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You have 30 seconds……. Lesson objective: To be able to explain the characteristics and spatial distribution of earthquakes . Key terminology Focus Epicentre Asthenosphere Lithosphere P and S waves Surface waves Friction . spatial extent, predictability, frequency, magnitude,
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Lesson objective: To be able to explain the characteristics and spatial distribution of earthquakes Key terminology Focus Epicentre Asthenosphere Lithosphere P and S waves Surface waves Friction spatial extent, predictability, frequency, magnitude, duration, speed of onset and effects.
Why do plates move? The theory….. Top layer of mantle – Soft, malleable rock the asthenosphere Lithosphere – dragged and pushed by convection currents
Explain why Earthquakes occur, using the following terms: • Plate boundary, friction, pressure, energy, seismic shock wave, focus, epicentre.
Shock Waves • These are energy waves created by the pressure release when two plates slip past eachother. • These travel below the surface of the Earth.
Seismic Waves These are fast moving and can travel through solids and liquids. These are slower and can travel through solids only.
Surface Waves • Energy released by Earthquakes can be transferred as movement along the Earth’s surface. • The two wave types are Love waves and Rayleigh waves.
Surface Waves These are fast moving and do not tend to affect bodies of water. These can be very destructive on solid ground. These are slower moving, and their motion can disrupt bodies of water, creating large waves and currents.
Measuring Earthquakes • Richter Scale: This measures the energy released by an earthquake. It is a logarithmic scale, which means that a Scale 6 ‘quake is 10 times more powerful than a Scale 5 ‘quake.
Measuring Earthquakes • Mercalli Scale This measures the damage experienced as a result of an earthquake, and is calculated by visual evidence. http://elearning.niu.edu/simulations/images/S_portfolio/Mercalli/Mercalli_Scale.swf
How predictable? • Time of earthquake • Date of earthquake • Exact location of epicentre • Fault upon which the quake occurs • The magnitude of the earthquake • The economic impact of the earthquake • The death toll of the earthquake For each of the elements explain how predictable it is.
Now, examples • Japan Tohoku: March 11th 2011 • http://mrphillipsibgeog.wikispaces.com/1.+Characteristics • Key points: Eurasian, Philippine, Pacific, 10.2cm, 7.2 and 9,