QuakeIndex

quarry blast · reviewed by a seismologist

M 1.8ml

7 km WSW of Townsend, Montana

· -2.0 km deep · released about 13 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Broadwater County 10 kmJefferson County 39 kmMeagher County 62 kmGallatin County 92 kmSilver Bow County 92 kmMadison County 109 kmLewis and Clark County 110 kmCascade County 116 kmPowell 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
Magnitude
M 1.8 (ml)
Depth
-2.0 km below the surface
Felt
no reports yet
Nearest
Broadwater County, 10 km ENE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2908 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 13 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 1,100,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 810,000× the energy of this one
  3. Around the size people start to feel M 3.0 72× the energy of this one
  4. This earthquake M 1.8 about 13 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 46.2852, -111.6038. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Broadwater County, MT 10 km (6 mi) WSW of here earthquakes near Broadwater County
Jefferson County, MT 39 km (24 mi) ENE of here earthquakes near Jefferson County
Meagher County, MT 62 km (39 mi) WSW of here earthquakes near Meagher County
Gallatin County, MT 92 km (57 mi) NNW of here earthquakes near Gallatin County
Silver Bow County, MT 92 km (57 mi) ENE of here earthquakes near Silver Bow County
Madison County, MT 109 km (68 mi) NNE of here earthquakes near Madison County

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

Aftershocks so far

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

  1. 1.6 5 km W of Townsend, Montana
  2. 1.7 6 km WSW of Townsend, Montana
  3. 1.5 7 km SSW of The Silos, Montana
  4. 1.7 3 km NW of Manhattan, Montana
  5. 1.6 3 km WNW of Manhattan, Montana
  6. 2.5 2 km ESE of Logan, Montana
  7. 1.9 9 km WSW of Townsend, Montana
  8. 2.5 4 km NW of Manhattan, Montana
  9. 1.6 7 km WSW of Townsend, 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.