Megathrust earthquakes, or just thrust earthquakes, occur at subduction zones at destructive plate boundaries (convergent boundaries), where one tectonic plate's forced (or subducts) under another. Due to the shallow dip of the plate boundary, these earthquakes are among the world's largest, with moment magnitudes (M_w) that can exceed 9.0. The major subduction zone's associated with the Pacific and Indian Oceans and are responsible for the volcanic activity associated with the Pacific Ring of F… (More on Megathrust)