QuakeIndex

Earthquake · reviewed by a seismologist

M 4.0mw

83 km SSW of Port Alexander, Alaska

· 26 km deep · released about 15 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 4.0 (mw)
Depth
26 km below the surface
Felt
no reports yet
Measured shaking
intensity II (ShakeMap)
Nearest
Prince of Wales-Hyder Census Area, 120 km E
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 15 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 5.0 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 11,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 500× the energy of this one
  3. Magna, Utah 2020 M 5.7 350× the energy of this one
  4. This earthquake M 4.0 about 15 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 32× 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 55.5329, -135.0571. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Prince of Wales-Hyder Census Area, AK 120 km (75 mi) W of here earthquakes near Prince of Wales-Hyder Census Area

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

Aftershocks so far

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

  1. 1.8 91 km SSW of Port Alexander, Alaska
  2. 2.0 74 km S of Port Alexander, Alaska
  3. 2.2 100 km S of Port Alexander, Alaska
  4. 4.4 91 km S of Port Alexander, Alaska
  5. 2.4 74 km SW of Port Alexander, Alaska
  6. 2.8 87 km SSW of Port Alexander, Alaska
  7. 3.3 86 km SSW of Port Alexander, Alaska
  8. 2.7 90 km SSW of Port Alexander, Alaska
  9. 2.3 84 km SSW of Port Alexander, Alaska
  10. 2.9 91 km SW of Edna Bay, Alaska
  11. 2.5 90 km SSW of Port Alexander, Alaska
  12. 3.3 109 km SSW of Port Alexander, Alaska
  13. 2.0 86 km SSW of Port Alexander, Alaska
  14. 1.9 112 km SSW of Port Alexander, Alaska
  15. 2.1 Southeastern 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

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