QuakeIndex

quarry blast · reviewed by a seismologist

M 1.8ml

27 km SE of Virginia City, Montana

· -2.0 km deep · released about 15 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Madison County 29 kmGallatin County 64 kmBeaverhead County 92 kmFremont County 100 kmPark County 102 kmClark County 103 kmSilver Bow County 115 kmJefferson County 117 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 1.8 (ml)
Depth
-2.0 km below the surface
Felt
no reports yet
Nearest
Madison County, 29 km NNW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1997 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 15 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.8 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 1,000,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 710,000× the energy of this one
  3. Around the size people start to feel M 3.0 63× the energy of this one
  4. This earthquake M 1.8 about 15 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 45.0993, -111.7273. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Madison County, MT 29 km (18 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 92 km (57 mi) E of here earthquakes near Beaverhead County
Fremont County, ID 100 km (62 mi) N of here earthquakes near Fremont County
Park County, MT 102 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 3 km NNW of Alder, Montana
  2. 1.6 13 km S of Ennis, Montana
  3. 2.1 44 km NNE of Spencer, Idaho
  4. 3.0 18 km NNE of Ennis, Montana
  5. 1.6 42 km NE of Spencer, Idaho
  6. 2.5 13 km NNW of Ennis, Montana
  7. 1.9 12 km NNW of Ennis, Montana
  8. 2.3 34 km S of Virginia City, Montana
  9. 1.9 8 km ESE of Sheridan, Montana
  10. 1.7 19 km NNE of Ennis, Montana
  11. 3.3 17 km NNE of Ennis, Montana
  12. 2.9 20 km SSE of Harrison, Montana
  13. 1.7 17 km S of Pony, Montana
  14. 1.6 41 km S of Virginia City, Montana
  15. 1.6 11 km NNE of Ennis, 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 6,500 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.