QuakeIndex

Earthquake · reviewed by a seismologist

M 3.1ml

122 km SSE of Perryville, Alaska

· 8.1 km deep · released about 1,300 lb 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 3.1 (ml)
Depth
8.1 km below the surface
Felt
no reports yet
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 701 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 1,300 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.1 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 250,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 11,000× the energy of this one
  3. Magna, Utah 2020 M 5.7 7,900× the energy of this one
  4. This earthquake M 3.1 about 1,300 lb of TNT
  5. Around the size people start to feel M 3.0 this one released 1.4× 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 54.9539, -158.1860. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 2.5 75 km SSE of Perryville, Alaska
  2. 3.9 125 km SE of Perryville, Alaska
  3. 3.4 142 km SE of Perryville, Alaska
  4. 2.3 124 km SE of Perryville, Alaska
  5. 2.6 130 km SE of Perryville, Alaska
  6. 2.7 136 km SSE of Perryville, Alaska
  7. 3.0 121 km SE of Perryville, Alaska
  8. 2.0 123 km SSE of Perryville, Alaska
  9. 2.7 96 km SSE of Perryville, Alaska
  10. 2.3 109 km SE of Perryville, Alaska
  11. 2.6 95 km SSE of Perryville, Alaska
  12. 2.3 107 km SSE of Perryville, Alaska
  13. 2.1 100 km SE of Perryville, Alaska
  14. 2.1 95 km SSE of Perryville, Alaska
  15. 2.6 128 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 45,000,000 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.