Earth is tearing apart beneath the Pacific Northwest

Scientists imaged the Cascadia subduction zone off Vancouver Island using seismic reflection from the 2021 CASIE21 experiment, revealing large faults that split the Juan de Fuca and Explorer plates. A 5-kilometer offset shows the slab actively tearing apart, forming microplates and new boundaries rather than shutting down abruptly. This first clear view of a subduction zone “dying” illustrates how tectonic systems fragment piece by piece.