QuakeIndex

Earthquake · reviewed by a seismologist

M 4.1mb

241 km SE of Atka, Alaska

· 10 km deep · released about 21 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 4.1 (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 2451 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 21 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 5.1 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 7,900× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 350× the energy of this one
  3. Magna, Utah 2020 M 5.7 250× the energy of this one
  4. This earthquake M 4.1 about 21 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 45× 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 50.5544, -171.9354. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 2.8 202 km SE of Atka, Alaska
  2. 3.7 228 km SE of Atka, Alaska
  3. 3.3 215 km SE of Atka, Alaska
  4. 3.3 213 km SE of Atka, Alaska
  5. 3.7 195 km SE of Atka, Alaska
  6. 2.7 211 km SE of Atka, Alaska
  7. 2.6 253 km SE of Atka, Alaska
  8. 3.6 212 km SE of Atka, Alaska
  9. 2.3 193 km SE of Atka, Alaska
  10. 3.1 259 km SE of Atka, Alaska
  11. 2.6 202 km SE of Atka, Alaska
  12. 2.6 249 km SE of Atka, Alaska
  13. 3.0 247 km SE of Atka, Alaska
  14. 2.9 214 km SE of Atka, Alaska
  15. 3.2 226 km SE of Atka, 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.

On USGS

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