QuakeIndex

Earthquake · reviewed by a seismologist

M 1.9ml

Earthquake near Morton, WA

USGS: 22 km S of Morton, Washington

97 km (60 mi) NNE of Portland, OR

5:53 am PDT, Jul 23, 2018 · · 23 km deep · released about 22 lb of TNT

10 km30 km60 km120 km N Lewis County 28 kmCowlitz County 39 kmSkamania County 42 kmClark County 68 kmPierce County 78 kmThurston County 80 kmColumbia County 81 kmMultnomah County 91 kmWahkiakum County 93 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
5:53 am PDT on 23 July 2018 ()
Where
23 km (14 mi) S of Morton, WA · earthquakes near Morton
Magnitude
M 1.9 (ml)
Depth
23 km below the surface
Felt
no reports yet
Nearest
Lewis County, 28 km NNW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2992 days ago

A magnitude 1.9 earthquake was recorded 23 km (14 mi) S of Morton, WA, at 5:53 am PDT on 23 July 2018 (12:53 UTC). This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

How big was it?

This earthquake released about 22 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.9 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 680,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 480,000× the energy of this one
  3. Around the size people start to feel M 3.0 43× the energy of this one
  4. This earthquake M 1.9 about 22 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 · 17 km S of this epicentre
  2. 5.2 37 km NNE of Amboy, Washington · 17 km S of this epicentre
  3. 5.2 23 km S of Morton, Washington · 1 km WSW of this epicentre
  4. 5.1 28 km ENE of Amboy, Washington · 38 km SSE of this epicentre
  5. 5.1 Washington · 15 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 46.3552, -122.2205. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Lewis County, WA 28 km (17 mi) NNW earthquakes near Lewis County
Cowlitz County, WA 39 km (24 mi) WSW earthquakes near Cowlitz County
Skamania County, WA 42 km (26 mi) SSE earthquakes near Skamania County
Clark County, WA 68 km (42 mi) SSW earthquakes near Clark County
Pierce County, WA 78 km (48 mi) N earthquakes near Pierce County
Thurston County, WA 80 km (49 mi) NW earthquakes near Thurston County

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

Aftershocks so far

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

  1. 1.9 23 km NE of Amboy, Washington
  2. 2.2 37 km SSE of Morton, Washington
  3. 1.6 14 km SE of Mossyrock, Washington
  4. 1.6 15 km ESE of Morton, Washington
  5. 1.7 20 km N of Amboy, Washington
  6. 1.5 28 km NNW of Amboy, Washington
  7. 1.6 6 km ESE of Ashford, Washington
  8. 2.9 1 km WSW of Onalaska, Washington
  9. 2.9 Washington-Oregon border region
  10. 1.6 4 km NE of Amboy, Washington
  11. 2.5 16 km NE of Kalama, Washington
  12. 3.1 3 km NNE of Onalaska, Washington
  13. 1.6 14 km SSW of Morton, Washington
  14. 1.6 21 km SSE of Mossyrock, Washington
  15. 1.6 12 km SSE of Toledo, 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.