QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8ml

Earthquake near Aloha, OR

No earthquake was likely felt in Aloha in the 24 hours to 8:42 am PST (16:42 UTC). The last one was M 1.5, 5 km (3 mi) SSW, at 1:30 pm PDT on 11 June 2025, estimated intensity II (weak) in town. Every earthquake near Aloha

This page: a magnitude 1.8 earthquake was recorded 8 km (5 mi) southwest of Aloha, OR, at 11:59 am PDT on 17 August 2018 (18:59 UTC), 7.8 km deep.

USGS: 7 km SW of Aloha, Oregon

25 km (15 mi) WSW of Portland, OR · 9 km (5 mi) S of Hillsboro, OR

11:59 am PDT, Aug 17, 2018 · · 7.8 km deep · released about 14 lb of TNT

10 km30 km60 km120 km N Washington County 17 kmYamhill County 37 kmMultnomah County 42 kmClark County 51 kmColumbia County 56 kmTillamook County 64 kmClackamas County 66 kmMarion County 67 kmPolk County 71 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
11:59 am PDT on 17 August 2018 ()
Where
8 km (5 mi) southwest of Aloha, OR · earthquakes near Aloha
Magnitude
M 1.8 (ml)
Depth
7.8 km below the surface
Felt
no reports yet
Nearest
Washington County, 17 km NW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 3010 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 Aloha, 8 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: Hillsboro, Beaverton, King City, Cornelius, Rockcreek, Cedar Hills.

How big was it?

This earthquake released about 14 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 1,100,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 760,000× the energy of this one
  3. Around the size people start to feel M 3.0 68× the energy of this one
  4. This earthquake M 1.8 about 14 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. 5.2 5 km E of Bridgeton, Oregon · 31 km ENE of this epicentre
  2. 5.0 3 km SW of Portland, Oregon · 20 km ENE 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 45.4475, -122.9407. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Washington County, OR 17 km (11 mi) NW earthquakes near Washington County
Yamhill County, OR 37 km (23 mi) SW earthquakes near Yamhill County
Multnomah County, OR 42 km (26 mi) ENE earthquakes near Multnomah County
Clark County, WA 51 km (31 mi) NE earthquakes near Clark County
Columbia County, OR 56 km (35 mi) N earthquakes near Columbia County
Tillamook County, OR 64 km (40 mi) W earthquakes near Tillamook County

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

Aftershocks so far

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

  1. 2.0 Washington-Oregon border region
  2. 1.9 3 km E of Sherwood, Oregon
  3. 1.8 0 km E of Sherwood, Oregon
  4. 1.7 3 km SW of Tualatin, Oregon
  5. 1.6 3 km N of West Haven, Oregon
  6. 1.6 5 km SW of Deer Island, Oregon
  7. 1.6 7 km E of Molalla, Oregon
  8. 1.6 2 km E of Sherwood, Oregon
  9. 1.5 3 km SSW of Beaverton, Oregon
  10. 1.9 3 km WSW of Dundee, Oregon
  11. 1.5 18 km W of Yamhill, Oregon
  12. 1.6 1 km SSW of Cherry Grove, Washington
  13. 2.4 3 km WNW of Molalla, Oregon
  14. 1.5 4 km NW of North Portland, Oregon
  15. 1.5 Washington-Oregon border region

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.