QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8ml

45 km NNW of Stanley, Idaho

Yes. A magnitude 1.8 earthquake was recorded 45 km NNW of Stanley, Idaho, at 6:28 am MDT on 18 May 2020 (12:28 UTC), 14 km deep.

· 14 km deep · released about 17 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Valley County 44 kmBoise County 73 kmCuster County 86 kmAdams County 102 kmGem County 107 kmLemhi County 115 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 1.8 (ml)
Depth
14 km below the surface
Felt
no reports yet
Nearest
Valley County, 44 km NW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2368 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 3 km (2 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 17 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 5.8 900,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 640,000× the energy of this one
  3. Around the size people start to feel M 3.0 57× the energy of this one
  4. This earthquake M 1.8 about 17 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

The largest earthquake within 50 km since 2016 was M 6.5 on 2020-03-31 — about 10,000,000 times the energy of this one.

Before 2016, the USGS record lists 2 earthquakes of M5 or more within 50 km:

  1. 6.1 37 km N of Stanley, Idaho · 28 km E of this epicentre
  2. 6.0 44 km NNW of Stanley, Idaho · 14 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 44.5593, -115.2535. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Valley County, ID 44 km (27 mi) NW earthquakes near Valley County
Boise County, ID 73 km (46 mi) SSW earthquakes near Boise County
Custer County, ID 86 km (53 mi) ESE earthquakes near Custer County
Adams County, ID 102 km (63 mi) WNW earthquakes near Adams County
Gem County, ID 107 km (66 mi) WSW earthquakes near Gem County
Lemhi County, ID 115 km (72 mi) ENE earthquakes near Lemhi 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. 2.1 26 km NW of Stanley, Idaho
  2. 1.8 43 km NW of Stanley, Idaho
  3. 1.6 23 km WNW of Stanley, Idaho
  4. 2.3 12 km WNW of Stanley, Idaho
  5. 1.6 12 km WNW of Stanley, Idaho
  6. 1.9 37 km NW of Stanley, Idaho
  7. 2.4 10 km NW of Stanley, Idaho
  8. 2.5 11 km N of Stanley, Idaho
  9. 3.1 23 km NW of Stanley, Idaho
  10. 2.5 13 km NW of Stanley, Idaho
  11. 2.9 14 km NW of Stanley, Idaho
  12. 3.8 13 km WNW of Stanley, Idaho
  13. 2.9 9 km NNW of Stanley, Idaho
  14. 2.9 27 km NW of Stanley, Idaho
  15. 2.4 13 km NW 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.