QuakeIndex

Earthquake · reviewed by a seismologist

M 2.3ml

231 km SE of Old Harbor, Alaska

· 11 km deep · released about 85 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 2.3 (ml)
Depth
11 km below the surface
Felt
no reports yet
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2043 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 55.6158, -150.8859. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 2.8 206 km SSE of Chiniak, Alaska
  2. 3.3 264 km SSE of Old Harbor, Alaska
  3. 2.9 195 km SE of Old Harbor, Alaska
  4. 2.2 225 km SSE of Old Harbor, Alaska
  5. 2.5 south of Alaska
  6. 2.9 230 km SSE of Chiniak, Alaska
  7. 2.5 201 km SSE of Chiniak, Alaska
  8. 2.7 202 km SE of Old Harbor, Alaska
  9. 3.0 242 km SE of Old Harbor, Alaska
  10. 2.1 189 km SE of Old Harbor, Alaska
  11. 5.0 217 km SSE of Old Harbor, Alaska
  12. 2.5 252 km SE of Old Harbor, Alaska
  13. 2.4 240 km SSE of Old Harbor, Alaska
  14. 3.0 215 km SE of Old Harbor, Alaska
  15. 2.1 233 km SSE of Old Harbor, 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 4.2 on 2018-01-23 — it released about 710 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.