QuakeIndex

Earthquake · reviewed by a seismologist

M 3.1ml

13 km NNW of Marysville, Montana

· 4.8 km deep · released about 1,300 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Lewis and Clark County 29 kmPowell County 43 kmJefferson County 85 kmBroadwater County 89 kmCascade County 92 kmGranite County 96 kmDeer Lodge County 104 kmTeton County 107 kmSilver Bow County 110 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 3.1 (ml)
Depth
4.8 km below the surface
Felt
7 reports · strongest reported intensity III
Nearest
Lewis and Clark County, 29 km N
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1919 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage. 7 people have reported feeling it to USGS.

How big was it?

This earthquake released about 1,300 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.1 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 250,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 11,000× the energy of this one
  3. Magna, Utah 2020 M 5.7 7,900× the energy of this one
  4. This earthquake M 3.1 about 1,300 lb of TNT
  5. Around the size people start to feel M 3.0 this one released 1.4× more

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 46.8625, -112.3669. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Lewis and Clark County, MT 29 km (18 mi) S of here earthquakes near Lewis and Clark County
Powell County, MT 43 km (27 mi) E of here earthquakes near Powell County
Jefferson County, MT 85 km (53 mi) NNW of here earthquakes near Jefferson County
Broadwater County, MT 89 km (55 mi) NW of here earthquakes near Broadwater County
Cascade County, MT 92 km (57 mi) WSW of here earthquakes near Cascade County
Granite County, MT 96 km (60 mi) ENE of here earthquakes near Granite County

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

Aftershocks so far

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

  1. 1.6 2 km E of South Hills, Montana
  2. 1.8 8 km SSE of Marysville, Montana
  3. 1.9 13 km ESE of Lincoln, Montana
  4. 1.6 3 km SW of Helena Valley Northwest, Montana
  5. 1.6 5 km SSE of Lincoln, Montana
  6. 1.8 12 km ESE of Lincoln, Montana
  7. 2.0 5 km SSE of Lincoln, Montana
  8. 2.8 7 km SSE of Lincoln, Montana
  9. 1.6 1 km SSE of South Hills, Montana
  10. 3.3 6 km SSE of Lincoln, Montana
  11. 2.3 6 km SSE of Lincoln, Montana
  12. 1.9 Western Montana
  13. 2.8 7 km SSE of Lincoln, Montana
  14. 3.2 6 km SSE of Lincoln, Montana
  15. 1.6 1 km SSE of South Hills, 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 5.8 on 2017-07-06 — it released about 11,000 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.