QuakeIndex

Earthquake · reviewed by a seismologist

M 3.0ml

163 km SSW of Akhiok, Alaska

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

USGS · last changed by USGS · we first saw it 1821 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 55.6779, -155.5179. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 2.3 167 km SW of Akhiok, Alaska
  2. 2.9 167 km SW of Akhiok, Alaska
  3. 2.2 161 km SW of Akhiok, Alaska
  4. 3.0 190 km SE of Chignik, Alaska
  5. 2.6 177 km SSW of Akhiok, Alaska
  6. 2.9 185 km SSW of Akhiok, Alaska
  7. 1.8 157 km SSW of Akhiok, Alaska
  8. 3.0 169 km ESE of Chignik, Alaska
  9. 1.6 south of Alaska
  10. 2.8 190 km SSW of Akhiok, Alaska
  11. 2.6 158 km SSW of Akhiok, Alaska
  12. 2.6 166 km ESE of Chignik, Alaska
  13. 2.4 162 km SW of Akhiok, Alaska
  14. 2.5 152 km SW of Akhiok, Alaska
  15. 2.6 182 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 500 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.