QuakeIndex

Earthquake · reviewed by a seismologist

M 3.6ml

184 km ESE of Atka, Alaska

· 35 km deep · released about 3.8 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 3.6 (ml)
Depth
35 km below the surface
Felt
no reports yet
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 475 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 3.8 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.6 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 45,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 2,000× the energy of this one
  3. Magna, Utah 2020 M 5.7 1,400× the energy of this one
  4. This earthquake M 3.6 about 3.8 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 7.9× 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 51.7145, -171.6299. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 3.2 178 km E of Atka, Alaska
  2. 2.6 202 km ESE of Atka, Alaska
  3. 2.6 150 km E of Atka, Alaska
  4. 2.9 179 km ESE of Atka, Alaska
  5. 3.6 210 km SW of Nikolski, Alaska
  6. 2.9 212 km SW of Nikolski, Alaska
  7. 2.8 189 km WSW of Nikolski, Alaska
  8. 2.8 184 km E of Atka, Alaska
  9. 2.8 188 km E of Atka, Alaska
  10. 2.9 175 km E of Atka, Alaska
  11. 2.7 188 km E of Atka, Alaska
  12. 3.4 182 km E of Atka, Alaska
  13. 4.7 172 km E of Atka, Alaska
  14. 3.2 168 km E of Atka, Alaska
  15. 3.5 217 km ESE 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.

For this area

The largest earthquake within 50 km in our catalogue was M 5.2 on 2021-10-01 — it released about 250 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.