QuakeIndex

Earthquake · reviewed by a seismologist

M 1.5ml

Earthquake near Morton, WA

No earthquake was likely felt in Morton in the 24 hours to 12:34 pm PST (20:34 UTC). The last one was M 4.2, 100 km (62 mi) NNW, at 2:05 pm PDT on 29 September 2026, estimated intensity II (weak) in town; 9,329 felt reports to USGS. Every earthquake near Morton

This page: a magnitude 1.5 earthquake was recorded 12 km (8 mi) southwest of Morton, WA, at 9:34 am PDT on 1 August 2023 (16:34 UTC), 18 km deep.

USGS: 7 km ESE of Mossyrock, Washington

9:34 am PDT, Aug 1, 2023 · · 18 km deep · released about 5.9 lb of TNT

Every earthquake near Morton Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Lewis County 10 kmCowlitz County 39 kmThurston County 59 kmSkamania County 63 kmPierce County 65 kmColumbia County 80 kmClark County 81 kmWahkiakum County 81 kmMultnomah County 105 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
9:34 am PDT on 1 August 2023 ()
Where
12 km (8 mi) southwest of Morton, WA · earthquakes near Morton
Magnitude
M 1.5 (ml)
Depth
18 km below the surface
Felt
no reports yet
Nearest
Lewis County, 10 km NNE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1200 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 Morton, 12 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.

How big was it?

This earthquake released about 5.9 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.

  1. Mineral, Virginia 2011 M 5.8 2,500,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,800,000× the energy of this one
  3. Around the size people start to feel M 3.0 160× the energy of this one
  4. This earthquake M 1.5 about 5.9 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 15 earthquakes of M5 or more within 50 km; the five largest:

  1. 5.7 38 km NNE of Amboy, Washington · 36 km SSE of this epicentre
  2. 5.2 37 km NNE of Amboy, Washington · 36 km SSE of this epicentre
  3. 5.2 23 km S of Morton, Washington · 21 km SE of this epicentre
  4. 5.1 Washington · 35 km SSE of this epicentre
  5. 5.1 38 km NNE of Amboy, Washington · 36 km SSE 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 46.4938, -122.4057. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Lewis County, WA 10 km (6 mi) NNE earthquakes near Lewis County
Cowlitz County, WA 39 km (24 mi) SSW earthquakes near Cowlitz County
Thurston County, WA 59 km (37 mi) NNW earthquakes near Thurston County
Skamania County, WA 63 km (39 mi) SE earthquakes near Skamania County
Pierce County, WA 65 km (40 mi) NNE earthquakes near Pierce County
Columbia County, OR 80 km (50 mi) SW earthquakes near Columbia County

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

Aftershocks so far

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

  1. 3.5 20 km S of Morton, Washington
  2. 1.9 15 km S of Morton, Washington
  3. 2.1 20 km SSE of Mossyrock, Washington
  4. 2.0 11 km S of Morton, Washington
  5. 1.7 24 km N of Amboy, Washington
  6. 1.7 24 km N of Amboy, Washington
  7. 2.0 38 km NNE of Amboy, Washington
  8. 2.0 3 km ENE of Eatonville, Washington
  9. 1.6 6 km ENE of Mossyrock, Washington
  10. 1.8 7 km SSE of McKenna, Washington
  11. 1.8 10 km NE of Castle Rock, Washington
  12. 1.6 2 km N of Onalaska, Washington
  13. 2.9 3 km N of Onalaska, Washington
  14. 1.6 27 km S of Morton, Washington
  15. 2.5 27 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

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