QuakeIndex

Earthquake · reviewed by a seismologist

M 4.3mb

off the coast of Southeastern Alaska

· 5.2 km deep · released about 43 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 4.3 (mb)
Depth
5.2 km below the surface
Felt
3 reports · strongest reported intensity II
Measured shaking
intensity II (ShakeMap)
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1016 days ago

This was a light earthquake. It is usually felt clearly nearby and can rattle windows and dishes, but damage is uncommon. 3 people have reported feeling it to USGS.

How big was it?

This earthquake released about 43 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 5.3 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 4,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 180× the energy of this one
  3. Magna, Utah 2020 M 5.7 130× the energy of this one
  4. This earthquake M 4.3 about 43 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 89× 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 57.8837, -139.0981. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 4.0 152 km WSW of Elfin Cove, Alaska
  2. 3.3 158 km WSW of Elfin Cove, Alaska
  3. 2.9 154 km WSW of Elfin Cove, Alaska
  4. 2.7 159 km WSW of Elfin Cove, Alaska
  5. 1.8 136 km W of Elfin Cove, Alaska
  6. 2.6 143 km WSW of Elfin Cove, Alaska
  7. 2.0 161 km S of Yakutat, Alaska
  8. 1.9 137 km W of Elfin Cove, Alaska
  9. 2.2 154 km W of Elfin Cove, Alaska
  10. 2.3 151 km W of Elfin Cove, Alaska
  11. 2.0 off the coast of Southeastern Alaska
  12. 2.5 Southeastern Alaska
  13. 2.2 160 km WSW of Elfin Cove, Alaska
  14. 2.7 146 km W of Elfin Cove, Alaska

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.