explosion · reviewed by a seismologist
M 1.5ml
Earthquake near Vernonia, OR
No earthquake was likely felt in Vernonia in the 24 hours to 4:38 am PST (12:38 UTC). The last one was M 3.0, 26 km (16 mi) E, at 7:25 am PDT on 22 October 2026, estimated intensity II (weak) in town; 113 felt reports to USGS. Every earthquake near Vernonia
No: USGS classifies this as a explosion, not an earthquake. A magnitude 1.5 explosion was recorded 14 km (8 mi) south-southeast of Vernonia, OR, at 11:29 am PDT on 4 October 2023 (18:29 UTC), less than 1 km deep.
USGS: 13 km SSE of Vernonia, Oregon
45 km (28 mi) WNW of Portland, OR · 29 km (18 mi) NW of Hillsboro, OR
- When
- 11:29 am PDT on 4 October 2023 ()
- Where
- 14 km (8 mi) south-southeast of Vernonia, OR · earthquakes near Vernonia
- Magnitude
- M 1.5 (ml)
- Depth
- -0.4 km below the surface
- Felt
- no reports yet
- Nearest
- Washington County, 21 km S
- Status
- Reviewed by a seismologist
USGS · last changed by USGS · we first saw it 343 days ago
Earthquake alerts for Vernonia, 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 10 km (6 mi) from the epicentre. In Vernonia, 14 km away, the estimate is intensity II (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: Banks, North Plains, Scappoose, Forest Grove, Warren, Cornelius.
USGS catalogues this as explosion, not an earthquake.
How big was it?
This earthquake released about 5.7 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.5 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 2,600,000× the energy of this one
- Magna, Utah 2020 M 5.7 1,900,000× the energy of this one
- Around the size people start to feel M 3.0 170× the energy of this one
- This earthquake M 1.5 about 5.7 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 2 earthquakes of M5 or more within 50 km:
- 5.2 5 km E of Bridgeton, Oregon · 45 km ESE of this epicentre
- 5.0 3 km SW of Portland, Oregon · 44 km SE 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 45.7398, -123.1497. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Washington County, OR | 21 km (13 mi) | S | earthquakes near Washington County |
| Columbia County, OR | 23 km (14 mi) | NNE | earthquakes near Columbia County |
| Clark County, WA | 52 km (32 mi) | E | earthquakes near Clark County |
| Clatsop County, OR | 53 km (33 mi) | NW | earthquakes near Clatsop County |
| Yamhill County, OR | 56 km (35 mi) | SSW | earthquakes near Yamhill County |
| Tillamook County, OR | 57 km (35 mi) | WSW | earthquakes near Tillamook County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
43 earthquakes have been recorded within 50 km since this one.
- 1.6 2 km NNE of Columbia City, Oregon
- 1.8 8 km SW of Scappoose, Oregon
- 2.2 2 km SSW of Banks, Oregon
- 2.0 16 km W of Forest Grove, Oregon
- 1.8 5 km N of West Haven, Oregon
- 1.6 21 km W of Forest Grove, Oregon
- 1.6 10 km WSW of Felida, Washington
- 1.5 4 km SSW of Aloha, Oregon
- 2.0 4 km N of Newberg, Oregon
- 2.0 5 km NW of North Portland, Oregon
- 2.1 1 km ESE of Banks, Oregon
- 1.6 5 km ENE of Prescott, Oregon
- 1.6 1 km WSW of Kalama, Washington
- 1.7 4 km NNE of Kalama, Washington
- 1.8 5 km WNW of Deer Island, 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
- 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.