QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8ml

Earthquake near Big Timber, MT

USGS: 28 km ENE of Wilsall, Montana

5:14 pm MDT, Jul 31, 2017 · · 6.0 km deep · released about 14 lb of TNT

Every earthquake near Big Timber Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Sweet Grass County 45 kmWheatland County 56 kmMeagher County 69 kmPark County 74 kmStillwater County 89 kmGallatin County 93 kmBroadwater County 93 kmGolden Valley County 94 kmJudith Basin County 102 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
5:14 pm MDT on 31 July 2017 ()
Where
43 km (27 mi) NW of Big Timber, MT · earthquakes near Big Timber
Magnitude
M 1.8 (ml)
Depth
6.0 km below the surface
Felt
no reports yet
Nearest
Sweet Grass County, 45 km SE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 3349 days ago

A magnitude 1.8 earthquake was recorded 43 km (27 mi) NW of Big Timber, MT, at 5:14 pm MDT on 31 July 2017 (23:14 UTC). This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

How big was it?

This earthquake released about 14 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.8 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 1,100,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 760,000× the energy of this one
  3. Around the size people start to feel M 3.0 68× the energy of this one
  4. This earthquake M 1.8 about 14 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 46.1177, -110.3312. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Sweet Grass County, MT 45 km (28 mi) SE earthquakes near Sweet Grass County
Wheatland County, MT 56 km (35 mi) NE earthquakes near Wheatland County
Meagher County, MT 69 km (43 mi) NW earthquakes near Meagher County
Park County, MT 74 km (46 mi) SSW earthquakes near Park County
Stillwater County, MT 89 km (56 mi) SE earthquakes near Stillwater County
Gallatin County, MT 93 km (58 mi) SW earthquakes near Gallatin County

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

Aftershocks so far

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

  1. 1.8 23 km ENE of Wilsall, Montana
  2. 3.8 9 km NNW of Livingston, Montana
  3. 2.2 30 km ENE of Wilsall, Montana
  4. 1.9 23 km SE of White Sulphur Springs, Montana
  5. 2.7 32 km NE of Wilsall, Montana
  6. 2.4 32 km ENE of Wilsall, Montana
  7. 1.7 32 km ENE of Wilsall, Montana
  8. 2.1 29 km ENE of Wilsall, Montana
  9. 1.7 28 km ENE of Wilsall, Montana
  10. 1.5 30 km ENE of Wilsall, Montana
  11. 1.5 29 km ENE of Wilsall, Montana
  12. 1.8 29 km ENE of Wilsall, Montana
  13. 1.6 29 km ENE of Wilsall, Montana
  14. 2.3 30 km ENE of Wilsall, Montana
  15. 1.8 28 km ENE of Wilsall, 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.