This document discusses plate tectonics and how it relates to earthquakes and volcanoes. There are three types of plate boundaries - divergent where plates separate, convergent where they collide, and transform where they slide past each other. Convergent boundaries often create subduction zones and can result in earthquakes, volcanoes, or mountain ranges depending on the type of crust involved. Earthquakes release pressure from plate movement and different seismic wave types travel through the Earth's layers at different speeds. Volcanoes form at hotspots and plate boundaries as magma rises from the mantle to the surface.