QuakeIndex

Earthquake · reviewed by a seismologist

M 3.2ml

196 km ESE of Nikolski, Alaska

Yes. A magnitude 3.2 earthquake was recorded 196 km ESE of Nikolski, Alaska at 01:27 UTC on 2023-09-24, 10 km deep.

· 10 km deep · released about 1,900 lb of TNT

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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 3.2 (ml)
Depth
10 km below the surface
Felt
no reports yet
Nearest mapped fault
Alaska-Aleutian subduction zone, 17 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 1070 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage.

At this magnitude and depth, people at rest would likely notice it out to about 45 km (28 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 1,900 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.2 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 180,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 7,900× the energy of this one
  3. Magna, Utah 2020 M 5.7 5,600× the energy of this one
  4. This earthquake M 3.2 about 1,900 lb of TNT
  5. Around the size people start to feel M 3.0 this one released 2× 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 since 2016 was M 5.9 on 2017-05-24 — about 11,000 times the energy of this one.

Before 2016, the USGS record lists 10 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.5 183 km S of Unalaska, Alaska · 21 km N of this epicentre
  2. 6.0 221 km S of Unalaska, Alaska · 31 km ESE of this epicentre
  3. 6.0 218 km SE of Nikolski, Alaska · 32 km S of this epicentre
  4. 5.9 163 km SE of Nikolski, Alaska · 41 km W of this epicentre
  5. 5.4 214 km ESE of Nikolski, Alaska · 19 km SE 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 52.0378, -166.3717. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 2.9 190 km S of Unalaska, Alaska
  2. 2.6 209 km S of Unalaska, Alaska
  3. 3.4 195 km S of Unalaska, Alaska
  4. 2.6 203 km ESE of Nikolski, Alaska
  5. 3.2 200 km ESE of Nikolski, Alaska
  6. 4.2 213 km S of Unalaska, Alaska
  7. 2.7 198 km SE of Nikolski, Alaska
  8. 2.3 219 km SE of Nikolski, Alaska
  9. 2.1 166 km ESE of Nikolski, Alaska
  10. 2.4 195 km S of Unalaska, Alaska
  11. 1.7 202 km S of Unalaska, Alaska
  12. 3.2 184 km SE of Nikolski, Alaska
  13. 2.6 198 km ESE of Nikolski, Alaska
  14. 2.9 154 km ESE of Nikolski, Alaska
  15. 3.7 189 km SE of Nikolski, 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.