QuakeIndex

Earthquake · reviewed by a seismologist

M 2.8ml

185 km SE of Perryville, Alaska

· 34 km deep · released about 480 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 2.8 (ml)
Depth
34 km below the surface
Felt
no reports yet
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1810 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 480 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.8 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 32,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 22,000× the energy of this one
  3. Around the size people start to feel M 3.0 2× the energy of this one
  4. This earthquake M 2.8 about 480 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 54.7693, -157.0199. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 2.6 186 km SE of Chignik, Alaska
  2. 3.3 188 km SE of Perryville, Alaska
  3. 3.4 168 km SSE of Chignik, Alaska
  4. 2.3 184 km SSE of Chignik, Alaska
  5. 2.7 145 km SE of Perryville, Alaska
  6. 2.9 164 km SE of Chignik, Alaska
  7. 3.0 194 km SE of Perryville, Alaska
  8. 2.3 148 km SE of Perryville, Alaska
  9. 2.1 146 km SE of Perryville, Alaska
  10. 2.5 201 km SE of Perryville, Alaska
  11. 2.1 159 km SE of Chignik, Alaska
  12. 2.0 142 km SSE of Chignik, Alaska
  13. 2.6 150 km SE of Perryville, Alaska
  14. 2.3 147 km SE of Perryville, Alaska
  15. 3.0 167 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 5.3 on 2021-07-29 — it released about 5,600 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.