QuakeIndex

Earthquake · reviewed by a seismologist

M 2.8ml

18 km N of Avon, Montana

· 13 km deep · released about 480 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Powell County 27 kmLewis and Clark County 43 kmGranite County 76 kmJefferson County 82 kmDeer Lodge County 86 kmBroadwater County 97 kmSilver Bow County 97 kmMissoula County 103 kmCascade County 112 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 2.8 (ml)
Depth
13 km below the surface
Felt
8 reports · strongest reported intensity IV
Nearest
Powell County, 27 km WNW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 3127 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage. 8 people have reported feeling it to USGS.

How big was it?

This earthquake released about 480 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.8 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 32,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 22,000× the energy of this one
  3. Around the size people start to feel M 3.0 2× the energy of this one
  4. This earthquake M 2.8 about 480 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 46.7645, -112.5910. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Powell County, MT 27 km (17 mi) ESE of here earthquakes near Powell County
Lewis and Clark County, MT 43 km (27 mi) SSW of here earthquakes near Lewis and Clark County
Granite County, MT 76 km (47 mi) ENE of here earthquakes near Granite County
Jefferson County, MT 82 km (51 mi) NNW of here earthquakes near Jefferson County
Deer Lodge County, MT 86 km (53 mi) NNE of here earthquakes near Deer Lodge County
Broadwater County, MT 97 km (60 mi) WNW of here earthquakes near Broadwater County

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

Aftershocks so far

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

  1. 1.5 13 km ESE of Lincoln, Montana
  2. 1.6 19 km ESE of Lincoln, Montana
  3. 2.5 13 km ESE of Lincoln, Montana
  4. 2.9 14 km ESE of Lincoln, Montana
  5. 1.8 15 km WNW of Marysville, Montana
  6. 2.2 14 km ESE of Lincoln, Montana
  7. 1.6 14 km SE of Lincoln, Montana
  8. 2.7 12 km NNE of Lincoln, Montana
  9. 2.4 16 km SE of Lincoln, Montana
  10. 2.4 16 km E of Ovando, Montana
  11. 1.5 15 km E of Ovando, Montana
  12. 2.0 15 km E of Ovando, Montana
  13. 2.5 13 km E of Ovando, Montana
  14. 1.9 14 km ESE of Lincoln, Montana
  15. 1.5 14 km ESE of Lincoln, 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.

For this area

The largest earthquake within 50 km in our catalogue was M 5.8 on 2017-07-06 — it released about 32,000 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.