QuakeIndex

explosion · reviewed by a seismologist

M 1.7ml

Earthquake near Longview, WA

No earthquake was likely felt in Longview in the 24 hours to 12:25 pm PST (20:25 UTC). The last one was M 3.0, 29 km (18 mi) SSE, at 7:25 am PDT on 22 October 2026, estimated intensity II (weak) in town; 113 felt reports to USGS. Every earthquake near Longview

No: USGS classifies this as a explosion, not an earthquake. A magnitude 1.7 explosion was recorded 46 km (28 mi) west of Longview, WA, at 3:44 pm PST on 12 December 2018 (23:44 UTC), less than 1 km deep.

USGS: 11 km WSW of Cathlamet, Washington

98 km (61 mi) NW of Portland, OR

3:44 pm PST, Dec 12, 2018 · · -0.8 km deep · released about 11 lb of TNT

10 km30 km60 km120 km N Wahkiakum County 16 kmClatsop County 21 kmColumbia County 43 kmPacific County 47 kmCowlitz County 66 kmWashington County 76 kmTillamook County 81 kmClark County 92 kmLewis County 100 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
3:44 pm PST on 12 December 2018 ()
Where
46 km (28 mi) west of Longview, WA · earthquakes near Longview
Magnitude
M 1.7 (ml)
Depth
-0.8 km below the surface
Felt
no reports yet
Nearest
Wahkiakum County, 16 km NNE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2892 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

At this magnitude and depth, people at rest would likely notice it out to about 12 km (7 mi) from the epicentre. In Longview, 46 km away, the estimate is intensity I (not felt). 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: Astoria, Clatskanie.

USGS catalogues this as explosion, not an earthquake.

How big was it?

This earthquake released about 11 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.7 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 1,400,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,000,000× the energy of this one
  3. Around the size people start to feel M 3.0 89× the energy of this one
  4. This earthquake M 1.7 about 11 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 46.1668, -123.5292. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Wahkiakum County, WA 16 km (10 mi) NNE earthquakes near Wahkiakum County
Clatsop County, OR 21 km (13 mi) SW earthquakes near Clatsop County
Columbia County, OR 43 km (27 mi) SE earthquakes near Columbia County
Pacific County, WA 47 km (30 mi) NNW earthquakes near Pacific County
Cowlitz County, WA 66 km (41 mi) E earthquakes near Cowlitz County
Washington County, OR 76 km (47 mi) SSE earthquakes near Washington 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. 1.8 4 km NNW of West Longview, Washington
  2. 1.5 19 km WSW of Vernonia, Oregon
  3. 1.9 4 km WSW of Cathlamet, Washington
  4. 1.8 6 km SW of Clatskanie, Oregon
  5. 1.7 Washington-Oregon border region
  6. 1.7 Oregon
  7. 1.9 Washington-Oregon border region
  8. 1.7 3 km NW of West Longview, Washington
  9. 2.7 11 km W of Deer Island, Oregon
  10. 1.5 10 km W of Vernonia, Oregon
  11. 1.7 12 km NNE of Vernonia, Oregon
  12. 1.5 10 km NNE of Vernonia, Oregon
  13. 1.8 4 km NNW of Skamokawa Valley, Washington
  14. 1.9 19 km WSW of Vernonia, Oregon
  15. 1.5 8 km NE of Nehalem, Oregon

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.