QuakeIndex

quarry blast · reviewed by a seismologist

M 1.5ml

8 km WSW of Townsend, Montana

· -2.0 km deep · released about 6.2 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Broadwater County 11 kmJefferson County 38 kmMeagher County 63 kmSilver Bow County 91 kmGallatin County 94 kmLewis and Clark County 108 kmMadison County 111 kmCascade County 115 kmPowell County 116 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
Broadwater County, 11 km ENE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1894 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 6.2 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 2,500,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,700,000× the energy of this one
  3. Around the size people start to feel M 3.0 150× the energy of this one
  4. This earthquake M 1.5 about 6.2 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 46.3010, -111.6320. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Broadwater County, MT 11 km (7 mi) WSW of here earthquakes near Broadwater County
Jefferson County, MT 38 km (24 mi) ENE of here earthquakes near Jefferson County
Meagher County, MT 63 km (39 mi) WSW of here earthquakes near Meagher County
Silver Bow County, MT 91 km (57 mi) ENE of here earthquakes near Silver Bow County
Gallatin County, MT 94 km (59 mi) NNW of here earthquakes near Gallatin County
Lewis and Clark County, MT 108 km (67 mi) SSE of here earthquakes near Lewis and Clark County

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

Aftershocks so far

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

  1. 1.7 5 km W of Ponderosa Pines, Montana
  2. 2.3 3 km WSW of Ponderosa Pines, Montana
  3. 2.1 3 km SW of Ponderosa Pines, Montana
  4. 2.0 11 km WSW of Radersburg, Montana
  5. 2.4 3 km WSW of Ponderosa Pines, Montana
  6. 1.8 5 km NW of Helena Valley Southeast, Montana
  7. 1.7 Western Montana
  8. 2.1 3 km NW of Elkhorn, Montana
  9. 1.6 4 km WNW of Elkhorn, Montana
  10. 1.7 3 km NNE of Logan, Montana
  11. 2.1 2 km WSW of Logan, Montana
  12. 1.8 5 km NW of Logan, Montana
  13. 2.2 11 km NE of Townsend, Montana
  14. 1.6 2 km E of South Hills, Montana
  15. 1.7 9 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.

For this area

The largest earthquake within 50 km in our catalogue was M 4.0 on 2019-07-14 — it released about 4,900 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.