QuakeIndex

Fault · Alaska

Alaska-Aleutian subduction zone

2,990 kmlong (1,858 mi), as mapped
> 5 mm/yrhow fast it slips
last 150 yearssince it last broke the surface
664quakes of M2.5+ within 10 km since 2016

Updated , with the latest earthquake of M2.5 or more within 10 km of the trace: M 4.2, 161 km SSE of Atka, Alaska.

In plain English

The two sides grind past each other faster than 5 mm a year — more than half a metre (20 inches) every century.

It has broken the ground surface within the last 150 years.

The largest earthquake recorded near it was M 6.9 in 1906 (182 km SSE of Atka, Alaska) — about 790,000 times the energy of an M3.0, the size people start to feel. It released about 370 kilotons of TNT.

USGS maps it as 2 sections: Aleutian fault, Aleutian megathrust.

This week vs. its last ten years

0/100

quiet

No quakes of M1.5+ within 5 km of the trace in the last 7 days. A normal week: 0–1.

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

Denali faultCascadia megathrustFairweather fault systemCascadia fold and fault beltTransition faultPamplona faultGulf of Alaska shear zoneTotschunda faultCastle Mountain faultYakutat fault (also known as Foothills fault)Mission faultBitterroot faultOlympia structureChaix Hills fault (Chugach-St. Elias fold and thrust belt)Calawah faultNorth Ninitat faultKosakuts fault (Chugach-St. Elias fold and thrust belt)Hope Creek fault (Chugach-St. Elias fold and thrust belt)Seattle faultPatton Bay faultCoal Glacier fault (Chugach-St. Elias fold and thrust belt)Southern Whidbey Island faultMalaspina fault (Chugach-St. Elias fold and thrust belt)South Ninitat faultWhite River syncline (Chugach-St. Elias fold and thrust belt)Yakataga anticline (Chugach-St. Elias fold and thrust belt)Boundary faultMiddle Ground Shoal anticline (Cook Inlet folds)Miller Creek fault (Chugach-St. Elias fold and thrust belt)Rattlesnake Mountain faultLangley Hill faultSullivan fault (Chugach-St. Elias fold and thrust belt)Ten Fathom faultLake Creek-Boundary Creek faultRagged Mountain faultUtsalady Point faultSaddle Hill faultKayak faultPass Creek faultBancas Point faultBirch Bay faultTacoma faultGrays Harbor faultCherry Creek faultGranite Point anticline (Cook Inlet folds)Saddle Mountain faultsSandy Point faultYaga syncline (Chugach-St. Elias fold and thrust belt)Boulder Creek-Canyon Creek faultWingham faultOtmeloi fault M 6.9 · 1906 · 182 km SSE of Atka, Alaska M 6.9 · 1965 · 240 km SE of Atka, Alaska M 6.7 · 1905 · 254 km SW of Adak, Alaska M 6.5 · 1957 · 183 km S of Unalaska, Alaska M 6.4 · 1957 · 146 km S of Adak, Alaska M 6.3 · 1915 · 159 km SSE of Adak, Alaska
The Alaska-Aleutian subduction zone as mapped at the surface (glowing), with the other mapped faults nearby, 400 of the M2.5+ earthquakes within 10 km of it since 2016 (dots) and the epicentres of the large historic earthquakes recorded near it (rings). 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 6.9 182 km SSE of Atka, Alaska
    January 27, 1906 · epicentre 5 km from the trace
  2. M 6.9 240 km SE of Atka, Alaska
    July 29, 1965 · epicentre 5 km from the trace
  3. M 6.7 254 km SW of Adak, Alaska
    September 14, 1905 · epicentre 10 km from the trace
  4. M 6.5 183 km S of Unalaska, Alaska
    April 19, 1957 · epicentre 3 km from the trace
  5. M 6.4 146 km S of Adak, Alaska
    March 10, 1957 · epicentre 12 km from the trace
  6. M 6.3 159 km SSE of Adak, Alaska
    April 3, 1915 · epicentre on the trace
  7. M 5.4 166 km SSW of Adak, Alaska
    September 9, 2019 · epicentre 1 km from the trace
  8. M 5.4 260 km SE of Perryville, Alaska
    April 25, 2022 · epicentre on 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 4.2 161 km SSE of Atka, Alaska
    2026-10-27 · 4 km from the trace
  2. M 4.0 195 km SE of Akutan, Alaska
    2026-10-21 · 8 km from the trace
  3. M 2.7 149 km SSE of Old Harbor, Alaska
    2026-10-19 · 6 km from the trace
  4. M 3.1 187 km SE of Akutan, Alaska
    2026-10-09 · 1 km from the trace
  5. M 2.9 184 km SSE of Unalaska, Alaska
    2026-10-07 · 6 km from the trace
  6. M 2.9 194 km SSE of Akutan, Alaska
    2026-09-14 · 9 km from the trace

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.