QuakeIndex

Earthquake · reviewed by a seismologist

M 5.0mb

212 km WSW of Adak, Alaska

· 31 km deep · released about 480 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 5.0 (mb)
Depth
31 km below the surface
Felt
no reports yet
Measured shaking
intensity IV (ShakeMap)
USGS impact alert
green
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 4 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 480 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 6.0 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 350× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 16× the energy of this one
  3. Magna, Utah 2020 M 5.7 11× the energy of this one
  4. This earthquake M 5.0 about 480 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 1,000× 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 51.2916, -179.5551. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 2.6 196 km WSW of Adak, Alaska
  2. 3.0 240 km WSW of Adak, Alaska
  3. 3.0 210 km WSW of Adak, Alaska
  4. 2.4 238 km WSW of Adak, Alaska
  5. 2.6 242 km WSW of Adak, Alaska
  6. 2.9 199 km W of Adak, Alaska
  7. 2.9 229 km WSW of Adak, Alaska
  8. 2.3 207 km W of Adak, Alaska
  9. 2.8 239 km WSW of Adak, Alaska
  10. 2.6 198 km WSW of Adak, Alaska
  11. 2.6 178 km WSW of Adak, Alaska
  12. 2.1 176 km WSW of Adak, Alaska
  13. 2.7 191 km WSW of Adak, Alaska
  14. 2.3 224 km W of Adak, Alaska
  15. 2.4 200 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 6.1 on 2021-09-24 — it released about 45 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.