QuakeIndex

explosion · reviewed by a seismologist

M 1.8ml

Earthquake near Tualatin, OR

No earthquake was likely felt in Tualatin in the 24 hours to 10:33 pm PST (06:33 UTC). The last one was M 1.6, 4 km (3 mi) SSE, at 1:25 pm PST on 2 March 2026, estimated intensity II (weak) in town; 1 felt report to USGS. Every earthquake near Tualatin

No: USGS classifies this as a explosion, not an earthquake. A magnitude 1.8 explosion was recorded 2 km (1 mi) southwest of Tualatin, OR, at 4:22 pm PST on 11 November 2020 (00:22 UTC), less than 1 km deep.

USGS: 2 km SW of Tualatin, Oregon

21 km (13 mi) SSW of Portland, OR · 6 km (3 mi) S of Tigard, OR

4:22 pm PST, Nov 11, 2020 · · -0.4 km deep · released about 16 lb of TNT

10 km30 km60 km120 km N Washington County 32 kmMultnomah County 35 kmYamhill County 44 kmClark County 50 kmClackamas County 52 kmMarion County 55 kmColumbia County 67 kmPolk County 71 kmTillamook County 77 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
4:22 pm PST on 11 November 2020 ()
Where
2 km (1 mi) southwest of Tualatin, OR · earthquakes near Tualatin
Magnitude
M 1.8 (ml)
Depth
-0.4 km below the surface
Felt
no reports yet
Nearest
Washington County, 32 km NW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2192 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 14 km (9 mi) from the epicentre. In Tualatin, 2 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: King City, Durham, Sherwood, Stafford, Tigard, Wilsonville.

USGS catalogues this as explosion, not an earthquake.

How big was it?

This earthquake released about 16 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.8 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 970,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 680,000× the energy of this one
  3. Around the size people start to feel M 3.0 61× the energy of this one
  4. This earthquake M 1.8 about 16 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 3 earthquakes of M5 or more within 50 km:

  1. 5.6 4 km E of Scotts Mills, Oregon · 40 km SSE of this epicentre
  2. 5.2 5 km E of Bridgeton, Oregon · 29 km NNE of this epicentre
  3. 5.0 3 km SW of Portland, Oregon · 16 km NNE 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 45.3733, -122.7855. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Washington County, OR 32 km (20 mi) NW earthquakes near Washington County
Multnomah County, OR 35 km (22 mi) NE earthquakes near Multnomah County
Yamhill County, OR 44 km (27 mi) WSW earthquakes near Yamhill County
Clark County, WA 50 km (31 mi) NNE earthquakes near Clark County
Clackamas County, OR 52 km (32 mi) ESE earthquakes near Clackamas County
Marion County, OR 55 km (34 mi) SSE earthquakes near Marion County

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

Aftershocks so far

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

  1. 1.9 12 km WNW of Scappoose, Oregon
  2. 1.5 1 km NW of Wilsonville, Oregon
  3. 1.7 6 km ESE of Molalla, Oregon
  4. 1.8 8 km S of Scappoose, Oregon
  5. 1.7 13 km ESE of Scotts Mills, Oregon
  6. 1.7 8 km SE of Molalla, Oregon
  7. 1.6 3 km ESE of Sherwood, Oregon
  8. 2.0 2 km WNW of Molalla, Oregon
  9. 1.7 4 km ESE of Silverton, Oregon
  10. 1.9 3 km NNE of Hubbard, Oregon
  11. 1.7 Washington-Oregon border region
  12. 1.7 5 km SSW of Saint Paul, Oregon
  13. 1.5 7 km ESE of Estacada, Oregon
  14. 1.7 8 km E of Molalla, Oregon
  15. 1.6 8 km SW of Aloha, 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.