QuakeIndex

Earthquake · reviewed by a seismologist

M 3.3ml

4 km NNE of Marysville, Montana

· 5.0 km deep · released about 1.3 tons of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Lewis and Clark County 38 kmPowell County 49 kmJefferson County 76 kmBroadwater County 79 kmCascade County 92 kmGranite County 97 kmDeer Lodge County 101 kmSilver Bow County 103 kmMeagher County 107 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 3.3 (ml)
Depth
5.0 km below the surface
Felt
15 reports · strongest reported intensity III
Nearest
Lewis and Clark County, 38 km N
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2353 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage. 15 people have reported feeling it to USGS.

How big was it?

This earthquake released about 1.3 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.3 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 130,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 5,600× the energy of this one
  3. Magna, Utah 2020 M 5.7 4,000× the energy of this one
  4. This earthquake M 3.3 about 1.3 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 2.8× 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 46.7898, -112.2885. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Lewis and Clark County, MT 38 km (23 mi) S of here earthquakes near Lewis and Clark County
Powell County, MT 49 km (31 mi) E of here earthquakes near Powell County
Jefferson County, MT 76 km (47 mi) NNW of here earthquakes near Jefferson County
Broadwater County, MT 79 km (49 mi) NW of here earthquakes near Broadwater County
Cascade County, MT 92 km (57 mi) SW of here earthquakes near Cascade County
Granite County, MT 97 km (61 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. 1.8 16 km ESE of Lincoln, MT
  2. 2.1 15 km SE of Lincoln, Montana
  3. 1.8 15 km ESE of Lincoln, Montana
  4. 1.8 14 km SE of Lincoln, Montana
  5. 1.7 4 km WSW of South Hills, Montana
  6. 2.1 16 km NNE of Avon, Montana
  7. 1.9 16 km NNE of Avon, Montana
  8. 2.0 16 km NNE of Avon, Montana
  9. 1.9 15 km ESE of Lincoln, Montana
  10. 2.5 Western Montana
  11. 3.1 15 km SE of Lincoln, Montana
  12. 2.4 4 km NNW of Helena Valley Northeast, Montana
  13. 2.3 13 km WSW of Craig, Montana
  14. 1.9 12 km ESE of Lincoln, Montana
  15. 1.6 15 km ESE of Lincoln, 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 5,600 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.