QuakeIndex

Earthquake · reviewed by a seismologist

M 4.7mb

166 km S of Adak, Alaska

Yes. A magnitude 4.7 earthquake was recorded 166 km S of Adak, Alaska at 07:09 UTC on 2016-11-29, 31 km deep.

· 31 km deep · released about 170 tons of TNT

10 km30 km60 km120 km N
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 4.7 (mb)
Depth
31 km below the surface
Felt
no reports yet
Nearest mapped fault
Alaska-Aleutian subduction zone, 11 km from its surface trace — near is not the same as on
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1198 days ago

This was a light earthquake. It is usually felt clearly nearby and can rattle windows and dishes, but damage is uncommon.

At this magnitude and depth, people at rest would likely notice it out to about 156 km (97 mi) from the epicentre. Estimated from magnitude, depth and distance with the intensity equation USGS Did You Feel It? uses; felt reports, where there are any, are the measurement.

How big was it?

This earthquake released about 170 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 5.7 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 1,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 45× the energy of this one
  3. Magna, Utah 2020 M 5.7 32× the energy of this one
  4. This earthquake M 4.7 about 170 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 350× 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.

For this area

The largest earthquake within 50 km (31 mi) since our catalogue begins in 2016. No other earthquake of M4 or more has been recorded this close in that time.

Before 2016, the USGS record lists 11 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.4 146 km S of Adak, Alaska · 48 km WNW of this epicentre
  2. 6.3 159 km SSE of Adak, Alaska · 43 km ENE of this epicentre
  3. 5.8 176 km S of Adak, Alaska · 48 km WSW of this epicentre
  4. 5.8 164 km S of Adak, Alaska · 37 km W of this epicentre
  5. 5.7 Andreanof Islands, Aleutian Islands, Alaska · 27 km S of this epicentre

Since 2016: the QuakeIndex catalogue (US, M1.5+), built from the USGS FDSN event service. Before 2016: USGS ComCat, M5+ from 1900. Distances are between epicentres. This is the record, not a forecast.

Where

Epicentre 50.4018, -176.2082. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 4.5 161 km S of Adak, Alaska
  2. 1.8 147 km S of Adak, Alaska
  3. 1.9 180 km S of Adak, Alaska
  4. 1.6 183 km S of Adak, Alaska
  5. 2.5 188 km S of Adak, Alaska
  6. 2.2 170 km S of Adak, Alaska
  7. 2.5 165 km SSE of Adak, Alaska
  8. 2.8 193 km S of Adak, Alaska
  9. 3.1 149 km SSE of Adak, Alaska
  10. 1.9 177 km S of Adak, Alaska
  11. 3.3 179 km SSE of Adak, Alaska
  12. 2.1 180 km S of Adak, Alaska
  13. 2.8 178 km S of Adak, Alaska
  14. 2.0 160 km S of Adak, Alaska
  15. 2.7 167 km S of Adak, 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.

On USGS

QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.