QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8ml

141 km SSE of Atka, Alaska

· 9.4 km deep · released about 15 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 1.8 (ml)
Depth
9.4 km below the surface
Felt
no reports yet
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2239 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 15 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.8 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 1,000,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 710,000× the energy of this one
  3. Around the size people start to feel M 3.0 63× the energy of this one
  4. This earthquake M 1.8 about 15 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 51.0055, -173.4931. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 2.5 102 km SSE of Atka, Alaska
  2. 2.7 173 km SSE of Atka, Alaska
  3. 2.9 152 km SSE of Atka, Alaska
  4. 3.0 171 km SSE of Atka, Alaska
  5. 2.3 161 km SSE of Atka, Alaska
  6. 3.0 186 km SSE of Atka, Alaska
  7. 2.2 155 km SSE of Atka, Alaska
  8. 2.2 150 km SSE of Atka, Alaska
  9. 2.3 165 km SSE of Atka, Alaska
  10. 1.7 160 km SSE of Atka, Alaska
  11. 2.7 Andreanof Islands, Aleutian Islands, Alaska
  12. 2.1 165 km SSE of Atka, Alaska
  13. 3.2 132 km SE of Atka, Alaska
  14. 2.2 173 km SSE of Atka, Alaska
  15. 2.7 173 km SSE of Atka, 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 4.4 on 2019-06-06 — 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.