QuakeIndex

Earthquake · reviewed by a seismologist

M 2.5ml

163 km ESE of Chignik, Alaska

· 44 km deep · released about 170 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 2.5 (ml)
Depth
44 km below the surface
Felt
no reports yet
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1809 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 170 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.5 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 89,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 63,000× the energy of this one
  3. Around the size people start to feel M 3.0 5.6× the energy of this one
  4. This earthquake M 2.5 about 170 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 55.6824, -156.0209. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 2.5 152 km SW of Akhiok, Alaska
  2. 3.3 150 km ESE of Chignik, Alaska
  3. 2.0 154 km ESE of Chignik, Alaska
  4. 2.6 182 km SE of Chignik, Alaska
  5. 2.7 135 km ESE of Chignik, Alaska
  6. 2.4 194 km SE of Chignik, Alaska
  7. 3.4 163 km SE of Chignik, Alaska
  8. 2.5 134 km ESE of Chignik, Alaska
  9. 2.3 183 km ESE of Chignik, Alaska
  10. 2.2 155 km ESE of Chignik, Alaska
  11. 2.3 170 km SSW of Akhiok, Alaska
  12. 2.2 145 km ESE of Chignik, Alaska
  13. 2.3 159 km SE of Chignik, Alaska
  14. 2.5 191 km SE of Chignik, Alaska
  15. 3.7 156 km SE of Chignik, 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 4.8 on 2021-07-29 — it released about 2,800 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.