QuakeIndex

Earthquake · reviewed by a seismologist

M 2.2ml

Earthquake near Thompson Falls, MT

No earthquake was likely felt in Thompson Falls in the 24 hours to 3:49 pm MST (22:49 UTC). The last one was M 3.3, 37 km (23 mi) WSW, at 11:03 pm MST on 10 February 2025, estimated intensity II (weak) in town; 93 felt reports to USGS. Every earthquake near Thompson Falls

This page: a magnitude 2.2 earthquake was recorded 31 km (19 mi) north of Thompson Falls, MT, at 4:27 am MDT on 12 September 2016 (10:27 UTC), 10 km deep.

USGS: 25 km E of Trout Creek, Montana

4:27 am MDT, Sep 12, 2016 · · 10 km deep · released about 56 lb of TNT

10 km30 km60 km120 km N Sanders County 14 kmShoshone County 74 kmLincoln County 77 kmMineral County 84 kmLake County 92 kmFlathead County 102 kmKootenai County 109 kmBonner County 113 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
4:27 am MDT on 12 September 2016 ()
Where
31 km (19 mi) north of Thompson Falls, MT · earthquakes near Thompson Falls
Montana today
every earthquake in Montana in the last 24 hours
Magnitude
M 2.2 (ml)
Depth
10 km below the surface
Felt
no reports yet
Nearest
Sanders County, 14 km SSE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 3712 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

At this magnitude and depth, people at rest would likely notice it out to about 15 km (9 mi) from the epicentre. In Thompson Falls, 31 km away, the estimate is intensity II (weak). Estimated from magnitude, depth and distance with the intensity equation USGS Did You Feel It? uses; felt reports, where there are any, are the measurement.

How big was it?

This earthquake released about 56 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.2 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 270,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 190,000× the energy of this one
  3. Around the size people start to feel M 3.0 17× the energy of this one
  4. This earthquake M 2.2 about 56 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.

For this area

No earthquake of M4 or more has been recorded within 50 km since our catalogue begins in 2016.

Before 2016, the USGS record since 1900 lists no earthquake of M5 or more within 50 km.

Since 2016: the QuakeIndex catalogue (US, M1.5+), built from the USGS FDSN event service. Before 2016: USGS ComCat, M5+ from 1900. Distances are between epicentres. This is the record, not a forecast.

Where

Epicentre 47.8707, -115.2665. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Sanders County, MT 14 km (9 mi) SSE earthquakes near Sanders County
Shoshone County, ID 74 km (46 mi) SW earthquakes near Shoshone County
Lincoln County, MT 77 km (48 mi) N earthquakes near Lincoln County
Mineral County, MT 84 km (52 mi) S earthquakes near Mineral County
Lake County, MT 92 km (57 mi) ESE earthquakes near Lake County
Flathead County, MT 102 km (63 mi) ENE earthquakes near Flathead County

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

Aftershocks so far

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

  1. 2.6 4 km NW of Happys Inn, Montana
  2. 1.8 17 km WNW of Niarada, Montana
  3. 1.8 6 km NNW of Plains, Montana
  4. 2.2 16 km ENE of Happys Inn, Montana
  5. 1.6 13 km WNW of Marion, Montana
  6. 1.7 18 km NW of Marion, Montana
  7. 1.7 6 km S of Happys Inn, Montana
  8. 2.1 22 km NNE of Trout Creek, Montana
  9. 1.7 2 km NNW of Happys Inn, Montana
  10. 1.7 20 km ENE of Trout Creek, Montana
  11. 2.0 2 km W of Happys Inn, Montana
  12. 1.9 5 km ENE of Weeksville, Montana
  13. 1.6 17 km SW of Happys Inn, Montana
  14. 1.8 14 km SW of Thompson Falls, Montana
  15. 2.4 16 km WNW of Lonepine, 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.