QuakeIndex

Earthquake · reviewed by a seismologist

M 2.5ml

40 km SSE of Chignik, Alaska

· 60 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
60 km below the surface
Felt
1 report · strongest reported intensity I
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 499 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage. 1 person has reported feeling it to USGS.

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 55.9622, -158.1411. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 2.1 7 km NNE of Chignik Lagoon, Alaska
  2. 3.2 62 km SE of Perryville, Alaska
  3. 2.0 53 km ESE of Perryville, Alaska
  4. 2.1 48 km SE of Chignik, Alaska
  5. 2.5 9 km N of Chignik, Alaska
  6. 2.3 26 km SSE of Chignik, Alaska
  7. 2.0 50 km SE of Chignik, Alaska
  8. 2.5 38 km SSE of Chignik, Alaska
  9. 3.1 43 km SE of Chignik, Alaska
  10. 3.1 55 km SE of Chignik, Alaska
  11. 2.6 56 km SE of Chignik, Alaska
  12. 2.4 31 km SSE of Chignik Lake, Alaska
  13. 2.2 27 km ENE of Chignik, Alaska
  14. 2.1 27 km SSE of Chignik, Alaska
  15. 2.4 6 km NNE of Chignik Lagoon, 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 5.1 on 2016-08-27 — it released about 7,900 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.