Earthquake · reviewed by a seismologist
M 1.5ml
Idaho-Montana border region
Yes. A magnitude 1.5 earthquake was recorded in the Idaho-Montana border region, at 3:04 am MST on 30 November 2023 (10:04 UTC), 5.9 km deep.
- When
- Magnitude
- M 1.5 (ml)
- Depth
- 5.9 km below the surface
- Felt
- no reports yet
- Nearest
- Madison County, 37 km N
- Status
- Reviewed by a seismologist
USGS · last changed by USGS · we first saw it 1077 days ago
Earthquake alerts for Big Sky, MT
Get a notification in this browser when USGS records an earthquake near Big Sky, 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 8 km (5 mi) from the epicentre. 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 5.4 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.5 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 2,800,000× the energy of this one
- Magna, Utah 2020 M 5.7 2,000,000× the energy of this one
- Around the size people start to feel M 3.0 180× the energy of this one
- This earthquake M 1.5 about 5.4 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 in our catalogue was M 4.3 on 2016-06-13 — about 18,000 times the energy of this one.
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 44.9888, -111.9322. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Madison County, MT | 37 km (23 mi) | N | earthquakes near Madison County |
| Beaverhead County, MT | 77 km (48 mi) | WNW | earthquakes near Beaverhead County |
| Gallatin County, MT | 84 km (52 mi) | NE | earthquakes near Gallatin County |
| Clark County, ID | 85 km (53 mi) | SSW | earthquakes near Clark County |
| Fremont County, ID | 93 km (58 mi) | SSE | earthquakes near Fremont County |
| Silver Bow County, MT | 116 km (72 mi) | NNW | earthquakes near Silver Bow County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
56 earthquakes have been recorded within 50 km since this one.
- 1.8 40 km NNE of Spencer, Idaho
- 2.0 11 km S of Ennis, Montana
- 1.7 22 km WNW of Hebgen Lake Estates, Montana
- 1.6 43 km W of Hebgen Lake Estates, Montana
- 1.5 28 km S of Ennis, Montana
- 1.6 31 km NNE of Spencer, Idaho
- 1.7 29 km WNW of Hebgen Lake Estates, Montana
- 1.5 21 km W of Hebgen Lake Estates, Montana
- 1.6 40 km NE of Spencer, Idaho
- 1.9 31 km SSE of Virginia City, Montana
- 1.6 29 km SSE of Virginia City, Montana
- 2.2 41 km NE of Spencer, Idaho
- 1.8 25 km WNW of Hebgen Lake Estates, Montana
- 2.1 29 km WNW of Hebgen Lake Estates, Montana
- 1.9 33 km S of Virginia City, 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.