Overview
- Researchers imaged a roughly 75‑kilometer fault actively breaking the Explorer plate beneath the northern Cascadia subduction zone off Vancouver Island.
- High‑resolution profiles show deep fractures and a vertical offset nearing five kilometers, with nearby zones going quiet seismically where fragments appear detached.
- The team interprets the observations as a staged shutdown of subduction that rips the plate into microplates and opens slab windows.
- The findings do not change the near‑term earthquake risk for the Pacific Northwest but could refine models of how seismic energy and volcanic activity evolve over time.
- The data come from the 2021 CASIE21 seismic reflection survey using a 15‑kilometer underwater sensor array aboard the research vessel Marcus G. Langseth, led by Brandon Shuck with coauthor Suzanne Carbotte.