QuakeIndex

Earthquake · reviewed by a seismologist

M 2.5ml

Alaska Peninsula

Yes. A magnitude 2.5 earthquake was recorded in the Alaska Peninsula at 01:05 UTC on 2023-10-23, 12 km deep.

· 12 km deep · released about 170 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Lake and Peninsula Borough 47 kmKodiak Island Borough 109 kmBristol Bay Borough 119 km
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 2.5 (ml)
Depth
12 km below the surface
Felt
no reports yet
Nearest
Lake and Peninsula Borough, 47 km WNW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1044 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 19 km (12 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 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.5 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 89,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 63,000× the energy of this one
  3. Around the size people start to feel M 3.0 5.6× the energy of this one
  4. This earthquake M 2.5 about 170 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 in our catalogue was M 5.3 on 2018-05-11 — about 16,000 times the energy of this one.

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 57.8858, -155.7323. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Lake and Peninsula Borough, AK 47 km (29 mi) WNW earthquakes near Lake and Peninsula Borough
Kodiak Island Borough, AK 109 km (68 mi) E earthquakes near Kodiak Island Borough
Bristol Bay Borough, AK 119 km (74 mi) NW earthquakes near Bristol Bay Borough

Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.

Aftershocks so far

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

  1. 1.7 85 km NW of Karluk, Alaska
  2. 1.6 68 km SE of King Salmon, Alaska
  3. 1.6 86 km NW of Karluk, Alaska
  4. 2.4 75 km ENE of Ugashik, Alaska
  5. 1.7 72 km W of Karluk, Alaska
  6. 1.8 84 km NW of Karluk, Alaska
  7. 1.5 86 km NW of Karluk, Alaska
  8. 1.9 78 km W of Karluk, Alaska
  9. 1.6 87 km NW of Karluk, Alaska
  10. 1.9 87 km NW of Karluk, Alaska
  11. 2.2 83 km ENE of Ugashik, Alaska
  12. 1.5 75 km WNW of Karluk, Alaska
  13. 2.1 79 km ESE of Egegik, Alaska
  14. 2.0 86 km E of Ugashik, Alaska
  15. 2.2 56 km W of Karluk, 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.