Earthquake · reviewed by a seismologist
M 0.5ml
Earthquake near Castle Rock, WA
Yes. A magnitude 0.5 earthquake was recorded 20 km (13 mi) east-southeast of Castle Rock, WA, at 11:56 pm PDT on 21 October 2026 (06:56 UTC), 18 km deep. No felt reports to USGS yet.
USGS: 20 km ESE of Castle Rock, Washington
78 km (48 mi) N of Portland, OR
- When
- 11:56 pm PDT on 21 October 2026 ()
- Where
- 20 km (13 mi) east-southeast of Castle Rock, WA · earthquakes near Castle Rock
- Magnitude
- M 0.5 (ml)
- Depth
- 18 km below the surface
- Felt
- no reports yet
- Nearest
- Cowlitz County, 5 km SSW
- Status
- Reviewed by a seismologist
USGS · last changed by USGS · we first saw it 10 hours ago
Earthquake alerts for Castle Rock, WA
Get a notification in this browser when USGS records an earthquake near Castle Rock, WA. No account or email needed.
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 it was probably too small to be felt, even directly above it. 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: West Side Highway, Kelso, Longview Heights, Longview, Rainier, West Longview.
How big was it?
This earthquake released about 0.18 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 1.5 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 83,000,000× the energy of this one
- Magna, Utah 2020 M 5.7 59,000,000× the energy of this one
- Around the size people start to feel M 3.0 5,200× the energy of this one
- This earthquake M 0.5 about 0.18 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 16 earthquakes of M5 or more within 50 km; the five largest:
- 5.7 38 km NNE of Amboy, Washington · 35 km E of this epicentre
- 5.2 37 km NNE of Amboy, Washington · 35 km E of this epicentre
- 5.2 23 km S of Morton, Washington · 34 km ENE of this epicentre
- 5.1 28 km ENE of Amboy, Washington · 47 km ESE of this epicentre
- 5.1 Washington · 37 km E 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 46.2372, -122.6473. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Cowlitz County, WA | 5 km (3 mi) | SSW | earthquakes near Cowlitz County |
| Lewis County, WA | 43 km (27 mi) | NNE | earthquakes near Lewis County |
| Columbia County, OR | 47 km (29 mi) | SW | earthquakes near Columbia County |
| Clark County, WA | 53 km (33 mi) | SSE | earthquakes near Clark County |
| Skamania County, WA | 58 km (36 mi) | ESE | earthquakes near Skamania County |
| Wahkiakum County, WA | 60 km (37 mi) | W | earthquakes near Wahkiakum County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
3 earthquakes have been recorded within 50 km since this one.
- 0.4 16 km NNE of Amboy, Washington
- 3.0 3 km W of Columbia City, Oregon
- 1.7 24 km S of Morton, 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.