QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8ml

Earthquake near Salmon, ID

No earthquake was likely felt in Salmon in the 24 hours to 7:55 pm MST (02:55 UTC). The last one was M 4.3, 102 km (64 mi) S, at 11:05 am MDT on 8 June 2025, estimated intensity II (weak) in town; 27 felt reports to USGS. Every earthquake near Salmon

This page: a magnitude 1.8 earthquake was recorded 48 km (30 mi) south of Salmon, ID, at 9:35 am MDT on 24 March 2025 (15:35 UTC), 3.8 km deep.

USGS: 37 km NE of Challis, Idaho

9:35 am MDT, Mar 24, 2025 · · 3.8 km deep · released about 15 lb of TNT

10 km30 km60 km120 km N Lemhi County 20 kmCuster County 60 kmBeaverhead County 90 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
9:35 am MDT on 24 March 2025 ()
Where
48 km (30 mi) south of Salmon, ID · earthquakes near Salmon
Idaho today
every earthquake in Idaho in the last 24 hours
Magnitude
M 1.8 (ml)
Depth
3.8 km below the surface
Felt
no reports yet
Nearest
Lemhi County, 20 km N
Nearest mapped fault
Lemhi fault, 11 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 597 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 13 km (8 mi) from the epicentre. In Salmon, 48 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 15 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 1,000,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 710,000× the energy of this one
  3. Around the size people start to feel M 3.0 63× the energy of this one
  4. This earthquake M 1.8 about 15 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 3 earthquakes of M5 or more within 50 km:

  1. 5.6 18 km ESE of Challis, Idaho · 32 km SSW of this epicentre
  2. 5.1 9 km SE of Challis, Idaho · 40 km SSW of this epicentre
  3. 5.0 9 km E of Challis, Idaho · 31 km SSW 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 44.7453, -113.8970. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Lemhi County, ID 20 km (13 mi) N earthquakes near Lemhi County
Custer County, ID 60 km (37 mi) SSW earthquakes near Custer County
Beaverhead County, MT 90 km (56 mi) ENE earthquakes near Beaverhead County
Butte County, ID 131 km (81 mi) SSE earthquakes near Butte County

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

Aftershocks so far

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

  1. 2.5 30 km SW of Salmon, Idaho
  2. 1.7 25 km SSE of Challis, Idaho
  3. 2.0 8 km SSW of Challis, Idaho
  4. 2.3 7 km E of Challis, Idaho
  5. 3.2 18 km N of Leadore, Idaho
  6. 2.6 4 km NW of Challis, Idaho
  7. 2.4 2 km NW of Challis, Idaho
  8. 1.7 14 km NNE of Challis, Idaho
  9. 2.3 19 km NNE of Challis, Idaho
  10. 2.3 33 km NNW of Challis, Idaho
  11. 1.7 32 km NNW of Challis, Idaho
  12. 1.6 32 km NNW of Challis, Idaho
  13. 2.0 33 km NNW of Challis, Idaho
  14. 2.0 33 km NNW of Challis, Idaho
  15. 1.6 32 km NNW 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.