QuakeIndex

quarry blast · reviewed by a seismologist

M 1.5ml

29 km S of Ennis, Montana

· -2.0 km deep · released about 5.4 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Madison County 31 kmGallatin County 65 kmBeaverhead County 92 kmFremont County 98 kmPark County 101 kmClark County 102 kmSilver Bow County 116 kmJefferson County 118 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 1.5 (ml)
Depth
-2.0 km below the surface
Felt
no reports yet
Nearest
Madison County, 31 km NNW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2084 days ago

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

USGS catalogues this as quarry blast, not an earthquake.

How big was it?

This earthquake released about 5.4 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.5 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 2,800,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 2,000,000× the energy of this one
  3. Around the size people start to feel M 3.0 180× the energy of this one
  4. This earthquake M 1.5 about 5.4 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 45.0877, -111.7170. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Madison County, MT 31 km (19 mi) SSE of here earthquakes near Madison County
Gallatin County, MT 65 km (40 mi) SW of here earthquakes near Gallatin County
Beaverhead County, MT 92 km (57 mi) E of here earthquakes near Beaverhead County
Fremont County, ID 98 km (61 mi) N of here earthquakes near Fremont County
Park County, MT 101 km (63 mi) WSW of here earthquakes near Park County
Clark County, ID 102 km (63 mi) NNE of here earthquakes near Clark County

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

Aftershocks so far

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

  1. 1.6 41 km S of Virginia City, Montana
  2. 1.6 11 km NNE of Ennis, Montana
  3. 1.6 20 km W of Hebgen Lake Estates, Montana
  4. 2.1 25 km WNW of Hebgen Lake Estates, Montana
  5. 1.7 42 km NNE of Spencer, Idaho
  6. 2.1 32 km S of Virginia City, Montana
  7. 1.9 30 km WNW of Hebgen Lake Estates, Montana
  8. 2.1 47 km ENE of Lima, Montana
  9. 2.3 45 km NE of Spencer, Idaho
  10. 1.9 27 km WNW of Hebgen Lake Estates, Montana
  11. 1.8 42 km W of Hebgen Lake Estates, Montana
  12. 2.7 26 km SSE of Virginia City, Montana
  13. 1.7 28 km SE of Virginia City, Montana
  14. 1.6 17 km SSE of Big Sky, Montana
  15. 1.5 23 km W 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.

For this area

The largest earthquake within 50 km in our catalogue was M 4.3 on 2016-06-13 — it released about 18,000 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.