you have 30 seconds……

You have 30 seconds…….

Lesson objective: To be able to explain the characteristics and spatial distribution of earthquakes

Key terminology Focus EpicentreAsthenosphere 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

Add these annotations to your plate margin diagrams.

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.

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.

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 ScaleThis 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

Analyse these two techniques

Richter Mercalli

Strengths

Weaknesses

Where would these rank on the Mercalli scale?

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.+Ch

aracteristics

• Key points: Eurasian, Philippine, Pacific, 10.2cm, 7.2 and 9,