QuakeIndex

Earthquake · reviewed by a seismologist

M 2.3ml

Earthquake near Big Sky, MT

No earthquake was likely felt in Big Sky in the 24 hours to 3:06 pm MST (22:06 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 2.3 earthquake was recorded 26 km (16 mi) east-southeast of Big Sky, MT, at 1:39 am MDT on 19 July 2024 (07:39 UTC), 11 km deep.

USGS: 23 km WNW of Corwin Springs, Montana

55 km (34 mi) S of Bozeman, MT

1:39 am MDT, Jul 19, 2024 · · 11 km deep · released about 72 lb of TNT

Every earthquake near Big Sky Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Gallatin County 37 kmPark County 52 kmMadison County 68 kmSweet Grass County 112 kmFremont County 113 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
1:39 am MDT on 19 July 2024 ()
Where
26 km (16 mi) east-southeast of Big Sky, MT · earthquakes near Big Sky
Montana today
every earthquake in Montana in the last 24 hours
Magnitude
M 2.3 (ml)
Depth
11 km below the surface
Felt
no reports yet
Nearest
Gallatin County, 37 km NNW
Nearest mapped fault
Emigrant fault, 13 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 844 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 15 km (9 mi) from the epicentre. In Big Sky, 26 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 72 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 5.8 210,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 150,000× the energy of this one
  3. Around the size people start to feel M 3.0 13× the energy of this one
  4. This earthquake M 2.3 about 72 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 4.4 on 2017-06-16 — about 1,500 times the energy of this one.

Before 2016, the USGS record lists 6 earthquakes of M5 or more within 50 km; the five largest:

  1. 7.2 The 1959 Hebgen Lake, Montana Earthquake · 45 km SSW of this epicentre
  2. 6.5 14 km N of Madison Junction, Wyoming · 49 km SSE of this epicentre
  3. 6.3 22 km SW of Mammoth, Wyoming · 45 km SSE of this epicentre
  4. 6.1 30 km SSW of Big Sky, Montana · 42 km WSW of this epicentre
  5. 5.7 13 km SSW of Mammoth, Wyoming · 44 km SE 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 45.1880, -111.0658. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Gallatin County, MT 37 km (23 mi) NNW earthquakes near Gallatin County
Park County, MT 52 km (32 mi) NE earthquakes near Park County
Madison County, MT 68 km (42 mi) WNW earthquakes near Madison County
Sweet Grass County, MT 112 km (69 mi) NE earthquakes near Sweet Grass County
Fremont County, ID 113 km (70 mi) SSW earthquakes near Fremont County
Jefferson County, MT 130 km (81 mi) NW earthquakes near Jefferson County

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

Aftershocks so far

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

  1. 1.9 22 km SSW of Mammoth, Wyoming
  2. 1.5 23 km SSW of Mammoth, Wyoming
  3. 1.7 23 km SSW of Mammoth, Wyoming
  4. 1.5 16 km NE of West Yellowstone, Montana
  5. 1.5 16 km NE of West Yellowstone, Montana
  6. 2.8 16 km NE of West Yellowstone, Montana
  7. 1.5 16 km NE of West Yellowstone, Montana
  8. 1.7 13 km S of Bozeman, Montana
  9. 2.1 16 km E of Hebgen Lake Estates, Montana
  10. 1.5 14 km NNW of Emigrant, Montana
  11. 1.9 26 km NNW of Hebgen Lake Estates, Montana
  12. 1.7 22 km WNW of Hebgen Lake Estates, Montana
  13. 1.6 6 km E of Hebgen Lake Estates, Montana
  14. 2.1 6 km E of Hebgen Lake Estates, Montana
  15. 1.6 3 km ESE of Hebgen Lake Estates, 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.