QuakeIndex

Fault · Alaska

Pass Creek fault

24 kmlong (15 mi), as mapped
< 0.2 mm/yrhow fast it slips
< 15,000 yearssince it last broke the surface
16quakes 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 4.6 in 2025 (24 km WSW of Petersville, Alaska) — about 250 times the energy of an M3.0, the size people start to feel. It released about 120 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: 0–0.

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

Denali faultCastle Mountain fault
The Pass Creek fault as mapped at the surface (glowing), with the other mapped faults nearby, 16 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 4.6 24 km WSW of Petersville, Alaska
    August 6, 2025 · 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 2.6 37 km WSW of Petersville, Alaska
    2026-03-10 · 8 km from the trace
  2. M 3.2 38 km NNW of Skwentna, Alaska
    2025-12-24 · 5 km from the trace
  3. M 4.6 24 km WSW of Petersville, Alaska
    2025-08-06 · 10 km from the trace
  4. M 2.7 52 km NNW of Skwentna, Alaska
    2024-10-28 · 9 km from the trace
  5. M 2.7 35 km W of Petersville, Alaska
    2024-07-07 · 9 km from the trace
  6. M 2.8 37 km WSW of Petersville, Alaska
    2024-03-07 · 5 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.