Week 1 &2 '

• The Earth is a differentiated planet. i.e. the materials it is composed of are separated into layers according to density – the more dense near the centre and the less dense near the surface
• Body waves


  Split into P-waves and S-waves
• 1. waves (Primary Waves)


  • They are compressional, travel through solids and liquids
• 1. waves (Secondary Waves)


  • Shear or Transverse, travel through solids only
• Refraction of the seismic waves reveals a detailed "visual" of the internal layers
• Lack of S-waves past the shadow zone provides evidence the outer core is liquid
• Structure of the Earth - Layers based on chemical composition


  • Crust
  • Mantle
  • Core
• Structure of the Earth - Layers based on physical properties


  • Lithosphere
  • Asthenosphere
  • Mesosphere
  • Outer Core
  • Inner Core
• The Earth's Crust is comprised of 2 distinct types of crust: Oceanic Crust and Continental Crust
• Continental Crust


  • Complex structure with many different types of rock, Granite is the most abundant rock type, oldest rocks are 3,900 million years old, average thickness of 45km
• Oceanic Crust


  • Simple layered structure: Layer 1 - loose sediment, Layer 2 - sedimentary rock, Layer 3 - Basalt, oldest rock is 200 million years old, average thickness of 8km
• Layers of the Earth get hotter and more dense towards the centre of the planet
• Energy that provides the Earth's heat


  • Gravity
  • Friction collisions
  • Nuclear fission and decay of radioisotopes
• State and differentiate between the two types of body waves – P & S
• Classify the layers of the earth based on physical properties and chemical characteristics
• Describe the chemical composition of the crust and differentiate between oceanic and continental crust
• Outline the features and composition of each of the earth's layers