QuakeIndex

Earthquake · reviewed by a seismologist

M 2.7ml

Earthquake near Big Sky, MT

No earthquake was likely felt in Big Sky in the 24 hours to 11:47 am MST (18:47 UTC). The last one was M 3.7, 68 km (42 mi) SE, at 7:22 am MDT on 28 October 2025, estimated intensity II (weak) in town; 11 felt reports to USGS. Every earthquake near Big Sky

This page: a magnitude 2.7 earthquake was recorded 44 km (28 mi) west-southwest of Big Sky, MT, at 12:21 pm MST on 19 January 2022 (19:21 UTC), 10 km deep.

USGS: 26 km SSE of Virginia City, Montana

12:21 pm MST, Jan 19, 2022 · · 10 km deep · released about 340 lb of TNT

Every earthquake near Big Sky Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Madison County 29 kmGallatin County 73 kmBeaverhead County 83 kmClark County 95 kmFremont County 99 kmPark County 112 kmSilver Bow County 112 kmJefferson 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
12:21 pm MST on 19 January 2022 ()
Where
44 km (28 mi) west-southwest of Big Sky, MT · earthquakes near Big Sky
Montana today
every earthquake in Montana in the last 24 hours
Magnitude
M 2.7 (ml)
Depth
10 km below the surface
Felt
no reports yet
Nearest
Madison County, 29 km N
Nearest mapped fault
Madison fault, 20 km from its surface trace — near is not the same as on
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1685 days ago

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

At this magnitude and depth, people at rest would likely notice it out to about 23 km (14 mi) from the epicentre. In Big Sky, 44 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 340 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.7 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 45,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 32,000× the energy of this one
  3. Around the size people start to feel M 3.0 2.8× the energy of this one
  4. This earthquake M 2.7 about 340 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

The largest earthquake within 50 km since 2016 was M 4.3 on 2016-06-13 — about 290 times the energy of this one.

Before 2016, the USGS record lists 5 earthquakes of M5 or more within 50 km:

  1. 6.1 30 km SSW of Big Sky, Montana · 23 km E of this epicentre
  2. 5.2 32 km WNW of Hebgen Lake Estates, Montana · 31 km SE of this epicentre
  3. 5.2 26 km WNW of Hebgen Lake Estates, Montana · 37 km SE of this epicentre
  4. 5.0 31 km W of Hebgen Lake Estates, Montana · 34 km SE of this epicentre
  5. 5.0 39 km W of Hebgen Lake Estates, Montana · 43 km SSE of this epicentre

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 45.0678, -111.8453. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Madison County, MT 29 km (18 mi) N earthquakes near Madison County
Gallatin County, MT 73 km (45 mi) NE earthquakes near Gallatin County
Beaverhead County, MT 83 km (51 mi) W earthquakes near Beaverhead County
Clark County, ID 95 km (59 mi) SSW earthquakes near Clark County
Fremont County, ID 99 km (61 mi) SSE earthquakes near Fremont County
Park County, MT 112 km (69 mi) ENE earthquakes near Park County

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

Aftershocks so far

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

  1. 1.7 30 km NW of Hebgen Lake Estates, Montana
  2. 1.6 36 km NNE of Spencer, Idaho
  3. 1.5 11 km N of Ennis, Montana
  4. 2.0 38 km NNE of Spencer, Idaho
  5. 1.7 37 km SSE of Virginia City, Montana
  6. 1.9 29 km WNW of Hebgen Lake Estates, Montana
  7. 1.5 43 km NE of Spencer, Idaho
  8. 2.1 34 km S of Virginia City, Montana
  9. 1.5 35 km S of Virginia City, Montana
  10. 1.7 33 km S of Virginia City, Montana
  11. 2.3 40 km NE of Spencer, Idaho
  12. 1.6 17 km S of Pony, Montana
  13. 2.4 30 km WNW of Hebgen Lake Estates, Montana
  14. 1.5 29 km WNW of Hebgen Lake Estates, Montana
  15. 1.6 42 km S of Alder, 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.