QuakeIndex

Earthquake · reviewed by a seismologist

M 4.2mwr

Earthquake near Challis, ID

No earthquake was likely felt in Challis in the 24 hours to 6:49 pm MST (01:49 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 4.2 earthquake was recorded 36 km (23 mi) west-southwest of Challis, ID, at 9:32 am MST on 27 January 2025 (16:32 UTC), 9.2 km deep. 328 people have reported feeling it to USGS.

USGS: 26 km NW of Clayton, Idaho

9:32 am MST, Jan 27, 2025 · · 9.2 km deep · released about 30 tons of TNT

10 km30 km60 km120 km N Custer County 36 kmLemhi County 85 kmValley County 90 kmBoise County 96 kmCamas County 101 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
9:32 am MST on 27 January 2025 ()
Where
36 km (23 mi) west-southwest of Challis, ID · earthquakes near Challis
Idaho today
every earthquake in Idaho in the last 24 hours
Magnitude
M 4.2 (mwr)
Depth
9.2 km below the surface
Felt
328 reports · strongest reported intensity V
Measured shaking
intensity IV (ShakeMap)
USGS impact alert
green
Nearest
Custer County, 36 km ESE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 117 days ago

This was a light earthquake. It is usually felt clearly nearby and can rattle windows and dishes, but damage is uncommon.

At this magnitude and depth, people at rest would likely notice it out to about 112 km (70 mi) from the epicentre. In Challis, 36 km away, the estimate is intensity III (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.

Likely felt in: Challis 36 km, intensity III. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 30 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 5.2 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 5,600× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 250× the energy of this one
  3. Magna, Utah 2020 M 5.7 180× the energy of this one
  4. This earthquake M 4.2 about 30 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 63× more

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 6.5 on 2020-03-31 — about 2,800 times the energy of this one.

Before 2016, the USGS record lists 6 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.1 37 km N of Stanley, Idaho · 25 km NW of this epicentre
  2. 6.0 44 km NNW of Stanley, Idaho · 40 km NW of this epicentre
  3. 5.5 22 km E of Clayton, Idaho · 46 km ESE of this epicentre
  4. 5.4 23 km E of Clayton, Idaho · 49 km ESE of this epicentre
  5. 5.1 9 km SE of Challis, Idaho · 41 km E 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 44.4068, -114.6681. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Custer County, ID 36 km (23 mi) ESE earthquakes near Custer County
Lemhi County, ID 85 km (53 mi) NE earthquakes near Lemhi County
Valley County, ID 90 km (56 mi) NW earthquakes near Valley County
Boise County, ID 96 km (59 mi) WSW earthquakes near Boise County
Camas County, ID 101 km (63 mi) S earthquakes near Camas County
Blaine County, ID 126 km (78 mi) SSE earthquakes near Blaine 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. 2.4 17 km NE of Stanley, Idaho
  2. 2.1 17 km NW of Stanley, Idaho
  3. 1.7 24 km NW of Stanley, Idaho
  4. 1.6 22 km NW of Stanley, Idaho
  5. 1.7 22 km NW of Stanley, Idaho
  6. 1.8 26 km NW of Clayton, Idaho
  7. 1.9 23 km NW of Stanley, Idaho
  8. 1.9 20 km WNW of Stanley, Idaho
  9. 1.8 16 km NE of Stanley, Idaho
  10. 1.6 16 km NE of Stanley, Idaho
  11. 1.9 21 km WNW of Stanley, Idaho
  12. 1.8 15 km NE of Stanley, Idaho
  13. 2.2 17 km NE of Stanley, Idaho
  14. 2.1 17 km NNE of Stanley, Idaho
  15. 2.3 16 km NE 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.