QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8ml

128 km SSW of McCarthy, Alaska

· 1.6 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
1.6 km below the surface
Felt
no reports yet
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 184 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 60.3050, -143.4260. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 1.7 105 km SSW of McCarthy, Alaska
  2. 1.7 124 km SSW of McCarthy, Alaska
  3. 3.0 138 km ESE of Cordova, Alaska
  4. 1.5 130 km S of McCarthy, Alaska
  5. 1.8 133 km S of McCarthy, Alaska
  6. 2.5 113 km S of McCarthy, Alaska
  7. 1.7 118 km SSW of McCarthy, Alaska
  8. 1.5 119 km ESE of Cordova, Alaska
  9. 1.8 112 km ESE of Cordova, Alaska
  10. 2.1 139 km S of McCarthy, Alaska
  11. 1.6 112 km S of McCarthy, Alaska
  12. 1.7 132 km ESE of Cordova, Alaska
  13. 1.7 104 km SSW of McCarthy, Alaska
  14. 1.9 119 km S of McCarthy, Alaska
  15. 2.0 106 km E of Cordova, 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 4.3 on 2020-08-09 — it released about 5,600 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.