QuakeIndex

Earthquake · reviewed by a seismologist

M 1.6ml

Earthquake near Castle Rock, WA

No earthquake was likely felt in Castle Rock in the 24 hours to 6:48 am PST (14:48 UTC). The last one was M 1.6, 11 km (7 mi) NE, at 4:32 pm PDT on 8 October 2026, estimated intensity II (weak) in town. Every earthquake near Castle Rock

This page: a magnitude 1.6 earthquake was recorded 21 km (13 mi) east of Castle Rock, WA, at 4:04 am PDT on 27 July 2026 (11:04 UTC), 17 km deep.

USGS: 20 km E of Castle Rock, Washington

79 km (49 mi) N of Portland, OR

4:04 am PDT, Jul 27, 2026 · · 17 km deep · released about 7.6 lb of TNT

Every earthquake near Castle Rock Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Cowlitz County 6 kmLewis County 42 kmColumbia County 48 kmClark County 54 kmSkamania County 58 kmWahkiakum County 60 kmThurston County 78 kmMultnomah County 80 kmWashington County 85 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
4:04 am PDT on 27 July 2026 ()
Where
21 km (13 mi) east of Castle Rock, WA · earthquakes near Castle Rock
Magnitude
M 1.6 (ml)
Depth
17 km below the surface
Felt
no reports yet
Nearest
Cowlitz County, 6 km SSW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 106 days ago

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. In Castle Rock, 21 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: West Side Highway, Kelso, Longview Heights, Longview, Rainier, West Longview.

How big was it?

This earthquake released about 7.6 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.6 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 2,000,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,400,000× the energy of this one
  3. Around the size people start to feel M 3.0 130× the energy of this one
  4. This earthquake M 1.6 about 7.6 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:

  1. 5.7 38 km NNE of Amboy, Washington · 35 km E of this epicentre
  2. 5.2 37 km NNE of Amboy, Washington · 34 km E of this epicentre
  3. 5.2 23 km S of Morton, Washington · 33 km ENE of this epicentre
  4. 5.1 28 km ENE of Amboy, Washington · 47 km ESE of this epicentre
  5. 5.1 Washington · 36 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 46.2467, -122.6405. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Cowlitz County, WA 6 km (4 mi) SSW earthquakes near Cowlitz County
Lewis County, WA 42 km (26 mi) NNE earthquakes near Lewis County
Columbia County, OR 48 km (30 mi) SW earthquakes near Columbia County
Clark County, WA 54 km (34 mi) SSE earthquakes near Clark County
Skamania County, WA 58 km (36 mi) ESE earthquakes near Skamania County
Wahkiakum County, WA 60 km (38 mi) W earthquakes near Wahkiakum County

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

Aftershocks so far

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

  1. 1.6 20 km E of Castle Rock, Washington
  2. 0.1 37 km NNE of Amboy, Washington
  3. 0.6 21 km ESE of Castle Rock, Washington
  4. 1.8 20 km E of Castle Rock, Washington
  5. 0.1 38 km NNE of Amboy, Washington
  6. 0.8 20 km E of Castle Rock, Washington
  7. 0.1 38 km NNE of Amboy, Washington
  8. 0.1 38 km NNE of Amboy, Washington
  9. -0.2 39 km NE of Amboy, Washington
  10. -0.0 32 km N of Amboy, Washington
  11. 1.0 28 km ENE of Yacolt, Washington
  12. 0.6 21 km ESE of Castle Rock, Washington
  13. 1.0 33 km S of Morton, Washington
  14. 0.5 38 km NNE of Amboy, Washington
  15. 1.8 23 km NE of Amboy, 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

QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.