GEOGRAPHY http://www.langley-sec.solihull.sch.uk/AQA-Rivers-Revision.pdf

Restless Earth Density Colour Age Rock Type More dense – heavier Distribution of plates; contrasts between continental and oceanic plates. Destructive, constructive and conservative plate margins. Density Colour Age Rock Type More dense – heavier Darker Younger Basalt Less dense Lighter (in colour) Older Granit

Destructive, constructive and conservative Restless Earth Destructive, constructive and conservative plate margins. oceanic and continental plate move towards each other. The dense oceanic plate is forced under the continental plate. As it sinks below the continental plate the oceanic plate melts due to friction in the subduction zone. The crust becomes molten called magma. This may be forced to the surface of the earth causing a volcanic eruption. The movement of the oceanic plate is not smooth. Due to friction the plate gets stuck. Pressure then builds up. The plate will eventually slip sometimes causing an earthquake.

Mid ocean ridge? Plates move away from each other due to convection currents in the magma Magna rises from the mantle through the opening. The magna erupts to the surface of the earth. When the magma reaches the surface the lava cools and creates new crust.

Formation of ocean trenches?

Shield Volcanoes Composite Volcanoes Destructive Steep sides frequent Explosive Less frequent Made of alternative layers of ash + lava Eg mount fuji frequent Non violent Gentle slopes Low-wide base cone Thin-runny lava E.g.. Mauna loa Constructive PB

Andes: fold mountain The length of the west coast of south America. Oceanic and continental crust Farming Grow crops on low valleys. Cash crops: HEP: Hydroelectic action Steep slopes, narrow valleys = easily dammed. Snow melt increases supplies. El Platinal dam 2nd biggest in Peru Mining Lot of important minable material. Iron, nickel, silver, Gold, Coal, Oil. Mining in Yanacocha is open cast (largest in the world) Tourism

Key techniques for monitoring a volcano Warning signs Monitoring techniques Hundreds of small earthquakes are caused as magma rises up through cracks in the Earth's crust. Seismometers are used to detect earthquakes. Temperatures around the volcano rise as activity increases. Thermal imaging techniques and satellite cameras can be used to detect heat around a volcano. When a volcano is close to erupting it starts to release gases. The higher the sulfur content of these gases, the closer the volcano is to erupting. Gas samples may be taken and chemical sensors used to measure sulfur levels.

Preparing for an eruption A detailed plan is needed for dealing with a possible eruption. Everyone who could be affected needs to know the plan and what they should do if it needs to be put into action. Planning for a volcanic eruption includes: creating an exclusion zone around the volcano being ready and able to evacuate residents having an emergency supply of basic provisions, such as food funds need to be available to deal with the emergency and a good communication system needs to be in place

Predicting & Preparing Earthquakes Predicting & Preparing Seismometer: used to pick up the vibrations in the Earth’s crust. An increase may indicate earthquake. Radon gas: escapes from cracks in crust. Sudden increase= earthquake. Training: holding drills, education via TV, Radio. Emergency kits: stored in homes, tinned food. First aid, blankets. Earthquake proof buildings: designed to absorb the energy from earthquake.

Richer Scale Mercalli Scale Scale 1 – 10+ I – XII Measuring Tool Seismograph Observation Measures The energy released by earthquake The effects caused by earthquake Calculation Information resulted from seismometers that measure the shock waves and movement Quantified from observation of effect on earth’s surface, human, objects and man made structures.

Conservative Plate Boundary : San Andreas

CASE STUDY: Haiti (LEDC) 3m affected EFFECTS 280,000 buildings collapsed =90% of all 316,000 killed Transport & communication links damaged 16,500 schools damaged 1/5 jobs lost Huge economy impact Flattened homes= living on the streets n cars. Roads blocked 10 days after

CASE STUDY: Japan (MEDC) EFFECTS Thousands trapped in the rubble 10 trains were derailed A 500m wall of flame swept through the city 5,390 died 180,000 buildings were damaged. Such as Panasonic were forced to close 230,000 homeless After shocks Risk of disease- No sewage system &disposal of dead bodies were delayed

HAITI JAPAN,KOBE Caribbean + N. American plates moving same direction. Shallow focus of 13km below surface. Epicentre 16km west of capital, Port-au-Prince. Seismologists warned of huge earthquake as fault been ‘locked’ for 250yrs. JAPAN,KOBE