GEOL 1250 Lecture Notes - Lecture 13: Outer Core, Inner Core, Asthenosphere
28 May 2016
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Document Summary
Where the crust ends and mantle begins. Inner core is solid and outer core is liquid. Therefore, the earth"s core must be molten. P waves are focused at the antipodes of the earthquake. Therefore, the center of the core must be solid. Similar to light in a magnifying glass (how the waves are bent) Velocity of p waves depend on density of the rock and elastic property of the rock. The denser the rock, the more rigid, the higher the velocity of the waves. When waves move into the mantle, the velocity jumps up. Indicating a change in the rock composition. When waves cross the lithosphere to the asthenosphere, it reaches a low velocity zone. Mass and density of the rock below you can change gravity. The higher the density of the rock, the higher the gravitational acceleration. Continental crust: thick (35-70 km) and low density (2. 7 g/cm3) Oceanic crust: thin (5-8km) and high density (2. 9 g/cm3)
