This class continues the story of plate tectonics delving more deeply into the Earth’s interior, particularly the mantle. Over the last couple of decades seismic tomography and computer modeling have given us increasingly more detailed and fascinating images of structures in the Earth’s mantle and their effect on crustal and surface processes. While our understanding of mantle processes has grown significantly during this time, there is still much we don’t know. For example, there is a healthy debate on the concept of “mantle plumes.” What are they? Are they responsible for “hot spots” on the Earth’s surface (e.g., Hawaii, Iceland, Yellowstone) or is some other tectonic process responsible? Do they even exist? In this four-session class we will review plate tectonics, the anatomy of our planet, and the processes which cause the normally solid mantle to melt, resulting in volcanism.  We will review some of the latest science and images of the mantle revealed by seismic tomography and how they apply to the mantle plume controversy. Lastly, we will review areas in the U.S. where there are significant risks for earthquakes including the East Tennessee Seismic Zone, in which we live (did you feel the earthquake here in early May?). These seismic hazards are due to stresses that are likely connected to the mantle processes discussed previously.