QuakeIndex

Fault · Alaska

Northern Foothills thrust fault (Northern Foothills fold and thrust belt)

204 kmlong (127 mi), as mapped
0.2–1 mm/yrhow fast it slips
< 15,000 yearssince it last broke the surface
20quakes of M2.5+ within 10 km since 2016

In plain English

The two sides move 0.2 to 1 mm a year — 2 to 10 cm every century.

Its most recent surface rupture is younger than 15,000 years.

The largest earthquake recorded near it was M 7.1 in 1947 (Central Alaska) — about 1,300,000 times the energy of an M3.0, the size people start to feel. It released about 610 kilotons of TNT.

This week vs. its last ten years

89/100

elevated

1 quake of M1.5+ within 5 km of the trace in the last 7 days — busier than 89% of weeks since 2016. A normal week: 0–0.

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

Denali faultPark Road fault (Northern Foothills fold and thrust belt)Molybdenum Ridge fault (Northern Foothills fold and thrust belt)Dot ''T'' Johnson fault (Northern Foothills fold and thrust belt)McGinnis Glacier fault (Northern Foothills fold and thrust belt)Susitna Glacier faultGranite Mountain fault (Northern Foothills fold and thrust belt)Billy Creek fault (Northern Foothills fold and thrust belt)Donnelly Dome fault (Northern Foothills fold and thrust belt)Canteen fault (Northern Foothills fold and thrust belt) M 7.1 · 1947 · Central Alaska M 6.4 · 1947 · 23 km ENE of Ferry, Alaska M 6.2 · 1948 · 30 km SSW of Fort Greely, Alaska M 6.0 · 1929 · 39 km SW of Salcha, Alaska
The Northern Foothills thrust fault (Northern Foothills fold and thrust belt) as mapped at the surface (glowing), with the other mapped faults nearby, 20 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 7.1 Central Alaska
    October 16, 1947 · epicentre 19 km from the trace
  2. M 6.4 23 km ENE of Ferry, Alaska
    October 20, 1947 · epicentre 12 km from the trace
  3. M 6.2 30 km SSW of Fort Greely, Alaska
    February 11, 1948 · epicentre 14 km from the trace
  4. M 6.0 39 km SW of Salcha, Alaska
    July 4, 1929 · epicentre 18 km from the trace
  5. M 4.3 41 km W of Clear, Alaska, Alaska
    December 8, 2016 · epicentre 10 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 3.7 60 km SW of Salcha, Alaska
    2026-07-02 · 1 km from the trace
  2. M 3.3 45 km SW of Harding-Birch Lakes, Alaska
    2026-01-31 · 3 km from the trace
  3. M 3.2 54 km ENE of Ferry, Alaska
    2025-12-20 · 2 km from the trace
  4. M 2.5 59 km SW of Salcha, Alaska
    2024-10-12 · 8 km from the trace
  5. M 2.6 54 km SW of Harding-Birch Lakes, Alaska
    2024-07-31 · 8 km from the trace
  6. M 2.6 Central Alaska
    2022-09-17 · 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.