QuakeIndex

Earthquake · reviewed by a seismologist

M 4.6mb

117 km ESE of Akutan, Alaska

· 35 km deep · released about 120 tons of TNT

10 km30 km60 km120 km N
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 4.6 (mb)
Depth
35 km below the surface
Felt
1 report · strongest reported intensity II
Measured shaking
intensity III (ShakeMap)
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1626 days ago

This was a light earthquake. It is usually felt clearly nearby and can rattle windows and dishes, but damage is uncommon. 1 person has reported feeling it to USGS.

How big was it?

This earthquake released about 120 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 5.6 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 1,400× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 63× the energy of this one
  3. Magna, Utah 2020 M 5.7 45× the energy of this one
  4. This earthquake M 4.6 about 120 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 250× 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 53.8278, -164.0690. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 1.9 108 km E of Akutan, Alaska
  2. 1.9 99 km S of False Pass, Alaska
  3. 2.5 Unimak Island region, Alaska
  4. 2.2 109 km ESE of Akutan, Alaska
  5. 3.1 Unimak Island region, Alaska
  6. 3.1 110 km ESE of Akutan, Alaska
  7. 2.1 104 km SSW of False Pass, Alaska
  8. 2.8 109 km ESE of Akutan, Alaska
  9. 2.7 114 km ESE of Akutan, Alaska
  10. 3.1 116 km ESE of Akutan, Alaska
  11. 2.1 102 km ESE of Akutan, Alaska
  12. 2.0 93 km SSW of False Pass, Alaska
  13. 1.9 113 km SSW of False Pass, Alaska
  14. 2.7 Unimak Island region, Alaska
  15. 2.1 90 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 5.1 on 2021-01-11 — it released about 5.6 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.