QuakeIndex

Earthquake · reviewed by a seismologist

M 4.6ml

117 km SE of Old Harbor, Alaska

· 7.8 km deep · released about 120 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 4.6 (ml)
Depth
7.8 km below the surface
Felt
no reports yet
Tsunami
USGS flagged this event for tsunami evaluation. Follow tsunami.gov for official messages.
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2395 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 120 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 5.6 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 1,400× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 63× the energy of this one
  3. Magna, Utah 2020 M 5.7 45× the energy of this one
  4. This earthquake M 4.6 about 120 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 250× 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 56.3283, -152.2191. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 2.7 117 km SE of Old Harbor, Alaska
  2. 3.0 Kodiak Island region, Alaska
  3. 2.6 107 km SSE of Old Harbor, Alaska
  4. 2.9 159 km SSE of Old Harbor, Alaska
  5. 3.1 south of Alaska
  6. 2.8 Kodiak Island region, Alaska
  7. 2.4 73 km SE of Old Harbor, Alaska
  8. 2.9 139 km SE of Old Harbor, Alaska
  9. 4.1 108 km SSE of Old Harbor, Alaska
  10. 2.4 103 km SSE of Old Harbor, Alaska
  11. 4.5 105 km SSE of Old Harbor, Alaska
  12. 2.7 97 km SSE of Old Harbor, Alaska
  13. 2.5 134 km SSE of Old Harbor, Alaska
  14. 1.7 120 km SSE of Old Harbor, Alaska
  15. 2.2 114 km SSE of Old Harbor, 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.