QuakeIndex

Earthquake · reviewed by a seismologist

M 3.8mb

224 km ESE of Atka, Alaska

· 10 km deep · released about 7.6 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 3.8 (mb)
Depth
10 km below the surface
Felt
no reports yet
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2164 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage.

How big was it?

This earthquake released about 7.6 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.8 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 22,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 1,000× the energy of this one
  3. Magna, Utah 2020 M 5.7 710× the energy of this one
  4. This earthquake M 3.8 about 7.6 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 16× 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 51.4773, -171.1536. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 3.3 183 km SW of Nikolski, Alaska
  2. 3.5 203 km SW of Nikolski, Alaska
  3. 2.9 187 km ESE of Atka, Alaska
  4. 3.8 Fox Islands, Aleutian Islands, Alaska
  5. 2.6 Fox Islands, Aleutian Islands, Alaska
  6. 2.6 191 km ESE of Atka, Alaska
  7. 3.7 197 km SW of Nikolski, Alaska
  8. 3.8 180 km ESE of Atka, Alaska
  9. 2.9 243 km SSW of Nikolski, Alaska
  10. 3.0 183 km ESE of Atka, Alaska
  11. 3.1 182 km SW of Nikolski, Alaska
  12. 3.1 196 km ESE of Atka, Alaska
  13. 2.7 Fox Islands, Aleutian Islands, Alaska
  14. 3.2 193 km SW of Nikolski, Alaska
  15. 3.7 221 km SSW of Nikolski, 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 5.8 on 2020-08-16 — it released about 1,000 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.