QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8ml

6 km NNW of Plains, Montana

· 9.0 km deep · released about 13 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Sanders County 34 kmMineral County 45 kmLake County 64 kmShoshone County 76 kmMissoula County 94 kmFlathead County 108 kmClearwater County 109 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 1.8 (ml)
Depth
9.0 km below the surface
Felt
no reports yet
Nearest
Sanders County, 34 km NW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1176 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 13 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.8 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 1,100,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 810,000× the energy of this one
  3. Around the size people start to feel M 3.0 72× the energy of this one
  4. This earthquake M 1.8 about 13 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 47.5132, -114.9085. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Sanders County, MT 34 km (21 mi) SE of here earthquakes near Sanders County
Mineral County, MT 45 km (28 mi) NNE of here earthquakes near Mineral County
Lake County, MT 64 km (39 mi) WSW of here earthquakes near Lake County
Shoshone County, ID 76 km (47 mi) ENE of here earthquakes near Shoshone County
Missoula County, MT 94 km (58 mi) NW of here earthquakes near Missoula County
Flathead County, MT 108 km (67 mi) SW of here earthquakes near Flathead County

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

Aftershocks so far

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

  1. 1.7 21 km SSE of Happys Inn, Montana
  2. 1.6 16 km WSW of Kerr, Montana
  3. 2.0 17 km W of Niarada, Montana
  4. 1.6 4 km NW of Niarada, Montana
  5. 1.8 17 km WNW of Niarada, 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.