QuakeIndex

Fault · Alaska

McGinnis Glacier fault (Northern Foothills fold and thrust belt)

39 kmlong (24 mi), as mapped
< 0.2 mm/yrhow fast it slips
< 15,000 yearssince it last broke the surface
4quakes of M2.5+ within 10 km since 2016

In plain English

The two sides move less than 0.2 mm a year — under 2 cm a century. Slow faults can still produce large earthquakes, just rarely.

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

The largest earthquake recorded near it was M 6.2 in 1948 (30 km SSW of Fort Greely, Alaska) — about 70,000 times the energy of an M3.0, the size people start to feel. It released about 33 kilotons of TNT.

This week vs. its last ten years

Too quiet to rank: fewer than half a year's worth of weeks with any M1.5+ quake within 5 km, in ten years. A single quake here would read as "unusual", so we do not score it.

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

Denali faultNorthern Foothills thrust fault (Northern Foothills fold and thrust belt)Molybdenum Ridge fault (Northern Foothills fold and thrust belt)Susitna Glacier faultGranite Mountain fault (Northern Foothills fold and thrust belt)Donnelly Dome fault (Northern Foothills fold and thrust belt) M 6.2 · 1948 · 30 km SSW of Fort Greely, Alaska
The McGinnis Glacier fault (Northern Foothills fold and thrust belt) as mapped at the surface (glowing), with the other mapped faults nearby, 4 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 6.2 30 km SSW of Fort Greely, Alaska
    February 11, 1948 · epicentre 19 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 2.6 49 km SW of Fort Greely, Alaska
    2026-01-29 · 3 km from the trace
  2. M 2.5 49 km SSW of Fort Greely, Alaska
    2024-07-10 · 2 km from the trace
  3. M 2.9 49 km NNW of Paxson, Alaska
    2018-12-07 · 5 km from the trace
  4. M 2.5 46 km SW of Fort Greely, Alaska
    2017-10-06 · 1 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.