QuakeIndex

Earthquake · reviewed by a seismologist

M 3.2ml

123 km SSE of Akutan, Alaska

Yes. A magnitude 3.2 earthquake was recorded 123 km SSE of Akutan, Alaska, at 7:08 am AKDT on 12 October 2018 (15:08 UTC), 20 km deep.

· 20 km deep · released about 1,900 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 3.2 (ml)
Depth
20 km below the surface
Felt
no reports yet
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1185 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 42 km (26 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 5.1 on 2017-05-24 — about 710 times the energy of this one.

Before 2016, the USGS record lists 6 earthquakes of M5 or more within 50 km; the five largest:

  1. 5.4 112 km SE of Akutan, Alaska · 37 km NE of this epicentre
  2. 5.4 149 km SE of Akutan, Alaska · 35 km ESE of this epicentre
  3. 5.2 121 km SE of Akutan, Alaska · 34 km NE of this epicentre
  4. 5.1 162 km SSE of Akutan, Alaska · 39 km SSE of this epicentre
  5. 5.0 111 km SE of Akutan, Alaska · 41 km NE 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 53.1694, -164.8450. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 1.8 81 km SSE of Akutan, Alaska
  2. 3.1 95 km SE of Akutan, Alaska
  3. 2.5 95 km SE of Akutan, Alaska
  4. 1.7 80 km SSE of Akutan, Alaska
  5. 2.7 78 km SSE of Akutan, Alaska
  6. 3.4 94 km SE of Akutan, Alaska
  7. 2.7 164 km SSE of Akutan, Alaska
  8. 2.7 83 km SSE of Akutan, Alaska
  9. 2.7 145 km SSE of Akutan, Alaska
  10. 3.6 100 km SE of Akutan, Alaska
  11. 3.8 79 km SSE of Akutan, Alaska
  12. 2.4 96 km SE of Akutan, Alaska
  13. 2.6 139 km SE of Akutan, Alaska
  14. 3.1 136 km SE of Akutan, Alaska
  15. 2.2 78 km SE of Akutan, 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.