Presentation on theme: "Restless Earth Revision Revise the topic Practice exam technique."— Presentation transcript:
Restless Earth Revision Revise the topic Practice exam technique
Draw Get into groups of four and number yourselves. Draw your plate boundary: 1. destructive 2. collision 3. constructive 4. conservative 2 minutes Practice drawing these diagrams. Use them in the exam.
Diagrams Four plate boundaries Convection currents Shield and composite/strato- volcanoes Structure of Earth (probably wont be asked to draw this one; need to be able to interpret it)
Review and Rate Read the summary of the topic. Rate each section: how confident do you feel with each part?
The Earths Structure Earths interior has a layered structure, with different composition and physical properties. Interpreting a cross-section of the Earth, with details (temperature, density, composition, physical state) of layered structure (including the asthenosphere)
Different types of crust. OCEANIC This is heavy (density of 3.0), made of Minerals rich in Iron and Magnesium Is about 6-10 km thick on average and is usually under 200 million years old. CONTINENTAL This is lighter (density of 2.6), made of minerals rich in silica and aluminium, is about 30-70km thick and is mainly over 1500 million years old. Contrast continental and oceanic crust.
Convection Currents Solid Crust Convection cell in the mantle Plumes of heat rise in the mantle Convection in the liquid outer core
Earths Tectonic Plates and their Boundaries Mapping the distribution of the three plate margin types, and naming major plates.
Types of Volcano A composite or stratovolcano e.g. Mount Pinatubo, Philippines A shield volcano e.g. Mauna Loa, Hawaii Very hot, runny, basaltic lava. Eruptions rarely violent. Thick, viscous, andesitic lava. Explosive eruptions.
Contrasting earthquake effects in named locations Impacts on property versus people. Loma Prieta earthquake, USA Date: Tuesday 17 October 1989, at Magnitude: 6.9 on the Richter Scale Epicentre: in a mountainous part of Santa Cruz County, 90 km south-east of San Francisco Death toll: 63 Injured: 3,757 Homeless: 12,000 Property cost: $10 billion Kashmir, Pakistan Date: Saturday 8 October 2005 Magnitude: 7.6 on the Richter Scale Epicentre: Muzaffarabad, the capital of Pakistani- administered Kashmir Death toll: 75,000 Injured: 75,000 Homeless: 2.8 million Property cost: $440 million Impacts worst on property in developed countries. Impacts worst on people in developing countries.
Contrasting economic and social volcanic hazard impacts Mount St Helens, USA Date: Sunday 18th May 1980 at 8.33 am. Magnitude: 5 on the Volcanic Explosivity Index 5 (paroxysmal). Homes destroyed: 200 Death toll: 61 (most as a result of poisonous gases which accompanied the blast). Evacuated: 2,000 people Property cost: $1.1 billion. Mount Nyiragongo, DR Congo Date: 17th January Magnitude: Gentle; 1 on the Volcanic Explosivity Index (VEI). Homes destroyed: 12,500 Death toll: 100 (mostly from poisonous gas and getting trapped in lava). Evacuated: 400,000 Lava: hot, runny, basaltic Homeless: 120,000 Economic impacts worse in developed countries. Social impacts worse in developing countries.
Predicting Earthquakes Earthquakes are not as easy to predict as volcanic eruptions. However, there are still some ways of monitoring the chances of an earthquake: Laser beams can be used to detect plate movement. A seismometer is used to pick up the vibrations in the Earth's crust. An increase in vibrations may indicate a possible earthquake. Radon gas escapes from cracks in the Earth's crust. Levels of radon gas can be monitored - a sudden increase may suggest an earthquake.
Preparing for Earthquakes People living in earthquake zones need to know what they should do in the event of a quake. Training people my involve holding earthquake drills and educating people via TV or radio. People may put together emergency kits and store them in their homes. An emergency kit may include first-aid items, blankets and tinned food. Earthquake proof buildings have been constructed in many major cities, eg The Transamerica Pyramid in San Francisco. Buildings such as this are designed to absorb the energy of an earthquake and to withstand the movement of the Earth. Roads and bridges can also be designed to withstand the power of earthquakes.
Earthquake-proof building design Developed country Developing country
Predicting Volcanic Eruptions Warning signsMonitoring 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 sulphur levels.
Predicting and Preparing for Volcanic Eruptions
Preparing for Volcanic Eruptions 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.
Haiti, 2010 ImpactsResponseProblems Death toll: 200,000 (estimated) Homeless: 1.5 million (estimated) Tens of thousands without food, water and medical supplies Port-au-Prince port badly damaged US took control of Port-au-Prince airport UN World Food Programme increased food aid to survivors, e.g. 2 million meals delivered on one day US carried out air drops The Haitian authorities were not prepared for the earthquake Port-au-Prince airport has limited capacity Lack of fuel
Glossary You need to be familiar with these words so that you can: –understand what questions mean (easier) –define them (harder) Use the glossary sheet as a check list. Tick them off once when you when you understand them and again when you can define them. Concentrate at first on the terms in bold.
(a) Identify one advantage and one disadvantage that Sakurajima has brought to Japan. (2)
(b) Explain one reason way in which the impact of a volcanic eruption might be different in a less developed country. (2) More deaths/greater impacts on people. Accept other reasonable suggestions. Explanation: People more likely to live in risky locations Cant afford safe, well-built houses so buildings often collapse Communications poor, so warning and evacuation may not happen (so effectively) Poverty Slow/inadequate relief effort may lead to lack of shelter, clean water and food. Disease may spread Governments dont have the money or resources to provide aid
(c) Using examples, explain how eruptions can be predicted. (4)
Warning signsMonitoring 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 sulphur levels.