QuakeIndex

Earthquake · reviewed by a seismologist

M 2.1ml

8 km NNW of Stanley, Idaho

Yes. A magnitude 2.1 earthquake was recorded 8 km NNW of Stanley, Idaho, at 11:10 am MDT on 13 July 2018 (17:10 UTC), 7.1 km deep.

· 7.1 km deep · released about 46 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Custer County 57 kmBoise County 69 kmValley County 81 kmCamas County 90 kmElmore County 108 kmLemhi County 110 kmGem County 118 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
Idaho today
every earthquake in Idaho in the last 24 hours
Magnitude
M 2.1 (ml)
Depth
7.1 km below the surface
Felt
no reports yet
Nearest
Custer County, 57 km E
Nearest mapped fault
Sawtooth fault, 12 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 3043 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 16 km (10 mi) from the epicentre. 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 46 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.1 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 330,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 230,000× the energy of this one
  3. Around the size people start to feel M 3.0 21× the energy of this one
  4. This earthquake M 2.1 about 46 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 2 earthquakes of M5 or more within 50 km:

  1. 6.1 37 km N of Stanley, Idaho · 29 km N of this epicentre
  2. 6.0 44 km NNW of Stanley, Idaho · 36 km NNW 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 44.2960, -114.9620. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Custer County, ID 57 km (35 mi) E earthquakes near Custer County
Boise County, ID 69 km (43 mi) WSW earthquakes near Boise County
Valley County, ID 81 km (50 mi) NW earthquakes near Valley County
Camas County, ID 90 km (56 mi) S earthquakes near Camas County
Elmore County, ID 108 km (67 mi) SSW earthquakes near Elmore County
Lemhi County, ID 110 km (69 mi) NE earthquakes near Lemhi 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. 2.2 19 km N of Stanley, Idaho
  2. 1.9 20 km N of Stanley, Idaho
  3. 1.8 21 km N of Stanley, Idaho
  4. 1.9 20 km N of Stanley, Idaho
  5. 2.4 20 km N of Stanley, Idaho
  6. 2.4 21 km N of Stanley, Idaho
  7. 2.4 25 km SSW of Clayton, Idaho
  8. 2.4 36 km NNW of Stanley, Idaho
  9. 1.7 7 km N of Stanley, Idaho
  10. 2.0 7 km N of Stanley, Idaho
  11. 1.5 11 km W of Clayton, Idaho
  12. 1.7 32 km ESE of Lowman, Idaho
  13. 1.6 11 km W of Clayton, Idaho
  14. 1.6 19 km NW of Clayton, Idaho
  15. 1.6 9 km NNW 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.