QuakeIndex

Earthquake · reviewed by a seismologist

M 3.1ml

130 km S of Unalaska, Alaska

· 28 km deep · released about 1,300 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 3.1 (ml)
Depth
28 km below the surface
Felt
no reports yet
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 631 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 1,300 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.1 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 250,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 11,000× the energy of this one
  3. Magna, Utah 2020 M 5.7 7,900× the energy of this one
  4. This earthquake M 3.1 about 1,300 lb of TNT
  5. Around the size people start to feel M 3.0 this one released 1.4× more

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 52.7002, -166.6646. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 2.4 118 km S of Unalaska, Alaska
  2. 2.7 139 km S of Unalaska, Alaska
  3. 4.4 123 km S of Unalaska, Alaska
  4. 2.7 129 km S of Unalaska, Alaska
  5. 2.8 136 km S of Unalaska, Alaska
  6. 2.6 124 km S of Unalaska, Alaska
  7. 2.1 121 km S of Unalaska, Alaska
  8. 3.4 138 km S of Unalaska, Alaska
  9. 3.4 125 km S of Unalaska, Alaska
  10. 3.3 140 km S of Unalaska, Alaska
  11. 2.7 109 km S of Unalaska, Alaska
  12. 2.2 120 km S of Unalaska, Alaska
  13. 2.3 128 km S of Unalaska, Alaska
  14. 2.4 118 km S of Unalaska, Alaska
  15. 5.2 126 km S of Unalaska, 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 2017-05-24 — it released about 16,000 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.