QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8ml

18 km S of Lima, Montana

Yes. A magnitude 1.8 earthquake was recorded 18 km S of Lima, Montana, at 6:02 pm MDT on 28 June 2019 (00:02 UTC), 6.9 km deep.

· 6.9 km deep · released about 14 lb of TNT

10 km30 km60 km120 km N Clark County 30 kmBeaverhead County 76 kmJefferson County 79 kmFremont County 95 kmButte County 98 kmMadison County 109 kmMadison County 110 kmLemhi 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
Montana today
every earthquake in Montana in the last 24 hours
Magnitude
M 1.8 (ml)
Depth
6.9 km below the surface
Felt
no reports yet
Nearest
Clark County, 30 km SE
Nearest mapped fault
Red Rock fault, 15 km from its surface trace — near is not the same as on
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2692 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 11 km (7 mi) from the epicentre. 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 14 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.8 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 1,100,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 760,000× the energy of this one
  3. Around the size people start to feel M 3.0 68× the energy of this one
  4. This earthquake M 1.8 about 14 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

The largest earthquake within 50 km since 2016 was M 4.6 on 2019-04-09 — about 17,000 times the energy of this one.

Before 2016, the USGS record lists 2 earthquakes of M5 or more within 50 km:

  1. 5.1 19 km NW of Lima, Montana · 34 km NNW of this epicentre
  2. 5.1 22 km NW of Lima, Montana · 37 km NNW of this epicentre

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 44.4758, -112.6243. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Clark County, ID 30 km (18 mi) SE earthquakes near Clark County
Beaverhead County, MT 76 km (47 mi) NNW earthquakes near Beaverhead County
Jefferson County, ID 79 km (49 mi) SSE earthquakes near Jefferson County
Fremont County, ID 95 km (59 mi) ESE earthquakes near Fremont County
Butte County, ID 98 km (61 mi) SSW earthquakes near Butte County
Madison County, ID 109 km (67 mi) SE earthquakes near Madison County

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

Aftershocks so far

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

  1. 2.6 0 km S of Lima, Montana
  2. 3.3 3 km SSE of Lima, Montana
  3. 2.5 2 km SSE of Lima, Montana
  4. 1.7 14 km NW of Lima, Montana
  5. 1.7 30 km NNE of Spencer, Idaho
  6. 1.5 7 km ENE of Lima, Montana
  7. 2.9 6 km ENE of Lima, Montana
  8. 1.5 9 km ENE of Lima, Montana
  9. 1.6 Idaho-Montana border region
  10. 1.7 31 km N of Spencer, Idaho
  11. 1.5 21 km SSW of Lima, Montana
  12. 1.6 Idaho-Montana border region
  13. 1.6 10 km ESE of Lima, Montana
  14. 1.9 32 km N of Spencer, Idaho
  15. 2.0 28 km N 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.

On USGS

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