QuakeIndex

Earthquake · reviewed by a seismologist

M 1.6ml

Earthquake near Amboy, WA

USGS: 3 km NE of Amboy, Washington

48 km (30 mi) NNE of Portland, OR · 36 km (22 mi) NNE of Vancouver, WA

6:47 pm PDT, Apr 15, 2018 · · 9.4 km deep · released about 6.4 lb of TNT

10 km30 km60 km120 km N Clark County 19 kmCowlitz County 35 kmSkamania County 37 kmMultnomah County 43 kmColumbia County 51 kmWashington County 68 kmLewis County 71 kmHood River County 76 kmWahkiakum County 87 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
6:47 pm PDT on 15 April 2018 ()
Where
4 km (2 mi) NE of Amboy, WA · earthquakes near Amboy
Magnitude
M 1.6 (ml)
Depth
9.4 km below the surface
Felt
no reports yet
Nearest
Clark County, 19 km SSW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 3089 days ago

A magnitude 1.6 earthquake was recorded 4 km (2 mi) NE of Amboy, WA, at 6:47 pm PDT on 15 April 2018 (01:47 UTC). This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

Earthquakes near other towns within 30 km: Yacolt, Lewisville, Venersborg, Battle Ground, La Center, Dollar Corner.

How big was it?

This earthquake released about 6.4 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 2,400,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,700,000× the energy of this one
  3. Around the size people start to feel M 3.0 150× the energy of this one
  4. This earthquake M 1.6 about 6.4 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 17 earthquakes of M5 or more within 50 km; the five largest:

  1. 5.7 38 km NNE of Amboy, Washington · 35 km NNE of this epicentre
  2. 5.2 5 km E of Bridgeton, Oregon · 40 km SSW of this epicentre
  3. 5.2 37 km NNE of Amboy, Washington · 34 km NNE of this epicentre
  4. 5.2 23 km S of Morton, Washington · 48 km NNE of this epicentre
  5. 5.1 28 km ENE of Amboy, Washington · 25 km ENE 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 45.9378, -122.4175. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Clark County, WA 19 km (12 mi) SSW earthquakes near Clark County
Cowlitz County, WA 35 km (22 mi) NW earthquakes near Cowlitz County
Skamania County, WA 37 km (23 mi) ENE earthquakes near Skamania County
Multnomah County, OR 43 km (27 mi) S earthquakes near Multnomah County
Columbia County, OR 51 km (32 mi) W earthquakes near Columbia County
Washington County, OR 68 km (42 mi) SW earthquakes near Washington County

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

Aftershocks so far

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

  1. 1.8 24 km N of Amboy, Washington
  2. 1.8 23 km SSE of Mossyrock, Washington
  3. 1.8 23 km SSE of Mossyrock, Washington
  4. 1.5 Washington-Oregon border region
  5. 1.8 12 km NNW of Amboy, Washington
  6. 2.0 8 km S of Scappoose, Oregon
  7. 1.6 20 km NE of Kalama, Washington
  8. 1.6 8 km E of Kalama, Washington
  9. 2.1 Washington
  10. 1.5 2 km NNW of Venersborg, Washington
  11. 1.7 23 km NNE of Amboy, Washington
  12. 1.6 1 km NNW of Walnut Grove, Washington
  13. 1.5 14 km ESE of Yacolt, Washington
  14. 1.6 16 km ESE of Yacolt, Washington
  15. 1.6 24 km NNW of Carson, 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.