QuakeIndex

Earthquake · reviewed by a seismologist

M 2.1ml

5 km WNW of Saint Ignatius, Montana

· 17 km deep · released about 40 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Lake County 34 kmMissoula County 40 kmMineral County 73 kmSanders County 89 kmFlathead County 107 kmPowell County 109 kmGranite County 119 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
17 km below the surface
Felt
no reports yet
Nearest
Lake County, 34 km N
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 521 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 40 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 5.8 380,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 270,000× the energy of this one
  3. Around the size people start to feel M 3.0 24× the energy of this one
  4. This earthquake M 2.1 about 40 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 47.3387, -114.1677. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Lake County, MT 34 km (21 mi) S of here earthquakes near Lake County
Missoula County, MT 40 km (25 mi) NNW of here earthquakes near Missoula County
Mineral County, MT 73 km (45 mi) ENE of here earthquakes near Mineral County
Sanders County, MT 89 km (55 mi) ESE of here earthquakes near Sanders County
Flathead County, MT 107 km (66 mi) S of here earthquakes near Flathead County
Powell County, MT 109 km (67 mi) WNW of here earthquakes near Powell County

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

Aftershocks so far

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

  1. 0.9 9 km WSW of Condon, Montana
  2. 1.9 2 km NNE of Alberton, Montana
  3. 1.5 6 km S of Frenchtown, Montana
  4. 1.7 6 km S of Frenchtown, Montana
  5. 1.9 18 km E of Saint Ignatius, Montana
  6. 1.9 6 km S of Huson, Montana
  7. 1.9 3 km SSW of Alberton, Montana
  8. 1.7 2 km ENE of Alberton, Montana
  9. 2.2 2 km NE of Alberton, Montana
  10. 1.7 4 km WNW of Wye, Montana
  11. 2.6 13 km ESE of Kicking Horse, Montana
  12. 1.7 4 km SSW of Alberton, Montana
  13. 2.1 3 km S of Alberton, Montana
  14. 2.0 15 km ENE of Ronan, 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.