QuakeIndex

Earthquake · reviewed by a seismologist

M 2.1ml

Earthquake near Anaconda, MT

No earthquake was likely felt in Anaconda in the 24 hours to 1:27 am MST (08:27 UTC). The last one was M 6.5, 251 km (156 mi) SW, at 5:52 pm MDT on 31 March 2020, estimated intensity III (weak) in town; 23,163 felt reports to USGS. Every earthquake near Anaconda

This page: a magnitude 2.1 earthquake was recorded 46 km (29 mi) south-southwest of Anaconda, MT, at 11:50 pm MDT on 25 August 2018 (05:50 UTC), 3.0 km deep.

USGS: 26 km ENE of Wisdom, Montana

11:50 pm MDT, Aug 25, 2018 · · 3.0 km deep · released about 46 lb of TNT

10 km30 km60 km120 km N Deer Lodge County 39 kmSilver Bow County 43 kmBeaverhead County 71 kmGranite County 75 kmRavalli County 82 kmJefferson County 95 kmLemhi County 107 kmMadison County 108 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
11:50 pm MDT on 25 August 2018 ()
Where
46 km (29 mi) south-southwest of Anaconda, MT · earthquakes near Anaconda
Montana today
every earthquake in Montana in the last 24 hours
Magnitude
M 2.1 (ml)
Depth
3.0 km below the surface
Felt
no reports yet
Nearest
Deer Lodge County, 39 km N
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 3000 days ago

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 17 km (11 mi) from the epicentre. In Anaconda, 46 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 46 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 5.8 330,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 230,000× the energy of this one
  3. Around the size people start to feel M 3.0 21× the energy of this one
  4. This earthquake M 2.1 about 46 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

No earthquake of M4 or more has been recorded within 50 km since our catalogue begins in 2016.

Before 2016, the USGS record since 1900 lists no earthquake of M5 or more within 50 km.

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 45.7452, -113.1663. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Deer Lodge County, MT 39 km (24 mi) N earthquakes near Deer Lodge County
Silver Bow County, MT 43 km (27 mi) ENE earthquakes near Silver Bow County
Beaverhead County, MT 71 km (44 mi) SSE earthquakes near Beaverhead County
Granite County, MT 75 km (47 mi) NNW earthquakes near Granite County
Ravalli County, MT 82 km (51 mi) WNW earthquakes near Ravalli County
Jefferson County, MT 95 km (59 mi) ENE earthquakes near Jefferson County

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

Aftershocks so far

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

  1. 2.7 10 km WNW of Wisdom, Montana
  2. 1.6 32 km SSW of Anaconda, Montana
  3. 2.4 7 km W of Wisdom, Montana
  4. 1.9 6 km NW of Wisdom, Montana
  5. 1.6 4 km WSW of Wisdom, Montana
  6. 1.9 8 km WNW of Wisdom, Montana
  7. 3.4 12 km WNW of Wisdom, Montana
  8. 2.2 30 km NNW of Dillon, Montana
  9. 2.0 10 km WNW of Wisdom, Montana
  10. 1.8 21 km NNW of Wisdom, Montana
  11. 1.9 21 km NNW of Wisdom, Montana
  12. 1.7 22 km NNW of Wisdom, Montana
  13. 1.7 22 km NNW of Wisdom, Montana
  14. 1.6 22 km NNW of Wisdom, Montana
  15. 1.8 21 km NNW of Wisdom, 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

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