QuakeIndex

Earthquake · reviewed by a seismologist

M 3.0ml

175 km SE of Perryville, Alaska

· 21 km deep · released about 950 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 3.0 (ml)
Depth
21 km below the surface
Felt
no reports yet
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1794 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 950 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.0 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 350,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 16,000× the energy of this one
  3. Magna, Utah 2020 M 5.7 11,000× the energy of this one
  4. This earthquake M 3.0 about 950 lb of TNT

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 54.8601, -157.0739. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 2.8 162 km SE of Perryville, Alaska
  2. 2.8 202 km SE of Perryville, Alaska
  3. 3.3 207 km SE of Perryville, Alaska
  4. 3.3 158 km SE of Perryville, Alaska
  5. 3.1 139 km SE of Chignik, Alaska
  6. 3.3 164 km SE of Chignik, Alaska
  7. 2.5 201 km SE of Perryville, Alaska
  8. 2.6 153 km SSE of Chignik, Alaska
  9. 2.8 140 km SE of Perryville, Alaska
  10. 2.5 161 km SE of Chignik, Alaska
  11. 2.3 144 km SE of Perryville, Alaska
  12. 3.0 203 km SE of Perryville, Alaska
  13. 2.8 137 km SSE of Chignik, Alaska
  14. 3.6 207 km SE of Perryville, Alaska
  15. 2.6 204 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 5.4 on 2021-07-29 — it released about 4,000 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.