QuakeIndex

Earthquake · reviewed by a seismologist

M 5.3mb

128 km SE of Perryville, Alaska

· 35 km deep · released about 1.3 kilotons 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 5.3 (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 1821 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 1.3 kilotons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 6.3 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 130× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 5.6× the energy of this one
  3. Magna, Utah 2020 M 5.7 4× the energy of this one
  4. This earthquake M 5.3 about 1.3 kilotons of TNT
  5. Around the size people start to feel M 3.0 this one released 2,800× 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 55.1526, -157.6035. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 2.6 133 km SE of Perryville, Alaska
  2. 2.4 158 km SE of Perryville, Alaska
  3. 2.6 152 km SSE of Chignik, Alaska
  4. 2.9 Alaska Peninsula
  5. 4.1 149 km SE of Perryville, Alaska
  6. 2.4 140 km SE of Perryville, Alaska
  7. 2.7 127 km SSE of Chignik, Alaska
  8. 2.6 140 km SSE of Chignik, Alaska
  9. 2.4 136 km SE of Perryville, Alaska
  10. 2.3 107 km SSE of Chignik, Alaska
  11. 2.5 100 km SE of Perryville, Alaska
  12. 4.3 134 km SE of Chignik, Alaska
  13. 2.7 143 km SE of Perryville, Alaska
  14. 3.7 135 km SE of Perryville, Alaska
  15. 3.4 136 km SE of Perryville, 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 8.2 on 2021-07-29 — it released about 22,000 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.