QuakeIndex

Earthquake · reviewed by a seismologist

M 4.1mwr

11 km E of Dillon, Montana

· 17 km deep · released about 21 tons of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Beaverhead County 33 kmMadison County 46 kmSilver Bow County 76 kmClark County 105 kmJefferson County 105 kmGallatin County 108 kmDeer Lodge County 109 kmLemhi County 115 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 4.1 (mwr)
Depth
17 km below the surface
Felt
225 reports · strongest reported intensity V
Measured shaking
intensity IV (ShakeMap)
USGS impact alert
green
Nearest
Beaverhead County, 33 km WSW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 5 days ago

This was a light earthquake. It is usually felt clearly nearby and can rattle windows and dishes, but damage is uncommon. 225 people have reported feeling it to USGS.

How big was it?

This earthquake released about 21 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 5.1 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 7,900× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 350× the energy of this one
  3. Magna, Utah 2020 M 5.7 250× the energy of this one
  4. This earthquake M 4.1 about 21 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 45× more

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 45.2265, -112.4871. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Beaverhead County, MT 33 km (21 mi) ENE of here earthquakes near Beaverhead County
Madison County, MT 46 km (29 mi) WSW of here earthquakes near Madison County
Silver Bow County, MT 76 km (47 mi) S of here earthquakes near Silver Bow County
Clark County, ID 105 km (65 mi) N of here earthquakes near Clark County
Jefferson County, MT 105 km (65 mi) SSW of here earthquakes near Jefferson County
Gallatin County, MT 108 km (67 mi) WSW of here earthquakes near Gallatin County

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

Aftershocks so far

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

  1. 2.1 26 km SE of Dillon, Montana
  2. 2.0 13 km N of Dillon, Montana
  3. 1.6 11 km NNE of Dillon, Montana
  4. 2.5 9 km NNE of Dillon, Montana
  5. 1.5 14 km NNE of Dillon, Montana
  6. 2.5 10 km NNE of Dillon, Montana
  7. 1.8 27 km SW of Dillon, Montana
  8. 1.6 16 km SSW of Dillon, Montana
  9. 1.5 12 km N of Dillon, Montana
  10. 1.7 17 km NNE of Dillon, Montana
  11. 2.2 30 km NNW of Dillon, Montana
  12. 2.1 3 km SE of Twin Bridges, Montana
  13. 1.9 37 km SW of Dillon, Montana
  14. 2.4 13 km N of Dillon, Montana
  15. 1.6 23 km N of Dillon, 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.