Structure of the Earth

Lithosphere: This layer includes both the crust, and the upper most part of the mantle. It is about 100 km thick and is able to move and flow over the rest of the upper mantle. This is the zone that creates earthquakes, mountains, volcanoes, and continental drifting. It is broken up into portions called tectonic plates.

Oceanic Plate: The part of the lithosphere that surfaces in the ocean basins. It is rich in iron and magnesium. Though it is denser then the continental plates it is much less thick at about 10 km. The magnetic forces that run along these plates is helpful proof for the fact that there are plate tectonics, as well as the fact that there is a large mountain range under water.

Continental Plate: A layer of sedimentary, igneous and metamorphic rocks which from the continents. It consists mostly of granite rock and is less dense then the oceanic crust, though it is much thick at about 35-40 km. The fact that the size and shape of the continents on these plates has changed over time is solid proof for plate tectonics.

Asthenoshpere: The highly vicious portion of the upper mantle. It is beneath the lithosphere at a depth of 100-200 km below the surface of the Earth. It is involved in plate movements. Pressure and heat help keep it like plastic with a low density meaning that seismic waves are able to easily pass through it. This is the layer on which the lithospheric plates move, causing plate tectonics.

Convection Currents: There are the currents that pass through the asthenosphere that is causing the plates of the lithosphere to move. It is the movement of molecules through liquids.