QuakeIndex

Earthquake · reviewed by a seismologist

M 3.3ml

32 km NW of Stanley, Idaho

Yes. A magnitude 3.3 earthquake was recorded 32 km NW of Stanley, Idaho, at 10:07 pm MDT on 31 March 2020 (04:07 UTC), 6.7 km deep.

· 6.7 km deep · released about 1.3 tons of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Valley County 57 kmBoise County 60 kmCuster County 81 kmGem County 100 kmCamas County 108 kmAdams County 109 kmElmore 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 3.3 (ml)
Depth
6.7 km below the surface
Felt
no reports yet
Nearest
Valley County, 57 km NNW
Nearest mapped fault
Sawtooth fault, 14 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 2335 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage.

At this magnitude and depth, people at rest would likely notice it out to about 52 km (32 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 1.3 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.3 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 130,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 5,600× the energy of this one
  3. Magna, Utah 2020 M 5.7 4,000× the energy of this one
  4. This earthquake M 3.3 about 1.3 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 2.8× 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 63,000 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 · 32 km ENE of this epicentre
  2. 6.0 44 km NNW of Stanley, Idaho · 25 km NNE 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 44.4126, -115.2496. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Valley County, ID 57 km (36 mi) NNW earthquakes near Valley County
Boise County, ID 60 km (37 mi) SW earthquakes near Boise County
Custer County, ID 81 km (50 mi) E earthquakes near Custer County
Gem County, ID 100 km (62 mi) WSW earthquakes near Gem County
Camas County, ID 108 km (67 mi) SSE earthquakes near Camas County
Adams County, ID 109 km (68 mi) WNW earthquakes near Adams 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. 2.5 38 km NW of Stanley, Idaho
  2. 2.6 23 km WNW of Stanley, Idaho
  3. 2.7 27 km WNW of Stanley, Idaho
  4. 2.9 26 km NW of Stanley, Idaho
  5. 2.9 26 km NW of Stanley, Idaho
  6. 3.4 15 km WNW of Stanley, Idaho
  7. 3.0 25 km NW of Stanley, Idaho
  8. 2.8 35 km NW of Stanley, Idaho
  9. 2.7 33 km NW of Stanley, Idaho
  10. 2.6 23 km WNW of Stanley, Idaho
  11. 2.9 32 km NNW of Stanley, Idaho
  12. 3.9 28 km NW of Stanley, Idaho
  13. 3.2 26 km WNW of Stanley, Idaho
  14. 2.5 20 km NW of Stanley, Idaho
  15. 2.7 13 km WNW 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.