Geography- Tectonic Activity

The Earth has 4 layers:

Inner Core: Centre and hottest part of Earth. Iron and Nickel.

Outer Core: layer surrounding inner core. Liquid layer of Iron and Nickel.

Mantle: Made of magma. Upper part hard, lower soft.

Crust: Outer layer. Hard rock, humans live.

Two Types Of Crust: Continental (land) and Oceanic (water)

the Earth's crust is broken up into pieces called plates. The movement of plates is called plate tectonics.

CONVECTION CURRENTS are created by heat rising and falling in the mantle.

PLATE BOUNDARY is where two plates meet.

Tensional, Constructive: Plates Move Apart

Compressional, Collision: Plates move towards each other

Conservative, Transform: Plates slide past each other

Tensional and Constructive boundaries move plates apart due to convection currents inside of the Earth.

As the plates move apart, magma rises from the mantle.                                         The magma erupts to the Earth's surface. When the magma reaches the surface, it cools and hardens to form a new layer of igneous rock.  This is repeated, and eventually a volcano is formed.

Construtive boundaries tend to be formed under the sea,

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Continental and Oceanic Plates.

When these move together, the oceanic plate goes under the continental plate because it is denser.

SUBDUCTION ZONE: Is the point where the oceanic plate goes under the continental plate.