QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8ml

22 km SW of Heart Butte, Montana

· 15 km deep · released about 13 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Pondera County 61 kmGlacier County 65 kmTeton County 65 kmFlathead County 78 kmLake County 95 kmToole County 112 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
15 km below the surface
Felt
no reports yet
Nearest
Pondera County, 61 km ENE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2177 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 13 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 1,200,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 840,000× the energy of this one
  3. Around the size people start to feel M 3.0 75× the energy of this one
  4. This earthquake M 1.8 about 13 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 48.1240, -113.0268. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Pondera County, MT 61 km (38 mi) W of here earthquakes near Pondera County
Glacier County, MT 65 km (40 mi) S of here earthquakes near Glacier County
Teton County, MT 65 km (40 mi) WNW of here earthquakes near Teton County
Flathead County, MT 78 km (49 mi) ESE of here earthquakes near Flathead County
Lake County, MT 95 km (59 mi) NE of here earthquakes near Lake County
Toole County, MT 112 km (69 mi) WSW of here earthquakes near Toole County

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

Aftershocks so far

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

  1. 2.1 27 km E of Swan Lake, Montana
  2. 2.5 24 km E of Swan Lake, Montana
  3. 2.4 27 km E of Swan Lake, Montana
  4. 1.6 19 km SSE of East Glacier Park Village, Montana
  5. 2.0 19 km SW of Heart Butte, 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.