QuakeIndex

Earthquake · reviewed by a seismologist

M 4.7mwr

48 km SE of Halibut Cove, Alaska

· 37 km deep · released about 170 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 4.7 (mwr)
Depth
37 km below the surface
Felt
238 reports · strongest reported intensity IV
Measured shaking
intensity IV (ShakeMap)
USGS impact alert
green
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 1317 days ago

This was a light earthquake. It is usually felt clearly nearby and can rattle windows and dishes, but damage is uncommon. 238 people have reported feeling it to USGS.

How big was it?

This earthquake released about 170 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 5.7 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 1,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 45× the energy of this one
  3. Magna, Utah 2020 M 5.7 32× the energy of this one
  4. This earthquake M 4.7 about 170 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 350× 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 59.2779, -150.6426. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 1.5 34 km SE of Fox River, Alaska
  2. 1.8 43 km SSE of Halibut Cove, Alaska
  3. 2.6 62 km SE of Port Graham, Alaska
  4. 1.5 Kenai Peninsula, Alaska
  5. 1.9 37 km SE of Fox River, Alaska
  6. 1.7 Kodiak Island region, Alaska
  7. 1.6 6 km SSE of Halibut Cove, Alaska
  8. 1.5 14 km ENE of Halibut Cove, Alaska
  9. 1.7 68 km SSE of Halibut Cove, Alaska
  10. 1.5 Kenai Peninsula, Alaska
  11. 1.8 76 km SE of Halibut Cove, Alaska
  12. 1.6 21 km ESE of Halibut Cove, Alaska
  13. 2.0 55 km SE of Halibut Cove, Alaska
  14. 1.5 19 km S of Halibut Cove, Alaska
  15. 1.6 Kenai Peninsula, 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.