QuakeIndex

Earthquake · reviewed by a seismologist

M 1.5ml

27 km NE of Winston, Montana

· 2.7 km deep · released about 5.7 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Broadwater County 38 kmMeagher County 40 kmCascade County 73 kmJefferson County 77 kmLewis and Clark County 88 kmJudith Basin County 95 kmPowell County 116 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
2.7 km below the surface
Felt
no reports yet
Nearest
Broadwater County, 38 km S
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2784 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 46.6667, -111.4302. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Broadwater County, MT 38 km (23 mi) N of here earthquakes near Broadwater County
Meagher County, MT 40 km (25 mi) WNW of here earthquakes near Meagher County
Cascade County, MT 73 km (45 mi) S of here earthquakes near Cascade County
Jefferson County, MT 77 km (48 mi) NE of here earthquakes near Jefferson County
Lewis and Clark County, MT 88 km (55 mi) SE of here earthquakes near Lewis and Clark County
Judith Basin County, MT 95 km (59 mi) WSW of here earthquakes near Judith Basin 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. 1.5 7 km ENE of Townsend, Montana
  2. 1.6 8 km ENE of Townsend, Montana
  3. 1.8 7 km W of Townsend, Montana
  4. 1.7 10 km WSW of Townsend, Montana
  5. 1.6 8 km WSW of Townsend, Montana
  6. 2.4 4 km NNW of Helena Valley Northeast, Montana
  7. 1.6 6 km WSW of Townsend, Montana
  8. 2.1 6 km NE of Helena Valley Northeast, Montana
  9. 1.6 6 km W of Townsend, Montana
  10. 1.7 5 km W of Townsend, Montana
  11. 1.5 4 km WNW of Townsend, Montana
  12. 1.5 6 km W of Townsend, Montana
  13. 2.3 14 km NNE of Helena Valley Northwest, Montana
  14. 1.7 9 km ENE of Townsend, Montana
  15. 1.6 6 km WSW of Townsend, 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

QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.