QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8ml

Eastern Montana

· 5.9 km deep · released about 15 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Liberty County 28 kmToole County 44 kmPondera County 70 kmChouteau County 84 kmHill County 92 kmTeton County 96 kmCascade County 118 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
5.9 km below the surface
Felt
no reports yet
Nearest
Liberty County, 28 km NE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1866 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 15 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 1,000,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 730,000× the energy of this one
  3. Around the size people start to feel M 3.0 65× the energy of this one
  4. This earthquake M 1.8 about 15 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 48.3790, -111.3002. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Liberty County, MT 28 km (17 mi) SW of here earthquakes near Liberty County
Toole County, MT 44 km (27 mi) SE of here earthquakes near Toole County
Pondera County, MT 70 km (44 mi) ENE of here earthquakes near Pondera County
Chouteau County, MT 84 km (52 mi) NW of here earthquakes near Chouteau County
Hill County, MT 92 km (57 mi) WSW of here earthquakes near Hill County
Teton County, MT 96 km (60 mi) NE of here earthquakes near Teton County

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

Aftershocks so far

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

  1. 1.7 27 km ESE of Shelby, Montana
  2. 1.7 24 km WSW of Chester, 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.