QuakeIndex

Earthquake · reviewed by a seismologist

M 4.3mb

120 km SSE of Unalaska, Alaska

· 25 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
25 km below the surface
Felt
no reports yet
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1145 days ago

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 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 52.9511, -165.6009. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 1.8 74 km SSE of Unalaska, Alaska
  2. 1.9 90 km SSE of Akutan, Alaska
  3. 1.8 115 km SE of Unalaska, Alaska
  4. 3.7 102 km SSE of Akutan, Alaska
  5. 1.7 109 km SSE of Unalaska, Alaska
  6. 2.2 91 km SE of Unalaska, Alaska
  7. 1.9 97 km SSE of Akutan, Alaska
  8. 1.9 120 km SE of Unalaska, Alaska
  9. 1.7 79 km SE of Unalaska, Alaska
  10. 2.2 109 km SSE of Unalaska, Alaska
  11. 1.8 76 km SSE of Unalaska, Alaska
  12. 2.1 83 km S of Akutan, Alaska
  13. 2.1 78 km SE of Unalaska, Alaska
  14. 2.3 102 km SSE of Akutan, Alaska
  15. 3.8 101 km SSE of Akutan, 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.