QuakeIndex

explosion · reviewed by a seismologist

M 1.7ml

Earthquake near Molalla, OR

No earthquake was likely felt in Molalla in the 24 hours to 1:18 pm PST (21:18 UTC). The last one was M 2.1, 8 km (5 mi) ESE, at 12:47 pm PDT on 1 September 2026, estimated intensity II (weak) in town. Every earthquake near Molalla

No: USGS classifies this as a explosion, not an earthquake. A magnitude 1.7 explosion was recorded 9 km (5 mi) southeast of Molalla, OR, at 1:19 pm PST on 18 February 2020 (21:19 UTC), less than 1 km deep.

USGS: 8 km SE of Molalla, Oregon

50 km (31 mi) SSE of Portland, OR · 43 km (27 mi) SSE of Tigard, OR

1:19 pm PST, Feb 18, 2020 · · -0.5 km deep · released about 11 lb of TNT

10 km30 km60 km120 km N Marion County 23 kmClackamas County 24 kmMultnomah County 50 kmYamhill County 67 kmLinn County 68 kmWashington County 69 kmPolk County 75 kmClark County 75 kmHood River County 80 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
1:19 pm PST on 18 February 2020 ()
Where
9 km (5 mi) southeast of Molalla, OR · earthquakes near Molalla
Magnitude
M 1.7 (ml)
Depth
-0.5 km below the surface
Felt
no reports yet
Nearest
Marion County, 23 km SSW
Nearest mapped fault
Mount Angel fault, 18 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 2459 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 Molalla, 9 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: Mulino, Beavercreek, Canby, Mount Angel, Estacada, Silverton.

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 5.7 970,000× the energy of this one
  3. Around the size people start to feel M 3.0 86× 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 lists 2 earthquakes of M5 or more within 50 km:

  1. 5.6 4 km E of Scotts Mills, Oregon · 11 km SW of this epicentre
  2. 5.0 3 km SW of Portland, Oregon · 48 km NNW 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 45.0985, -122.4913. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Marion County, OR 23 km (14 mi) SSW earthquakes near Marion County
Clackamas County, OR 24 km (15 mi) ENE earthquakes near Clackamas County
Multnomah County, OR 50 km (31 mi) N earthquakes near Multnomah County
Yamhill County, OR 67 km (41 mi) WNW earthquakes near Yamhill County
Linn County, OR 68 km (42 mi) S earthquakes near Linn County
Washington County, OR 69 km (43 mi) NW earthquakes near Washington County

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

Aftershocks so far

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

  1. 1.9 3 km NNE of Hubbard, Oregon
  2. 1.7 Washington-Oregon border region
  3. 1.7 5 km SSW of Saint Paul, Oregon
  4. 1.5 7 km ESE of Estacada, Oregon
  5. 1.7 8 km E of Molalla, Oregon
  6. 1.6 5 km E of Hubbard, Oregon
  7. 1.5 6 km SE of Molalla, Oregon
  8. 1.8 3 km W of Saint Paul, Oregon
  9. 1.6 14 km ESE of Scotts Mills, Oregon
  10. 1.8 3 km NW of Mount Hood Village, Oregon
  11. 1.6 1 km SSE of King City, Oregon
  12. 1.6 8 km ESE of Molalla, Oregon
  13. 1.7 4 km WNW of Molalla, Oregon
  14. 2.7 4 km WNW of Molalla, Oregon
  15. 1.7 3 km SSW of Scotts Mills, 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.