QuakeIndex

Earthquake · reviewed by a seismologist

M 2.6ml

13 km WSW of Cascade, Montana

· 26 km deep · released about 240 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Cascade County 40 kmLewis and Clark County 41 kmTeton County 71 kmPowell County 92 kmMeagher County 103 kmBroadwater County 106 kmPondera County 112 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 2.6 (ml)
Depth
26 km below the surface
Felt
2 reports · strongest reported intensity III
Nearest
Cascade County, 40 km E
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 798 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage. 2 people have reported feeling it to USGS.

How big was it?

This earthquake released about 240 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.6 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 63,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 45,000× the energy of this one
  3. Around the size people start to feel M 3.0 4× the energy of this one
  4. This earthquake M 2.6 about 240 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 47.2475, -111.8726. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Cascade County, MT 40 km (25 mi) W of here earthquakes near Cascade County
Lewis and Clark County, MT 41 km (25 mi) ENE of here earthquakes near Lewis and Clark County
Teton County, MT 71 km (44 mi) SSE of here earthquakes near Teton County
Powell County, MT 92 km (57 mi) ENE of here earthquakes near Powell County
Meagher County, MT 103 km (64 mi) NW of here earthquakes near Meagher County
Broadwater County, MT 106 km (66 mi) NNW of here earthquakes near Broadwater County

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

Aftershocks so far

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

  1. 1.5 16 km NE of Helena Valley Northwest, Montana
  2. 1.6 14 km SSE of Craig, Montana
  3. 2.4 21 km SSE of Craig, Montana
  4. 2.0 20 km NNE of Helena Valley Northeast, Montana
  5. 1.6 6 km SE of Craig, Montana
  6. 2.5 23 km SSE of Craig, Montana
  7. 1.9 23 km SSE of Craig, Montana
  8. 2.1 22 km NNE of Helena Valley Northeast, Montana
  9. 1.6 14 km NNE of Marysville, Montana
  10. 2.5 5 km N of Craig, Montana
  11. 1.7 3 km NNE of Craig, Montana
  12. 2.0 22 km SSE of Craig, 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.