Cascadia subduction zone

The subduction zone beneath the Pacific Northwest of North America, where the Juan de Fuca Plate and adjacent oceanic plates descend beneath the North American Plate.

An accreted basaltic terrane forming important parts of the forearc basement in the Pacific Northwest. Spatial variations in its thickness, stiffness and permeability can affect the interpretation of gravity anomalies and the fluid/stress environment above the megathrust. A proposed relation to central Cascadia creep uses gravity, geodetic and paleoseismic observations, rather than lithology alone.^[ref]