QuakeIndex

Earthquake · automatic estimate, may change

M 2.3ml

177 km SE of Chignik, Alaska

· 56 km deep · released about 85 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N
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 2.3 (ml)
Depth
56 km below the surface
Felt
no reports yet
Status
Automatic — a machine’s first estimate, which may change

USGS · last changed by USGS · we first saw it 1851 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

How big was it?

This earthquake released about 85 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.3 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 180,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 130,000× the energy of this one
  3. Around the size people start to feel M 3.0 11× the energy of this one
  4. This earthquake M 2.3 about 85 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 55.0237, -156.6944. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 2.8 171 km SE of Perryville, Alaska
  2. 2.5 156 km SE of Chignik, Alaska
  3. 2.5 153 km SSE of Chignik, Alaska
  4. 2.7 134 km SE of Chignik, Alaska
  5. 3.0 203 km SE of Chignik, Alaska
  6. 2.5 174 km SE of Chignik, Alaska
  7. 4.0 140 km SSE of Chignik, Alaska
  8. 3.9 201 km SE of Chignik, Alaska
  9. 2.5 208 km SE of Perryville, Alaska
  10. 2.8 152 km SE of Chignik, Alaska
  11. 3.3 205 km SE of Perryville, Alaska
  12. 3.0 204 km SE of Perryville, Alaska
  13. 3.1 194 km SE of Perryville, Alaska
  14. 2.9 144 km SE of Chignik, Alaska
  15. 5.1 200 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 5.5 on 2021-07-30 — it released about 63,000 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.