QuakeIndex

mining explosion · reviewed by a seismologist

M 3.2ml

Earthquake near Colstrip, MT

USGS: 10 km S of Colstrip, Montana

1:39 pm MST, Nov 11, 2020 · · 0.0 km deep · released about 1,900 lb of TNT

Every earthquake near Colstrip Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Rosebud County 42 kmTreasure County 68 kmBig Horn County 80 kmPowder River County 95 kmCuster County 99 kmSheridan County 114 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
1:39 pm MST on 11 November 2020 ()
Where
10 km (6 mi) S of Colstrip, MT · earthquakes near Colstrip
Magnitude
M 3.2 (ml)
Depth
0.0 km below the surface
Felt
no reports yet
Nearest
Rosebud County, 42 km N
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2074 days ago

A magnitude 3.2 earthquake was recorded 10 km (6 mi) S of Colstrip, MT, at 1:39 pm MST on 11 November 2020 (20:39 UTC). This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage.

Earthquakes near other towns within 30 km: Lame Deer.

USGS catalogues this as mining explosion, not an earthquake.

How big was it?

This earthquake released about 1,900 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.2 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 180,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 7,900× the energy of this one
  3. Magna, Utah 2020 M 5.7 5,600× the energy of this one
  4. This earthquake M 3.2 about 1,900 lb of TNT
  5. Around the size people start to feel M 3.0 this one released 2× more

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.

For this area

No earthquake of M4 or more has been recorded within 50 km since our catalogue begins in 2016.

Before 2016, the USGS record since 1900 lists no earthquake of M5 or more within 50 km.

Since 2016: the QuakeIndex catalogue (US, M1.5+), built from the USGS FDSN event service. Before 2016: USGS ComCat, M5+ from 1900. Distances are between epicentres. This is the record, not a forecast.

Where

Epicentre 45.7949, -106.6470. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Rosebud County, MT 42 km (26 mi) N earthquakes near Rosebud County
Treasure County, MT 68 km (42 mi) NW earthquakes near Treasure County
Big Horn County, MT 80 km (50 mi) WSW earthquakes near Big Horn County
Powder River County, MT 95 km (59 mi) ESE earthquakes near Powder River County
Custer County, MT 99 km (62 mi) ENE earthquakes near Custer County
Sheridan County, WY 114 km (71 mi) S earthquakes near Sheridan County

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

Aftershocks so far

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

  1. 3.2 19 km N of Colstrip, Montana
  2. 3.0 16 km W of Colstrip, Montana
  3. 3.1 11 km SW of Colstrip, Montana
  4. 3.2 17 km SW of Colstrip, Montana
  5. 3.3 12 km SW of Colstrip, Montana
  6. 2.9 10 km SSE of Colstrip, Montana
  7. 3.3 15 km SE of Colstrip, Montana
  8. 2.9 13 km NNW of Muddy, Montana
  9. 2.9 10 km WSW of Colstrip, Montana
  10. 3.2 8 km NNE of Colstrip, Montana
  11. 3.2 11 km WSW of Colstrip, Montana
  12. 3.1 25 km W of Colstrip, Montana
  13. 3.2 8 km NNW of Colstrip, Montana
  14. 2.9 8 km SSW of Colstrip, Montana
  15. 3.1 7 km SW of Colstrip, 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.