QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8ml

25 km E of Smiths Ferry, Idaho

Yes. A magnitude 1.8 earthquake was recorded 25 km E of Smiths Ferry, Idaho, 88 km (55 mi) NNE of Boise City, ID, at 1:24 pm MST on 8 February 2021 (20:24 UTC), 6.5 km deep.

88 km (55 mi) NNE of Boise City, ID

· 6.5 km deep · released about 17 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Boise County 38 kmGem County 58 kmValley County 60 kmAdams County 82 kmWashington County 83 kmPayette County 86 kmAda County 104 kmElmore County 106 kmCanyon County 108 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
6.5 km below the surface
Felt
no reports yet
Nearest
Boise County, 38 km S
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2103 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 12 km (7 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 5.8 870,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 620,000× the energy of this one
  3. Around the size people start to feel M 3.0 55× 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 4.0 on 2020-11-06 — about 1,700 times the energy of this one.

Before 2016, the USGS record since 1900 lists no earthquake of M5 or more within 50 km.

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 44.3233, -115.7728. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Boise County, ID 38 km (23 mi) S earthquakes near Boise County
Gem County, ID 58 km (36 mi) WSW earthquakes near Gem County
Valley County, ID 60 km (38 mi) NNE earthquakes near Valley County
Adams County, ID 82 km (51 mi) NW earthquakes near Adams County
Washington County, ID 83 km (51 mi) W earthquakes near Washington County
Payette County, ID 86 km (53 mi) WSW earthquakes near Payette County

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

Aftershocks so far

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

  1. 2.4 23 km W of Stanley, Idaho
  2. 2.1 37 km NW of Stanley, Idaho
  3. 2.2 38 km NW of Stanley, Idaho
  4. 2.4 42 km NW of Stanley, Idaho
  5. 1.7 36 km NW of Stanley, Idaho
  6. 3.6 37 km NW of Stanley, Idaho
  7. 2.2 31 km NW of Stanley, Idaho
  8. 1.9 42 km NW of Stanley, Idaho
  9. 3.4 37 km NW of Stanley, Idaho
  10. 2.3 46 km NW of Stanley, Idaho
  11. 1.6 42 km NNW of Stanley, Idaho
  12. 1.8 southern Idaho
  13. 2.0 43 km NW of Stanley, Idaho
  14. 1.7 41 km NW of Stanley, Idaho
  15. 2.3 25 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.