QuakeIndex

Earthquake · reviewed by a seismologist

M 1.9ml

Earthquake near Anaconda, MT

No earthquake was likely felt in Anaconda in the 24 hours to 10:38 am MST (17:38 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 1.9 earthquake was recorded 47 km (29 mi) northwest of Anaconda, MT, at 11:04 am MDT on 18 June 2018 (17:04 UTC), 1.2 km deep.

USGS: 11 km WNW of Philipsburg, Montana

11:04 am MDT, Jun 18, 2018 · · 1.2 km deep · released about 19 lb of TNT

10 km30 km60 km120 km N Granite County 2 kmDeer Lodge County 39 kmRavalli County 62 kmPowell County 64 kmMissoula County 80 kmSilver Bow County 80 kmJefferson County 109 kmLewis and Clark County 115 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
11:04 am MDT on 18 June 2018 ()
Where
47 km (29 mi) northwest of Anaconda, MT · earthquakes near Anaconda
Montana today
every earthquake in Montana in the last 24 hours
Magnitude
M 1.9 (ml)
Depth
1.2 km below the surface
Felt
no reports yet
Nearest
Granite County, 2 km NNE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 3068 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 14 km (9 mi) from the epicentre. In Anaconda, 47 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 19 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.9 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 790,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 560,000× the energy of this one
  3. Around the size people start to feel M 3.0 50× the energy of this one
  4. This earthquake M 1.9 about 19 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 46.3813, -113.4327. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Granite County, MT 2 km (1 mi) NNE earthquakes near Granite County
Deer Lodge County, MT 39 km (24 mi) SE earthquakes near Deer Lodge County
Ravalli County, MT 62 km (38 mi) WSW earthquakes near Ravalli County
Powell County, MT 64 km (40 mi) NE earthquakes near Powell County
Missoula County, MT 80 km (50 mi) NNW earthquakes near Missoula County
Silver Bow County, MT 80 km (50 mi) SE earthquakes near Silver Bow County

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

Aftershocks so far

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

  1. 1.9 7 km WSW of Drummond, Montana
  2. 1.9 10 km NW of Garrison, Montana
  3. 1.6 10 km WSW of Drummond, Montana
  4. 1.7 15 km WSW of Drummond, Montana
  5. 1.6 6 km NW of Drummond, Montana
  6. 1.5 4 km S of Drummond, Montana
  7. 1.9 19 km W of Drummond, Montana
  8. 1.8 18 km W of Drummond, Montana
  9. 1.5 18 km W of Drummond, Montana
  10. 2.4 18 km W of Drummond, Montana
  11. 2.2 18 km W of Drummond, Montana
  12. 1.7 10 km WSW of Garrison, Montana
  13. 1.8 6 km W of Drummond, Montana
  14. 1.6 Western Montana
  15. 2.0 11 km WSW of Drummond, 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.