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Quick Questions 1. 2. 3. 4. 5. 6. 7. 8. You have 25 mins 20 marks Where are most earthquakes and volcanoes found? (2 marks) What is an active volcano? (1 mark) What is a dormant volcano? (1 mark) What are the effects of a volcanic eruption? (2 marks) What is the Richter scale? (1 mark) Name another method of measuring earthquakes? (1 mark) State three primary effects of an earthquake. (3 marks) Using examples that you have studied explain why more deaths occur in LEDC's than MEDC's when earthquakes occur (3 marks) 9. For a region you have studied describe the primary & secondary impacts of a natural hazard (6marks) Lesson Objectives Evaluate the maps of volcanic activity and population density. Understand and explain why people are living in areas of high risk. Weigh up the advantages and disadvantages of living close to a volcano. Population Density Map Is there a link between where people live and where volcanic activity takes place? Volcanic Activity • It is estimated that over 500 million people (one twelfth of the world’s population) live in active zones. • The hazards are obvious, so there must be reasons why people continue to live in these areas. • Most of the time, the majority of people are able to go about their daily business without worrying about the potential risks. But why? http://www.mefeedia.com/watch/29251129 Activity One 10 minutes • Colour (only the outline!) the advantages and disadvantages of living close to a volcano. • What do you identify as the biggest advantage/disadvantage – explain your answer. Minerals • Valuable minerals such as copper, gold, silver, lead, zinc and even diamonds are all associated with volcanic regions as they are associated with the rising magma which may cool and harden beneath the volcano. • As hot water circulate within the cooled magma, the metals are taken by the water and re-deposited in greater concentrations. • Thus volcanic areas are excellent areas for mining creating economic activities through job opportunities and the value of the mined minerals. • Example: Copper, Gold and Silver mining began around Mount St Helens as early as 1892. Geothermal Energy • Heat from magma sources close to the surface in volcanic areas can be used as a source of Geothermal energy which can be harnessed to produce electricity. • In these instances, superheated steam, created by the heating of water in permeable rocks in magma can be used to drive turbines. This use of energy is renewable and sustainable, it has the added advantage of being pollution free. • Example: Over 20 countries around the world generate geothermal power, including the US, Italy, New Zealand and Iceland. In fact 17% of Iceland's electricity is created in this way. In farming areas around Reykjavik (Iceland), geothermal energy is also used to heat greenhouses enabling the growing of fruit, vegetables and flowers. Fertile Soils • Volcanic soils are some of the most fertile in the world due to the weathering of volcanic products such as ash lava and rock, which release valuable nutrients and minerals which enrich the soil as well as improving soil characteristics such as moisture retention. • In tropical areas in particular, for example Hawaii, climate conditions mean that the weathering of lava etc. is fairly quick resulting in the growth of lush vegetation due to the rapid soil formation. As volcanic areas are therefore ideal for growing crops, they attract large populations. • Example: In Italy large numbers live on the slopes of Vesuvius and Etna (one in five Sicilians are believed to live on the slopes of Etna) due to the fertile soils which provide rich opportunities for growing products such as olives and fruit. Tourism • Due to the spectacular scenery associated with volcanic landscapes and unique features such as flows, volcanoes, particularly those having experienced recent eruptive activity are particularly popular with tourists. lava • This is a huge economic benefit due to the resulting multiplier effect. Tourism attracts custom for businesses such as hotel, cafes etc. creating jobs and improving the local economy. • Example: Yellowstone National Park in the USA with the famous Old Faithful geyser receives around 3 million visitors a year. Iceland is famous for its volcanic landscape and its hot springs and geysers have attracted many tourists. The Blue Lagoon, near Reykjavik is a spa popular with tourists for its known positive effectives on the skin. Unwillingness to leave home • Due to the infrequency of some volcanic eruptions, some people, particularly those who have not experienced a volcanic eruption in their lifetime are reluctant to leave their homes in order to move to safety and ignore warnings, preferring to live with the threat of a volcanic eruption. Some believe that there will be time to move / be rescued should an eruption begin. Lack of choice • It should also be recognised that some people have no choice but to live in these areas. In areas of poverty, people do not have the resources available to move and for many farming on the fertile soils in the shadow of a volcano may be the only livelihood they know. Areas of earthquake activity ECONOMIC REASONS: • Some earthquake areas like Turkey and Iceland are popular tourist areas and provide many jobs for the locals. • Landslides triggered by earthquake tremors, have caused loss of lives at numerous mining sites around the world. In 2007, an earthquake measuring 7.7 hit an area of many large copper mines in Chile, killing 2 people and injuring 117. in August 2008, a moderate tremor at a coal mine in a north-eastern province in China killed 6 workers and injured 1. • The people consider the risk is acceptable as they can make a good living from mining. Areas of earthquake activity SOCIAL REASONS: • People in middle-income countries (MICs) feel safe in earthquake zones because of the advantages that have been made in earthquake proof buildings. • Since 1981, all new buildings in Japan have had to be earthquake proof. • It is also common to have disaster plans to tell people what to do in an emergency. • People believe that the chance of being affected by and earthquake is very low. Areas of earthquake activity ENVIRONMENTAL REASONS: • Some places are known for their beauty and some individuals buy houses in exclusive areas despite the potential earthquake risks, e.g. Malibu, California. • People feel safer as buildings can now be built to be earthquake proof. Homework Question • Do you think the benefits of living in a hazard zone outweigh the problems? (8 marks) • Remember to talk about living close to volcanoes and living in earthquake prone zones!