Transcript Slide 1
Quick Questions
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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!