QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8ml

39 km ESE of Cardston, Canada

· 6.9 km deep · released about 17 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Glacier County 35 kmToole County 91 kmPondera County 98 kmFlathead 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 1.8 (ml)
Depth
6.9 km below the surface
Felt
no reports yet
Nearest
Glacier County, 35 km SSW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2347 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 17 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 5.8 900,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 640,000× the energy of this one
  3. Around the size people start to feel M 3.0 57× the energy of this one
  4. This earthquake M 1.8 about 17 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 49.0090, -112.8477. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Glacier County, MT 35 km (22 mi) NNE of here earthquakes near Glacier County
Toole County, MT 91 km (57 mi) WNW of here earthquakes near Toole County
Pondera County, MT 98 km (61 mi) NNW of here earthquakes near Pondera County
Flathead County, MT 119 km (74 mi) NE of here earthquakes near Flathead County

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

Aftershocks so far

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

  1. 2.3 40 km SSE of Magrath, Canada
  2. 2.3 6 km SSW of Cardston, Canada
  3. 1.7 21 km SSE of Cardston, Canada
  4. 2.0 43 km NNW of Santa Rita, Montana
  5. 2.4 38 km NNW of Santa Rita, Montana
  6. 1.9 40 km SSE of Magrath, Canada
  7. 1.5 20 km NW of Santa Rita, Montana
  8. 2.7 17 km NNW of Santa Rita, Montana
  9. 2.8 8 km S of Cardston, Canada
  10. 1.7 14 km S of Cardston, Canada
  11. 2.0 Alberta, Canada
  12. 1.9 35 km SE of Cardston, Canada
  13. 1.5 23 km NW of Santa Rita, Montana
  14. 2.4 22 km NW of Santa Rita, Montana
  15. 2.1 42 km NW of Santa Rita, 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.