QuakeIndex

Earthquake · reviewed by a seismologist

M 2.5ml

11 km E of Harrison, Montana

· 6.0 km deep · released about 170 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Gallatin County 42 kmMadison County 46 kmJefferson County 58 kmBroadwater County 72 kmSilver Bow County 82 kmPark County 90 kmMeagher County 114 kmBeaverhead 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 2.5 (ml)
Depth
6.0 km below the surface
Felt
1 report · strongest reported intensity II
Nearest
Gallatin County, 42 km ESE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2310 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage. 1 person has reported feeling it to USGS.

How big was it?

This earthquake released about 170 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.5 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 89,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 63,000× the energy of this one
  3. Around the size people start to feel M 3.0 5.6× the energy of this one
  4. This earthquake M 2.5 about 170 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 45.6926, -111.6402. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Gallatin County, MT 42 km (26 mi) WNW of here earthquakes near Gallatin County
Madison County, MT 46 km (29 mi) NNE of here earthquakes near Madison County
Jefferson County, MT 58 km (36 mi) SE of here earthquakes near Jefferson County
Broadwater County, MT 72 km (45 mi) S of here earthquakes near Broadwater County
Silver Bow County, MT 82 km (51 mi) ESE of here earthquakes near Silver Bow County
Park County, MT 90 km (56 mi) WNW of here earthquakes near Park 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. 1.9 12 km NNW of Ennis, Montana
  2. 2.2 12 km NNW of Ennis, Montana
  3. 2.3 16 km SSW of Radersburg, Montana
  4. 1.6 15 km ESE of Harrison, Montana
  5. 1.8 2 km N of Pony, Montana
  6. 1.5 7 km NNE of Big Sky, Montana
  7. 2.2 2 km SE of Three Forks, Montana
  8. 1.6 5 km SW of Ponderosa Pines, Montana
  9. 2.2 5 km WSW of Ponderosa Pines, Montana
  10. 1.6 17 km W of Pony, Montana
  11. 1.5 7 km WSW of Ennis, Montana
  12. 1.6 13 km NNW of Ennis, Montana
  13. 2.1 13 km NNW of Ennis, Montana
  14. 2.3 13 km NNW of Ennis, Montana
  15. 2.4 12 km NNW 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 4.2 on 2019-08-16 — it released about 350 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.