QuakeIndex

Earthquake · reviewed by a seismologist

M 5.6mww

214 km SW of Port McNeill, Canada

· 10 km deep · released about 3.8 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 5.6 (mww)
Depth
10 km below the surface
Felt
23 reports · strongest reported intensity IV
Measured shaking
intensity III (ShakeMap)
USGS impact alert
green
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 46 days ago

This was a moderate earthquake. Shaking at this size can damage poorly built structures close to the epicentre. 23 people have reported feeling it to USGS.

How big was it?

This earthquake released about 3.8 kilotons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 6.6 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 45× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 2× the energy of this one
  3. Magna, Utah 2020 M 5.7 1.4× the energy of this one
  4. This earthquake M 5.6 about 3.8 kilotons of TNT
  5. Around the size people start to feel M 3.0 this one released 7,900× 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.

Where

Epicentre 49.4982, -129.5616. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 4.1 257 km SW of Port McNeill, Canada
  2. 4.2 174 km WSW of Port McNeill, Canada
  3. 5.6 215 km SW of Port McNeill, Canada
  4. 4.4 195 km SW of Port McNeill, Canada
  5. 4.1 188 km SW of Port McNeill, Canada
  6. 4.1 193 km SW of Port McNeill, Canada

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.

For this area

The largest earthquake within 50 km in our catalogue was M 6.8 on 2018-10-22 — it released about 63 times the energy of this one.

From the QuakeIndex catalogue, built from the USGS FDSN event service.

On USGS

QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.