QuakeIndex

Earthquake · reviewed by a seismologist

M 4.7mb

198 km SW of Adak, Alaska

· 24 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 (mb)
Depth
24 km below the surface
Felt
no reports yet
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 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 50.5816, -178.5832. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 2.2 177 km SW of Adak, Alaska
  2. 2.1 203 km SW of Adak, Alaska
  3. 3.7 208 km SW of Adak, Alaska
  4. 2.6 217 km SSW of Adak, Alaska
  5. 3.2 157 km SW of Adak, Alaska
  6. 1.9 211 km SSW of Adak, Alaska
  7. 3.0 194 km SSW of Adak, Alaska
  8. 2.6 151 km SW of Adak, Alaska
  9. 2.7 163 km SW of Adak, Alaska
  10. 1.9 191 km SW of Adak, AK
  11. 2.0 207 km SW of Adak, Alaska
  12. 4.3 222 km SW of Adak, Alaska
  13. 4.0 149 km SW of Adak, Alaska
  14. 3.6 206 km SW of Adak, Alaska
  15. 2.1 212 km SSW of Adak, 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.