QuakeIndex

Earthquake · reviewed by a seismologist

M 2.9ml

14 km NNE of Twin Bridges, Montana

· 5.0 km deep · released about 680 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Silver Bow County 40 kmMadison County 46 kmJefferson County 53 kmBeaverhead County 77 kmDeer Lodge County 83 kmGallatin County 87 kmBroadwater County 95 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 2.9 (ml)
Depth
5.0 km below the surface
Felt
2 reports · strongest reported intensity III
Nearest
Silver Bow County, 40 km NW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 43 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage. 2 people have reported feeling it to USGS.

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.

Where

Epicentre 45.6640, -112.2590. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Silver Bow County, MT 40 km (25 mi) SE of here earthquakes near Silver Bow County
Madison County, MT 46 km (29 mi) NW of here earthquakes near Madison County
Jefferson County, MT 53 km (33 mi) SSW of here earthquakes near Jefferson County
Beaverhead County, MT 77 km (48 mi) NE of here earthquakes near Beaverhead County
Deer Lodge County, MT 83 km (52 mi) SE of here earthquakes near Deer Lodge County
Gallatin County, MT 87 km (54 mi) W of here earthquakes near Gallatin County

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

Aftershocks so far

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

  1. 1.8 5 km E of Butte, Montana
  2. 1.8 5 km ESE of Walkerville, Montana
  3. 2.1 12 km NW of Ennis, Montana
  4. 1.5 13 km NNW of Ennis, Montana
  5. 1.8 5 km E of Butte, Montana
  6. 2.0 2 km NNW of Pony, Montana
  7. 1.8 6 km E of Walkerville, Montana
  8. 1.5 4 km E of Butte, Montana
  9. 1.9 5 km E of Butte, Montana
  10. 1.6 5 km E of Butte, Montana
  11. 2.3 14 km NNE of Twin Bridges, 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 50 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.