QuakeIndex

explosion · reviewed by a seismologist

M 1.6ml

Earthquake near Tillamook, OR

No earthquake was likely felt in Tillamook in the 24 hours to 2:04 pm PST (22:04 UTC). The last one was M 7.0, 573 km (356 mi) S, at 10:44 am PST on 5 December 2024, estimated intensity II (weak) in town; 16,883 felt reports to USGS. Every earthquake near Tillamook

No: USGS classifies this as a explosion, not an earthquake. A magnitude 1.6 explosion was recorded 23 km (14 mi) east-southeast of Tillamook, OR, at 10:28 am PST on 21 November 2023 (18:28 UTC), less than 1 km deep.

USGS: 23 km ESE of Tillamook, Oregon

72 km (45 mi) W of Portland, OR · 50 km (31 mi) WSW of Hillsboro, OR

10:28 am PST, Nov 21, 2023 · · -0.7 km deep · released about 6.4 lb of TNT

10 km30 km60 km120 km N Tillamook County 17 kmYamhill County 26 kmWashington County 39 kmPolk County 58 kmClatsop County 69 kmColumbia County 70 kmLincoln County 90 kmMultnomah County 90 kmClark County 92 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
10:28 am PST on 21 November 2023 ()
Where
23 km (14 mi) east-southeast of Tillamook, OR · earthquakes near Tillamook
Magnitude
M 1.6 (ml)
Depth
-0.7 km below the surface
Felt
no reports yet
Nearest
Tillamook County, 17 km WNW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1086 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 11 km (7 mi) from the epicentre. In Tillamook, 23 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.

Earthquakes near other towns within 30 km: Bay City, Yamhill.

USGS catalogues this as explosion, not an earthquake.

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 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 45.4107, -123.5555. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Tillamook County, OR 17 km (10 mi) WNW earthquakes near Tillamook County
Yamhill County, OR 26 km (16 mi) SE earthquakes near Yamhill County
Washington County, OR 39 km (24 mi) ENE earthquakes near Washington County
Polk County, OR 58 km (36 mi) SSE earthquakes near Polk County
Clatsop County, OR 69 km (43 mi) N earthquakes near Clatsop County
Columbia County, OR 70 km (43 mi) NNE earthquakes near Columbia County

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

Aftershocks so far

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

  1. 1.9 21 km W of Forest Grove, Oregon
  2. 2.0 7 km WNW of McMinnville, Oregon
  3. 2.0 2 km WNW of Dundee, Oregon
  4. 1.6 15 km ESE of Wheeler, Oregon
  5. 1.9 7 km S of Dayton, Oregon
  6. 1.6 9 km E of Wheeler, Oregon
  7. 2.2 10 km W of Cape Meares, Oregon
  8. 1.6 2 km SW of Oceanside, Oregon
  9. 1.7 8 km SW of Vernonia, Oregon
  10. 2.1 4 km NE of Lafayette, Oregon
  11. 1.5 2 km NW of Sheridan, Oregon
  12. 1.6 24 km NNW of Sheridan, Oregon
  13. 1.7 2 km E of Amity, Oregon
  14. 3.2 5 km SE of Amity, Oregon
  15. 1.6 6 km S of Dayton, 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.