QuakeIndex

Earthquake · reviewed by a seismologist

M 5.8mww

off the coast of Oregon

Yes. A magnitude 5.8 earthquake was recorded off the coast of Oregon at 01:21 UTC on 2021-12-08, 10 km deep. 13 people have reported feeling it to USGS.

· 10 km deep · released about 7.6 kilotons of TNT

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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
Magnitude
M 5.8 (mww)
Depth
10 km below the surface
Felt
13 reports · strongest reported intensity III
USGS impact alert
green
Tsunami
USGS flagged this event for tsunami evaluation. Follow tsunami.gov for official messages.
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 325 days ago

This was a moderate earthquake. Shaking at this size can damage poorly built structures close to the epicentre.

At this magnitude and depth, people at rest would likely notice it out to about 310 km (193 mi) from the epicentre. 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.

How big was it?

This earthquake released about 7.6 kilotons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 6.8 would have released about 32 times as much.

  1. Ridgecrest, California 2019 M 7.1 89× the energy of this one
  2. Loma Prieta, California 1989 M 6.9 45× the energy of this one
  3. Northridge, California 1994 M 6.7 22× the energy of this one
  4. This earthquake M 5.8 about 7.6 kilotons of TNT
  5. Magna, Utah 2020 M 5.7 this one released 1.4× more
  6. Around the size people start to feel M 3.0 this one released 16,000× more

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

Tied for the largest within 50 km (31 mi) since 2016, with M 5.8 on 2021-12-08.

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 44.2612, -129.3797. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 4.8 off the coast of Oregon
  2. 4.0 off the coast of Oregon
  3. 4.0 off the coast of Oregon
  4. 3.9 off the coast of Oregon
  5. 4.5 off the coast of Oregon
  6. 3.8 off the coast of Oregon
  7. 5.1 off the coast of Oregon
  8. 3.8 off the coast of Oregon
  9. 4.0 off the coast of Oregon
  10. 4.3 off the coast of Oregon
  11. 4.4 off the coast of Oregon
  12. 3.3 off the coast of Oregon
  13. 4.9 off the coast of Oregon
  14. 3.6 off the coast of Oregon
  15. 4.1 off the coast of 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.