QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8ml

4 km ESE of Shelby, Montana

· 5.0 km deep · released about 16 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Toole County 18 kmPondera County 43 kmLiberty County 56 kmTeton County 83 kmGlacier County 91 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 1.8 (ml)
Depth
5.0 km below the surface
Felt
no reports yet
Nearest
Toole County, 18 km NNE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 3843 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 16 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.8 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 970,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 680,000× the energy of this one
  3. Around the size people start to feel M 3.0 61× the energy of this one
  4. This earthquake M 1.8 about 16 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 48.4927, -111.7960. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Toole County, MT 18 km (11 mi) SSW of here earthquakes near Toole County
Pondera County, MT 43 km (27 mi) NE of here earthquakes near Pondera County
Liberty County, MT 56 km (35 mi) W of here earthquakes near Liberty County
Teton County, MT 83 km (52 mi) NNE of here earthquakes near Teton County
Glacier County, MT 91 km (57 mi) ESE of here earthquakes near Glacier County
Chouteau County, MT 121 km (75 mi) NW of here earthquakes near Chouteau County

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

Aftershocks so far

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

  1. 1.5 12 km WSW of Sunburst, Montana
  2. 1.6 9 km ESE of Cut Bank, Montana
  3. 1.7 27 km ESE of Shelby, Montana
  4. 1.8 11 km NNE of Santa Rita, Montana
  5. 1.7 24 km WSW of Chester, Montana
  6. 2.3 13 km NNE of Santa Rita, Montana
  7. 1.6 16 km NNE of Santa Rita, Montana
  8. 2.3 18 km NNE of Santa Rita, Montana
  9. 2.0 17 km W of Sunburst, Montana
  10. 1.8 Eastern Montana
  11. 2.0 12 km NNE of Santa Rita, Montana
  12. 2.3 8 km S of Valier, Montana
  13. 1.9 24 km ESE of Shelby, Montana
  14. 1.9 26 km ESE of Shelby, Montana
  15. 2.0 16 km W of Sunburst, 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.