EESC1168 Lecture Notes - Lecture 7: San Andreas Fault, Plate Tectonics, Tibetan Plateau
1 Feb 2017
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Past lecture slides and readings are on canvas. Review sheet will be posted on friday. Volcanoes, earthquakes, and tsunamis all arise due to movement of the earth"s crust. Plate tectonics = deformation and movement within earth"s outer layers. Crust = low-density rock at earth"s surface. Lithosphere = rigid, outer layer of earth. Volcanoes and earthquakes at the boundaries between plates and at hot spots away from boundaries. Asthenosphere = soft, weaker layer below lithosphere. See it when it flows to the surface as magma. Transform fault = plates slide past each other. First, melted magma flows upward and cools new ocean floor is formed. Lithosphere moves away from the new material ( seafloor spreading") Lithosphere is pulled back into the asthenosphere and melted at subduction zones. Divergence zones: creation of new land and mid-ocean ridges. Plates pull apart, resulting in a spreading center. Ex: iceland - growing, lots of magma. Transform faults: plates push past each other.
