QuakeIndex

Earthquake · reviewed by a seismologist

M 1.5ml

Earthquake near Anaconda, MT

No earthquake was likely felt in Anaconda in the 24 hours to 1:19 pm MST (20:19 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 1.5 earthquake was recorded 38 km (24 mi) north-northwest of Anaconda, MT, at 7:31 am MDT on 22 June 2018 (13:31 UTC), less than 1 km deep.

USGS: 5 km ESE of Maxville, Montana

7:31 am MDT, Jun 22, 2018 · · 0.2 km deep · released about 5.7 lb of TNT

10 km30 km60 km120 km N Granite County 20 kmDeer Lodge County 38 kmPowell County 49 kmSilver Bow County 72 kmRavalli County 82 kmMissoula County 86 kmJefferson County 92 kmLewis and Clark County 97 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
7:31 am MDT on 22 June 2018 ()
Where
38 km (24 mi) north-northwest of Anaconda, MT · earthquakes near Anaconda
Montana today
every earthquake in Montana in the last 24 hours
Magnitude
M 1.5 (ml)
Depth
0.2 km below the surface
Felt
no reports yet
Nearest
Granite County, 20 km WSW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 3063 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 10 km (6 mi) from the epicentre. In Anaconda, 38 km away, the estimate is intensity I (not felt). 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 5.7 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.5 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 2,600,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,900,000× the energy of this one
  3. Around the size people start to feel M 3.0 170× the energy of this one
  4. This earthquake M 1.5 about 5.7 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

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 46.4368, -113.1673. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Granite County, MT 20 km (13 mi) WSW earthquakes near Granite County
Deer Lodge County, MT 38 km (24 mi) S earthquakes near Deer Lodge County
Powell County, MT 49 km (30 mi) NNE earthquakes near Powell County
Silver Bow County, MT 72 km (45 mi) SSE earthquakes near Silver Bow County
Ravalli County, MT 82 km (51 mi) WSW earthquakes near Ravalli County
Missoula County, MT 86 km (53 mi) NW earthquakes near Missoula County

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

Aftershocks so far

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

  1. 1.9 10 km NW of Garrison, Montana
  2. 2.3 Western Montana
  3. 1.6 10 km WSW of Drummond, Montana
  4. 1.6 21 km NE of Drummond, Montana
  5. 1.7 15 km WSW of Drummond, Montana
  6. 1.5 21 km NNW of Drummond, Montana
  7. 1.6 6 km NW of Drummond, Montana
  8. 1.6 10 km WNW of Avon, Montana
  9. 1.5 4 km S of Drummond, Montana
  10. 1.9 19 km W of Drummond, Montana
  11. 1.8 18 km W of Drummond, Montana
  12. 1.5 18 km W of Drummond, Montana
  13. 2.4 18 km W of Drummond, Montana
  14. 2.2 18 km W of Drummond, Montana
  15. 2.3 18 km SSW of Ovando, 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.