01:16
Plate Tectonics and Heat
Geophysicist and geologist Tanya Atwater talks about plate tectonics as a mechanism by which Earth's interior sheds the tremendous heat that builds up as a result of radioactive decay.
02:37
Isostasy
Geophysicist and geologist Tanya Atwater discusses isostasy, which allows objects at the surface of Earth to float in equilibrium, and talks about how it helps define Earth's topography.
02:41
Over the Edge: Undersea Volcanic and Tectonic Activity
For large stretches the deep ocean basin is flat. But seamounts, guyots, island arcs and trenches, all of which result at least in part from tectonic activity, break up the sameness.