QuakeIndex

Earthquake · reviewed by a seismologist

M 4.5mb

139 km WSW of Adak, Alaska

· 49 km deep · released about 85 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 4.5 (mb)
Depth
49 km below the surface
Felt
no reports yet
Measured shaking
intensity III (ShakeMap)
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1146 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 85 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 5.5 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 2,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 89× the energy of this one
  3. Magna, Utah 2020 M 5.7 63× the energy of this one
  4. This earthquake M 4.5 about 85 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 180× 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 51.3823, -178.4870. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 2.0 127 km WSW of Adak, Alaska
  2. 3.3 120 km WSW of Adak, Alaska
  3. 1.9 127 km W of Adak, Alaska
  4. 1.8 133 km W of Adak, Alaska
  5. 1.8 130 km W of Adak, Alaska
  6. 1.9 124 km W of Adak, Alaska
  7. 2.1 129 km W of Adak, Alaska
  8. 2.0 125 km WSW of Adak, Alaska
  9. 1.6 126 km W of Adak, Alaska
  10. 1.9 118 km SW of Adak, Alaska
  11. 2.1 108 km WSW of Adak, Alaska
  12. 2.0 130 km W of Adak, Alaska
  13. 1.7 129 km W of Adak, Alaska
  14. 1.6 125 km W of Adak, Alaska
  15. 2.1 140 km WSW 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.

For this area

The largest earthquake within 50 km in our catalogue was M 6.2 on 2017-05-08 — it released about 350 times the energy of this one.

From the QuakeIndex catalogue, built from the USGS FDSN event service.

On USGS

QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.