QuakeIndex

Earthquake · automatic estimate, may change

M 3.1ml

39 km SE of Fox River, Alaska

Yes. A magnitude 3.1 earthquake was recorded 39 km SE of Fox River, Alaska, at 1:37 am AKDT on 31 October 2025 (09:37 UTC), 21 km deep. The magnitude and location are an automatic first estimate and may change.

· 21 km deep · released about 1,300 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 3.1 (ml)
Depth
21 km below the surface
Felt
no reports yet
Nearest
Kenai Peninsula Borough, 133 km NW
Status
Automatic — a machine’s first estimate, which may change

USGS · last changed by USGS · we first saw it 290 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 36 km (22 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 1,300 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.1 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 250,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 11,000× the energy of this one
  3. Magna, Utah 2020 M 5.7 7,900× the energy of this one
  4. This earthquake M 3.1 about 1,300 lb of TNT
  5. Around the size people start to feel M 3.0 this one released 1.4× 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 5.4 on 2025-10-30 — about 2,800 times the energy of this one.

Before 2016, the USGS record lists 4 earthquakes of M5 or more within 50 km:

  1. 6.2 43 km ESE of Halibut Cove, Alaska · 31 km SSW of this epicentre
  2. 6.0 6 km SSE of Fox River, Alaska · 34 km WNW of this epicentre
  3. 5.9 13 km N of Fox River, Alaska · 48 km NW of this epicentre
  4. 5.6 7 km SE of Fritz Creek, Alaska · 47 km W 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 59.6590, -150.3871. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Kenai Peninsula Borough, AK 133 km (83 mi) NW earthquakes near Kenai Peninsula 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. 1.8 8 km SSE of Fox River, Alaska
  2. 1.9 23 km SE of Fox River, Alaska
  3. 1.8 46 km ESE of Fox River, Alaska
  4. 1.7 11 km ENE of Fox River, Alaska
  5. 1.6 26 km ESE of Halibut Cove, Alaska
  6. 2.3 27 km SE of Fox River, Alaska
  7. 2.8 35 km SE of Fox River, Alaska
  8. 2.3 13 km E of Fox River, Alaska
  9. 2.2 32 km SE of Halibut Cove, Alaska
  10. 1.6 30 km NE of Fox River, Alaska
  11. 2.2 19 km SE of Fox River, Alaska
  12. 1.7 8 km SSE of Fox River, Alaska
  13. 2.7 35 km ENE of Fox River, Alaska
  14. 1.8 44 km SW of Lowell Point, Alaska
  15. 1.7 38 km ESE of Fox River, 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.