QuakeIndex

Earthquake · reviewed by a seismologist

M 1.6ml

26 km ENE of Helena Valley Northeast, Montana

· 12 km deep · released about 7.6 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Broadwater County 56 kmCascade County 59 kmMeagher County 62 kmLewis and Clark County 65 kmJefferson County 84 kmPowell County 97 kmJudith Basin County 105 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 1.6 (ml)
Depth
12 km below the surface
Felt
no reports yet
Nearest
Broadwater County, 56 km SSE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2783 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 7.6 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.6 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 2,000,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,400,000× the energy of this one
  3. Around the size people start to feel M 3.0 130× the energy of this one
  4. This earthquake M 1.6 about 7.6 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 46.8230, -111.6518. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Broadwater County, MT 56 km (35 mi) NNW of here earthquakes near Broadwater County
Cascade County, MT 59 km (37 mi) SSW of here earthquakes near Cascade County
Meagher County, MT 62 km (38 mi) WNW of here earthquakes near Meagher County
Lewis and Clark County, MT 65 km (40 mi) ESE of here earthquakes near Lewis and Clark County
Jefferson County, MT 84 km (52 mi) NNE of here earthquakes near Jefferson County
Powell County, MT 97 km (60 mi) E of here earthquakes near Powell County

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

Aftershocks so far

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

  1. 1.6 6 km SE of Craig, Montana
  2. 2.5 23 km SSE of Craig, Montana
  3. 1.9 23 km SSE of Craig, Montana
  4. 2.7 3 km ENE of Helena, Montana
  5. 1.8 3 km E of Helena, Montana
  6. 2.1 22 km NNE of Helena Valley Northeast, Montana
  7. 2.9 28 km ENE of Helena Valley Northeast, Montana
  8. 2.7 28 km ENE of Helena Valley Northeast, Montana
  9. 2.1 29 km ENE of Helena Valley Northeast, Montana
  10. 2.2 1 km NW of East Helena, Montana
  11. 2.5 5 km N of Craig, Montana
  12. 1.7 3 km NNE of Craig, Montana
  13. 2.2 30 km ENE of Helena Valley Northeast, Montana
  14. 2.3 30 km ENE of Helena Valley Northeast, Montana
  15. 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.