Earthquake · reviewed by a seismologist
M 1.7ml
Earthquake near Deer Lodge, MT
No earthquake was likely felt in Deer Lodge in the 24 hours to 4:51 pm MST (23:51 UTC). The last one was M 3.2, 33 km (20 mi) N, at 11:22 am MST on 9 December 2025, estimated intensity II (weak) in town; 1 felt report to USGS. Every earthquake near Deer Lodge
This page: a magnitude 1.7 earthquake was recorded 18 km (11 mi) west-northwest of Deer Lodge, MT, at 2:04 pm MDT on 8 September 2021 (20:04 UTC), 12 km deep.
USGS: 10 km WSW of Garrison, Montana
- When
- 2:04 pm MDT on 8 September 2021 ()
- Where
- 18 km (11 mi) west-northwest of Deer Lodge, MT · earthquakes near Deer Lodge
- Montana today
- every earthquake in Montana in the last 24 hours
- Magnitude
- M 1.7 (ml)
- Depth
- 12 km below the surface
- Felt
- no reports yet
- Nearest
- Granite County, 39 km WSW
- Status
- Reviewed by a seismologist
USGS · last changed by USGS · we first saw it 1890 days ago
Earthquake alerts for Deer Lodge, MT
Get a notification in this browser when USGS records an earthquake near Deer Lodge, 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 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 3 km (2 mi) from the epicentre. In Deer Lodge, 18 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 9.6 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.7 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 1,600,000× the energy of this one
- Magna, Utah 2020 M 5.7 1,100,000× the energy of this one
- Around the size people start to feel M 3.0 99× the energy of this one
- This earthquake M 1.7 about 9.6 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
The largest earthquake within 50 km since 2016 was M 5.0 on 2017-07-06 — about 99,000 times the energy of this one.
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 46.4842, -112.9333. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Granite County, MT | 39 km (24 mi) | WSW | earthquakes near Granite County |
| Powell County, MT | 40 km (25 mi) | N | earthquakes near Powell County |
| Deer Lodge County, MT | 46 km (29 mi) | SSW | earthquakes near Deer Lodge County |
| Silver Bow County, MT | 69 km (43 mi) | SSE | earthquakes near Silver Bow County |
| Jefferson County, MT | 78 km (49 mi) | ESE | earthquakes near Jefferson County |
| Lewis and Clark County, MT | 82 km (51 mi) | NNE | earthquakes near Lewis and Clark County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
27 earthquakes have been recorded within 50 km since this one.
- 1.9 3 km E of Avon, Montana
- 1.6 10 km WSW of Drummond, Montana
- 1.6 21 km NE of Drummond, Montana
- 2.2 4 km ENE of Avon, Montana
- 2.9 Western Montana
- 1.7 9 km SW of Lincoln, Montana
- 1.8 11 km SW of Lincoln, Montana
- 1.7 16 km SSE of Lincoln, Montana
- 1.7 4 km ESE of Avon, Montana
- 1.7 15 km WSW of Drummond, Montana
- 1.5 21 km NNW of Drummond, Montana
- 1.7 5 km SE of Avon, Montana
- 1.6 6 km NW of Drummond, Montana
- 1.6 10 km WNW of Avon, Montana
- 1.7 10 km N of Elliston, 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.