QuakeIndex

Earthquake · reviewed by a seismologist

M 2.1ml

145 km SE of Perryville, Alaska

· 1.8 km deep · released about 43 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 2.1 (ml)
Depth
1.8 km below the surface
Felt
no reports yet
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1864 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 43 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.1 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 350,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 250,000× the energy of this one
  3. Around the size people start to feel M 3.0 22× the energy of this one
  4. This earthquake M 2.1 about 43 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 55.1297, -157.2938. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 2.2 121 km SE of Perryville, Alaska
  2. 3.3 156 km SSE of Chignik, Alaska
  3. 2.4 134 km SSE of Chignik, Alaska
  4. 4.0 135 km SSE of Chignik, Alaska
  5. 2.2 121 km SE of Perryville, Alaska
  6. 2.5 128 km SSE of Chignik, Alaska
  7. 2.3 111 km SSE of Chignik, Alaska
  8. 2.5 132 km SE of Perryville, Alaska
  9. 2.6 158 km SE of Chignik, Alaska
  10. 2.1 113 km SSE of Chignik, Alaska
  11. 3.2 119 km SSE of Chignik, Alaska
  12. 3.3 159 km SSE of Chignik, Alaska
  13. 3.3 152 km SSE of Chignik, Alaska
  14. 3.6 136 km SE of Perryville, Alaska
  15. 2.7 115 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 5.9 on 2021-07-29 — it released about 500,000 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.