Earthquake · reviewed by a seismologist
M 1.6md
Earthquake near Dillon, MT
No earthquake was likely felt in Dillon in the 24 hours to 2:45 pm MST (21:45 UTC). The last one was M 2.0, 14 km (9 mi) N, at 2:45 pm MDT on 7 May 2026, estimated intensity II (weak) in town. Every earthquake near Dillon
This page: a magnitude 1.6 earthquake was recorded 23 km (15 mi) east-southeast of Dillon, MT, at 10:01 am MST on 20 February 2021 (17:01 UTC), 4.8 km deep.
USGS: 23 km ESE of Dillon, Montana
- When
- 10:01 am MST on 20 February 2021 ()
- Where
- 23 km (15 mi) east-southeast of Dillon, MT · earthquakes near Dillon
- Montana today
- every earthquake in Montana in the last 24 hours
- Magnitude
- M 1.6 (md)
- Depth
- 4.8 km below the surface
- Felt
- no reports yet
- Nearest
- Madison County, 41 km ENE
- Status
- Reviewed by a seismologist
USGS · last changed by USGS · we first saw it 2089 days ago
Earthquake alerts for Dillon, MT
Get a notification in this browser when USGS records an earthquake near Dillon, 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 11 km (7 mi) from the epicentre. In Dillon, 23 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 8.7 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.6 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 1,700,000× the energy of this one
- Magna, Utah 2020 M 5.7 1,200,000× the energy of this one
- Around the size people start to feel M 3.0 110× the energy of this one
- This earthquake M 1.6 about 8.7 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 4.6 on 2019-04-09 — about 28,000 times the energy of this one.
Before 2016, the USGS record lists one earthquake of M5 or more within 50 km:
- 5.6 16 km N of Dillon, Montana · 32 km NW 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 45.1342, -112.3618. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Madison County, MT | 41 km (25 mi) | ENE | earthquakes near Madison County |
| Beaverhead County, MT | 42 km (26 mi) | W | earthquakes near Beaverhead County |
| Silver Bow County, MT | 88 km (55 mi) | NNW | earthquakes near Silver Bow County |
| Clark County, ID | 94 km (58 mi) | S | earthquakes near Clark County |
| Gallatin County, MT | 103 km (64 mi) | ENE | earthquakes near Gallatin County |
| Jefferson County, MT | 113 km (70 mi) | NNE | earthquakes near Jefferson County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
48 earthquakes have been recorded within 50 km since this one.
- 1.8 3 km NNW of Alder, Montana
- 1.9 23 km SSE of Dillon, Montana
- 1.9 17 km N of Dillon, Montana
- 2.3 34 km S of Virginia City, Montana
- 1.9 8 km ESE of Sheridan, Montana
- 1.8 14 km N of Dillon, Montana
- 1.6 41 km S of Virginia City, Montana
- 1.6 Idaho-Montana border region
- 2.1 32 km S of Virginia City, Montana
- 2.3 13 km NNE of Dillon, Montana
- 1.6 26 km NW of Lima, Montana
- 2.1 47 km ENE of Lima, Montana
- 2.0 33 km NNW of Lima, Montana
- 1.5 3 km ESE of Twin Bridges, Montana
- 1.5 11 km NE of Lima, 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.