QuakeIndex

explosion · reviewed by a seismologist

M 1.9ml

Earthquake near Astoria, OR

USGS: 6 km N of Astoria, Oregon

11:07 am PDT, Apr 29, 2016 · · -0.2 km deep · released about 23 lb of TNT

10 km30 km60 km120 km N Clatsop County 26 kmWahkiakum County 31 kmPacific County 35 kmColumbia County 66 kmTillamook County 88 kmCowlitz County 88 kmWashington County 95 kmGrays Harbor County 97 kmThurston County 108 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
11:07 am PDT on 29 April 2016 ()
Where
6 km (4 mi) N of Astoria, OR · earthquakes near Astoria
Magnitude
M 1.9 (ml)
Depth
-0.2 km below the surface
Felt
no reports yet
Nearest
Clatsop County, 26 km SSE
Nearest mapped fault
Cascadia fold and fault belt, 20 km from its surface trace — near is not the same as on
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 558 days ago

A magnitude 1.9 earthquake was recorded 6 km (4 mi) N of Astoria, OR, at 11:07 am PDT on 29 April 2016 (18:07 UTC). This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

Earthquakes near other towns within 30 km: Warrenton, Long Beach, Gearhart, Seaside.

USGS catalogues this as explosion, not an earthquake.

How big was it?

This earthquake released about 23 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 5.8 660,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 470,000× the energy of this one
  3. Around the size people start to feel M 3.0 42× the energy of this one
  4. This earthquake M 1.9 about 23 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 since 1900 lists no earthquake of M5 or more within 50 km.

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 46.2433, -123.8217. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Clatsop County, OR 26 km (16 mi) SSE earthquakes near Clatsop County
Wahkiakum County, WA 31 km (19 mi) E earthquakes near Wahkiakum County
Pacific County, WA 35 km (22 mi) N earthquakes near Pacific County
Columbia County, OR 66 km (41 mi) ESE earthquakes near Columbia County
Tillamook County, OR 88 km (54 mi) S earthquakes near Tillamook County
Cowlitz County, WA 88 km (55 mi) E earthquakes near Cowlitz County

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

Aftershocks so far

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

  1. 1.6 3 km E of East Cathlamet, Washington
  2. 1.8 3 km WSW of South Bend, Washington
  3. 1.8 3 km S of Willapa, Washington
  4. 2.6 5 km WSW of Pe Ell, Washington
  5. 1.9 12 km SW of Lebam, Washington
  6. 1.9 5 km NW of Westport, Oregon
  7. 1.6 3 km ENE of East Cathlamet, Washington
  8. 1.9 4 km SW of Cathlamet, Washington
  9. 1.9 3 km WSW of Cathlamet, Washington
  10. 1.7 19 km WSW of Westport, Oregon
  11. 1.6 4 km SW of Cathlamet, Washington
  12. 1.6 5 km W of Clatskanie, Oregon
  13. 1.8 21 km WNW of Long Beach, Washington
  14. 2.0 4 km SW of Cathlamet, Washington
  15. 1.7 3 km SW of Cathlamet, 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.