QuakeIndex

Earthquake · reviewed by a seismologist

M 5.4mw

69 km SE of Old Harbor, Alaska

· 10 km deep · released about 1.9 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 5.4 (mw)
Depth
10 km below the surface
Felt
5 reports · strongest reported intensity III
Measured shaking
intensity IV (ShakeMap)
Tsunami
USGS flagged this event for tsunami evaluation. Follow tsunami.gov for official messages.
Nearest
Kodiak Island Borough, 135 km NW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1146 days ago

This was a moderate earthquake. Shaking at this size can damage poorly built structures close to the epicentre. 5 people have reported feeling it to USGS.

How big was it?

This earthquake released about 1.9 kilotons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 6.4 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 89× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 4× the energy of this one
  3. Magna, Utah 2020 M 5.7 2.8× the energy of this one
  4. This earthquake M 5.4 about 1.9 kilotons of TNT
  5. Around the size people start to feel M 3.0 this one released 4,000× 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 56.7493, -152.5231. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Kodiak Island Borough, AK 135 km (84 mi) SE of here earthquakes near Kodiak Island Borough

Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.

Aftershocks so far

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

  1. 2.6 117 km SE of Old Harbor, Alaska
  2. 2.8 115 km SE of Old Harbor, Alaska
  3. 2.8 116 km SE of Old Harbor, Alaska
  4. 2.5 112 km SE of Old Harbor, Alaska
  5. 3.4 117 km SE of Old Harbor, Alaska
  6. 4.7 116 km SE of Old Harbor, Alaska
  7. 2.7 107 km SE of Old Harbor, Alaska
  8. 3.0 109 km SSE of Old Harbor, Alaska
  9. 3.1 117 km SE of Old Harbor, Alaska
  10. 2.5 27 km SE of Old Harbor, Alaska
  11. 1.8 25 km SE of Old Harbor, Alaska
  12. 1.6 42 km SSE of Old Harbor, Alaska
  13. 1.5 40 km ESE of Old Harbor, Alaska
  14. 1.8 48 km SE of Old Harbor, Alaska
  15. 2.1 51 km SE 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.