QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8ml

Earthquake near Port Orford, OR

USGS: 22 km WNW of Port Orford, Oregon

9:35 pm PDT, Oct 4, 2021 · · 23 km deep · released about 13 lb of TNT

Every earthquake near Port Orford Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Curry County 59 kmCoos County 68 kmJosephine County 108 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
9:35 pm PDT on 4 October 2021 ()
Where
23 km (14 mi) WNW of Port Orford, OR · earthquakes near Port Orford
Magnitude
M 1.8 (ml)
Depth
23 km below the surface
Felt
no reports yet
Nearest
Curry County, 59 km SE
Nearest mapped fault
Cascadia fold and fault belt, 10 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 1817 days ago

A magnitude 1.8 earthquake was recorded 23 km (14 mi) WNW of Port Orford, OR, at 9:35 pm PDT on 4 October 2021 (04:35 UTC). This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

How big was it?

This earthquake released about 13 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 5.7 810,000× the energy of this one
  3. Around the size people start to feel M 3.0 72× the energy of this one
  4. This earthquake M 1.8 about 13 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

The largest earthquake within 50 km since 2016 was M 4.5 on 2019-11-30 — about 14,000 times the energy of this one.

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 42.8157, -124.7592. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Curry County, OR 59 km (37 mi) SE earthquakes near Curry County
Coos County, OR 68 km (42 mi) NE earthquakes near Coos County
Josephine County, OR 108 km (67 mi) ESE earthquakes near Josephine County
Del Norte County, CA 135 km (84 mi) SSE earthquakes near Del Norte County

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

Aftershocks so far

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

  1. 2.0 48 km WSW of Port Orford, Oregon
  2. 1.8 10 km NNE of Nesika Beach, Oregon
  3. 2.5 42 km W of Port Orford, Oregon
  4. 1.7 12 km SSE of Port Orford, Oregon
  5. 2.6 10 km NW of Langlois, Oregon
  6. 2.1 11 km S of Port Orford, Oregon
  7. 1.9 12 km NW of Nesika Beach, Oregon
  8. 2.4 12 km SSE of Port Orford, Oregon
  9. 2.6 11 km SSE of Port Orford, Oregon
  10. 3.1 12 km SSE of Port Orford, Oregon
  11. 1.7 11 km SSE of Port Orford, Oregon
  12. 1.6 14 km NW of Nesika Beach, Oregon
  13. 2.2 46 km WSW of Port Orford, Oregon
  14. 1.5 40 km WNW of Port Orford, Oregon
  15. 2.0 21 km WSW of Bandon, 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.