QuakeIndex

Earthquake · reviewed by a seismologist

M 2.6ml

Earthquake near Challis, ID

No earthquake was likely felt in Challis in the 24 hours to 1:12 am MST (08:12 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 2.6 earthquake was recorded 49 km (30 mi) southwest of Challis, ID, at 11:01 am MDT on 14 March 2018 (17:01 UTC), 21 km deep.

USGS: 21 km E of Stanley, Idaho

11:01 am MDT, Mar 14, 2018 · · 21 km deep · released about 240 lb of TNT

10 km30 km60 km120 km N Custer County 35 kmCamas County 78 kmBoise County 86 kmLemhi County 102 kmValley County 104 kmBlaine County 107 kmElmore 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
11:01 am MDT on 14 March 2018 ()
Where
49 km (30 mi) southwest of Challis, ID · earthquakes near Challis
Idaho today
every earthquake in Idaho in the last 24 hours
Magnitude
M 2.6 (ml)
Depth
21 km below the surface
Felt
no reports yet
Nearest
Custer County, 35 km ENE
Nearest mapped fault
Sawtooth fault, 25 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 3075 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage.

At this magnitude and depth, people at rest would likely notice it out to about 11 km (7 mi) from the epicentre. In Challis, 49 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 240 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.6 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 63,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 45,000× the energy of this one
  3. Around the size people start to feel M 3.0 4× the energy of this one
  4. This earthquake M 2.6 about 240 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 4 earthquakes of M5 or more within 50 km:

  1. 6.1 37 km N of Stanley, Idaho · 43 km NNW of this epicentre
  2. 5.5 22 km E of Clayton, Idaho · 46 km ENE of this epicentre
  3. 5.4 23 km E of Clayton, Idaho · 46 km E of this epicentre
  4. 5.1 9 km SE of Challis, Idaho · 49 km ENE 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 44.2013, -114.6757. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Custer County, ID 35 km (22 mi) ENE earthquakes near Custer County
Camas County, ID 78 km (49 mi) S earthquakes near Camas County
Boise County, ID 86 km (54 mi) WSW earthquakes near Boise County
Lemhi County, ID 102 km (63 mi) NE earthquakes near Lemhi County
Valley County, ID 104 km (65 mi) NW earthquakes near Valley County
Blaine County, ID 107 km (66 mi) SSE earthquakes near Blaine 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. 2.0 7 km N of Stanley, Idaho
  2. 1.6 8 km N of Stanley, Idaho
  3. 2.0 9 km NNW of Stanley, Idaho
  4. 2.4 7 km NNW of Stanley, Idaho
  5. 1.8 9 km N of Stanley, Idaho
  6. 2.1 6 km N of Stanley, Idaho
  7. 2.4 8 km N of Stanley, Idaho
  8. 2.4 southern Idaho
  9. 2.6 7 km NNW of Stanley, Idaho
  10. 3.2 9 km NNW of Stanley, Idaho
  11. 1.7 9 km N of Stanley, Idaho
  12. 2.4 6 km N of Stanley, Idaho
  13. 2.3 10 km N of Stanley, Idaho
  14. 2.1 8 km NNW of Stanley, Idaho
  15. 1.9 10 km N of Stanley, 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.