QuakeIndex

Earthquake · reviewed by a seismologist

M 1.6ml

5 km W of Mackay, Idaho

Yes. A magnitude 1.6 earthquake was recorded 5 km W of Mackay, Idaho, at 12:23 pm MDT on 4 September 2020 (18:23 UTC), 3.8 km deep.

· 3.8 km deep · released about 6.4 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Butte County 48 kmCuster County 60 kmBlaine County 62 kmCamas County 99 kmLincoln County 109 kmJefferson County 110 kmLemhi County 114 kmClark County 114 kmMinidoka 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 1.6 (ml)
Depth
3.8 km below the surface
Felt
no reports yet
Nearest
Butte County, 48 km ESE
Nearest mapped fault
Lost River fault, 9 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 2259 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 10 km (6 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 6.4 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 2,400,000× 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 1.6 about 6.4 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. 6.9 The 1983 Borah Peak Earthquake, Idaho · 21 km NW of this epicentre
  2. 5.4 29 km NW of Mackay, Idaho · 25 km NW of this epicentre
  3. 5.4 23 km E of Clayton, Idaho · 49 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 43.9135, -113.6865. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Butte County, ID 48 km (30 mi) ESE earthquakes near Butte County
Custer County, ID 60 km (38 mi) NW earthquakes near Custer County
Blaine County, ID 62 km (38 mi) SSW earthquakes near Blaine County
Camas County, ID 99 km (61 mi) WSW earthquakes near Camas County
Lincoln County, ID 109 km (68 mi) SSW earthquakes near Lincoln County
Jefferson County, ID 110 km (69 mi) E earthquakes near Jefferson County

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

Aftershocks so far

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

  1. 2.2 27 km ENE of Bellevue, Idaho
  2. 2.4 26 km ENE of Bellevue, Idaho
  3. 2.3 26 km E of Clayton, Idaho
  4. 2.4 27 km E of Clayton, Idaho
  5. 2.3 28 km E of Clayton, Idaho
  6. 1.8 27 km E of Clayton, Idaho
  7. 2.3 27 km E of Clayton, Idaho
  8. 2.2 26 km E of Clayton, Idaho
  9. 2.4 26 km E of Clayton, Idaho
  10. 2.4 26 km E of Clayton, Idaho
  11. 2.1 26 km E of Clayton, Idaho
  12. 2.0 26 km E of Clayton, Idaho
  13. 1.6 26 km N of Mackay, Idaho
  14. 2.2 28 km E of Clayton, Idaho
  15. 1.6 41 km NNW of Mackay, 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.