QuakeIndex

Earthquake · reviewed by a seismologist

M 1.9ml

Earthquake near Challis, ID

No earthquake was likely felt in Challis in the 24 hours to 2:44 pm MST (21:44 UTC). The last one was M 2.0, 9 km (6 mi) SSW, at 1:32 am MDT on 17 August 2026, estimated intensity II (weak) in town. Every earthquake near Challis

This page: a magnitude 1.9 earthquake was recorded 16 km (10 mi) south-southeast of Challis, ID, at 5:32 pm MDT on 8 October 2016 (23:32 UTC), 5.0 km deep.

USGS: 16 km SSE of Challis, Idaho

5:32 pm MDT, Oct 8, 2016 · · 5.0 km deep · released about 24 lb of TNT

10 km30 km60 km120 km N Custer County 14 kmLemhi County 65 kmButte County 109 kmCamas County 109 kmBlaine County 110 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
5:32 pm MDT on 8 October 2016 ()
Where
16 km (10 mi) south-southeast of Challis, ID · earthquakes near Challis
Idaho today
every earthquake in Idaho in the last 24 hours
Magnitude
M 1.9 (ml)
Depth
5.0 km below the surface
Felt
no reports yet
Nearest
Custer County, 14 km SW
Nearest mapped fault
Lone Pine fault, 2 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 3684 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 Challis, 16 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 24 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 5.8 640,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 450,000× the energy of this one
  3. Around the size people start to feel M 3.0 40× the energy of this one
  4. This earthquake M 1.9 about 24 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 7 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.9 The 1983 Borah Peak Earthquake, Idaho · 42 km SSE of this epicentre
  2. 5.6 18 km ESE of Challis, Idaho · 15 km NE of this epicentre
  3. 5.5 22 km E of Clayton, Idaho · 10 km S of this epicentre
  4. 5.4 29 km NW of Mackay, Idaho · 38 km SSE of this epicentre
  5. 5.4 23 km E of Clayton, Idaho · 16 km S 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 44.3732, -114.1403. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Custer County, ID 14 km (9 mi) SW earthquakes near Custer County
Lemhi County, ID 65 km (40 mi) NNE earthquakes near Lemhi County
Butte County, ID 109 km (67 mi) SE earthquakes near Butte County
Camas County, ID 109 km (68 mi) SSW earthquakes near Camas County
Blaine County, ID 110 km (68 mi) S earthquakes near Blaine County
Valley County, ID 129 km (80 mi) WNW earthquakes near Valley County

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

Aftershocks so far

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

  1. 2.1 10 km W of Clayton, Idaho
  2. 1.8 12 km SE of Challis, Idaho
  3. 2.1 22 km SSW of Clayton, Idaho
  4. 1.9 21 km SSW of Clayton, Idaho
  5. 1.8 22 km SSW of Clayton, Idaho
  6. 2.3 22 km SSW of Clayton, Idaho
  7. 2.0 21 km SSW of Clayton, Idaho
  8. 2.0 23 km SSW of Clayton, Idaho
  9. 1.8 22 km SSW of Clayton, Idaho
  10. 2.3 16 km S of Clayton, Idaho
  11. 1.6 22 km SSW of Clayton, Idaho
  12. 1.6 20 km ENE of Challis, Idaho
  13. 2.4 22 km SSW of Clayton, Idaho
  14. 2.2 22 km SSW of Clayton, Idaho
  15. 1.7 22 km SSW of Clayton, 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.