QuakeIndex

Earthquake · reviewed by a seismologist

M 4.1mw

86 km S of Akhiok, Alaska

· 24 km deep · released about 21 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 4.1 (mw)
Depth
24 km below the surface
Felt
no reports yet
Measured shaking
intensity III (ShakeMap)
USGS impact alert
green
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1144 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 21 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 5.1 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 7,900× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 350× the energy of this one
  3. Magna, Utah 2020 M 5.7 250× the energy of this one
  4. This earthquake M 4.1 about 21 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 45× 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 56.1725, -154.3263. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 2.9 48 km SSE of Akhiok, Alaska
  2. 1.6 68 km SSW of Akhiok, Alaska
  3. 2.1 81 km S of Akhiok, Alaska
  4. 4.5 104 km SSE of Akhiok, Alaska
  5. 2.0 55 km SSE of Akhiok, Alaska
  6. 2.4 71 km S of Akhiok, Alaska
  7. 2.2 104 km S of Akhiok, Alaska
  8. 4.4 94 km S of Akhiok, Alaska
  9. 3.9 117 km SSW of Akhiok, Alaska
  10. 1.5 43 km SSW of Akhiok, Alaska
  11. 2.1 64 km SSW of Akhiok, Alaska
  12. 2.2 92 km S of Akhiok, Alaska
  13. 2.1 48 km SSW of Akhiok, Alaska
  14. 3.6 122 km SSW of Akhiok, Alaska
  15. 2.2 45 km SSE of Akhiok, 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.