) NE of here earthquakes near Broadwater County
Meagher County, MT 34 km (21 mi) WSW of here earthquakes near Meagher County
Jefferson County, MT 68 km (42 mi) ENE of here earthquakes near Jefferson County
Cascade County, MT 98 km (61 mi) S of here earthquakes near Cascade County
Judith Basin County, MT 101 km (63 mi) SW of here earthquakes near Judith Basin County
Gallatin County, MT 103 km (64 mi) N of here earthquakes near Gallatin County

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

Aftershocks so far

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

  1. 1.7 7 km SSW of The Silos, Montana
  2. 1.9 8 km WSW of Townsend, Montana
  3. 1.8 4 km WNW of Ponderosa Pines, Montana
  4. 1.6 8 km W of Townsend, Montana
  5. 2.2 11 km S of Radersburg, Montana
  6. 1.5 6 km SSW of The Silos, Montana
  7. 1.5 7 km SSW of The Silos, Montana
  8. 1.9 7 km SSW of The Silos, Montana
  9. 1.7 6 km WSW of Townsend, Montana
  10. 2.2 30 km ENE of Helena Valley Northeast, Montana
  11. 2.3 30 km ENE of Helena Valley Northeast, Montana
  12. 1.6 6 km WSW of Townsend, Montana
  13. 1.9 7 km WSW of Radersburg, Montana
  14. 2.6 15 km E of Townsend, Montana
  15. 2.4 20 km NNW of Springhill, Montana

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

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