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Geography Summer Exam Revision

====== Plate Tectonics: ======

Plates: Below are examples which you need to learn for the test.

Colliding: The Himalayas are an example of the collision of two continental plates

Separating: Mid-Atlantic Ridge

Sliding Past Each Other: San Andreas Fault

Structure Of The Earth

Plate: Plate Boundary: Where plates meet Crust: The thin outer layer of the earth Mantle: Consists of both hot molten and semi-hot molten rock known as magma. It moves around in very slow currents. Outer Core: Consists of liquid nickel and iron (molten) Inner Core: The solid centre of the earth.

Convection Currents

The earth's core heats the magma up towards the earth's crust. As the magma rises it begins to cool. The cool magma becomes heavier and heavier causing it to sink back towards the earths core or magma chamber. This circular movement causes a continuous movement of magma (convection currents) in the mantle. Convection currents cause tectonic plates to move very slowly.

Earthquakes

The four parts of an earthquake are:

Focus (the point within the earth where an earthquake rupture starts) Epicentre (point on surface directly above focus) Shock Waves (waves that transmit energy released by earthquakes, spread out in circles from core focus)) Fault (large crack in the earths crust)

Case Study: Chile

300km from capitol Santiago 35km from the pacific ocean 8.8 on the magnitude scale More than 500 people left dead Damage cost was $30 billion Central towns hit by t-sunmai waves Febuary 10th 2010 More than 400,00 severely damaged/destroyed

Volcanos

Formation of a volcano

When two volcanos separate or collide, magma can rise from the mantle. It fills the space in the crust -vent in an eruption Magma cools and hardens at the surface. This is called lava Layers of ash and lava build up around the vent This forms a cone shaped mountain with a crater

Mass Movement

Sea

Form of erosion -