QuakeIndex

Earthquake · reviewed by a seismologist

M 5.7mb

99 km ESE of Chignik, Alaska

· 35 km deep · released about 5.4 kilotons 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 5.7 (mb)
Depth
35 km below the surface
Felt
no reports yet
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 279 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 5.4 kilotons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 6.7 would have released about 32 times as much.

  1. Loma Prieta, California 1989 M 6.9 63× the energy of this one
  2. Northridge, California 1994 M 6.7 32× the energy of this one
  3. Mineral, Virginia 2011 M 5.8 1.4× the energy of this one
  4. This earthquake M 5.7 about 5.4 kilotons of TNT
  5. Around the size people start to feel M 3.0 this one released 11,000× 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 55.8758, -156.9924. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 2.2 south of Alaska
  2. 2.6 125 km ESE of Chignik, Alaska
  3. 2.4 south of Alaska
  4. 2.1 139 km ESE of Chignik, Alaska
  5. 2.9 129 km SE of Chignik, Alaska
  6. 2.5 126 km SE of Chignik, Alaska
  7. 2.5 112 km SE of Chignik, Alaska
  8. 2.0 131 km SE of Chignik, Alaska
  9. 1.7 67 km ESE of Chignik, Alaska
  10. 2.8 126 km SE of Chignik, Alaska
  11. 1.9 95 km SE of Chignik, Alaska
  12. 2.2 139 km SE of Chignik, Alaska
  13. 2.1 131 km SE of Chignik, Alaska
  14. 2.3 125 km SE of Chignik, Alaska
  15. 1.9 80 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 4.1 on 2018-06-16.

From the QuakeIndex catalogue, built from the USGS FDSN event service.

On USGS

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