QuakeIndex

Earthquake · reviewed by a seismologist

M 4.6mb

206 km SE of Perryville, Alaska

· 26 km deep · released about 120 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 4.6 (mb)
Depth
26 km below the surface
Felt
1 report · strongest reported intensity II
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1144 days ago

This was a light earthquake. It is usually felt clearly nearby and can rattle windows and dishes, but damage is uncommon. 1 person has reported feeling it to USGS.

How big was it?

This earthquake released about 120 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 5.6 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 1,400× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 63× the energy of this one
  3. Magna, Utah 2020 M 5.7 45× the energy of this one
  4. This earthquake M 4.6 about 120 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 250× 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 54.6727, -156.7281. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 2.4 158 km SE of Perryville, Alaska
  2. 3.8 198 km SE of Perryville, Alaska
  3. 2.9 202 km SE of Perryville, Alaska
  4. 3.0 162 km SE of Chignik, Alaska
  5. 3.2 166 km SSE of Chignik, Alaska
  6. 3.4 187 km SE of Perryville, Alaska
  7. 3.6 174 km SE of Perryville, Alaska
  8. 3.5 199 km SE of Chignik, Alaska
  9. 4.8 158 km SE of Perryville, Alaska
  10. 2.1 196 km SE of Perryville, Alaska
  11. 2.8 206 km SE of Perryville, Alaska
  12. 3.3 209 km SE of Perryville, Alaska
  13. 2.9 210 km SE of Perryville, Alaska
  14. 2.8 201 km SE of Perryville, Alaska
  15. 3.2 194 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 4.0 on 2017-10-06.

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

On USGS

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