explosion · reviewed by a seismologist
M 1.7ml
Earthquake near West Longview, WA
No earthquake was likely felt in West Longview in the 24 hours to 2:39 am PST (10:39 UTC). The last one was M 3.8, 29 km (18 mi) ENE, at 4:09 am PDT on 5 September 2026, estimated intensity III (weak) in town; 1,025 felt reports to USGS. Every earthquake near West Longview
No: USGS classifies this as a explosion, not an earthquake. A magnitude 1.7 explosion was recorded 4 km (2 mi) northwest of West Longview, WA, at 3:33 pm PST on 23 February 2021 (23:33 UTC), less than 1 km deep.
USGS: 3 km NW of West Longview, Washington
79 km (49 mi) NNW of Portland, OR
- When
- 3:33 pm PST on 23 February 2021 ()
- Where
- 4 km (2 mi) northwest of West Longview, WA · earthquakes near West Longview
- Magnitude
- M 1.7 (ml)
- Depth
- -0.3 km below the surface
- Felt
- no reports yet
- Nearest
- Cowlitz County, 27 km E
- Status
- Reviewed by a seismologist
USGS · last changed by USGS · we first saw it 614 days ago
Earthquake alerts for West Longview, WA
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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 12 km (7 mi) from the epicentre. In West Longview, 4 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: Longview Heights, West Side Highway, Longview, Kelso, Castle Rock, Rainier.
USGS catalogues this as explosion, not an earthquake.
How big was it?
This earthquake released about 11 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.7 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 1,400,000× the energy of this one
- Magna, Utah 2020 M 5.7 970,000× the energy of this one
- Around the size people start to feel M 3.0 86× the energy of this one
- This earthquake M 1.7 about 11 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 46.1970, -123.0283. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Cowlitz County, WA | 27 km (17 mi) | E | earthquakes near Cowlitz County |
| Columbia County, OR | 29 km (18 mi) | S | earthquakes near Columbia County |
| Wahkiakum County, WA | 32 km (20 mi) | WNW | earthquakes near Wahkiakum County |
| Clatsop County, OR | 56 km (35 mi) | WSW | earthquakes near Clatsop County |
| Clark County, WA | 63 km (39 mi) | SE | earthquakes near Clark County |
| Lewis County, WA | 66 km (41 mi) | NE | earthquakes near Lewis County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
53 earthquakes have been recorded within 50 km since this one.
- 1.5 6 km ENE of Prescott, Oregon
- 1.7 7 km ENE of Prescott, Oregon
- 1.5 8 km WSW of Napavine, Washington
- 1.8 5 km NNW of Winlock, Washington
- 1.7 3 km NNE of La Center, Washington
- 1.7 10 km NE of Castle Rock, Washington
- 2.1 9 km ENE of Kalama, Washington
- 1.6 1 km W of Winlock, Washington
- 1.8 6 km NW of Winlock, Washington
- 1.8 10 km NE of Castle Rock, Washington
- 1.6 9 km NE of Castle Rock, Washington
- 1.6 2 km WNW of Saint Helens, Oregon
- 2.1 1 km WNW of Deer Island, Oregon
- 1.7 1 km SW of Columbia City, Oregon
- 1.9 3 km WNW of Winlock, 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.