QuakeIndex

Earthquake · reviewed by a seismologist

M 3.7ml

100 km SE of Chignik, Alaska

· 13 km deep · released about 5.4 tons of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N
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 3.7 (ml)
Depth
13 km below the surface
Felt
no reports yet
Measured shaking
intensity II (ShakeMap)
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2289 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 5.4 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.7 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 32,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 1,400× the energy of this one
  3. Magna, Utah 2020 M 5.7 1,000× the energy of this one
  4. This earthquake M 3.7 about 5.4 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 11× 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 55.7893, -157.0728. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 2.3 107 km SSE of Chignik, Alaska
  2. 3.6 137 km SE of Chignik, Alaska
  3. 3.5 126 km SE of Chignik, Alaska
  4. 2.3 110 km ESE of Chignik, Alaska
  5. 3.2 137 km SE of Chignik, Alaska
  6. 2.1 88 km SE of Chignik, Alaska
  7. 2.5 95 km SE of Chignik, Alaska
  8. 3.2 135 km SE of Chignik, Alaska
  9. 3.3 113 km SE of Chignik, Alaska
  10. 3.3 101 km SE of Chignik, Alaska
  11. 2.8 124 km SE of Chignik, Alaska
  12. 3.5 118 km SSE of Chignik, Alaska
  13. 3.3 122 km SE of Chignik, Alaska
  14. 3.0 106 km SE of Chignik, Alaska
  15. 4.1 135 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.

On USGS

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