QuakeIndex

Earthquake · reviewed by a seismologist

M 4.8mwr

202 km W of Port McNeill, Canada

· 10 km deep · released about 240 tons 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 4.8 (mwr)
Depth
10 km below the surface
Felt
6 reports · strongest reported intensity II
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 287 days ago

A magnitude 4.8 earthquake was recorded 202 km W of Port McNeill, Canada at 03:51 UTC on 2017-12-04. 6 people have reported feeling it to USGS. This was a light earthquake. It is usually felt clearly nearby and can rattle windows and dishes, but damage is uncommon.

How big was it?

This earthquake released about 240 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 5.8 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 710× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 32× the energy of this one
  3. Magna, Utah 2020 M 5.7 22× the energy of this one
  4. This earthquake M 4.8 about 240 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 500× 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

The largest earthquake within 50 km in our catalogue was M 5.4 on 2017-01-07 — about 7.9 times the energy of this one.

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 50.5950, -129.9469. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 4.8 201 km W of Port McNeill, Canada
  2. 4.3 224 km W of Port McNeill, Canada
  3. 4.4 230 km W of Port McNeill, Canada
  4. 5.5 229 km W of Port McNeill, Canada
  5. 4.5 213 km W of Port McNeill, Canada
  6. 4.3 234 km W of Port McNeill, Canada
  7. 4.2 219 km W of Port McNeill, Canada
  8. 3.1 211 km W of Port McNeill, Canada
  9. 4.1 195 km W of Port McNeill, Canada
  10. 4.4 180 km WSW of Port McNeill, Canada
  11. 4.3 183 km WSW of Port McNeill, Canada
  12. 4.6 Vancouver Island, Canada region
  13. 4.2 199 km WSW of Port McNeill, Canada
  14. 4.6 218 km W of Port McNeill, Canada
  15. 4.2 Vancouver Island, Canada 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.