QuakeIndex

Earthquake · reviewed by a seismologist

M 2.3ml

155 km S of Atka, Alaska

Yes. A magnitude 2.3 earthquake was recorded 155 km S of Atka, Alaska at 22:30 UTC on 2019-11-01, 13 km deep.

· 13 km deep · released about 85 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 2.3 (ml)
Depth
13 km below the surface
Felt
no reports yet
Nearest mapped fault
Alaska-Aleutian subduction zone, 9 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 2565 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

At this magnitude and depth, people at rest would likely notice it out to about 15 km (9 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 85 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.3 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 180,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 130,000× the energy of this one
  3. Around the size people start to feel M 3.0 11× the energy of this one
  4. This earthquake M 2.3 about 85 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.

For this area

The largest earthquake within 50 km since 2016 was M 4.2 on 2016-03-19 — about 710 times the energy of this one.

Before 2016, the USGS record lists 3 earthquakes of M5 or more within 50 km:

  1. 5.8 131 km S of Atka, Alaska · 43 km WNW of this epicentre
  2. 5.8 165 km SSE of Atka, Alaska · 49 km E of this epicentre
  3. 5.4 198 km SSE of Atka, Alaska · 45 km SSE 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 50.8183, -173.8641. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 2.6 163 km S of Atka, Alaska
  2. 2.4 118 km SSE of Atka, Alaska
  3. 2.1 140 km SSE of Atka, Alaska
  4. 3.7 126 km SSE of Atka, Alaska
  5. 2.0 124 km S of Atka, Alaska
  6. 2.6 115 km S of Atka, Alaska
  7. 2.7 121 km S of Atka, Alaska
  8. 2.2 Andreanof Islands, Aleutian Islands, Alaska
  9. 2.8 143 km S of Atka, Alaska
  10. 2.6 121 km SSE of Atka, Alaska
  11. 2.6 138 km SSE of Atka, Alaska
  12. 2.2 128 km S of Atka, Alaska
  13. 2.3 203 km S of Atka, Alaska
  14. 2.9 151 km SSE of Atka, Alaska
  15. 2.2 181 km SSE of Atka, 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.