QuakeIndex

quarry blast · reviewed by a seismologist

M 1.6ml

28 km S of Ennis, Montana

· -2.0 km deep · released about 8.7 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Madison County 31 kmGallatin County 64 kmBeaverhead County 93 kmFremont County 99 kmPark County 101 kmClark County 103 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 1.6 (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 720 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 8.7 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.6 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 1,700,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,200,000× the energy of this one
  3. Around the size people start to feel M 3.0 110× the energy of this one
  4. This earthquake M 1.6 about 8.7 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 45.0912, -111.7107. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Madison County, MT 31 km (19 mi) SSE of here earthquakes near Madison County
Gallatin County, MT 64 km (40 mi) SW of here earthquakes near Gallatin County
Beaverhead County, MT 93 km (58 mi) E of here earthquakes near Beaverhead County
Fremont County, ID 99 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 103 km (64 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

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

  1. 1.8 14 km WNW of Hebgen Lake Estates, Montana
  2. 1.6 34 km SSE of Virginia City, Montana
  3. 1.8 30 km WNW of Hebgen Lake Estates, Montana
  4. 2.7 48 km NE of Spencer, Idaho
  5. 1.7 47 km NW of Island Park, Idaho
  6. 2.4 47 km NW of Island Park, Idaho
  7. 2.3 49 km NNE of Spencer, Idaho
  8. 1.8 44 km NE of Spencer, Idaho
  9. 2.0 10 km WSW of Hebgen Lake Estates, Montana
  10. 2.9 30 km W of Hebgen Lake Estates, Montana
  11. 2.6 10 km W of Hebgen Lake Estates, Montana
  12. 1.8 47 km NE of Spencer, Idaho
  13. 1.7 27 km W of Hebgen Lake Estates, Montana
  14. 1.5 46 km NE of Spencer, Idaho
  15. 1.7 14 km WNW 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 11,000 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.