QuakeIndex

Earthquake · reviewed by a seismologist

M 2.8ml

0 km NW of Cardwell, Montana

· 7.8 km deep · released about 430 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Jefferson County 30 kmSilver Bow County 55 kmMadison County 60 kmBroadwater County 63 kmGallatin County 72 kmDeer Lodge County 95 kmBeaverhead County 109 kmMeagher County 113 kmPark 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 2.8 (ml)
Depth
7.8 km below the surface
Felt
no reports yet
Nearest
Jefferson County, 30 km NNW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 800 days ago

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

How big was it?

This earthquake released about 430 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.8 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 35,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 25,000× the energy of this one
  3. Around the size people start to feel M 3.0 2.2× the energy of this one
  4. This earthquake M 2.8 about 430 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 45.8620, -111.9545. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Jefferson County, MT 30 km (19 mi) SSE of here earthquakes near Jefferson County
Silver Bow County, MT 55 km (34 mi) E of here earthquakes near Silver Bow County
Madison County, MT 60 km (37 mi) N of here earthquakes near Madison County
Broadwater County, MT 63 km (39 mi) SW of here earthquakes near Broadwater County
Gallatin County, MT 72 km (45 mi) WNW of here earthquakes near Gallatin County
Deer Lodge County, MT 95 km (59 mi) ESE of here earthquakes near Deer Lodge County

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

Aftershocks so far

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

  1. 1.8 5 km E of Butte, Montana
  2. 2.4 7 km NW of Willow Creek, Montana
  3. 1.6 6 km E of Butte, Montana
  4. 1.9 5 km E of Butte, Montana
  5. 1.7 5 km E of Butte, Montana
  6. 1.6 6 km E of Butte, Montana
  7. 1.5 6 km E of Butte, Montana
  8. 1.6 6 km ENE of Butte, Montana
  9. 1.7 5 km E of Butte, Montana
  10. 1.8 5 km ENE of Butte, Montana
  11. 1.7 5 km ENE of Butte, Montana
  12. 1.5 6 km E of Butte, Montana
  13. 1.6 6 km E of Butte, Montana
  14. 1.6 4 km ENE of Butte, Montana
  15. 1.5 10 km NNE of Three Forks, 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.

For this area

The largest earthquake within 50 km in our catalogue was M 4.0 on 2016-09-03 — it released about 78 times the energy of this one.

From the QuakeIndex catalogue, built from the USGS FDSN event service.

On USGS

QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.