QuakeIndex

Earthquake · reviewed by a seismologist

M 2.3ml

Earthquake near Big Timber, MT

No earthquake was likely felt in Big Timber in the 24 hours to 2:42 pm MST (21:42 UTC). The last one was M 3.8, 51 km (32 mi) W, at 12:28 pm MST on 30 January 2023, estimated intensity II (weak) in town; 309 felt reports to USGS. Every earthquake near Big Timber

This page: a magnitude 2.3 earthquake was recorded 43 km (27 mi) northwest of Big Timber, MT, at 2:33 am MDT on 16 August 2017 (08:33 UTC), 16 km deep.

USGS: 30 km ENE of Wilsall, Montana

2:33 am MDT, Aug 16, 2017 · · 16 km deep · released about 77 lb of TNT

10 km30 km60 km120 km N Sweet Grass County 45 kmWheatland County 54 kmMeagher County 69 kmPark County 76 kmStillwater County 89 kmGolden Valley County 92 kmBroadwater County 94 kmGallatin County 94 kmJudith Basin County 101 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
2:33 am MDT on 16 August 2017 ()
Where
43 km (27 mi) northwest of Big Timber, MT · earthquakes near Big Timber
Montana today
every earthquake in Montana in the last 24 hours
Magnitude
M 2.3 (ml)
Depth
16 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 3374 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

At this magnitude and depth, people at rest would likely notice it out to about 10 km (6 mi) from the epicentre. In Big Timber, 43 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.

How big was it?

This earthquake released about 77 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 5.8 200,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 140,000× the energy of this one
  3. Around the size people start to feel M 3.0 12× the energy of this one
  4. This earthquake M 2.3 about 77 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 46.1253, -110.3180. 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 54 km (34 mi) NE earthquakes near Wheatland County
Meagher County, MT 69 km (43 mi) NW earthquakes near Meagher County
Park County, MT 76 km (47 mi) SSW earthquakes near Park County
Stillwater County, MT 89 km (55 mi) SE earthquakes near Stillwater County
Golden Valley County, MT 92 km (57 mi) ENE earthquakes near Golden Valley County

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

Aftershocks so far

13 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

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.