QuakeIndex

Earthquake · reviewed by a seismologist

M 3.1ml

Earthquake near Polson, MT

No earthquake was likely felt in Polson in the 24 hours to 9:37 pm MST (04:37 UTC). The last one was M 3.0, 32 km (20 mi) ENE, at 9:19 pm MDT on 14 March 2024, estimated intensity II (weak) in town; 1 felt report to USGS. Every earthquake near Polson

This page: a magnitude 3.1 earthquake was recorded 34 km (21 mi) east of Polson, MT, at 9:48 pm MST on 12 November 2016 (04:48 UTC), 8.0 km deep.

USGS: 20 km N of Condon, Montana

9:48 pm MST, Nov 12, 2016 · · 8.0 km deep · released about 1,200 lb of TNT

10 km30 km60 km120 km N Lake County 29 kmFlathead County 69 kmMissoula County 78 kmTeton County 108 kmSanders County 110 kmPowell County 113 kmLewis and Clark County 120 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
9:48 pm MST on 12 November 2016 ()
Where
34 km (21 mi) east of Polson, MT · earthquakes near Polson
Montana today
every earthquake in Montana in the last 24 hours
Magnitude
M 3.1 (ml)
Depth
8.0 km below the surface
Felt
no reports yet
Nearest
Lake County, 29 km WSW
Nearest mapped fault
Mission fault, 22 km from its surface trace — near is not the same as on
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2008 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage.

At this magnitude and depth, people at rest would likely notice it out to about 39 km (24 mi) from the epicentre. In Polson, 34 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.

Likely felt in: Polson 34 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 1,200 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 6.7 290,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 13,000× the energy of this one
  3. Magna, Utah 2020 M 5.7 9,100× the energy of this one
  4. This earthquake M 3.1 about 1,200 lb of TNT
  5. Around the size people start to feel M 3.0 this one released 1.2× 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.

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 lists one earthquake of M5 or more within 50 km:

  1. 5.5 Western Montana · 32 km NNW of this epicentre

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 47.7137, -113.7128. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Lake County, MT 29 km (18 mi) WSW earthquakes near Lake County
Flathead County, MT 69 km (43 mi) NNW earthquakes near Flathead County
Missoula County, MT 78 km (48 mi) S earthquakes near Missoula County
Teton County, MT 108 km (67 mi) E earthquakes near Teton County
Sanders County, MT 110 km (68 mi) W earthquakes near Sanders County
Powell County, MT 113 km (70 mi) SSE earthquakes near Powell County

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

Aftershocks so far

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

  1. 1.9 5 km WSW of Condon, Montana
  2. 2.0 21 km SSE of Swan Lake, Montana
  3. 1.9 12 km E of Finley Point, Montana
  4. 2.2 12 km ESE of Finley Point, Montana
  5. 1.6 12 km ESE of Finley Point, Montana
  6. 2.4 Western Montana
  7. 1.9 18 km E of Finley Point, Montana
  8. 2.3 19 km NNE of Seeley Lake, Montana
  9. 2.0 2 km ESE of Bear Dance, Montana
  10. 1.5 7 km ENE of Saint Ignatius, Montana
  11. 2.3 14 km SSE of Swan Lake, Montana
  12. 3.3 16 km SSE of Swan Lake, Montana
  13. 2.3 6 km N of Saint Ignatius, Montana
  14. 1.7 8 km NE of Bigfork, Montana
  15. 1.9 10 km WNW of Condon, MT

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.