QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8ml

9 km SW of Riggins, Idaho

· 12 km deep · released about 15 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Adams County 54 kmWallowa County 67 kmValley County 83 kmIdaho County 90 kmLewis County 97 kmWashington County 106 kmAsotin County 112 kmNez Perce County 112 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
Magnitude
M 1.8 (ml)
Depth
12 km below the surface
Felt
1 report · strongest reported intensity I
Nearest
Adams County, 54 km S
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1626 days ago

A magnitude 1.8 earthquake was recorded 9 km SW of Riggins, Idaho at 00:15 UTC on 2021-12-29. 1 person has reported feeling it to USGS. This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

How big was it?

This earthquake released about 15 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 1,000,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 710,000× the energy of this one
  3. Around the size people start to feel M 3.0 63× the energy of this one
  4. This earthquake M 1.8 about 15 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 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 45.3620, -116.3960. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Adams County, ID 54 km (34 mi) S earthquakes near Adams County
Wallowa County, OR 67 km (41 mi) WNW earthquakes near Wallowa County
Valley County, ID 83 km (52 mi) SE earthquakes near Valley County
Idaho County, ID 90 km (56 mi) NE earthquakes near Idaho County
Lewis County, ID 97 km (60 mi) N earthquakes near Lewis County
Washington County, ID 106 km (66 mi) SSW earthquakes near Washington County

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

Aftershocks so far

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

  1. 1.9 17 km NW of New Meadows, Idaho
  2. 1.7 26 km NE of Riggins, Idaho
  3. 1.5 20 km NW of New Meadows, Idaho
  4. 2.0 17 km NW of New Meadows, Idaho
  5. 2.4 21 km NW of New Meadows, Idaho
  6. 2.3 13 km NNW of New Meadows, Idaho
  7. 1.6 20 km SE of White Bird, Idaho
  8. 2.3 19 km NW of New Meadows, Idaho
  9. 2.0 33 km NE of Halfway, Oregon
  10. 1.8 5 km NNW of New Meadows, Idaho
  11. 2.7 24 km WNW of New Meadows, 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.