QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8ml

4 km WNW of Ponderosa Pines, Montana

· 7.2 km deep · released about 15 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Broadwater County 33 kmJefferson County 50 kmGallatin County 62 kmMeagher County 72 kmMadison County 88 kmPark County 94 kmSilver Bow County 97 kmSweet Grass 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
7.2 km below the surface
Felt
no reports yet
Nearest
Broadwater County, 33 km N
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 680 days ago

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

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 46.0410, -111.4232. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Broadwater County, MT 33 km (20 mi) S of here earthquakes near Broadwater County
Jefferson County, MT 50 km (31 mi) E of here earthquakes near Jefferson County
Gallatin County, MT 62 km (38 mi) NNW of here earthquakes near Gallatin County
Meagher County, MT 72 km (45 mi) SSW of here earthquakes near Meagher County
Madison County, MT 88 km (55 mi) NNE of here earthquakes near Madison County
Park County, MT 94 km (59 mi) NW of here earthquakes near Park County

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

Aftershocks so far

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

  1. 2.4 16 km ESE of Harrison, Montana
  2. 1.6 3 km NNW of Townsend, Montana
  3. 2.5 16 km ESE of Harrison, Montana
  4. 2.4 17 km ESE of Harrison, Montana
  5. 1.6 6 km NE of Three Forks, Montana
  6. 1.6 6 km W of Townsend, Montana
  7. 1.6 2 km E of Churchill, Montana
  8. 1.7 7 km W of Townsend, Montana
  9. 1.7 8 km WSW of Townsend, Montana
  10. 1.9 8 km WSW of Townsend, Montana
  11. 1.6 7 km W of Townsend, Montana
  12. 2.1 6 km NE of Logan, Montana
  13. 1.6 8 km W of Townsend, Montana
  14. 1.9 8 km W of Townsend, Montana
  15. 1.6 7 km SSW of The Silos, 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 4.2 on 2019-08-16 — it released about 4,000 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.