QuakeIndex

Earthquake · reviewed by a seismologist

M 2.3ml

Western Montana

· 5.0 km deep · released about 85 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Jefferson County 43 kmBroadwater County 43 kmGallatin County 57 kmMadison County 74 kmSilver Bow County 85 kmMeagher County 87 kmPark County 96 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 2.3 (ml)
Depth
5.0 km below the surface
Felt
3 reports · strongest reported intensity III
Nearest
Jefferson County, 43 km WNW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1671 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage. 3 people have reported feeling it to USGS.

How big was it?

This earthquake released about 85 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.3 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 180,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 130,000× the energy of this one
  3. Around the size people start to feel M 3.0 11× the energy of this one
  4. This earthquake M 2.3 about 85 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 45.9428, -111.5675. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Jefferson County, MT 43 km (27 mi) ESE of here earthquakes near Jefferson County
Broadwater County, MT 43 km (27 mi) S of here earthquakes near Broadwater County
Gallatin County, MT 57 km (35 mi) NNW of here earthquakes near Gallatin County
Madison County, MT 74 km (46 mi) NNE of here earthquakes near Madison County
Silver Bow County, MT 85 km (53 mi) E of here earthquakes near Silver Bow County
Meagher County, MT 87 km (54 mi) SW of here earthquakes near Meagher County

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

Aftershocks so far

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

  1. 1.9 9 km W of Townsend, Montana
  2. 1.6 5 km SSW of Willow Creek, Montana
  3. 2.1 3 km WNW of Pony, Montana
  4. 1.8 5 km NNW of Logan, Montana
  5. 1.5 Western Montana
  6. 2.0 3 km WNW of Pony, Montana
  7. 1.8 18 km N of Ennis, Montana
  8. 2.5 3 km WNW of Pony, Montana
  9. 1.6 Western Montana
  10. 1.6 3 km WSW of Ponderosa Pines, Montana
  11. 1.6 8 km W of Townsend, Montana
  12. 1.7 6 km WSW of Townsend, Montana
  13. 1.6 14 km ESE of Harrison, Montana
  14. 1.5 10 km WNW of Four Corners, Montana
  15. 1.6 5 km SE 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 4.2 on 2019-08-16 — it released about 710 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.