Continental Rift Valley Definition = A lowlying area formed when continental plates are moving away from each other. Boundary = Divergent Example = East African Rift System Continental Rift Valley Mid- Ocean Ridge Definition = an underwater mountain range Boundary = Divergent Example = Mid-Atlantic Ridge Mid – Ocean Ridge Sea-Floor Spreading Definition = new oceanic crust material is created as plates move away from each other Boundary = Divergent Example = Mid-Atlantic Ridge Volcanic and Island Arcs Definition = A chain of volcanoes parallel to a mountain belt that are shaped like an arc when viewed from above. They are formed when one plate sinks below another plate. Boundary = Convergent Example = The Aleutian Islands Deep Sea (Ocean) Trench Definition = a long narrow depression in the ocean floor that is formed when an oceanic plate sinks below another plate Boundary = Congergent Example = The Mariana Trench is the deepest part of the ocean Mountain Range Definition = a group or chain of mountains Boundary = Convergent OR Divergent Example = Himalayas (convergent) Subduction Zone Definition = the area where one plate sinks below another plate Boundary = Convergent Example = Mount Ranier Earthquakes Definition = sudden release of energy in the Earth's crust that produces seismic waves Boundary = Convergent, Divergent, AND Transform! Example: Haiti