QuakeIndex

Fault · Alaska

Kosakuts fault (Chugach-St. Elias fold and thrust belt)

70 kmlong (43 mi), as mapped
1–5 mm/yrhow fast it slips
< 130,000 yearssince it last broke the surface
22quakes 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.

Its most recent surface rupture is younger than 130,000 years.

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: 0–0.

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

Denali faultPamplona faultChaix Hills fault (Chugach-St. Elias fold and thrust belt)Hope Creek fault (Chugach-St. Elias fold and thrust belt)Coal Glacier fault (Chugach-St. Elias fold and thrust belt)White River syncline (Chugach-St. Elias fold and thrust belt)Yakataga anticline (Chugach-St. Elias fold and thrust belt)Miller Creek fault (Chugach-St. Elias fold and thrust belt)Sullivan fault (Chugach-St. Elias fold and thrust belt)Yaga syncline (Chugach-St. Elias fold and thrust belt)
The Kosakuts fault (Chugach-St. Elias fold and thrust belt) as mapped at the surface (glowing), with the other mapped faults nearby, 22 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.

Most recent near it

  1. M 2.6 116 km S of McCarthy, Alaska
    2026-02-03 · 10 km from the trace
  2. M 2.6 122 km S of McCarthy, Alaska
    2025-11-05 · 3 km from the trace
  3. M 2.6 117 km S of McCarthy, Alaska
    2025-10-01 · 7 km from the trace
  4. M 2.6 120 km S of McCarthy, Alaska
    2024-09-09 · 5 km from the trace
  5. M 2.7 129 km SSE of McCarthy, Alaska
    2024-08-27 · 10 km from the trace
  6. M 2.5 118 km S of McCarthy, Alaska
    2024-05-19 · 8 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.