This document provides a summary of key concepts about earthquakes, volcanoes, and plate tectonics in 3 sections and includes review questions at the end of each section. The sections discuss how earthquakes and volcanoes form due to the movement and interaction of tectonic plates. Most volcanoes occur at plate boundaries, and earthquakes are commonly caused by the buildup and release of stress along boundaries. Plate tectonics provides the driving force that results in earthquakes and volcanic activity.