QuakeIndex

Earthquake · reviewed by a seismologist

M 2.1ml

26 km SE of Dillon, Montana

· 5.0 km deep · released about 43 lb of TNT

10 km30 km60 km120 km N Beaverhead County 41 kmMadison County 49 kmClark County 84 kmSilver Bow County 97 kmGallatin County 109 kmFremont County 117 kmLemhi County 118 km
Distance rings around the epicentre, with the nearest towns at their true direction and later quakes as coloured dots. Not a shaking map — see the USGS ShakeMap for that.
When
Magnitude
M 2.1 (ml)
Depth
5.0 km below the surface
Felt
1 report · strongest reported intensity II
Nearest
Beaverhead County, 41 km WNW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 23 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage. 1 person has reported feeling it to USGS.

How big was it?

This earthquake released about 43 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.

  1. Mineral, Virginia 2011 M 5.8 350,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 250,000× the energy of this one
  3. Around the size people start to feel M 3.0 22× the energy of this one
  4. This earthquake M 2.1 about 43 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 45.0473, -112.3912. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Beaverhead County, MT 41 km (25 mi) ESE of here earthquakes near Beaverhead County
Madison County, MT 49 km (30 mi) SW of here earthquakes near Madison County
Clark County, ID 84 km (52 mi) N of here earthquakes near Clark County
Silver Bow County, MT 97 km (60 mi) SSE of here earthquakes near Silver Bow County
Gallatin County, MT 109 km (68 mi) WSW of here earthquakes near Gallatin County
Fremont County, ID 117 km (73 mi) NW of here earthquakes near Fremont County

Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.

Aftershocks so far

4 earthquakes have been recorded within 50 km since this one.

  1. 1.6 44 km NNE of Spencer, Idaho
  2. 1.9 45 km NNE of Spencer, Idaho
  3. 2.4 45 km NNE of Spencer, Idaho
  4. 1.8 46 km NNE of Spencer, Idaho

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 4.6 on 2019-04-09 — it released about 5,600 times the energy of this one.

From the QuakeIndex catalogue, built from the USGS FDSN event service.

On USGS

QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.