Why do people live in Why do people live in hazardous places?hazardous places?

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Hazards and risksHazards and risks• Hazard is the potential to cause harm; • Risk on the other hand is the likelihood of harm (in

defined circumstances, and usually qualified by some statement of the severity of the harm).

• E.g. Flour would not be considered by many to be a hazardous substance. However, if a baker was exposed over a period of time to airborne flour dust and/or dust by skin contact, he/she could develop dermatitis (an inflammation of the skin), conjunctivitis (inflammation of the eyes), rhinitis (information of the nose) and even asthma - inflammation of the lungs which can cause a great deal of distress and may even by life threatening. 

• So flour is NOT a hazard, but in special circumstances it can be a risk.

• And risks need to be protected against – a mask for instance  

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SoSo•A natural event (e.g. earthquake, flood,

landslide, volcanic eruption, tropical storm) that has the potential to cause damage, destruction and death present as a natural hazard.

•The risk of being in the area needs to be considered.

•How frequently is there a risk? How serious can it be? Is there anything that can be done to reduce the risk?

•This is a risk assessmentrisk assessment

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This aspect of it will come into next This aspect of it will come into next year’s work – the bit we have left out year’s work – the bit we have left out so that we can spend time reviewing so that we can spend time reviewing the unit and tying up the loose ends!the unit and tying up the loose ends!

•So the long term aims of any area subject to hazards is to Carry out risk assessments As a result of these assessments, adjust

behaviour – this could be implement training and information, change building design, change zoning laws, move settlements – lots of things

Improve prediction

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So today’s lesson will be looking at So today’s lesson will be looking at why people stay in these potentially why people stay in these potentially

very risky placesvery risky places•From the viewpoint of:

Physical/ environmental Human/social Economic

•For each of these let’s consider volcanoes, earthquakes and tropical cyclic storms.

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Physical/environmental that Physical/environmental that encourage people to stayencourage people to stay

•How often do these hazards arise?•What are the positive environmental

points of these places?•What are the negative ones?

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Human/social aspects that Human/social aspects that encourage people to stayencourage people to stay

•What about the people and the place they live might attract them to stay?

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Economic influences that encourage Economic influences that encourage people to staypeople to stay

•What the kind of financial influences there might be?

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Why do people live near Why do people live near volcanoes? volcanoes? • At first it may seem odd that people would want

to live close to a volcano or any tectonic activity.

• After all, volcanoes have a nasty habit of exploding, discharging liquid rock, ash, poisonous gasses, red hot clouds of embers, and generally doing things that kill people.

• Earthquakes shake you up quite a bit!• And storms can create their own kind of

mayhem.• Yet, throughout history, people have

deliberately chosen to risk all those hazards and live near them, even on the slopes of active volcanoes that have erupted within living memory.

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•They chose to live close to there because they felt that the advantages outweighed the disadvantages.

•Most volcanoes are perfectly safe for long periods in between eruptions, and those that do erupt more frequently are usually thought of, by the people who live there, as being predictable.

•Today, about 500 million people live on or close to volcanoes and many millions more live in earthquake zones and in the paths of tropical storms

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•We even have major cities close to active volcanoes. Popocatapetl is a volcanic mountain less than 50 miles from Mexico City in Mexico.

• In short, the main things that attract people to live near active volcanoes are minerals, geothermal energy, fertile soils and tourism.

•Lets look at each one...

What about living near a volcano What about living near a volcano (and the potential of earthquakes (and the potential of earthquakes

too)?too)?

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MineralsMinerals

• Magna rising from deep inside the earth contains a range of minerals.

• As the rock cools, minerals are precipitated out and, due to processes like the movement of superheated water and gasses through the rock, different minerals are precipitated at different locations.

• This means that minerals such as tin, silver, gold, copper and even diamonds can be found in volcanic rocks.

• Most of the metallic minerals mined around the world, particularly copper, gold, silver, lead and zinc are associated with rocks found deep below extinct volcanoes.

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MineralsMinerals• This makes the areas ideal for both large

scale commercial mining and smaller scale local activities by individuals and small groups of locals.

• Active and dormant volcanoes have the same mineralization, so like extinct volcanoes, they are rich sources of minerals.

• Hot gasses escaping through vents also bring minerals to the surface, notably sulphur, which collects around the vents as it condenses and solidifies.

• Locals collect the sulphur and sell it.

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Geothermal EnergyGeothermal Energy• Geothermal energy means heat energy from

the earth. • It's unusual to use the heat directly, by

building your house on top of a steam vent for example, because it's unpredictable, dangerous and messy.

• The heat from underground steam is used to drive turbines and produce electricity, or to heat water supplies that are then used to provide household heating and hot water.

• Where steam doesn't naturally occur it is possible to drill several deep holes into very hot rocks, pump cool water down one hole and extract steam from another hole close by.

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Geothermal EnergyGeothermal Energy• The steam isn't used directly because it

contains too many dissolved minerals that could precipitate out and clog pipes, corrode metal components and possibly poison the water supply.

• Countries such as Iceland make extensive use of geothermal power, with approximately two thirds of Iceland's electricity coming from steam powered turbines.

• New Zealand and to a lesser extent, Japan, also make effective use of geothermal energy.

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Geothermal in Iceland [mini case Geothermal in Iceland [mini case study]study]• Iceland has over 200

volcanoes and 800 hot springs

•10% of the land is lava fields (see ahead to fertile soils)

•New land is being created all the time as the Eurasian and North American plate diverge.

•There are several ways in which Iceland uses the volcanoes to positive effects

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Geothermal in IcelandGeothermal in Iceland

• It is also used for recreational purposes

• Blaa Lonio - The Blue Lagoon. In the middle of this huge lava field sits this pool of seawater naturally heated by the geothermal activity below the surface

• The hot water from the springs are carried by pipeline, 45 km, to Reykjavik, the capital. The water’s temperature is 3000C.

• There the people have cheap reliable energy which does not damage the environment.

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ElectricityElectricity•26% of Iceland’s electricity comes from

Geothermal Power.•Travel brochures say that Reykjavik “is

the most unpolluted capital in Europe.” • It’s true what the postcards say - the

city is absolutely pristine. The air is crystal clear.

•The geothermal electricity generation has a lot to do with this.

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• Southeast of Reykjavik, the town of Hveragerdi serves as a geothermal farming centre for the capital.

• Puffs of steam coming out of the ground all over the place.

• There were greenhouses everywhere, often surrounded by steaming cracks in the ground.

• The extreme climate of Iceland is actually able to produce much in the way of tropical fruits and vegetables with the help of geothermal steam.

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• Iceland is Europe’s largest producer of bananas and most come from in or around Hveragerdi.

• Except for the geothermal farms everywhere, Hveragerdi looked a lot like a small quiet town that would have fit right in place in central England.

• With its seemingly unlimited geothermal energy combined with ample hydro-electric power from glacial rivers, Iceland is looking to become one of the first countries in the world to do away with fossil fuels entirely. Now if only the rest of us lived on a plate boundary!

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Fertile SoilsFertile Soils• Volcanic rocks are rich in minerals, but when the

rocks are fresh the minerals are not available to plants.

• When they do become soils though, they form some of the richest ones on the planet.

• Places such as the African Rift Valley, Mt Elgon in Uganda, and the slopes of Vesuvius in Italy all have productive soils thanks to the breaking down of volcanic rocks and ash.

• The Naples area, which includes Mount Vesuvius, has such rich soils thanks to two large eruptions 35,000 and 12000 years ago. Both eruptions produced very thick deposits of ash and broken rocks which have weathered to rich soils.

• Today, the area is intensively cultivated and produces grapes, vegetables, orange and lemon trees, herbs, flowers and has become a major tomato growing region.

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TourismTourism• Volcanoes attract millions of visitors every

year, for different reasons. • As an example of the wilder side of nature,

there are few things that can beat seeing an erupting volcano blowing red hot ash and rock thousands of feet into the air.

• Even the less active ones that are just puffing out steam and smoke are impressive sights and attract tourists from around the world.

• Around the volcano may be warm bathing lakes, hot springs, bubbling mud pools and steam vents.

• Geysers are always popular tourist attractions, such as Old Faithful in the Yellowstone National Park, USA. Old Faithful is such a popular tourist feature that it even has its own 24 hour Old Faithful webcam.

This one is in New Zealand

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TourismTourism• Iceland markets itself as a land of fire and ice,

attracting tourists with a mix of volcanoes and glaciers, often both in the same place.

• The wild, raw and barren volcanic landscapes also attract tourists who want to see what the early planet may have looked like.

• Tourism creates jobs in shops, restaurants, hotels and tourist centres / national parks.

• Locals economies can profit from volcanism throughout the year, whereas skiing, for example, has only a limited winter season.

• In Uganda, a country trying hard to increase its tourist industry, the volcanic region around Mt Elgon is being heavily promoted for it's landscape, huge waterfalls, wildlife, climbing and hiking and its remote 'get away from it all' location.

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Building MaterialsBuilding Materials• Blocks of lava are

used for building materials

• Granite is a volcanic rock

• Ash is used in cement to build with.

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They stay there because there is They stay there because there is nowhere else to go – it is homenowhere else to go – it is home

• Land is cheap in volcanic and earthquake zones. Some people are too poor to leave their home (especially in LEDCs) – also poor education does not explain why they should move further away

• Even when people can afford to leave the area they may be too attached to their homes to leave. Their families have been there for generations.

• And there are so many people living in these dangerous areas, that it would difficult if not impossible to re-house them, especially as many areas – like those near Pinatubo - that provide food for so many other people.

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Science is getting betterScience is getting better• People feel safer with technological advances • Monitoring equipment that can foretell volcanic activity • They can measure

the escape of gas (sulphur dioxide – bad egg smell) Small earthquakes which act as a warning Swelling of the sides of the volcano also warns of things to come

• Quakeproof construction techniques are becoming more advanced.

• But so far we are no closer to being to time earthquakes accurately but building resistant structure is improving.

• But foretelling the effect of tropical storms is improving all the time. At last those who feel the impact are becoming better at constructing defences and saving the lives of those who live in its path.

• The building techniques are improving too.

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Looking at tropical stormsLooking at tropical storms•There are no all embracing positives

with living close to an area subject to hazards, as is the case with volcanoes.

•So what you need here is examples of as many different reasons that have an influence of at least one group in at least 2 or 3 places!

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Tropical stormsTropical storms• Physical/

environmental• They don’t happen

often• Many of the places

have reasonable rainfall and are warm

• Many have useful land, near the sea – good for fishing

• Human/Social• Links to family• Links to culture• Local work• Links to location• Economic• Lack money to move• Farmers – own land• Local resources – fishing• Tourism