QuakeIndex

Earthquake · reviewed by a seismologist

M 2.1ml

40 km SW of Dillon, Montana

· 4.2 km deep · released about 44 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Beaverhead County 20 kmLemhi County 67 kmClark County 94 kmMadison County 96 kmSilver Bow County 105 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 2.1 (ml)
Depth
4.2 km below the surface
Felt
no reports yet
Nearest
Beaverhead County, 20 km NE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1758 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 44 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.1 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 340,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 240,000× the energy of this one
  3. Around the size people start to feel M 3.0 22× the energy of this one
  4. This earthquake M 2.1 about 44 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 44.9873, -113.0355. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Beaverhead County, MT 20 km (12 mi) SW of here earthquakes near Beaverhead County
Lemhi County, ID 67 km (42 mi) E of here earthquakes near Lemhi County
Clark County, ID 94 km (59 mi) NW of here earthquakes near Clark County
Madison County, MT 96 km (59 mi) WSW of here earthquakes near Madison County
Silver Bow County, MT 105 km (65 mi) SSW of here earthquakes near Silver Bow County
Custer County, ID 125 km (78 mi) NE of here earthquakes near Custer County

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

Aftershocks so far

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

  1. 1.7 14 km NW of Lima, Montana
  2. 1.9 23 km SSE of Dillon, Montana
  3. 2.0 28 km WSW of Dillon, Montana
  4. 1.6 26 km NW of Lima, Montana
  5. 2.0 30 km W of Lima, Montana
  6. 2.0 33 km NNW of Lima, Montana
  7. 1.6 22 km WSW of Lima, Montana
  8. 2.4 21 km WSW of Lima, Montana
  9. 2.0 40 km SW of Dillon, Montana
  10. 1.8 39 km SW of Dillon, Montana
  11. 1.9 39 km SW of Dillon, Montana
  12. 1.6 39 km SW of Dillon, Montana
  13. 2.4 41 km SW of Dillon, Montana
  14. 2.4 40 km NNE of Leadore, Idaho
  15. 2.6 41 km NE of Leadore, Idaho

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.