Earthquake · reviewed by a seismologist
M 2.1ml
12 km NW of Ennis, Montana
- When
- Magnitude
- M 2.1 (ml)
- Depth
- 3.9 km below the surface
- Felt
- no reports yet
- Nearest
- Madison County, 15 km SSW
- Status
- Reviewed by a seismologist
USGS · last changed by USGS · we first saw it 33 days ago
This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.
How big was it?
This earthquake released about 47 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.1 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 320,000× the energy of this one
- Magna, Utah 2020 M 5.7 230,000× the energy of this one
- Around the size people start to feel M 3.0 20× the energy of this one
- This earthquake M 2.1 about 47 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.
Where
Epicentre 45.4408, -111.8277. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction | |
|---|---|---|---|
| Madison County, MT | 15 km (9 mi) | NNE of here | earthquakes near Madison County |
| Gallatin County, MT | 52 km (33 mi) | W of here | earthquakes near Gallatin County |
| Jefferson County, MT | 78 km (49 mi) | SSE of here | earthquakes near Jefferson County |
| Silver Bow County, MT | 82 km (51 mi) | SE of here | earthquakes near Silver Bow County |
| Beaverhead County, MT | 90 km (56 mi) | ENE of here | earthquakes near Beaverhead County |
| Park County, MT | 101 km (63 mi) | W of here | earthquakes near Park County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
1 earthquake has been recorded within 50 km since this one.
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.
For this area
The largest earthquake within 50 km in our catalogue was M 4.0 on 2016-09-03 — it released about 710 times the energy of this one.
From the QuakeIndex catalogue, built from the USGS FDSN event service.
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.