Earthquake · reviewed by a seismologist
M 3.0ml
Earthquake near Polson, MT
No earthquake was likely felt in Polson in the 24 hours to 8:28 am MST (15:28 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 3.0 earthquake was recorded 36 km (22 mi) east of Polson, MT, at 8:44 am MST on 20 December 2016 (15:44 UTC), 3.6 km deep.
USGS: 20 km N of Condon, Montana
- When
- 8:44 am MST on 20 December 2016 ()
- Where
- 36 km (22 mi) east of Polson, MT · earthquakes near Polson
- Montana today
- every earthquake in Montana in the last 24 hours
- Magnitude
- M 3.0 (ml)
- Depth
- 3.6 km below the surface
- Felt
- no reports yet
- Nearest
- Lake County, 31 km WSW
- Nearest mapped fault
- Mission fault, 24 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
Earthquake alerts for Polson, MT
Get a notification in this browser when USGS records an earthquake near Polson, MT. No account or email needed.
Alerts are on for .
Not a warning. An alert comes after USGS publishes a quake, usually minutes after the shaking. For early warning use ShakeAlert, through your phone's Wireless Emergency Alerts or the MyShake app.
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 36 km (22 mi) from the epicentre. In Polson, 36 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 890 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.0 would have released about 32 times as much.
- Northridge, California 1994 M 6.7 380,000× the energy of this one
- Mineral, Virginia 2011 M 5.8 17,000× the energy of this one
- Magna, Utah 2020 M 5.7 12,000× the energy of this one
- This earthquake M 3.0 about 890 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:
- 5.5 Western Montana · 33 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 47.7143, -113.6855. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Lake County, MT | 31 km (19 mi) | WSW | earthquakes near Lake County |
| Flathead County, MT | 70 km (44 mi) | NNW | earthquakes near Flathead County |
| Missoula County, MT | 78 km (48 mi) | SSW | earthquakes near Missoula County |
| Teton County, MT | 106 km (66 mi) | E | earthquakes near Teton County |
| Sanders County, MT | 112 km (70 mi) | W | earthquakes near Sanders County |
| Powell County, MT | 112 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
47 earthquakes have been recorded within 50 km since this one.
- 1.8 16 km NNE of Seeley Lake, Montana
- 1.9 5 km WSW of Condon, Montana
- 2.0 21 km SSE of Swan Lake, Montana
- 1.9 12 km E of Finley Point, Montana
- 2.2 12 km ESE of Finley Point, Montana
- 1.6 12 km ESE of Finley Point, Montana
- 2.4 Western Montana
- 1.9 18 km E of Finley Point, Montana
- 2.3 19 km NNE of Seeley Lake, Montana
- 2.0 2 km ESE of Bear Dance, Montana
- 1.5 7 km ENE of Saint Ignatius, Montana
- 2.3 14 km SSE of Swan Lake, Montana
- 3.3 16 km SSE of Swan Lake, Montana
- 2.3 6 km N of Saint Ignatius, Montana
- 1.7 8 km NE of Bigfork, 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
- The official USGS event page — the source of record for every value above
- Did you feel it? Report it to USGS — reports go to USGS, not to us
- ShakeMap for this event, when USGS has produced one
QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.