explosion · reviewed by a seismologist
M 2.3ml
Earthquake near Milton-Freewater, OR
No earthquake was likely felt in Milton-Freewater in the 24 hours to 8:46 pm PST (04:46 UTC). The last one was M 2.1, 6 km (3 mi) S, at 11:31 am PDT on 18 June 2026, estimated intensity II (weak) in town. Every earthquake near Milton-Freewater
No: USGS classifies this as a explosion, not an earthquake. A magnitude 2.3 explosion was recorded 6 km (4 mi) south of Milton-Freewater, OR, at 4:09 pm PDT on 21 April 2020 (23:09 UTC), less than 1 km deep.
USGS: 5 km S of Milton-Freewater, Oregon
- When
- 4:09 pm PDT on 21 April 2020 ()
- Where
- 6 km (4 mi) south of Milton-Freewater, OR · earthquakes near Milton-Freewater
- Magnitude
- M 2.3 (ml)
- Depth
- -0.6 km below the surface
- Felt
- no reports yet
- Nearest
- Umatilla County, 42 km SW
- Nearest mapped fault
- Wallula fault system, 1 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 2395 days ago
Earthquake alerts for Milton-Freewater, OR
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Alerts are on for .
Not a warning. An alert comes after USGS publishes a quake, usually minutes after the shaking. For early warning use ShakeAlert, through your phone's Wireless Emergency Alerts or the MyShake app.
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 20 km (12 mi) from the epicentre. In Milton-Freewater, 6 km away, the estimate is intensity III (weak). 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.
Earthquakes near other towns within 30 km: Athena, College Place, Garrett, Walla Walla East, Walla Walla.
USGS catalogues this as explosion, not an earthquake.
How big was it?
This earthquake released about 98 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.3 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 150,000× the energy of this one
- Magna, Utah 2020 M 5.7 110,000× the energy of this one
- Around the size people start to feel M 3.0 9.8× the energy of this one
- This earthquake M 2.3 about 98 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:
- 6.0 3 km SW of Garrett, Washington · 17 km N 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 45.8817, -118.3968. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Umatilla County, OR | 42 km (26 mi) | SW | earthquakes near Umatilla County |
| Walla Walla County, WA | 42 km (26 mi) | N | earthquakes near Walla Walla County |
| Columbia County, WA | 59 km (37 mi) | NE | earthquakes near Columbia County |
| Union County, OR | 71 km (44 mi) | SSE | earthquakes near Union County |
| Franklin County, WA | 83 km (51 mi) | NNW | earthquakes near Franklin County |
| Garfield County, WA | 90 km (56 mi) | NE | earthquakes near Garfield County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
38 earthquakes have been recorded within 50 km since this one.
- 1.8 3 km W of Pendleton, Oregon
- 1.8 4 km SSW of Wallula, Washington
- 2.1 5 km S of Milton-Freewater, Oregon
- 2.0 10 km W of Pendleton, Oregon
- 2.3 7 km N of Helix, Oregon
- 1.7 8 km N of Helix, Oregon
- 1.9 9 km WNW of Touchet, Washington
- 1.8 4 km NNW of Pendleton, Oregon
- 1.6 11 km E of Milton-Freewater, Oregon
- 1.7 11 km E of Milton-Freewater, Oregon
- 2.0 4 km ESE of Milton-Freewater, Oregon
- 1.5 22 km NNE of Elgin, Oregon
- 1.7 4 km N of Touchet, Washington
- 1.6 19 km SE of Walla Walla East, Washington
- 1.7 6 km E of Wallula, Washington
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
- The official USGS event page — the source of record for every value above
- Did you feel it? Report it to USGS — reports go to USGS, not to us
- ShakeMap for this event, when USGS has produced one
QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.