QuakeIndex

Earthquake · reviewed by a seismologist

M 1.9ml

Earthquake near Polson, MT

No earthquake was likely felt in Polson in the 24 hours to 2:38 pm MST (21:38 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 1.9 earthquake was recorded 26 km (16 mi) east of Polson, MT, at 2:11 pm MDT on 5 July 2020 (20:11 UTC), 8.6 km deep.

USGS: 18 km E of Finley Point, Montana

2:11 pm MDT, Jul 5, 2020 · · 8.6 km deep · released about 22 lb of TNT

10 km30 km60 km120 km N Lake County 22 kmFlathead County 66 kmMissoula County 77 kmSanders County 102 kmTeton County 115 kmMineral County 116 kmPowell County 118 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
2:11 pm MDT on 5 July 2020 ()
Where
26 km (16 mi) east of Polson, MT · earthquakes near Polson
Montana today
every earthquake in Montana in the last 24 hours
Magnitude
M 1.9 (ml)
Depth
8.6 km below the surface
Felt
no reports yet
Nearest
Lake County, 22 km WSW
Nearest mapped fault
Mission fault, 15 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 2319 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 12 km (7 mi) from the epicentre. In Polson, 26 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.

Earthquakes near other towns within 30 km: Pablo.

How big was it?

This earthquake released about 22 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.9 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 680,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 480,000× the energy of this one
  3. Around the size people start to feel M 3.0 43× the energy of this one
  4. This earthquake M 1.9 about 22 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 lists one earthquake of M5 or more within 50 km:

  1. 5.5 Western Montana · 31 km N 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 47.7217, -113.8152. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Lake County, MT 22 km (14 mi) WSW earthquakes near Lake County
Flathead County, MT 66 km (41 mi) NNW earthquakes near Flathead County
Missoula County, MT 77 km (48 mi) S earthquakes near Missoula County
Sanders County, MT 102 km (63 mi) W earthquakes near Sanders County
Teton County, MT 115 km (72 mi) E earthquakes near Teton County
Mineral County, MT 116 km (72 mi) SW earthquakes near Mineral County

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

Aftershocks so far

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

  1. 1.7 20 km E of Finley Point, Montana
  2. 1.6 20 km E of Finley Point, Montana
  3. 1.6 20 km E of Finley Point, Montana
  4. 2.1 20 km E of Finley Point, Montana
  5. 1.8 17 km E of Condon, Montana
  6. 1.7 19 km E of Finley Point, Montana
  7. 1.6 16 km NNE of Condon, Montana
  8. 1.6 6 km SW of Woods Bay, Montana
  9. 1.7 1 km S of Woods Bay, Montana
  10. 2.1 6 km SW of Woods Bay, Montana
  11. 1.6 6 km SW of Woods Bay, Montana
  12. 1.8 14 km WNW of Condon, Montana
  13. 1.5 5 km NE of Saint Ignatius, Montana
  14. 2.1 27 km E of Swan Lake, Montana
  15. 2.5 24 km E of Swan Lake, 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.