Tectonics and Geodynamics of the Cascadia Subduction Zone

Abstract

The Cascadia subduction zone, where the young and thin oceanic Juan de Fuca plate sinks beneath western North America, represents a thermally hot endmember of global subduction systems. Cascadia exhibits complex and three-dimensional heterogeneities including variable coupling between the overriding and downgoing plates, the amount of water carried within and released by the oceanic plate, flow patterns within the mantle wedge and backarc, and the continuity and depth extent of the subducting slab. While recent research has benefitted from extensive onshore and offshore deployments of geophysical instrumentation, a consensus on many important aspects of Cascadia’s magmatic, tectonic, and geodynamic setting remains elusive.