QuakeIndex

Earthquake · reviewed by a seismologist

M 4.3ml

172 km ESE of Chignik, Alaska

· 23 km deep · released about 43 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 4.3 (ml)
Depth
23 km below the surface
Felt
no reports yet
Measured shaking
intensity III (ShakeMap)
USGS impact alert
green
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1820 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 43 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 5.3 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 4,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 180× the energy of this one
  3. Magna, Utah 2020 M 5.7 130× the energy of this one
  4. This earthquake M 4.3 about 43 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 89× 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 55.4663, -156.0668. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 3.1 171 km SSW of Akhiok, Alaska
  2. 3.0 175 km SSW of Akhiok, Alaska
  3. 2.3 137 km SE of Chignik, Alaska
  4. 3.2 south of Alaska
  5. 2.4 209 km SE of Chignik, Alaska
  6. 2.0 164 km ESE of Chignik, Alaska
  7. 3.3 176 km ESE of Chignik, Alaska
  8. 3.6 179 km ESE of Chignik, Alaska
  9. 3.8 168 km ESE of Chignik, Alaska
  10. 2.3 173 km ESE of Chignik, Alaska
  11. 2.9 171 km ESE of Chignik, Alaska
  12. 2.5 163 km ESE of Chignik, Alaska
  13. 3.3 149 km ESE of Chignik, Alaska
  14. 2.6 189 km ESE of Chignik, Alaska
  15. 2.5 137 km SE of Chignik, 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 4.4 on 2017-12-04 — it released about 1.4 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.