QuakeIndex

Earthquake · reviewed by a seismologist

M 2.8ml

35 km WSW of Augusta, Montana

· 32 km deep · released about 480 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Lewis and Clark County 45 kmPowell County 60 kmTeton County 64 kmMissoula County 89 kmLake County 98 kmPondera County 105 kmCascade County 112 kmGranite 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 2.8 (ml)
Depth
32 km below the surface
Felt
1 report · strongest reported intensity III
Nearest
Lewis and Clark County, 45 km SE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2424 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 480 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.8 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 32,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 22,000× the energy of this one
  3. Around the size people start to feel M 3.0 2× the energy of this one
  4. This earthquake M 2.8 about 480 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 47.3831, -112.8367. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Lewis and Clark County, MT 45 km (28 mi) NW of here earthquakes near Lewis and Clark County
Powell County, MT 60 km (37 mi) N of here earthquakes near Powell County
Teton County, MT 64 km (40 mi) SW of here earthquakes near Teton County
Missoula County, MT 89 km (55 mi) ENE of here earthquakes near Missoula County
Lake County, MT 98 km (61 mi) ESE of here earthquakes near Lake County
Pondera County, MT 105 km (65 mi) SSW of here earthquakes near Pondera County

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

Aftershocks so far

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

  1. 2.3 13 km ESE of Ovando, Montana
  2. 2.1 16 km ESE of Ovando, Montana
  3. 2.8 17 km ESE of Ovando, Montana
  4. 2.0 25 km NE of Ovando, Montana
  5. 2.7 26 km WSW of Augusta, Montana
  6. 1.8 16 km ESE of Ovando, Montana
  7. 1.7 16 km ESE of Ovando, Montana
  8. 1.8 25 km W of Augusta, Montana
  9. 1.6 36 km NE of Seeley Lake, Montana
  10. 2.4 37 km NE of Seeley Lake, Montana
  11. 1.5 8 km WNW of Lincoln, Montana
  12. 1.7 8 km WNW of Lincoln, Montana
  13. 2.0 27 km W of Augusta, Montana
  14. 1.5 37 km NE of Seeley Lake, Montana
  15. 1.6 35 km NE of Seeley Lake, 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.