QuakeIndex

Earthquake · reviewed by a seismologist

M 5.1mww

Unimak Island region, Alaska

· 35 km deep · released about 670 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 5.1 (mww)
Depth
35 km below the surface
Felt
no reports yet
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 279 days ago

This was a moderate earthquake. Shaking at this size can damage poorly built structures close to the epicentre.

How big was it?

This earthquake released about 670 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 6.1 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 250× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 11× the energy of this one
  3. Magna, Utah 2020 M 5.7 7.9× the energy of this one
  4. This earthquake M 5.1 about 670 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 1,400× 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 53.6763, -163.9531. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 2.0 105 km ESE of Akutan, Alaska
  2. 2.0 114 km ESE of Akutan, Alaska
  3. 2.7 165 km ESE of Akutan, Alaska
  4. 2.1 106 km ESE of Akutan, Alaska
  5. 1.8 99 km ESE of Akutan, Alaska
  6. 1.7 100 km ESE of Akutan, Alaska
  7. 2.6 160 km S of False Pass, Alaska
  8. 2.8 118 km ESE of Akutan, Alaska
  9. 3.5 100 km ESE of Akutan, Alaska
  10. 3.0 152 km S of False Pass, Alaska
  11. 3.9 149 km S of False Pass, Alaska
  12. 3.2 108 km ESE of Akutan, Alaska
  13. 1.5 103 km ESE of Akutan, Alaska
  14. 2.0 96 km SSW of False Pass, Alaska
  15. 1.8 116 km ESE of Akutan, 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 5.7 on 2020-08-13 — it released about 7.9 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.