QuakeIndex

Earthquake · reviewed by a seismologist

M 2.1ml

Earthquake near Pendleton, OR

USGS: 3 km S of Adams, Oregon

3:00 pm PDT, Apr 28, 2016 · · 20 km deep · released about 38 lb of TNT

10 km30 km60 km120 km N Umatilla County 21 kmWalla Walla County 58 kmUnion County 64 kmColumbia County 80 kmMorrow County 89 kmBenton County 93 kmFranklin County 93 kmWallowa County 107 kmGarfield County 110 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
3:00 pm PDT on 28 April 2016 ()
Where
20 km (12 mi) ENE of Pendleton, OR · earthquakes near Pendleton
Magnitude
M 2.1 (ml)
Depth
20 km below the surface
Felt
no reports yet
Nearest
Umatilla County, 21 km SW
Nearest mapped fault
Wallula fault system, 17 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 558 days ago

A magnitude 2.1 earthquake was recorded 20 km (12 mi) ENE of Pendleton, OR, at 3:00 pm PDT on 28 April 2016 (22:00 UTC). This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

Earthquakes near other towns within 30 km: Athena, Mission, Milton-Freewater.

How big was it?

This earthquake released about 38 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.1 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 390,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 280,000× the energy of this one
  3. Around the size people start to feel M 3.0 25× the energy of this one
  4. This earthquake M 2.1 about 38 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 one earthquake of M5 or more within 50 km:

  1. 6.0 3 km SW of Garrett, Washington · 34 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 45.7332, -118.5528. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Umatilla County, OR 21 km (13 mi) SW earthquakes near Umatilla County
Walla Walla County, WA 58 km (36 mi) N earthquakes near Walla Walla County
Union County, OR 64 km (40 mi) SE earthquakes near Union County
Columbia County, WA 80 km (49 mi) NE earthquakes near Columbia County
Morrow County, OR 89 km (55 mi) WSW earthquakes near Morrow County
Benton County, WA 93 km (58 mi) NW earthquakes near Benton County

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

Aftershocks so far

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

  1. 1.8 3 km W of Pendleton, Oregon
  2. 1.8 4 km SSW of Wallula, Washington
  3. 2.1 5 km S of Milton-Freewater, Oregon
  4. 2.0 10 km W of Pendleton, Oregon
  5. 2.3 7 km N of Helix, Oregon
  6. 1.7 8 km N of Helix, Oregon
  7. 1.9 9 km WNW of Touchet, Washington
  8. 1.8 4 km NNW of Pendleton, Oregon
  9. 1.6 11 km E of Milton-Freewater, Oregon
  10. 1.7 11 km E of Milton-Freewater, Oregon
  11. 2.0 4 km ESE of Milton-Freewater, Oregon
  12. 1.7 4 km N of Touchet, Washington
  13. 1.6 19 km SE of Walla Walla East, Washington
  14. 1.7 6 km E of Wallula, Washington
  15. 1.7 9 km ESE of Echo, Oregon

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.