Because geology is so central to human society, it is often in the news. Unfortunately, the biggest headlines are often the result of geologic natural disasters such as earthquakes and volcanoes. These large-scale, disruptive events have occurred throughout Earth’s history, and have changed the course of human civilizations. In this session, we will discuss the science behind volcanoes and earthquakes, including the factors that control where these natural hazards occur, how we measure their magnitudes, and what we can do to monitor and prepare for these disasters.