QuakeIndex

mining explosion · reviewed by a seismologist

M 2.9ml

Earthquake near Lame Deer, MT

No earthquake was likely felt in Lame Deer in the 24 hours to 4:34 pm MST (23:34 UTC). The last one was M 3.0, 29 km (18 mi) NNW, at 1:21 pm MDT on 2 June 2026, estimated intensity II (weak) in town. Every earthquake near Lame Deer

No: USGS classifies this as a mining explosion, not an earthquake. A magnitude 2.9 mining explosion was recorded 17 km (10 mi) northwest of Lame Deer, MT, at 11:36 am MST on 18 December 2024 (18:36 UTC), less than 1 km deep.

USGS: 13 km NNW of Muddy, Montana

11:36 am MST, Dec 18, 2024 · · 0.0 km deep · released about 680 lb of TNT

10 km30 km60 km120 km N Rosebud County 50 kmTreasure County 65 kmBig Horn County 66 kmPowder River County 104 kmSheridan County 106 kmCuster County 114 kmYellowstone County 115 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
11:36 am MST on 18 December 2024 ()
Where
17 km (10 mi) northwest of Lame Deer, MT · earthquakes near Lame Deer
Montana today
every earthquake in Montana in the last 24 hours
Magnitude
M 2.9 (ml)
Depth
0.0 km below the surface
Felt
no reports yet
Nearest
Rosebud County, 50 km NNE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 623 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage.

At this magnitude and depth, people at rest would likely notice it out to about 32 km (20 mi) from the epicentre. In Lame Deer, 17 km away, the estimate is intensity II (weak). Estimated from magnitude, depth and distance with the intensity equation USGS Did You Feel It? uses; felt reports, where there are any, are the measurement.

Likely felt in: Lame Deer 17 km, intensity II. Estimated for each town centre; each link is that town's own record.

USGS catalogues this as mining explosion, not an earthquake.

How big was it?

This earthquake released about 680 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.9 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 22,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 16,000× the energy of this one
  3. Around the size people start to feel M 3.0 1.4× the energy of this one
  4. This earthquake M 2.9 about 680 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.

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 45.7345, -106.8144. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Rosebud County, MT 50 km (31 mi) NNE earthquakes near Rosebud County
Treasure County, MT 65 km (41 mi) NNW earthquakes near Treasure County
Big Horn County, MT 66 km (41 mi) WSW earthquakes near Big Horn County
Powder River County, MT 104 km (65 mi) ESE earthquakes near Powder River County
Sheridan County, WY 106 km (66 mi) S earthquakes near Sheridan County
Custer County, MT 114 km (71 mi) ENE earthquakes near Custer County

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

Aftershocks so far

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

  1. 3.0 18 km WSW of Colstrip, Montana
  2. 3.0 9 km WSW of Colstrip, Montana
  3. 2.8 13 km W of Colstrip, Montana
  4. 3.2 12 km NW of Colstrip, Montana
  5. 3.0 14 km W of Colstrip, Montana
  6. 3.2 19 km N of Colstrip, Montana
  7. 3.0 16 km W of Colstrip, Montana
  8. 3.1 11 km SW of Colstrip, Montana
  9. 3.2 17 km SW of Colstrip, Montana
  10. 3.3 12 km SW of Colstrip, Montana
  11. 2.9 10 km SSE of Colstrip, Montana
  12. 3.3 15 km SE 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.