QuakeIndex

explosion · reviewed by a seismologist

M 1.7ml

Earthquake near Sherwood, OR

No earthquake was likely felt in Sherwood in the 24 hours to 6:50 am PST (14:50 UTC). The last one was M 1.6, 7 km (4 mi) E, at 1:25 pm PST on 2 March 2026, estimated intensity II (weak) in town; 1 felt report to USGS. Every earthquake near Sherwood

No: USGS classifies this as a explosion, not an earthquake. A magnitude 1.7 explosion was recorded 4 km (2 mi) southeast of Sherwood, OR, at 12:03 pm PDT on 28 August 2023 (19:03 UTC), less than 1 km deep.

USGS: 3 km SE of Sherwood, Oregon

26 km (16 mi) SSW of Portland, OR · 11 km (7 mi) S of Tigard, OR

12:03 pm PDT, Aug 28, 2023 · · -0.2 km deep · released about 10 lb of TNT

10 km30 km60 km120 km N Washington County 34 kmMultnomah County 39 kmYamhill County 41 kmMarion County 51 kmClackamas County 52 kmClark County 55 kmPolk County 66 kmColumbia County 71 kmTillamook County 76 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
12:03 pm PDT on 28 August 2023 ()
Where
4 km (2 mi) southeast of Sherwood, OR · earthquakes near Sherwood
Magnitude
M 1.7 (ml)
Depth
-0.2 km below the surface
Felt
no reports yet
Nearest
Washington County, 34 km NW
Nearest mapped fault
Mount Angel fault, 25 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 1171 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 Sherwood, 4 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: Wilsonville, King City, Tualatin, Durham, Stafford, Canby.

USGS catalogues this as explosion, not an earthquake.

How big was it?

This earthquake released about 10 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 1,500,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,100,000× the energy of this one
  3. Around the size people start to feel M 3.0 95× the energy of this one
  4. This earthquake M 1.7 about 10 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 · 36 km SSE of this epicentre
  2. 5.2 5 km E of Bridgeton, Oregon · 34 km NNE of this epicentre
  3. 5.0 3 km SW of Portland, Oregon · 21 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 45.3292, -122.8082. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Washington County, OR 34 km (21 mi) NW earthquakes near Washington County
Multnomah County, OR 39 km (24 mi) NE earthquakes near Multnomah County
Yamhill County, OR 41 km (25 mi) WSW earthquakes near Yamhill County
Marion County, OR 51 km (32 mi) SSE earthquakes near Marion County
Clackamas County, OR 52 km (32 mi) ESE earthquakes near Clackamas County
Clark County, WA 55 km (34 mi) NNE earthquakes near Clark County

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

Aftershocks so far

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

  1. 1.7 9 km SSW of Saint Paul, Oregon
  2. 1.8 10 km ESE of Molalla, Oregon
  3. 1.6 3 km NNE of Washougal, Washington
  4. 1.7 4 km ENE of Lafayette, Oregon
  5. 2.2 0 km SE of Barberton, Washington
  6. 2.0 4 km NNE of Lafayette, Oregon
  7. 1.7 11 km SE of Silverton, Oregon
  8. 1.6 3 km E of Sherwood, Oregon
  9. 1.9 7 km ESE of Molalla, Oregon
  10. 1.7 4 km ENE of Molalla, Oregon
  11. 1.8 5 km ENE of Molalla, Oregon
  12. 2.1 5 km ENE of Molalla, Oregon
  13. 2.0 2 km NE of Estacada, Oregon
  14. 1.6 8 km ESE of Molalla, Oregon
  15. 1.8 3 km WNW of Mulino, 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.