QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8ml

28 km NW of Mackay, Idaho

Yes. A magnitude 1.8 earthquake was recorded 28 km NW of Mackay, Idaho, at 3:50 am MST on 2 March 2019 (10:50 UTC), 22 km deep.

· 22 km deep · released about 17 lb of TNT

10 km30 km60 km120 km N Custer County 36 kmButte County 72 kmBlaine County 75 kmCamas County 94 kmLemhi County 95 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
Idaho today
every earthquake in Idaho in the last 24 hours
Magnitude
M 1.8 (ml)
Depth
22 km below the surface
Felt
no reports yet
Nearest
Custer County, 36 km NW
Nearest mapped fault
Lost River fault, 6 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 2809 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

At this magnitude and depth it was probably too small to be felt, even directly above it. 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 17 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 5.8 870,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 620,000× the energy of this one
  3. Around the size people start to feel M 3.0 55× the energy of this one
  4. This earthquake M 1.8 about 17 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 lists 6 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.9 The 1983 Borah Peak Earthquake, Idaho · 4 km ESE of this epicentre
  2. 5.6 18 km ESE of Challis, Idaho · 45 km N of this epicentre
  3. 5.5 22 km E of Clayton, Idaho · 29 km NW of this epicentre
  4. 5.4 29 km NW of Mackay, Idaho · 1 km WNW of this epicentre
  5. 5.4 23 km E of Clayton, Idaho · 24 km NW 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 44.0708, -113.8977. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Custer County, ID 36 km (22 mi) NW earthquakes near Custer County
Butte County, ID 72 km (45 mi) SE earthquakes near Butte County
Blaine County, ID 75 km (47 mi) S earthquakes near Blaine County
Camas County, ID 94 km (59 mi) SW earthquakes near Camas County
Lemhi County, ID 95 km (59 mi) N earthquakes near Lemhi County
Beaverhead County, MT 142 km (89 mi) NNE earthquakes near Beaverhead County

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

Aftershocks so far

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

  1. 2.1 17 km SE of Challis, Idaho
  2. 2.2 19 km ESE of Challis, Idaho
  3. 1.8 19 km E of Challis, Idaho
  4. 1.8 11 km ESE of Challis, Idaho
  5. 2.4 14 km SSE of Clayton, Idaho
  6. 2.4 26 km ESE of Challis, Idaho
  7. 2.3 23 km E of Challis, Idaho
  8. 1.9 22 km NNE of Sun Valley, Idaho
  9. 2.2 33 km NW of Mackay, Idaho
  10. 1.7 24 km ESE of Clayton, Idaho
  11. 2.3 16 km SSE of Clayton, Idaho
  12. 2.7 13 km SSE of Clayton, Idaho
  13. 1.7 21 km E of Clayton, Idaho
  14. 1.6 23 km E of Clayton, Idaho
  15. 1.8 9 km SE of Challis, 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.