QuakeIndex

Fault · Alaska

Boundary fault

56 kmlong (35 mi), as mapped
1–5 mm/yrhow fast it slips
< 1.6 million yearssince it last broke the surface
34quakes of M2.5+ within 10 km since 2016

In plain English

The two sides move 1 to 5 mm a year — 10 to 50 cm (4 to 20 inches) every century.

It has moved within the last 1.6 million years.

The largest earthquake recorded near it was M 4.2 in 2020 (49 km ENE of Yakutat, Alaska) — about 63 times the energy of an M3.0, the size people start to feel. It released about 30 tons of TNT.

This week vs. its last ten years

0/100

quiet

0 quakes of M1.5+ within 5 km of the trace in the last 7 days — busier than 0% of weeks since 2016. A normal week: 0–1.

Computed from the USGS catalogue · a description of the past, not a forecast · method

Alaska-Aleutian subduction zoneDenali faultFairweather fault systemTransition faultYakutat fault (also known as Foothills fault)Malaspina fault (Chugach-St. Elias fold and thrust belt)Bancas Point faultOtmeloi fault
The Boundary fault as mapped at the surface (glowing), with the other mapped faults nearby, 34 of the M2.5+ earthquakes within 10 km of it since 2016 (dots), . Traces: USGS Quaternary Fault and Fold Database. Historic epicentres are estimates.

Every year since 2016

Earthquakes of M2.5+ with an epicentre within 10 km of the mapped trace. Near is not the same as on: some will have slipped on neighbouring faults.

The big ones recorded near it

  1. M 4.2 49 km ENE of Yakutat, Alaska
    November 16, 2020 · epicentre 7 km from the trace

Before 1973 from the USGS ComCat historical catalogue (within 25 km; epicentres of old earthquakes are estimates). Since 2016, M4+ within 10 km.

Most recent near it

  1. M 2.9 50 km E of Yakutat, Alaska
    2026-09-24 · 7 km from the trace
  2. M 2.6 47 km ENE of Yakutat, Alaska
    2026-06-21 · 3 km from the trace
  3. M 2.6 59 km NNE of Yakutat, Alaska
    2026-06-04 · 9 km from the trace
  4. M 3.6 40 km NE of Yakutat, Alaska
    2026-01-24 · 1 km from the trace
  5. M 2.6 54 km NNE of Yakutat, Alaska
    2025-11-23 · 8 km from the trace
  6. M 3.6 45 km ENE of Yakutat, Alaska
    2025-03-03 · 5 km from the trace

Neighbouring faults

Fault trace, slip rate and age: USGS Quaternary Fault and Fold Database (public domain), simplified for the web. Earthquakes: USGS ComCat. QuakeIndex does not forecast earthquakes; a fault's history describes the past. For early warning use ShakeAlert.