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Resource from animation found at: http://www.iris.edu/hq/inclass/search Narration from the animation: Mantle Convection & Plate Tectonics: Basic Intro Convection in the mantle is commonly related to plate tectonic processes, but the primary cause is still under debate. Two forces acting on the plates include convective heat rising from deep in the Earth & the strong gravitational pull on the cold subducting plates. At shallow depths & lower pressure, the mantle rock melts forming magma that rises beneath the mid-ocean ridge, solidifying near or at the surface feeding the conveyor-belt-like plate. Earthquakes occur as magma pushes into the rock and as the cooling plate cracks and settles. Away from the ridge the oceanic plate dives beneath another oceanic plate, or beneath a thicker, yet more-buoyant continental plate in a process called subduction. Many earthquakes occur in the brittle plates around this zone. Immense friction at the contact periodically results in elastic rebound in the form of catastrophic Magnitude 9 earthquakes. The diving plate doesn't simply melt to form overlying volcanoes. What happens is, Water stored in the oceanic plate sweats out of the plate at depth. The water lowers the melting temperature of the overlying mantle rock, forming a higher-silica, gas rich magma that can produce violent eruptions. The movement of the tectonic plates is the primary way that the Earth is able to dissipate the heat that was generated both during the formation of the planet and from the ongoing decay of radioactive elements. 1:28