QuakeIndex

Earthquake · reviewed by a seismologist

M 1.5ml

Earthquake near Challis, ID

No earthquake was likely felt in Challis in the 24 hours to 11:01 pm MST (06:01 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 1.5 earthquake was recorded 47 km (29 mi) south-southeast of Challis, ID, at 6:00 am MDT on 15 August 2019 (12:00 UTC), 6.8 km deep. 1 person has reported feeling it to USGS.

USGS: 35 km NW of Mackay, Idaho

6:00 am MDT, Aug 15, 2019 · · 6.8 km deep · released about 6.2 lb of TNT

10 km30 km60 km120 km N Custer County 29 kmButte County 79 kmBlaine County 82 kmLemhi County 89 kmCamas 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
6:00 am MDT on 15 August 2019 ()
Where
47 km (29 mi) south-southeast of Challis, ID · earthquakes near Challis
Idaho today
every earthquake in Idaho in the last 24 hours
Magnitude
M 1.5 (ml)
Depth
6.8 km below the surface
Felt
1 report · strongest reported intensity III
Nearest
Custer County, 29 km WNW
Nearest mapped fault
Lost River fault, 7 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 2645 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 8 km (5 mi) from the epicentre. In Challis, 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 6.2 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 2,500,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,700,000× the energy of this one
  3. Around the size people start to feel M 3.0 150× the energy of this one
  4. This earthquake M 1.5 about 6.2 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 · 11 km SE of this epicentre
  2. 5.6 18 km ESE of Challis, Idaho · 38 km N of this epicentre
  3. 5.5 22 km E of Clayton, Idaho · 22 km NW of this epicentre
  4. 5.4 29 km NW of Mackay, Idaho · 7 km SSE of this epicentre
  5. 5.4 23 km E of Clayton, Idaho · 17 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 44.1323, -113.9423. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Custer County, ID 29 km (18 mi) WNW earthquakes near Custer County
Butte County, ID 79 km (49 mi) SE earthquakes near Butte County
Blaine County, ID 82 km (51 mi) S earthquakes near Blaine County
Lemhi County, ID 89 km (55 mi) N earthquakes near Lemhi County
Camas County, ID 97 km (60 mi) SW earthquakes near Camas County
Beaverhead County, MT 139 km (86 mi) NE earthquakes near Beaverhead County

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

Aftershocks so far

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

  1. 2.4 26 km ESE of Challis, Idaho
  2. 2.3 23 km E of Challis, Idaho
  3. 1.9 22 km NNE of Sun Valley, Idaho
  4. 2.2 33 km NW of Mackay, Idaho
  5. 1.7 24 km ESE of Clayton, Idaho
  6. 2.3 16 km SSE of Clayton, Idaho
  7. 2.7 13 km SSE of Clayton, Idaho
  8. 1.7 21 km E of Clayton, Idaho
  9. 1.6 23 km E of Clayton, Idaho
  10. 1.8 9 km SE of Challis, Idaho
  11. 1.8 30 km ESE of Clayton, Idaho
  12. 2.2 3 km ENE of Clayton, Idaho
  13. 2.1 23 km WNW of Mackay, Idaho
  14. 1.6 10 km SE of Challis, Idaho
  15. 2.3 28 km S 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.