QuakeIndex

Earthquake · reviewed by a seismologist

M 2.1ml

189 km SE of Old Harbor, Alaska

· 8.6 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
8.6 km below the surface
Felt
no reports yet
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2264 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 56.0267, -151.0820. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 3.2 203 km SSE of Old Harbor, Alaska
  2. 2.8 206 km SSE of Chiniak, Alaska
  3. 2.9 195 km SE of Old Harbor, Alaska
  4. 2.8 146 km SE of Old Harbor, Alaska
  5. 2.5 south of Alaska
  6. 2.5 201 km SSE of Chiniak, Alaska
  7. 3.2 174 km SE of Chiniak, Alaska
  8. 2.7 202 km SE of Old Harbor, Alaska
  9. 2.1 179 km SE of Old Harbor, Alaska
  10. 2.5 178 km SE of Chiniak, Alaska
  11. 3.0 156 km SE 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 1,400 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.