AQA A2 Geography
Updating Unit 3
Plate tectonics and associated hazards
David Redfern
Professor David Petley
November 2012
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Programme
9.45am Registration and coffee
10.00am: Requirements of the specification
 Plate Tectonics theory and the evidence used to support it
 Volcanic events: impact and management
 Seismic events: impact and management
 Case studies – depth and detail
11.00am: Morning break
11.15am
Keynote speaker: Professor David Petley (University of Durham).
The Christchurch Earthquake sequence: managing the aftermath of a series of unexpected seismic
events.
12.30pm Lunch
1.30 pm Assessment strategies
 Structured questions – their nature and demands
 Exemplar answers of the above, and the marking thereof
 Synoptic essays – what type of essays can be set
 Exemplar answers of the above, and the marking thereof
3.15pm: Associated skills activities
 Exemplars of materials that can be used to reinforce skills
 Attitudes and values exercises
3.45pm: Day ends
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Plate Tectonics and Associated Hazards
Things to learn
 The structure of the earth. You should know the meaning of the following terms: core, crust
(continental and oceanic), mantle, lithosphere, asthenosphere. Thermal convection currents
operating within the asthenosphere and sea-floor spreading
 Features of constructive (divergent) margins. You should be able to describe and know the
formation of oceanic ridges, submarine volcanic activity and rift valleys
 Features of destructive (convergent) margins. You should be able to know what is happening
at oceanic/continental convergence, oceanic/oceanic convergence and
continental/continental convergence. Features you should be able to describe and know the
formation of include: ocean trenches, fold mountains, island arcs, explosive volcanic activity
 Conservative margins
 Hot spots
 The distribution of volcanic activity
 Intrusive volcanic landforms to include: batholiths, laccoliths, dykes, sills and metamorphic
aureoles
 Extrusive volcanic landforms to include the main forms of lava: basaltic, andesitic and
rhyolitic. Features to include: lava plateaux, basic/shield volcanoes, acid/dome volcanoes/
ash and cinder cones, composite cones and calderas.
 Minor volcanic forms to include; solfatera, geysers, hot springs/boiling mud
 The impact of volcanic activity. You should be able to differentiate between primary effects
(tephra, pyroclastic flows, lava flows, volcanic gases) and secondary effects (lahars, flooding,
tsunamis, volcanic landslides, climate change)
 The focus and epicentre of earthquakes
 Distribution of earthquakes
 Magnitude and frequency of earthquakes
 The impact of earthquakes. You should be able to differentiate between the primary effect of
ground shaking and the secondary effects of soil liquefaction, landslides/avalanches, effects
on people and the built environment
 The nature and effects of tsunamis
Things to understand
The Theory of Plate Tectonics – you should understand how this theory developed and the
evidence that supports it its development and the evidence that supports it
Palaeomagnetism and sea-floor spreading – you should understand how magnetic striping
occurs, the importance of this palaeomagnetic evidence and how this indicates the process of
sea-floor spreading
The process of subduction - you should understand how this process occurs and
and its effects on the edges of both continental and oceanic plates
Vulcanicity - it is important to understand both the causes and nature of volcanic activity
Managing volcanic activity – you should understand how people and authorities are able to
manage volcanic activity. This could come about through your case studies (see below) as
response to an event is a detailed part of your investigation
Causes of earthquakes – you should understand what causes an earthquake and how seismic
waves travelling through the earth give information on the internal structure of the planet
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Measurement of earthquakes – you should understand how earthquakes are measured both in
terms of the instrument used and the scales on which they are recorded (Richter, Mercalli)
Causes of tsunamis – you should understand how such waves are generated
Managing earthquake activity – as with volcanic activity you should understand how people
and authorities are able to manage earthquake activity. This, again can come through case
studies
Case studies that need to be covered
 You are required to make two case studies of recent volcanic events. Recent, in this case,
means ideally within the last 30 years. The two events should be taken from contrasting
areas of the world. The best solution to these instructions is to choose one from a developing
country and one from a developed area. In this way you can best bring out the differences in
impact and the way in which the people/authorities coped with volcanic events. In each case
the following should be examined:
The nature of the volcanic hazard, i.e. the way in which the eruption took place
The impact of the event
How people and the authorities (local and external) responded to the hazard
 You are also required to make two case studies of recent seismic events, i.e. earthquakes.
Recent, in this case, means ideally within the last thirty years. The instructions are exactly
the same as those for the volcanic events above. In each case, though, the following should
be examined:
The nature of the seismic hazard, i.e. the strength of the earthquakes and any particular
features of it such as depth, ground acceleration, etc.
The impact of the event
The preparation within the area, and how people and authorities (local and external)
responded to the event
Good examples of events on which you could base your case studies include: Volcanic
activity – Montserrat (1995-96), Mt Etna (1991-93), Nyiragongo (2002) and Mount Merapi
(2010)
Earthquakes – Kobe (1995), Gujurat (2001), Sumatra (2004), Kashmir (2005) and Sichuan
(China) (2008). These events happen all the time and so it is very important to keep up with
the information. Case studies in text books and other publications will be the best the
authors can find for you up to the moment that everything goes to print. As geography
students it is very important to search out new events and use the information that you have
collected, in the examinations. Examiners will always credit at a high level, in this context,
students who make attempts to keep their work as up to date as possible. In recent times,
there were two very large earthquakes which were very well documented, those in Haiti,
Chile, Christchurch, Lorca and the Japanese tsunami. Try to find as much information as you
can about these events and their impact on the peoples of both countries. Do the same for
any volcanic or earthquake events that happen during the time before your exam.
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Questions
Here are a number of short to medium questions which can help in making sure that you have
understood the subject content of this section.
1. Explain the terms “lithosphere” and “asthenosphere”.
2. What are the differences between oceanic and continental plates?
3. When Alfred Wegener published his theory of continental drift, how did he describe the
distribution of land and ocean? Why did his theories fail to gain any real acceptance before the
1950s?
4. What was the original geological/biological evidence that Alfred Wegener used in his attempt to
show that the continents had drifted apart?
5. What is sea-floor spreading?
6. How does the study of palaeomagnetism show the evidence for sea-floor spreading?
7 Transform faults are associated with sea-floor spreading. How are transform faults created?
8. Study Figure A which shows what happens in continental areas when plates move apart.
Complete the diagram by adding labels to show what is taking place.
9. Explain the process of subduction.
10. Study Figure B which shows what happens when an oceanic plate meets a continental plate at a
point of convergence. Describe and comment on what is taking place.
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11. What happens when two continental plates meet?
12. What happens on conservative margins?
13. How do hot spots form?
14. Describe the distribution of volcanic activity on a global scale.
15. Describe the appearance and formation of shield volcanoes.
16. Draw a cross-section of a composite volcano and describe what happens during an eruption.
17. Describe the minor features that volcanic activity can produce.
18. What are the primary effects of a volcanic event?
19. What is a lahar?
20. How can tsunamis be generated by volcanic eruptions?
21. What causes an earthquake?
22. What information do seismic waves give us that helps in an understanding of the Earth’s
interior?
23. Explain the global distribution of earthquakes.
24. What is the Richter scale?
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25. Explain the process of soil liquefaction.
26. Describe the effects that earthquakes may have upon people and the built environment.
27. What determines the impact of a tsunami?
28. How have people sought to manage the volcanic hazard through prediction?
29. How can people and authorities attempt to lessen the impact of earthquake events?
30. Does your chance of surviving a volcanic eruption or an earthquake depend on your level of
wealth?
Variations in the type of volcanic activity in relation to types of plate margin and types of lava
Plate margin
Destructive
Hot spot
Constructive
Magma source
A chaotic mix of old
oceanic plate, ocean
sediments,
continental
fragments, often
weathered by water
Deep in the
asthenosphere
(mantle )
Deep in the
asthenosphere
(mantle )
Rock name
Andesite / Rhyolite
Basalt / Gabbro
Basalt / Gabbro
Magma chemistry
Medium to high
Acid, greater than
63% SiO2 (examples
granite and rhyolite)
Quite basic(alkali),
sometimes relatively
rich in sodium and
potassium ( alkaline)
low silica ( 50% )
Very basic (alkali)
Basalt low silica 45 52% and typically
high iron magnesium
Magma’s physical
character
Viscous, (solidifies
quickly) flows over
short distances ,
solidifies even on
steep slopes, allows
gases to build up
pressure – can
violently explode.
Quite non-viscous
(fairly runny), flows
over low angled
slopes or can erupt
as an ash.
Very non-viscous
(runny), flows long
distances over very
low angled slopes or
can create a black
ash (tephra) when
exploding with water
vapour (steam)
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The Sichuan earthquake and its aftershocks
The Sichuan quake of May 2008 was one of the most destructive on record. Although Sichuan
province is densely populated, tectonically unstable and earthquake-prone, the scale of the
destruction suggests other reasons for the disaster. Contrary to the Chinese government’s view,
there is strong evidence that infringements of China’s seismic building code made the region
especially vulnerable to a major earthquake. If this were the main cause of a disaster that killed
nearly 90,000 people and cost was $US150 billion, it suggests that the Sichuan quake was as much
the result of human factors as tectonic forces.
Tectonic background
On May 12th 2008 the province of Sichuan in central China was struck by a 7.9Mw earthquake. This
powerful quake had its focus just 19km below the surface, and was one of the most destructive in
recent history. It devastated a large area around the epicentre causing up to 90,000 deaths, injuring
375,000 people and making five million homeless.
Sichuan province is tectonically unstable and has a long history of earthquake activity: in 1933 a
7.5Mw quake killed more than 9,300 people. At the macro-scale, tectonic instability results from the
collision between the Indo-Australian plate and the Eurasian plate. In Sichuan this caused local
convergence between the Tibet Plateau and the Sichuan Basin. On May 12th stresses in the crust
triggered a sudden movement along a thrust fault on the northwest margin of the Sichuan Basin,
releasing powerful earth tremors across the region.
Earthquake impact
Severe ground shaking was the direct cause of death, injury and the catastrophic destruction of
housing, schools, hospitals, dams, power lines, roads and other infrastructure. An estimated 5.4
million buildings collapsed, and further 21 million were damaged. School buildings suffered massive
damage. In total, 7,000 classrooms were destroyed, killing 10,000 students. Chengdu, the capital of
Sichuan province was badly shaken, though compared to Dujiangyan City, close to the epicentre, it
escaped lightly. The scene in Dujiangyan was one of total devastation: most buildings were reduced
to rubble and bodies lay in the streets. Fewer than 60 out of 900 children survived when a three
storey school building collapsed. In the mountains the quake triggered mass movement and slope
failure. The town of Beichuan was partly buried by landslides and at least 700 were killed by a
landslide at Qingchuan. Landslides also blocked river valleys, creating 34 temporary barrier lakes.
Rising water levels on the largest barrier lake (Tanigiashan Lake on the Jian River) threatened to
breach the temporary earth dam forcing the authorities to evacuate 250,000 people downstream
to higher ground. Eventually an artificial channel, completed on June 7th, drained the lake.
The aftershocks – who or what was to blame?
Two things can explain the impact of earthquakes and other natural hazards on society: exposure
and vulnerability. In the context of earthquake hazards, exposure comprises the magnitude of the
quake, and the number of people living around the epicentre. Overall, exposure in Sichuan is high.
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We know that the region is tectonically active and that major earthquakes have occurred in the
past. Add to this the 15 million people that live close to the epicentre, (including 4 million in the
regional capital, Chengdhu) and it’s hardly surprising that the 2008 quake was a major disaster.
But the region’s high exposure is not the whole story. Other parts of the world such as southern
California and Japan have equally high exposure, yet it’s unlikely that even a 7.9M w quake could
cause so much death and destruction. For instance, the 1994 quake at Northridge (6.7M w) in the
outer suburbs of Los Angeles caused just 57 deaths. Even the Kobe quake in Japan (6.9M w) in 1995
had a death toll only a fraction of that in Sichuan.
The fact is that despite the magnitude of Sichuan quake, the ensuing disaster was exceptional in its
severity. Any inquest into why the quake was so deadly leads to one conclusion: the people of
Sichuan were extremely vulnerable to earthquake hazards. Vulnerability concerns preparedness
and the human response to hazards. The risks increase significantly in societies that are
inadequately prepared for natural hazards.
So why was Sichuan so vulnerable? The evidence seems to point to the poor design and shoddy
construction of so many buildings. True, since 1976 China has had a stringent earthquake building
code. Under China’s seismic intensity scale (1-12) the Sichuan region was classed as 7 – a high
enough risk to make the code mandatory for all new buildings. Essentially the code requires
builders to add steel to concrete and brick structures. Steel strengthens buildings and makes them
ductile, allowing them sway with ground shaking. Without it, buildings are brittle and easily snap
and collapse. Of course, before the quake, millions of buildings in Sichuan pre-dated the 1976 code.
These older buildings were mainly low-rise masonry constructions without steel reinforcement.
Concentrated mainly in poorer rural areas, these buildings were the most vulnerable. In the quake
hundreds of thousands simply collapsed, killing their occupants.
Even so, thousands of modern buildings, constructed under the 1976 regulations also failed,
suggesting widespread violation of the building code. Building failure was due to a combination of
severe ground shaking, poor design (especially lack of steel reinforcement) and the use of
inadequate construction materials, including inferior concrete. To save money, builders often failed
to use the appropriate amount of steel. Evidence of the laxness of building regulations was most
evident in the collapse of so many schools. This caused outrage among bereaved parents because
while schools collapsed, adjacent buildings often remained intact.
Chinese officials blamed the magnitude of the earthquake for the disaster. But local people claimed
the disaster was largely man-made: the result of substandard building work, corruption and lax
enforcement of building regulations. Their anger led to numerous public protests. According to the
New York Times parents campaigning for justice have been harassed by police, detained and
threatened with imprisonment. Others have been silenced by government promises of financial
compensation, including one-off payments and pensions.
Nor does discussion of human responsibility for the disaster stop with the quake’s impact. New
research suggests that human activity could even have contributed to the quake’s cause. It is well
documented that large dams can trigger earthquakes. Chinese and overseas experts have pointed
to the Zipingpu Dam, completed in 2006 and only 5km from the epicentre of the quake. They argue
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that the sheer weight of water in the dam – 315 million tonnes – could have weakened the thrust
fault, increasing the stresses and causing it to rupture.
Reconstruction
Response to the disaster by the Chinese government has been swift and decisive. China has
committed £800 million immediately to strengthening the 2,600 schools that remained standing.
However, the total bill for reconstruction will be $US150 billion, a figure which is even higher than
the $US120 reconstruction of Kobe in 1995. Priority will be given to building nearly 4 million new
homes, creating one million new jobs, and constructing high-quality buildings that are earthquakeproof. The reconstruction plan includes 169 new hospitals and nearly 4,500 new primary schools to
be built in Sichuan and neighbouring Gansu and Shaanxi provinces, which were also hit by the
quake. Three million homeless rural families will get new houses, and 860,000 city apartments will
be built. Welfare programmes will be expanded to help the 1.4 million people driven to poverty by
the disaster. The ultimate aim is to create an earthquake-resistant society, making Sichuan less
vulnerable in future.
Questions on the case study (Sichuan), introducing Stretch and Challenge
1. Describe and explain the causes of the Sichuan earthquake.
2. With reference to the Sichuan quake, explain the difference between the exposure and
vulnerability to earthquake hazards.
3. In what sense could the Sichuan earthquake be regarded as a man-made disaster?
4. Discuss the view that poverty is the real killer in earthquake disasters.
5. To what extent can it be argued that the impact of earthquakes is greater in rural than in
urban areas?
6. ‘The impact of earthquake hazards depends primarily on physical factors.’ Discuss.
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Mount Merapi – the ignored ‘mountain of fire’?
Cascading streams of lava, giant ash clouds that affect air travel, lahars pouring down river valleys,
mass evacuations and yet people refusing to leave the area following warnings, bodies encased in
hot ash, looting after the event, lives and livelihoods destroyed – all sound familiar? These are
classic characteristics of volcanic eruptions that have taken place around the world over time –
Etna, Eyjafjallajokull, Pinatubo, St Helens, Pompeii – and yet they all occurred in late 2010 during
one series of volcanic eruptions in Indonesia – which hardly gained a mention in the world’s media.
Mount Merapi is an active strato-volcano located in central Java. It is the most active volcano in
Indonesia and has erupted regularly since 1548. It is located approximately 28 km north of
Yogyakarta city, and thousands of people live on its flanks, with villages as high as 1,700 m above
sea level. Merapi is situated at a subduction zone, where the Indo-Australian plate is sliding
beneath the Eurasian plate. Stratigraphic analysis reveals that eruptions in the Merapi area began
about 400,000 years ago, and from then until about 10,000 years ago, eruptions were typically
effusive, and the out-flowing lava emitted was basaltic. Since then, eruptions have become more
explosive, with viscous andesitic lavas often generating lava domes. The collapse of these domes
has often generated large pyroclastic flows which cause further damage.
The name Merapi is loosely translated as 'Mountain of Fire'. Smoke can be seen emerging from the
mountain top at least 300 days a year, and several eruptions have caused fatalities. Hot gas from a
large explosion killed 27 people in November 1994, mostly in the town of Muntilan, west of the
volcano. Another large eruption occurred in 2006, shortly before the Yogyakarta earthquake.
Merapi therefore poses a significant risk the populated areas around it.
In late October 2010 the Centre for Volcanology and Geological Hazard Mitigation, (CVGHM),
reported that a pattern of increasing seismicity from Merapi had begun to emerge. Lava from
Mount Merapi began flowing down the Gendol river valley on 23–24 October signalling the
likelihood of an imminent eruption. On 25 October the Indonesian government raised the alert to
its highest level and warned villagers in threatened areas to move to safer ground. Over 75000
people living within a 20 km zone were told to evacuate. Officials said about 500 volcanic
earthquakes had been recorded on the mountain over the weekend of 23–24 October, and that the
magma had risen to about 1 km below the surface due to the seismic activity. On the afternoon of
25 October lava erupted from its southern and southeastern slopes. There were reports of panic at
some refugee shelters as hundreds of people fled from them. On 25 October the Indonesian
government raised the alert to its highest level and warned villagers within a 10km zone to move to
safer ground. The evacuation orders affected at least 19,000 people; however, the number that
complied at the time remained unclear.
Merapi is usually surrounded by beautiful verdant green countryside. When the volcano started
spewing hot clouds, buildings, cars, trees and paddy fields were covered in a layer of fine dusty ash,
lending everything an eerie grey sheen. Merapi also holds particular significance for the Javanese
beliefs; it is a sacred mountain. To keep the volcano quiet and to appease the spirits of the
mountain, the Javanese regularly bring offerings. In addition, the sultan appoints a spiritual
guardian to manage the mountain’s eruptions.
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The spiritual guardian of the mountain is believed by local people to have the power to speak to the
spirits of Mount Merapi. In October the guardian was Mbah Maridjan, the latest of a line of such
guardians in his family. He led ceremonies to appease the spirits of the volcano by presenting them
with offerings of rice and flowers in and around the crater. He described his job, for which he was
paid $1 a month, as being ‘to stop lava from flowing down; let the volcano breathe, but not cough.’
Javanese culture is full of mysticism and Maridjan took his job seriously. Too seriously perhaps?
Maridjan lived only about 5 km from the peak in his home village of Kinahrejo. Many villagers
believed that he would be warned in a vision if an eruption was imminent. In 2006, he refused to
leave his village despite an evacuation order after scientists warned of an imminent eruption. He
went with fifty other men to the village mosque when the volcano began to erupt. Following his
example, a hundred other families also refused to evacuate. He was badly burned in a subsequent
blast and spent five months in hospital after being rescued from his collapsed house. Maridjan
again refused to evacuate prior to the 26 October eruption, telling a friend that he could not leave
because he had a responsibility, and that because ‘my time to die in this place has almost come, I
can't leave.’ Thirteen other people, who were in his home trying to persuade him to leave, were
killed along with him when his house was hit by a pyroclastic flow. Only the mosque in his village
was left standing. Maridjan's body was found in a praying position; he was thought to have been
killed instantly by the 1,0000C cloud of gas and ash.
Heavy rain during the night of 3–4 November triggered lahars with mixtures of water and rock
debris cascading down the numerous rivers on the slopes of the volcano. The eruption on 4
November was reported as being five times stronger than the initial eruption on 26 October. Heat
clouds of 600 to 8000C spread as far as 11km from the crater reaching toward the edge of the then
15 km exclusion zone, and lava flowed into the mountain’s rivers.
Merapi erupted again early on 5 November. Due to continuous large eruptions of ash, the
government extended the safety zone to 20 km radius and Yogyakarta's airport was closed. The
eruptions and subsequent volcanic ash plumes caused disruption to aviation movements across
central and western Java. Some flights to and from Bandung, Jakarta and Solo were also affected
and some international and domestic airlines suspended operations into and from those cities.
Bronggang, a village 15 km from the crater, had streets blanketed by ash up to 30cm deep. 100,000
people had to be evacuated and the scientists monitoring the events were withdrawn from their
posts to a safer distance. Aid agencies attempted to respond quickly, for example they:



distributed hygiene kits to families who sought refuge in temporary shelters
provided face masks to children in schools and to evacuees in camps
brought in additional supplies, including tarpaulins and tents from warehouses in Jakarta
and elsewhere
After a period of multiple eruptions on 10 November the intensity and frequency of eruptions was
noticed to subside. By this time 153 people had been reported to have been killed and 320,000
were displaced. Ash continued to spread over western Java and was falling just short of Jakarta. On
the morning of 11 November the volcano was ejecting ash 1,000m into the air. The volcano was
observed by the Ozone Monitoring Instrument (OMI) on NASA’s Aura spacecraft and imagery
indicated that a sulphur dioxide plume had been released into the upper troposphere. The Volcanic
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Ash Advisory Centre in Darwin, Australia, also reported a sulphur dioxide cloud over the Indian
Ocean between 12,000 and 15,000m, in the upper troposphere.
By 18 November the death toll had increased to 275. Most of these were reported as being killed
by searing gas clouds and from respiratory complications and burns. Some victims died in road and
other accidents during the panicked exodus from the mountain. The toll had risen to 353 by 3
December when the mountain began to calm.
Why did such a classic and devastating volcanic eruption receive so little coverage? In a world
dominated by 24 hour news, was this just another disaster affecting a far-away place? Or was it
because no-one from the developed world was affected, and therefore was not important? Should
there be better technology and disaster management planning for the developing nations for this
sort of event? Whatever the answers to these questions, the Mount Merapi eruptions of 2010
make a fascinating study of the interplay between a physical event and its effects on human
activity.
Questions on the case study (Mount Merapi), introducing Stretch and Challenge
1. Discuss the view that the impact of volcanic hazards depends primarily on human factors.
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




Answer plan:
Discussion of the concept of a hazard and the distinction between physical and human
factors.
An understanding of human factors: population density; poverty; infrastructure, disaster
planning.
An understanding of physical factors: magnitude; speed; nature of eruption, extent.
Variations in the resilience to respond to/manage impacts
A critical understanding of the vulnerability of different regions, particularly an
understanding of the differences between richer and poorer areas and the contrast
between urban, rural and remote environments
Detailed and appropriate use of case studies throughout
2. To what extent can preparedness and planning mitigate the effects of volcanic hazards?
3. Evaluate how plate tectonics theory helps our understanding of the distribution of seismic
and volcanic events?
4. Natural disasters are not that; they are human disasters. Discuss.
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What caused the 2011 Japanese earthquake and tsunami?
The surface of the Earth is formed from continental-scale tectonic plates that are able to move. The
rates at which they actually move are slow — typically just a few centimetres per year, barely faster
than the rate at which our fingernails grow — but these movements are enough to generate the
devastating earthquakes that we occasionally experience. The various islands that form Japan have
been created by a collision between four tectonic plates (Figure 1).
Why does Japan have earthquakes?
The Japanese landmass itself sits on two continental plates — the northern part of the country lies
on the North American plate, while the south is on the Eurasian plate. To the east of Japan are two
oceanic plates — in the north is the Pacific plate, while to the south lies the Philippine plate. The
two oceanic plates are both moving in a generally westward direction at a rate of a few centimetres
per year. The zones at which the plates collide lie on the seabed to the east of Japan (Figure. 1) and
are marked by deep ocean trenches. At this point the oceanic plates are being forced under the
continental plates: this is the process of subduction. The contact surfaces — termed a fault —
between the plates are not smooth, meaning that the plates tend to stick together. The underlying
plate movement, which is driven by the generation of heat deep in the Earth, does not stop when
the plates are stuck. As a result, energy is stored within the rocks around the contact between the
plates, much in the way that energy is stored in an archer’s bow as she pulls back the string. In
general, the longer the time-gap between release events, the larger the amount of energy that is
stored. At the same time, the overlying (upper plate) is pulled downwards by the ongoing
movement of the continental plate. Eventually, sufficient energy is stored in the rocks to overcome
the friction between the plates, resulting in a sudden movement on the fault. This is the
earthquake. As this movement occurs, the stored energy is instantaneously released, creating
waves of earth movement that radiate outwards to cause such destruction. The overlying plate
pops back up again (Figure 2), lifting the seabed, and the overlying water, by several metres. A huge
volume of water is now higher than the surrounding sea, and thus flows outwards to generate a
tsunami. This is the process that occurred off eastern Japan on 11 March 2011.
Figure 1
Figure 2
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The Sendai earthquake
The earthquake in Sendai occurred on the fault that marks the boundary between the Pacific plate
to the east and the North American plate to the west. This area is known to have earthquake
activity, and indeed has been subject to large numbers of earthquakes in the past. However, this
section had not experienced a very large earthquake during the period in which instruments have
been recording seismic activity, suggesting that the plates were locked together. Indeed, the recent
earthquake activity in this area is lower than that to the north and south, which suggests that large
amounts of energy were stored in the plates, waiting to be released. The earthquake caused the
plates to move over a distance of at least 10 metres, and possibly much more, over a length of fault
that is about 400km from end to end. This resulted in a very large earthquake, now considered to
have been magnitude 9.0 on the Richter scale (meaning that it is the fourth largest earthquake ever
recorded). In this area, the Japanese landmass moved by up to 4 metres towards the east, and in
the area of the fault the seabed was uplifted by several metres, generating the catastrophic
tsunami.
Figure 3
After the earthquake
After large earthquakes, the stresses in the crust are left in an unevenly distributed state. This
always results in further earthquake activity over the following months and even years — this is the
so-called aftershock sequence. These aftershocks are quite intense initially — in the hours after the
earthquake typically occurring every few minutes — and then reduce as time passes. Typically, the
largest aftershock is a little more than one unit down on the magnitude scale — so for a magnitude
9.0 earthquake, we would expect to see one aftershock with a magnitude of about 7.8, and many
more smaller ones. However, there is no hard and fast rule about the largest aftershock, which can
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be a little larger than this, or substantially smaller. A magnitude 7.8 event is a large earthquake in
its own right and those living in the areas affected by the main earthquake needed to be prepared
for the possibility of such an event. However, it should be remembered that in terms of energy
released by the earthquake, one step up the earthquake magnitude scale represents an increase in
energy release of 33 times. A magnitude 9 earthquake is 33 times greater than one with a
magnitude of 8. So the aftershocks should have nothing like the destructive potential of the main
shock on 11 March. By May 2011, the largest aftershock had been magnitude 7.1. It reportedly
killed four and injured over 140 people.
The Christchurch earthquake
New Zealand’s location on the Pacific ‘Ring of Fire’ makes it particularly susceptible to tectonic
hazards. The country’s wealth, sophisticated monitoring systems and small population of 4.4 million
mean that it is much less vulnerable to the impacts of natural hazards than countries such as Haiti.
The earthquake which struck New Zealand on 4 September 2010 was similar in magnitude to the
one that hit Haiti in January 2010, measuring 7.1 on the Richter scale, compared with the Haiti
earthquake’s 7.0. In New Zealand there were no deaths and only two serious injuries, but Haiti
suffered more than 300,000 casualties and 1.3 million displaced people. Moreover, the disruption
caused by the September earthquake in New Zealand was quickly overcome, but there are still
displaced people, badly damaged buildings and serious problems of sanitation in Haiti. However,
New Zealand was not destined to escape unscathed from the tectonic forces at work in its South
Island. On 22 February 2011 a magnitude 6.3 aftershock of the September earthquake struck the
country’s second largest city of Christchurch, killing 181 people and seriously damaging the city. The
deaths from this earthquake make it the second most deadly natural disaster in New Zealand’s
history, while the estimated cost of rebuilding of around $NZ 15–16 billion will mean it is by far the
country’s most expensive.
New Zealand’s plate tectonics
New Zealand is located along a section of the Pacific Ring of Fire where the Pacific plate is
converging with Indo-Australian plate. Subduction along this boundary is responsible for volcanic
activity in the North Island, which is also the location of New Zealand’s major earthquakes. The
largest of these, with a magnitude of 8.2, occurred near the Wairarapa Plains on 23 January 1855.
New Zealand experiences between 10,000 and 15,000 earthquakes each year, of which around
100–150 are large enough to be felt, with several exceeding magnitude 6. On average magnitude 7
earthquakes occur once every 10 years, while magnitude 8 earthquakes occur once a century. The
South Island is less seismically active than the North Island and experiences fewer earthquakes of a
high magnitude. The September 2010 earthquake was the largest recorded in the Canterbury
region. The interaction of the Pacific and Indo-Australian plates in the South Island has resulted in
the major Alpine and Hope fault lines. It is movement along these faults, strike-slip faulting, and
numerous smaller faults that causes the South Island’s earthquakes, including the deadly February
2011 Christchurch earthquake.
Geology of the 2011 earthquake
The February 2011 earthquake resulted from movement along a previously unknown fault line
running approximately east–west and located to the southeast of Christchurch. A strike-slip fault
resulted in movement both east and west, although there was also upward movement (reverse
thrust) along the fault line. The relatively shallow (5 km) depth of the earthquake meant that, even
though its magnitude was lower, it was much more destructive than the 2010 earthquake. The
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February earthquake’s epicentre, in the Port Hills, 10 km southeast of the centre of Christchurch,
was also much closer to the city (Figure 1). It seems likely that the February earthquake was an
aftershock of the 2010 earthquake, although some geologists consider that it was a separate event
because it occurred along a separate fault. The February earthquake itself has produced over 300
aftershocks, the largest of which, in June 2011, again measured magnitude 6.3. Both the location of
the epicentre and the geology of the Canterbury Plains on which Christchurch is located
compounded the destruction caused by the earthquake. The hard volcanic rocks of the Port Hills
resulted in seismic energy being reflected back up to the surface. In addition, the fault line which
ruptured lies below the alluvial sediments of the Canterbury Plains. Because groundwater levels
were close to the surface, ground shaking during the earthquake caused liquefaction, which in turn
led to significant damage to buildings and infrastructure.
Hazard planning and mitigation in Christchurch
As would be expected, given New Zealand’s wealth and its experience of destructive earthquakes,
the country is well prepared for seismic hazards. A national network of instruments and data
centres, GeoNet, detects and monitors earthquakes and other hazardous events, and can provide
information to emergency services within minutes of a major earthquake. Funding for GeoNet is
provided by an Earthquake Commission, established by the government to provide earthquake
insurance to homeowners. The commission is also responsible for public education, including a
campaign designed to encourage New Zealanders to ‘Quake Safe’ their homes. New Zealand
adopted a building code for earthquake-resistant buildings as early as 1935. Codes are designed to
protect buildings from structural damage during moderate earthquakes and, in the case of major
earthquakes, to ensure that buildings do not collapse and people can escape, even if a building is
badly damaged. Older buildings have had to be reinforced, although only in the more earthquakeprone North Island. In the South Island, such strengthening was not seen as essential, so
Christchurch’s heritage buildings were much more vulnerable.
The impact of the earthquake
New Zealand’s preparedness was not able to prevent the deadly consequences of the February
earthquake for a number of reasons:
 The shallow focus and the relative proximity of the epicentre to Christchurch meant that the
effects measured 8 on the modified Mercalli intensity scale.
 Many buildings had already been weakened by the September earthquake
 The earthquake occurred on a Tuesday at 12.51 p.m., so the city centre of Christchurch was
crowded. The peak ground acceleration was 1.8 times the acceleration due to gravity. The
shaking intensity this caused in central Christchurch led to enormous damage to the city’s
buildings, around half of which were destroyed or severely damaged. Most disastrously, the
six-storey Canterbury Television building collapsed, killing 85 people. The six-storey PGC
House also collapsed, killing 18 people, and Christchurch’s tallest building, the 26-storey
Hotel Grand Chancellor, was displaced half a metre by the earthquake, and had to be
demolished. In total, more than 100,000 homes and other buildings in Christchurch were
severely damaged or destroyed by the earthquake, and more than 100 additional buildings
were damaged beyond repair by an aftershock in June 2011.
Liquefaction
Liquefaction was widespread and severe in Christchurch (Figure 2). It has always posed a risk to
Christchurch as large parts of the city are underlain by soft sediments, but the problem in 2011 was
exacerbated by the unseasonably high water content of the substrata. As the name implies,
liquefaction is a natural phenomenon that occurs when soils behave like a liquid and not a solid. A
number of conditions determine the likelihood of soils liquefying during an earthquake. These
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include soil properties such as grain size, the water content of the soil and the severity of the
earthquake. During an earthquake the individual soil particles become re-arranged. The resultant
shrinkage of the pore spaces causes water to be squeezed out. In built up areas liquefaction can
result in the destruction of infrastructure such as roads, pavements and underground pipes .
Rupturing of pipes in Christchurch resulted in many schools being closed even though the buildings
were relatively intact. Because the soil mass becomes compacted and decreases in volume,
subsidence is common. The ground can also shift sideways, a process known as lateral spreading.
Preventative measures
The most common way to reduce the impact of liquefaction is to increase the strength of
foundations. This can involve sinking deeper piles. Part of the AMI Stadium, for example, was
reinforced by a vast network of 10 m stone columns covering an area of over 12,000 m2.
Unfortunately, even this was not enough to prevent subsidence of two stands by around
40 cm. Structural engineers are now considering driving piles down 25 m to reach solid ground.
The February earthquake also resulted in significant slope failure in the south-eastern upland Port
Hills area. The volcanic rocks forming this southern region have steep slopes. Some are remnants of
ancient sea cliffs and are almost vertical. These areas experienced rock and debris falls that caused
both fatalities and considerable damage to properties adjacent to the cliff base.
Reconstruction
Following the September 2010 and February 2011 earthquakes, the government established the
Canterbury Earthquake Recovery Authority to spearhead the reconstruction of Christchurch. The
estimated cost is £13 billion. The city has been divided into four zones based on the amount of
damage, the cost of rebuilding and the ability of the land to sustain future earthquakes.




The worst affected residential area, the Red Zone, extends along the banks of the River Avon from
the Bexley wetlands at the Avon estuary to Avonside, close to the inner city. Land in this zone
suffered considerable lateral spreading associated with liquefaction. The government has agreed to
buy over 5,000 of the worst-affected insured properties or the land on which they are built, based
on the 2007 rateable value. Under the scheme these homes could not be repaired for at least 3
years.
In the Orange Zone there are another 10,000 homes, the fate of which is uncertain until further
geotechnical investigation is completed.
About 100,000 homes are located in the Green Zone and these are likely to be rebuilt.
The process for assessing the White Zone, which includes Port Hills and the central business district,
has yet to be fully developed.
The demographic impact
It was widely reported after the earthquake in Christchurch that 70,000 people had fled the city.
However, research on the impact of natural disasters in developed countries would suggest that
after 12 months a city of the size of Christchurch (380,000) is likely to have lost only about 10,000
people through outmigration. Before the earthquakes of 2010 and 2011, Christchurch had
population growth of about 12,000 a year, mainly due to in-migration. Statistics New Zealand had
projected this trend to continue for the next two decades. The rate of increase is now likely to be
lower. Some sectors of the city’s economy have suffered enormously but that could be partly offset
by new activity in the construction sector. Indeed, 6 months after the earthquake, although
unemployment had risen, it was still below the national average.
http://www.christchurchquakemap.co.nz
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Figure 1
Figure 2
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Fault lines within Turkey?
In late October and again in mid November, the world watched the harrowing scenes as earthquake
survivors were plucked from the ruins of the towns of Ercis and Van in eastern Turkey. Apart from
the familiar pictures and stories of rescue, survival and despair, what made these earthquakes and
their aftermath particularly interesting?
The geological background
The first earthquake struck close to the Iranian border, early afternoon on 23rd October. The U.S.
Geological Survey estimated its magnitude at 7.2. The second on 9th November struck in the
evening, magnitude 5.6. This seismically active region experiences many destructive quakes, due to
the collision of the Arabian and Eurasian Plates. The motion of these plates toward each other
squeezes a large piece of the continental crust known as the Anatolian Block creating two mountain
ranges, the Zagros and Alborz. These are the geological factors – but from a geopolitical
perspective, the region lies solidly within ‘Kurdistan’.
The ethnic dimension
The Kurds are said to be the largest ethnic group in the world without a country of their own. They
live across the borders of Iraq, Iran, Syria, Turkey and parts of the former Soviet Union – Armenia,
and Azerbaijan. It is estimated that they number 40 million, including those who have moved to
other parts of the world. They are unlike the Turks, Arabs or Persians, who form the majority
populations in the countries in which they live. They have a separate language, culture, and history,
but currently live, sometimes without recognition, in these countries. Their culture and identity
have often been oppressed by the regimes of the nations within which they live.
The national political dimension.
Politically there are several groups in the area representing the views of the Kurdish population,
some more extreme than others. At the more violent end of the spectrum is the outlawed
Kurdistan Workers’ Party (PKK), an armed group that has been fighting for autonomy since 1984.
The PKK had escalated its battle in recent months, killing 24 soldiers in an attack south of the city of
Van. The government responded with a wave of air strikes against PKK bases in Kurdish-controlled
northern Iraq, and an incursion of about 1,000 ground troops. Turkey says that 270 PKK rebels have
been killed since August 2011.
The national government’s response to the earthquake disaster in October was quick and effective.
Yet the prime minister acknowledged that a shortage of tents had left hundreds of thousands of
victims vulnerable to the rain and cold. Some of these had taken to looting aid convoys in search of
shelter. However, the more moderate pro-Kurdish BDP (Peace and Democratic Party) has accused
the national government of seeking to manage aid efforts for political gain – to show it in a
favourable light. The BDP is sympathetic to the cause of Kurdish autonomy and almost 4,000 BDP
activists, including 14 elected mayors, have been arrested since 2009.
On the other hand, some Turkish nationalists support the actions against the PKK and the BDP. In
Elazig, a town to the east, a mob attacked a Kurdish neighbourhood, raising the spectre of intercommunal violence. Some have gloated that the earthquake was ‘divine punishment’ for the Kurds.
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The local political dimension
Some commentators have also criticised inadequate controls over building standards prior to the
quake, which caused many buildings to collapse and kill hundreds of people. Some have said that
the contractors who built them, the municipal officials who issued licences and the controlling
engineers who signed them should be found, exposed and tried as a deterrent to others.
This has happened before. In 1999, two powerful earthquakes shook north western Turkey killing
thousands of people and causing heavy damage to the economy. In October 2004, a Turkish builder
was jailed for 25 years for negligence that resulted in the deaths of nearly 200 people in one of
those earthquakes. It was said that the disaster exposed high levels of corruption in Turkey's
building sector. The builder was accused of using improper practices - such as mixing sea sand and
pebbles with concrete. As a result, the country imposed stricter building codes, but did they work?
There are many tensions related to the recent earthquake in Turkey – geological, ethnic and
political, both regionally and locally. What can be done, and what will be done? Sometimes it takes
a tragedy to occur for politicians to act.
Activities.
1. The Kurds form a significant ethnic minority within Turkey, and appear to have suffered greatly in
the Turkish earthquakes in 2011. To what extent is it common for ethnic minorities to be more
vulnerable to the impacts of natural disasters?
2. Since the earthquakes occurred, there have been calls from within Turkey for reconciliation
between ethnic Turks and the Kurds. How likely is this to occur?
3. A wider geopolitical issue concerns the links between Turkey, the USA and Israel. You could
investigate these relationships in the contexts of relief efforts to both Turkey and to the Palestinian
territory Gaza.
Weblinks to follow up:
On the themes of Turkish/Kurdish reconciliation and wider geopolitical issues:
http://www.guardian.co.uk/commentisfree/2011/oct/27/earthquake-turkey-kurds-bring-peace
http://www.time.com/time/world/article/0,8599,2098136,00.html
http://www.bbc.co.uk/news/world-europe-14844902
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Assessment strategies
June 2010
Question 01
Study Figure 1, a photograph of an area in northern Pakistan after a recent earthquake. Using
Figure 1 only, comment on the evidence that suggests that an earthquake has recently taken
place.
7 marks
Mark scheme
Level 1: simple listing of features from the photograph such as landslides, tented community,
military lorries etc. with no commentary on any aspect.
1-4
Level 2: commentary on the nature of the evidence as seen. Some sophistication of description,
and/or evidence of geographical thinking.
5-7
Candidate A
It is clear that an earthquake has recently taken place for a number of reasons. In the foreground
piles of rubble lay where the houses once stood which infers that the earthquake tremors led the
houses to collapse. There are also many tents present as well where local people may now be living
as their houses may have collapsed.
In the background on the mountain side there is little vegetation compared with further up and the
rock appears fresh as if a landslide caused by the earthquake cleared many of the vegetation and
the top layer of the rock away. There are also quite a few trucks lined up on one of the streets
which look like they would not naturally be there. They could be rescue trucks to help evacuate
people out of the area or they could be transporting waste materials from the earthquake eg
rubble away from the area. Also there appears to be extremely few people and animals present in
the picture which could infer that the animals have fled and the people have been evacuated away
from the area due to the earthquake. (7)
Candidate B
From looking at Figure 1 it is clear that the area in question in Northern Pakistan has been severely
affected by an earthquake. The region is prone to many high magnitude events of 7.0 or larger
every year and this is partly due to the collision of the Eurasian plate with the Indian plate thus
indicating a continental/continental convergence. The evidence for a recent earthquake in the area
is shown by the mountain ranges which suggests that a landslide has occurred due to the severe
ground shaking caused by surface seismic waves. Furthermore the area is also deserted with no
sign of human activity which could suggest a high fatality rate or that the residents have tried to
escape the area. Furthermore Figure 1 also indicates that some of the buildings have collapsed
which is another consequence of severe ground shaking and buildings being constructed on
unconsolidated materials beneath. There are also seems to be a high level of smog in the area,
which suggests that underground pipes could have been broken which have led to fires. Finally it is
apparent that many of the trees in the area have shed their leaves which also is a sign that an
earthquake has just struck.
(5)
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Question 02
Describe how seismic waves and earthquakes can be measured.
8 marks
Mark scheme
Level 1: simple references to the scales given above, increasing numbers of the scale, but without
any precision in their use; or detailed explanation of one system only, including technology. 1-4
Level 2: recognition that there is more than one way in which to measure seismicity – by energy
levels, or by impact, or by technology. Some detail is given of more than one system. Also credit
commentary on usefulness if given when in this level.
5-8
Candidate A
Seismic waves and earthquakes can firstly be measured by a seismograph which determines the
strength of the earth’s movements. These readings are displayed on a graph which shows the
intensity and size of the movements. These readings can then be translated to a numerical scale
called the Richter Scale. The Richter Scale is a logarithmic scale from 1 to 10 showing the size of an
earthquake and associating it with the relative dangers of such an event. There is another scale
which measures the intensity of an earthquake on a scale from 1 to 12) with 12 being about 8.5 on
the Richter Scale. The primary waves (P waves) of an earthquake can be measured and cause lateral
movement of the earth’s surface perpendicular to the wave’s direction. Secondary waves (S waves)
cause horizontal movement parallel to the wave’s direction. Surface waves (L waves) are the
slowest and cause both directions of movement. All these types of waves can be measured and
used to predict the associated damage caused with the numerical figure thus showing how seismic
waves and earthquakes can be measured.
(4)
Candidate B
Seismic waves can be measured on a seismograph which records and locates the size of seismic
waves during an earthquake event. Seismographs can be used to help predict an earthquake
epicentre and they can also be used to help predict future earthquake events by determining which
areas are most likely to suffer from structural damage, landslides and soil liquefraction.
Seismographs measure the amplitude of the seismic waves by measuring the distance between
movement of the instrument and the spring which has inertia in it. The degree of movement
between the mass and the rest of the instrument helps geologists and scientists to accurately
measure the magnitude and size of seismic waves. Earthquakes are measured on a Richter scale
which records the magnitude of the event. The Richter Scale is logarithmic and so each unit
represents a 10 fold increase in strength and a 30 fold increase in energy released. So, therefore a
magnitude 7.1 earthquake is twice as big as a magnitude 6.9 event. Moreover earthquakes can be
measured on a 12 point Mercalli scale which reflects the effects of an earthquake. The more severe
the earthquake the more destructive the effects and the higher the score on the Mercalli scale. The
scale however relies on individual interpretations of the effects of an event and not everyone will
agree on its effects eg degree of ground shaking. Finally an earthquake can also be measured on
the moment magnitude scale which is a more up-to-date way of measuring earthquakes by
geologists. However the Richter Scale is still used to show the size of an earthquake for the public
and mass media. (8)
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Question 03
With reference to two seismic events you have studied from contrasting areas of the
world, compare the ways in which earthquakes and their impacts have been managed.
10 marks
Mark scheme.
Level 1: simple statements of management which could apply to any earthquake hazard. No specific
detail provided.
1-4
Level 2: specific statements of management strategies which can be clearly attributed to named
areas and/or earthquakes access this level. Comparison must be clearly recognisable for 7/8 marks.
5-8
Level 3: a fully developed answer, with good elaboration of the management strategy of two
seismic events. A rounded answer with a full comparison of the two events.
9-10
Candidate A
In 2010 seismic activity at the Atlantic and Caribbean plate boundary caused an earthquake on the
island of Haiti. This earthquake was very strong and highly destructive. Haiti is considered one of
the poorest nations on the planet and so naturally there was little infrastructure in terms of
predicting the earthquake or even warning people of the imminent danger. This did not help in its
management. The earthquake destroyed many buildings including homes, schools and hospitals
creating a huge gap in the social needs of the country. Foreign aid was desperately needed as the
people could not fund the clear up themselves. Massive investments from international
governments and non-governmental organisations was called upon. This aid provided temporary
shelter for displaced people, essential food and water needs and some medical support. Disease
spread quickly especially in urban areas where the amount of dead was too much for services to
deal with leading to bodies piling up in the streets. After the event management had to continue to
be funded by the foreign means but for Haiti any preventative or protection schemes are not
feasible. All the people were able to do was rebuild their lives from scratch.
In contrast the 1995 earthquake in Kobe Japan saw a very different style of management. Japan is a
highly developed and industrialised country with economic means to help itself without
international intervention. Although the Kobe earthquake caused massive damage and many
deaths the aftermath of the event was less demanding than that of Haiti. Japan had emergency
provisions in place to reduce the effects for example the able fire crews were able to deal with the
fire which quickly sprung up over the city, especially in the traditional wooden housing.
Furthermore Japan had the economic funds to act on the knowledge learnt from the event. Fire
breaks, gaps in urban areas to stop the spread of fires were installed across the city. Along with
open spaces for people to get to safety away from potentially collapsing buildings. Investments in
new building strategies led to earthquake proof/resistant building capable of withstanding seismic
activity thereby protecting people.
(6)
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Candidate B
The Great Hanshin earthquake or Kobe Japan earthquake took place on the 17 th January 1995 in the
early hours of the morning. The focus was 16km beneath the epicentre on Awaji Island, 20km from
Kobe. The tremors lasted 20 seconds. This earthquake was caused by the destructive plate margin
where the heavier oceanic Pacific plate sank under the lighter continental plate, Eurasian plate,
causing a subduction zone which eventually caused the earthquake. It measured 7.2 on the Richter
scale.
In total 6434 people lost their lives due to the earthquake and many thousands lost their homes.
Many of these people lost their lives due to the poor living conditions in their wooden houses with
most having very heavy lead roofs with up to 2 tonnes of weight on their roofs. In response to this
much stricter building laws were introduced so that not as many buildings would collapse if it were
to happen again. Other measures implemented included installing weights on top of high rise
buildings to stop them swaying as much in future earthquakes and reinforcing buildings with steel
girders again for added support. All these ways of managing the impacts of the earthquake were
quite easy for the Japanese government due to them being a developed country. However a similar
earthquake but in a different part of the world had much larger impacts upon the country.
The Gujarat earthquake in India in January 2001 was extremely devastating and one of the largest
earthquakes in that region of the world for around a 100 years. It caused 20000 deaths and left
around 1 million people homeless. Many died in the aftermath due to lack of resources whereas in
the Kobe earthquake the Japanese were much better equipped to manage the hazard. However,
the Indian government should be commended for them sending in thousands of troops to help with
the clear up as well as food, medicine and tenst for all the people affected, especially as all four
hospitals in Bhuj collapsed.
After the Gujarat earthquake there were fears of the spreading of diseases such as cholera and
typhoid but due to the swift response of the Indian government this did not happen. However,
around 20000 cattle died in the earthquake which severely affected the local people especially
from an agricultural perspective.
After the Kobe earthquake due to the country being more developed they were able to manage the
impacts a little better than in India. Large sums of money were funnelled into research and other
initiatives such as installing rubber on to the underside of bridges so they are less susceptible to
collapse because during the earthquake a lot of the freeways and train tracks collapsed.
Overall both earthquakes were extremely devastating but Japan were much better at recovering
from the impacts even though their total damage costs were around 20 times higher larger (Kobe –
100 billion dollars; Gujarat – 4/5 billion dollars). I believe this is due to Japan being much more
developed and having better plans for when earthquakes strike. Afterwards the Japanese also
introduced particular days of the year dedicated towards earthquake safety and children at school
have regular drills in how to act in an earthquake. This shows how well the impacts have been
managed by the Japanese. The rebuilding of the destroyed port very quickly also shows how well
managed the impacts were. (10)
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January 2011.
Question 01
Study Figure 1, a map showing a variety of tectonic features in the Philippines. Comment on the
degree to which the area of the Philippines might be subject to tectonic hazards. (7)
Mark scheme
Level 1: simple statements of tectonic activity on the islands: listing of volcanoes, trenches. Limited
or simplistic attempt to explain why these would present hazardous environments.
1-4
Level 2: attempts to explain or develop points made above, that suggest why the existence of
tectonic features may present hazards. Some explanation of what processes must underpin an
ocean trench/volcano/active fault zone and may create additional hazards. Assessment is explicit.
5-7
Candidate A
The Philippines has a very high chance of being subject to volcanic activity due to it being
surrounded by 5 different ocean trenches which suggests that subduction is occurring around the
country. Ocean trenches are formed by the subduction of continental/oceanic crust or
ocean/oceanic crust and as the denser oceanic plate descends under the lighter continental this
creates friction and the plates get stuck resulting in earthquakes. Volcanic activity is also found at
these subduction zones because as the oceanic plate descends into the mantle, the surroundings
get hotter and the plate melts. This molten magma forces its way up to the surface causing
volcanoes. Figure 1 shows 5 volcanoes all within 300km of an ocean trench.
There are also about 8 active faults, the biggest being on Luzon Island. This suggests seismic activity
is common in the area especially as these faults are known of, as opposed to blind faults. However,
Palawan has no active faults and is over 400km away from the Sulu Trench which could suggest that
Palawan is a part of the Philippines that doesn’t suffer tectonic hazards or may suffer them to a
lesser extent than north Philippines. (7)
Candidate B
Surrounding the coasts of the Philippines there are a number of trenches, for example, the east
Luzon trough and Manila Trench bordering the island of Luzon. These trenches are destructive as
they show a collision movement. They are both oceanic and therefore a result of volcanoes like
Pinatubo which is known to erupt and cause a hazardous impact on the island. This would result in
deaths, destruction of infrastructure and to the environment and also a deficit to the economy.
These destructive trenches may also result in earthquakes ranging from shallow to intermediate to
deep focus. This too would invoke a hazard warning on the area as it would result in destruction of
the area.
Earthquakes could result in landslides in the area and could trigger tsunamis if the earthquake was
on a larger scale. There are also a number of fault lines present in the Philippines. For example on
the island of Samar, there is a fault line that crosses the southern area. If these fault lines are
unstable, pressure would build up, amounting to an earthquake. This area could also be subject to
separation in millions of years to come. (4)
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Question 02
Outline the formation of hot spots and explain their relationship to plate movement. (8)
Mark scheme
Level 1: simple statements of process, such as location and the creation of volcanoes. No or limited
references to plate movement.
1-4
Level 2: more sophisticated statements of process, such as its cause. The existence of a chain of
seamounts/volcanoes with clear references to plate movement. 5-8
Candidate A
The heat generated at the core of the Earth (around 6000C) plus radioactive decay given off by the
materials in the mantle create convection currents. The circulation of the convection currents in the
asthenosphere cause hot material to rise up. Due to low pressure near the surface, it then expands,
doming the crust. The rock then melts, causing a magma reservoir. The magma is then extruded at
the surface during a volcano.
Plumes of magma in the lithosphere are the cause of hot spots and it is via this process that the
magma reaches the surface. As the plate moves away from the plume of magma in the mantle, it
carries the volcano with it which becomes extinct (as there is no magma in the mantle at the point
where the volcano is to extrude at the surface). The plume of magma therefore creates a whole
new volcano at the point where the extinct volcano was. This also becomes extinct.
If this process continues, an island chain may form. Hawaii is an example. It is a set of islands on top
of a hotspot. The volcanoes include Mauna Loa, a shield volcano started via the hot spot. Therefore
plate movement causes hot spots to create island volcanoes as discussed. (8)
Question 03
With reference to two volcanic events you have studied from contrasting areas of the world,
compare the nature of the volcanic hazard and their impact. (10)
Mark scheme.
Level 1: simple statements of nature and/or impact which could apply to any volcanic hazard. No
specific detail provided.
1-4
Level 2: specific statements of nature and/or impact which can be clearly attributed to named areas
and/or volcanoes access this level. Comparison is implicit.
5-8
Level 3: a fully developed answer, with good elaboration of the nature and impact of two volcanic
events. A rounded answer with a full explicit comparison of the two events.
9-10
Candidate A
The eruption of Mount Etna in Sicily between 1991 and 1993 produced huge lava flows due to the
basaltic nature of the lava which its low silica content makes it very runny. Volcanic activity from
Mount Etna is common and as a result, is very well monitored such that over 3000 people use the
fertile volcanic soil for farming. As Mt Etna is well managed the eruption had very little impact on
people although about 77 people have died over recent time – all tourists who ventured into the
hazardous zone.
The eruption of Mt Nyiragongo in 2002 unlike Mt Etna came as a shock to the population as no
prediction had been made however early signs of gas emissions which signals that lava is at the
surface alerted people to the eruption. Like Mt Etna the eruption was dominated by lava flows but
there were much more of a threat due to their proximity to a nearby town with 200000 residents.
27
The eruption killed about 150 people but had further widespread severe impacts that Mt Etna
didn’t face.
As a result of Mt Nyiragongo, 4000 people were evacuated and over 4500 fled. Because of Congo’s
corrupt government, there was widespread looting and chaos in the midst of the evacuation
causing people to be killed as a petrol store that people were looting from exploded. On the other
hand in Sicily, although evacuation took place the authorities and government were well managed
and in control as hard engineering techniques were used to prevent the flow of lava into nearby
towns. They did this by building a concrete wall to hold back the lava and dropping blocks in the
volcano to divert the flow, whilst building an underground trench for the lava to flow into. As a
result of these, few buildings were destroyed although homes and businesses near to the volcano
had to evacuate between 1991 and 1993.
To contrast, the population of Mt Nyiragongo’s eruption were left homeless – over 300000 had fled
to Rwanda and neighbouring countries causing problems in shelter and food supply. Lake Kivu
produced polluting gases causing breathing problems and although a ‘red alert’ was issued after the
eruption, it took 2 days for humanitarian aid to be brought in, suggesting poor communications and
organisation skills by the government and authorities.
Therefore although the volcanic events in Italy and Congo were of similar volcano composition, the
numbers of deaths were relatively the same but the secondary effects of homelessness, polluted
water from Lake Kivu were much more severe in Congo due to the poor management and response
to the eruption.
(9)
June 2011
Question 01
Study Figure 1 which is an image of the seabed of the North Atlantic Ocean and adjacent land
masses. Comment on the extent to which the features shown in the image support the theory of
plate tectonics.
(7 marks)
Mark scheme
Level 1 (1-4 marks)
Simple listing of features from the image such as MAR, constructive boundary, jigsaw fit, isolated
mountains/volcanoes with no commentary or elaboration on any aspect. Simple statements re
theory.
Level 2 (5-7 marks)
Commentary on the nature of the evidence as seen (as suggested in the nfa). Some sophistication of
description, and/or evidence of geographical thinking.
Candidate A
One feature shown in Figure 1 that supports the theory of plate tectonics is that if you took the east
coast of North America and placed it alongside the west coast of the British Isles and countries such
as Spain and France on the west coast of Europe, they would fit together like a jigsaw and this
shows that they were once joined together and this supports the theory to quite a large extent.
Another feature that supports the theory is that the mid-Atlantic ridge shows similar shape to the
continental shelves of Europe and North America and this also supports the theory to quite a large
extent because it shows a clear and related boundary between the European plate and the North
American plate. The mid-Atlantic ridge also supports the theory of plate tectonics to a large extent
because the way it is formed is by a constructive, or divergent, plate margin with the two plates
28
pulling away from each other forming a fissure volcano which creates new land when it erupts. This
pulling away of the plates support the theory of plate tectonics to a large extent because that part
of the theory is that the plates move in different directions to form different plate margins. (7)
Question 02
Describe the characteristics of, and explain the formation of, minor forms of extrusive volcanic
activity.
(8 marks)
Mark scheme
Level 1 (1-4 marks)
Simple identification of landforms, with no detail of either characteristics or formation. Imbalanced.
Only one landform – max Level 1
Level 2 (5-8 marks)
Detail of either characteristics or formation, possibly with some use of supportive material. The
answer progresses through the level as more is added at this level. Full mark answers are balanced.
Candidate A
One minor form of extrusive volcanic activity is a geyser. A geyser is where a very hot burst of water
is violently ejected from a hole in the ground, some reaching 50-75 feet in height, going off at
regular intervals, for example Old Faithful which goes off every 65 minutes in Yellowstone National
Park, USA.
They are formed when water underground has been heated to very high temperatures from
geothermal activity and as it heats up it evaporates into steam. The steam then builds up pressure
in the chamber and this results in the violent ejection.
Another minor form of extrusive volcanic activity are hot springs and these are pools of water that
have been heated up by geothermal activity such as hot rocks. However the water does not boil.
Boiling mud is another minor form of extrusive volcanic activity and this is formed in much the
same way as hot springs. However the hot rocks heat up the water when mixed with sediment
creating a mud but the temperature exceeds 100C causing it to boil.
One other form of extrusive volcanic activity are fumeroles. These are areas where the gases have
heated up to very high temperatures and escape out of cracks in the ground and a good example of
this is Solfatara near Mount Vesuvius in Italy where the sulphur has been super heated to form a
sulphurous gas.
(8)
Candidate B
Extrusive volcanic activity is when volcanic activity is expressed on the surface of the Earth. The
most common form of extrusive volcanic activity is volcanoes. They are formed when rising magma
erupts on the surface of the Earth and cools and solidifies. When this process has repeated many
times lava builds up to form a volcano. These may be very tall and conical shaped if the type of lava
erupted is andesitic or rhyolitic which are very viscous due to its high silica content and cannot
travel far before solidifying. Lahars can also be produced which occur when lava meets a water
source such as a river and mixes with the water to produce fast flowing mudflows.
Bubbling mud is also an extrusive landform. This occurs when steam heated by magma rises to the
surface of the Earth due to its low density through cracks and fissures in rocks. Upon reaching the
surface it mixes with sediments that produce mud that bubbles due to its very high temperature.
Sometimes large quantities of rising steam may produce geysers, such as Old Faithful in
29
Yellowstone National Park. Geysers are huge jets of water that rise for tens of metres into the air
before returning back to Earth, due to some form of compression under the surface. (5)
Question 03
In what ways does volcanic activity vary in relation to the type of plate margin along which it
occurs?
(10 marks)
Mark scheme.
Level 1 (1-4 marks)
Simple statements of variation of volcanic activity between plate margins. No specific detail or
elaboration provided; or activity at one margin discussed well.
Level 2 (5-8 marks)
Specific statements of a range of variations. Elaboration that demonstrates good understanding of
the interrelationships between type and frequency of volcanic activity at plate margins. May be use
of case studies to support.
Level 3 (9-10 marks)
A fully developed answer, with good elaboration of a range of variations between plate margins. A
rounded answer with a full comparison (most of features given in table above) of the two main
types of plate margin. Good use of case studies, though not a requirement.
Candidate A
Volcanic activity can occur at convergent or divergent plate margins, but it can also occur at
hotspots in which no plate margin is involved. At convergent margins two plates which are moving
together can be either both oceanic plates or one continental and the other oceanic. In the case of
one continental plate and one oceanic plate, volcanic eruptions are very violent and emit andesitic
or rhyolitic lava. These types of lava are very viscous due to its high silica content. This is because
the lava rises from the subduction zone through continental lithosphere which has a low density
and is filled with air spaces containing gases which become incorporated into the lava. This very
viscous lava often blocks off vents of volcanoes and when the pressure building up in the vent is
eventually released, the top of the volcano can be blown off leaving a huge crater, such as in the
2002 eruption of Mount Etna in Sicily. When the two plates involved are oceanic, explosions tend to
be less violent than this as the melted lithosphere which forms the lava is denser and so contains
fewer gases.
At divergent boundaries where plates are moving apart from one another, basaltic lava is erupted
between the gap. This type of lava is not very viscous due to its low silica content. This is because
no subduction of crust is involved so the lava is not made of melted lithosphere but has risen from
the mantle itself. The low viscosity of this lava causes it to flow very far before cooling and
solidifying. This forms shield volcanoes with very gentle slopes and a much wider base than more
conical shaped volcanoes involved with convergent plate margins. The low viscosity of the basaltic
lava also causes vey gentle eruptions, so shield volcanoes have a low explosivity. (9)
30
January 2012
Question 01
Study Figure 1 which shows the relationship between shaking intensity (measured by the Mercalli
Scale) and different types of building structure. Describe and comment on the information
provided. (7 marks)
Mark scheme
Level 1: simple statements of trends in the data; comments are simplistic; answer lacks balance.
1-4
Level 2: statements of description that are either quantitative or qualitative, and commentary is
sophisticated possibly linking to actual events; balanced answer.
5-7
Candidate A
The table firstly indicates the most obvious point that with weaker structured buildings plus the
increase in the intensity of shaking means there is a higher percentage of buildings damaged or
collapsed. The adobe (baked mud and clay) building structure has the highest % of buildings
damaged at each side if the Mercalli scale. Even at the lowest scale of intensity, adobe has 8% of
buildings damaged and at the other end of the scale the table indicates total destruction of
buildings with 100% damaged. The table also shows that reinforced masonry which is specifically
designed for seismic events proves to be the strongest structure. Even at a disastrous level of
shaking there is only 25% of buildings that have collapsed.
The table indicates that there is a large difference between reinforced masonry buildings depending
upon whether they are non-seismic or seismic design. At an X disastrous level of shaking intensity
there is a 41% difference in the % of buildings collapsed or damaged, with the non-seismic design
resulting in 66% buildings damaged. This in turn proves that buildings designed in a ‘life-safe’
manner are less likely to be damaged in the event of an earthquake and the level of observable
damage will be smaller. It also proves that buildings made of mud and clay are bound to suffer
liquefaction and therefore stand a minimal chance against seismic events while the more rigid
structures remain standing. (6)
Question 02
Outline the features of seismic waves. (8 marks)
Mark scheme
Level 1: simple statements of seismic waves, such as their cause and location. No, or minimal,
attempt to classify, nor recognise differences.
1-4
Level 2: more sophisticated statements of features of seismic waves with some attempt to classify
as given above. Greater depth of understanding will progress the answer within the level. 5-8
Candidate A
Seismic waves are released when an earthquake occurs. There are 3 main types of waves. Firstly,
there are P waves. These are the fastest waves and they can travel through solids and liquids
meaning that they can travel to opposite sides of the world by travelling through the Earth’s core.
Although they are the fastest waves they are the least damaging and cause the ground to move
forwards and backwards.
31
The second type of wave is S waves and these travel only through solids so are slightly slower than P
waves. However S waves cannot cause more damage as the waves cause the ground to shake at
right angles to the direction of travel.
Finally there are surface waves which can be split up into long waves and Raleigh waves. Surface
waves are the slowest waves and they only travel through the upper few km of the crust. They are
also the most damaging waves and are responsible for most of the destruction caused by
earthquakes. Long waves cause the ground to shake sideways violently and Raleigh waves cause the
ground to shake up and down violently. Both these movements cause damage to building
foundations causing these buildings to collapse. (8)
Question 03
Evaluate the management strategies adopted following one earthquake that you have studied.
(10 marks)
Mark scheme.
Level 1: Identifies strategies of management, but only at a superficial level. Loosely ties
management strategies to a specific earthquake event or area, or not all. Example used is very
thinly developed. Evaluation of effectiveness of strategies is simplistic.
1-4
Level 2: Clear identification of specific strategies and event/area in which they have been used.
Evaluates, with some detail, how effective, or otherwise, such strategies have been. Good use of
exemplar material.
5-8
Level 3: A fully developed answer which clearly links the strategies, and the area in which they
operated, to their effectiveness in the particular event/area. Answer contains very good use of
exemplar material. Explicit statements of evaluation.
9-10
Candidate A
On the 6th April 2009 at 3.32am an earthquake occurred in L’Aquila, Italy. The epicentre of the
earthquake was 3km with a 5km focus. The earthquake was considered a particularly disastrous
event as it resulted in a large number of buildings collapsing due to poor structure. The earthquake
occurred at a destructive plate boundary as the Eurasian plate subducts beneath the African plate.
The earth was being pulled apart due to the Apennines collapsing. As mentioned the buildings were
renaissance style and were not structurally ready for the earthquake. University halls of residence
pancaked and 26 hill top villages were affected. Due to corruption in southern Italy there was far
too much sand in the concrete and people cut corners due to paying protection money to the mafia
and camorra. The overall cost was $16 billion.
Therefore the Italian government responded rapidly to this event and developed a management
scheme. In open spaces temporary hospitals were set up with over 5000 operations. However this
proved a problem as there was hardly any bed space for patients afterwards. The event resulted in
50000 people being left homeless (most living in small villages such as Castel Nuevo). Therefore they
set tented villages as a temporary home. Due to a lack of blankets many people were left with no
choice but to temporarily move to Berlusconi’s (the Italian Prime Minister at the time) coastal
mansions for refuge. The EU did not play a huge role in the management scheme despite donating
money towards the recovery of the people of L’Aquila.
Overall this management scheme was mildly successful with a 2-3 hour response. However one
could suggest that it may have been more effective if it was part of a larger framework of other
relief and help schemes. (7)
32
Candidate B
In January 1995 the Philippine plate subducted beneath the Eurasian plate triggering a major
earthquake. The quake’s epicentre was Kobe in Japan and with a magnitude of 7.2 on the Richter
scale. There was widespread damage throughout the city. Over 5,200 lost their lives so it was vital
that the Japanese government identified the reasons for such devastation and addressed them.
One of the main concerns of death and injury in the event was the collapse of major building and
infrastructure. The Hanshin expressway travels through the city acting as the main route for traffic.
It collapsed as a result of the quake. Not only did the collapse cause the death of several hundred
people, it blocked the entrance to the city for the emergency services. As a result the reconstruction
of the expressway has incorporated some of the world’s leading technology in order to prevent any
future collapse. The concrete was reinforced with steel and carbon fibre. In addition the bridge now
sits on rubber blocks which can help absorb and mitigate the vibrations. These design alterations
and improvements have been a great success. The recent Tohoku earthquake measured 6 on the
Richter scale in Kobe yet all its infrastructure stood up to the tremors. This shows how the
management of the quake has helped minimise the chances of future quakes having a similarly
devastating effect.
Another major cause of death during the Kobe earthquake was the spread of fire due to ruptured
gas mains. The emergency services were unable to respond quickly due to the roads being blocked
by collapsed buildings due to liquefaction. After the event the Kobe road network was re-designed
with roads being cited as designated emergency routes. These roads had the buildings either side of
them set back from the road. This meant that even if buildings collapse the roads would still be
accessible to emergency services. This was a key strategy and one that is almost certain to save lives
when the next major quake occurs in the city.
After the quake hit Kobe, it was the middle of January. Much of the homeless struggled to find food
and shelter. This was a major concern to the management authorities. All petrol stations now have
to, by law, stock emergency supplies and shelters. In the case of a future earthquake, these
emergency supplies may prove vital in saving lives and act as assembly points for communities.
Kobe was demonstrated very efficient management of the risk posed to the city by earthquakes. The
city is now better prepared for when the next one strikes. (9)
June 2012
Study Figure 1, a satellite image of the Mayon volcano in the Philippines and the area to the
south and east. Comment on the nature of the hazards that this volcano may present. (7 marks)
Mark scheme
Level 1 (1-4): simple listing of features from the photograph such as lava, mudslides/lahars, city
nearby etc. with no commentary on any aspect. Generic comments without clear reference to the
photo.
Level 2 (5-7): commentary on the nature of the hazards seen/suggested. Some sophistication,
and/or evidence of geographical thinking. Uses Figure 1 to generate comment.
Candidate A
The volcano visible in Figure 6 displays a level of uniformity in shape and a cone-like structure that
would normally be associated with a strato-volcano. These volcanoes are extremely explosive and
thus pose several hazards. Firstly the volcano explosion may well produce pyroclastic flows from
the fragmented magma of the explosion. These flows at speeds of up to 1000 km per hour will
33
destroy all in their path. This will probably mean the destruction of Legazpi and the loss of many
lives, and probably most of those in a 10 to 20 km radius because the land appears to slope down
from Mayon to the sea at Legazpi 11 kms away. A second likely feature of such an eruption is a
lahar and indeed we can see evidence of past lahars in brown streaks down the mountain.
Alternatively if the visible streaks are waterways (rivers and streams) then lahars still pose a threat
because ash and debris from the explosion may turn the water to the powerful mud of a lahar. (6)
Candidate B
The Mayon volcano is just over 11km from the town of Legazpi. This is close enough that the lava
from an eruption would reach the town destroying all structures unless the lava is extremely
viscous. This threatens people’s lives and the Philippines government must relocate the residents of
Legazpi, a costly process that some residents may refuse.
This would be a drain on the economy, as would be rebuilding the town (assuming it is not inside an
exclusion zone). The Philippines would also lose a port town as a harbour is visible in the south east.
This means the loss of both exports and imports of some of the country’s goods.
Two landslides are visible on the mountainside suggesting pyroclastic flows may be a hazard to the
town, moreso that the lava. However, we cannot tell from this image how long these landslide have
been there. It could have occurred ten years ago, or much longer.
The worst hazard a volcano puts out is ash and dangerous chemical air pollution that can spread
very far – there is some evidence of smoke from the volcano in the image. Any ash would stop
planes flying over the area, which is a threat to tourism and so again an economic hazard. (7)
(02) Describe and explain the characteristic features of various types of volcano. (8 marks)
Mark scheme
Level 1 (1-4): simple identification of volcanoes, with limited detail of characteristics or reasoning; or
one type only.
Level 2 (5-8): detail of characteristics and reasoning, possibly with some use of supportive material.
The answer progresses through the level as more is added at this level. Full mark answers show
breadth of knowledge.
Candidate A
Fissure volcanoes are a type of volcano that are basaltic and erupt in a minor way but frequently.
They are formed when the runny basaltic lava escapes on to the surface and covers a large area
before solidifying, thus forming lava plateaux, such as that associated with the Laki eruption in
Iceland in the late 1700s.
Shield volcanic eruptions are also basaltic and are found mainly on constructive plate margins, but
also at hotspots. Shield volcanoes are quite gentle in gradient due again to the free-flowing basaltic
lava type. An example is Mauna Loa in Hawaii. Caldera volcanoes are a very interesting type of
volcano. They are made up of andesitic rock and are found usually on destructive plate boundaries.
They are formed when pressure builds up and the summit of the volcano is blown off the top. This
leaves a crater where a lake is sometimes formed. Calderas are arguably the most explosive type of
volcano and are very unpredictable. The Crater Lake volcano in the USA is an example. Acid
volcanoes are very steep sided due to the rhyolitic lava type that helps form them. This rhyolitic
lava is very viscous due to a very high silica content. It doesn’t get very far down the mountain
before cooling forming the steep sides. Acid volcanoes are very explosive and unpredictable. A
good example of an acid volcano is the Puy-de-Dôme in France. (8)
34
Candidate B
Strato-volcanoes are very distinctive volcanoes. They are very large with steep sides and are usually
very explosive. They are formed from alternating layers of ash and lava. This because they are
sometimes very explosive creating large amounts of lava but sometimes not so explosive so only
produce ash. An example is Mount St Helens.
Shield volcanoes are the opposite of the above. In their appearance they are very wide but not very
high, often only one tenth of the width. This is because they are not very explosive. Also the lava is
very runny, not very viscous and spread over a large area making it a fairly flat shape.
Calderas are huge volcanoes that are sometimes not immediately visible. They are the remains of
strato-volcanoes that blow their tops off creating a crater which is sometimes filled with a lake.
Often a smaller cone is in the centre of the crater. Yellowstone is a good example. (6)
(03) With reference to two volcanic events that you have studied from contrasting areas of the
world, compare the ways in which volcanoes and their impacts have been managed. (10 marks)
Mark scheme.
Level 1(1-4): simple statements of management which could apply to any volcanic hazard. No
specific detail provided.
Level 2 (5-8): specific statements
of management strategies which can be clearly attributed to named areas and/or volcanoes access
this level. Comparison is clear and purposeful.
Level 3 (9-10): a fully developed answer, with good elaboration of the management strategy of two
volcanic events. A rounded answer with a full comparison of the two events.
Candidate A
Volcanoes can be managed in three ways: through reducing vulnerability of potential victims;
through modifying the severity of the event and through reducing the losses suffered by people and
the areas affected. The eruption of Mount St Helens is a good example of how management has
succeeded in these areas. The comparable eruption of Nevada del Ruiz is the opposite.
Vulnerability modification was exceptionally efficient in the USA before Mt St Helens. USGS
scientists acknowledged the likelihood of an eruption as earthquakes increased and the water table
level began to fall. They distributed warnings to the authorities who organised and evacuation to 20
km in all directions. This ‘exclusion zone’ reduced the death toll from a potential hundreds to just
57. It was also aided in that locals were aware of volcanic threats because of a good education
system and people trusted the scientists and government in their decision.
Nevada de Ruiz did not receive sufficient or comparable vulnerability modification. Although US
scientists warned both the locals in the town of Armero and officials in the local government that
an eruption was imminent, locals refused to believe that their mountain could hurt them and
officials dismissed advice as attempts to lower property prices. Consequently 23000 people died in
the eruption as no evacuation was undertaken. The lack of education of the locals and official
xenophobia and distrust meant catastrophic damage took place.
Even modification in both cases was minimal because the most severe effects of a volcanic
eruption, pyroclastic flows and lahars are almost impossible to stop with current building materials
and diversion techniques. Nevertheless, had the buildings in Armero been better built, some may
have withstood the lahar.
Loss modification through aid (short term and longer term) was also far more efficient at Mt St
Helens. The US government provided a package of $631 million to go to the rebuilding and
sustaining of businesses that were hit by the eruption. This virtually covered the economic damages
35
of the eruption. The National Guard were also quick to arrive rescuing the stranded by air. Indeed
the recovery though swift was aided by the initial precautions taken.
At Nevada del Ruiz no government bailout was provided and authorities took up to 3 days to arrive.
In this time looters and kidnappers took advantage of the local chaos. On arrival relief was slowed
by broken equipment and poor coordination. This has meant that the area has not yet fully
recovered even now. Evidently the USA handled its eruption far better than Colombia and this was
due to both government efficiency and public education, both of which were aided by the USA’s
super wealth. (10)
Candidate B
Mount St Helens erupted in 1980, a large composite volcano in the USA. It killed 52 people and
destroyed entire forests. The USA responded well, they monitored the volcano pre-eruption and
evacuated anyone who would come willingly. They continue to monitor as there have been small
outputs of ash and gas in 2002 to 2004. They had rescue and response teams in within hours of the
eruption, a fast response time and put out any fires remaining. Burned wood was floated down
river to remove it, a costly operation as there were about half a million tons of timber (not all was
taken care of). An exclusion zone is still in place today around Mt St Helens.
The volcano on the Caribbean island of Montserrat erupted in 1997 and similar to Mt St Helens it
still erupts today. Both volcanoes have exclusion zones around them; two thirds of Montserrat is
uninhabited due to the hazards including the town and the old airport. Since Montserrat is an island
it was harder to evacuate people as they had to leave by boat, airplanes were not an option as the
volcano’s ash would disrupt the turbines. Montserrat required some international help such as
evacuated civilians having to seek asylum in the UK and USA.
Since the USA has a better economy and far more land than Montserrat they can easily relocate
their own people. Both America and Montserrat still constantly monitor their volcanoes.
Also both of these volcanoes hurt their surrounding civilisations but in different ways. America
spent approx $2 billion dollars clearing away the damage done to the environment such as felled
trees. America also lost lots of farmland around Mt St Helens raising unemployment in the area and
slightly raising the price of the lost foods as they were more scarce now.
On the other hand Montserrat has spent less on clean-up as two thirds of the island is in an
exclusion zone now. Their response cost less economically but they have had to cut down the
number of tourists they allow to enter which was one of their main sources of income. (8)
36
Mark scheme for the essay questions
Assessment
criteria
Knowledge of
content, ideas
and concepts
Level 1
1-10 (mid 6)
Basic grasp of
concepts and
ideas; points
lack
development
or depth.
Critical
understanding of
the above
Incomplete,
basic.
Use of examples/
case studies to
support
argument
Maps/Diagrams
Evidence of
synopticity:
Superficial
None
No evidence
Level 2
11-20 (mid 16)
The answer is
relevant and
accurate.
Reasonable
knowledge.
Imbalanced
theories
Reasonable critical
understanding of
concepts and
principles with
some use of
specialist
vocabulary.
Examples show
imbalances and/or
lack detail or depth.
Ineffective
Limited.
Level 3
21-30 (mid 26)
Sound and frequent
evidence of
thorough, detailed
and accurate
knowledge
Level 4
31-40 (mid 36)
Strong evidence of
thorough, detailed and
accurate knowledge
Sound and frequent
evidence of critical
understanding of
concepts and
principles, and of
specialist vocabulary.
Strong evidence of
critical understanding
of concepts and
principles and of
specialist vocabulary.
Examples are
developed, balanced
and support the
argument.
Effective
Strong
Examples are well
developed and
integrated.
Fully integrated
Full
Connections
between
different aspects
of the subject
Some ability to
identify, interpret
and synthesise
some of the
material.
Some ability to
identify, interpret
and synthesise a
range of material.
There is a high level of
insight, and an ability to
identify, interpret and
synthesise a wide range
of material with
creativity.
‘Thinking like a
geographer’
Limited ability to
understand the
roles of values,
attitudes and
decision-making
processes.
Some ability to
understand the roles
of values, attitudes
and decision-making
processes.
Evidence of maturity in
understanding the role
of values, attitudes and
decision-making
processes.
Arguments are not
fully developed nor
expressed clearly,
and the
organisation of
ideas is simple and
shows imbalances.
Some sense of
focus of task.
Explanations,
arguments and
assessments or
evaluations are
accurate, direct,
logical, purposeful,
expressed with
clarity and generally
balanced. Clear sense
of focus of task.
Explanations,
arguments and
assessments or
evaluations are direct,
focused, logical,
perceptive, mature,
purposeful, and are
expressed coherently
and confidently, and
show both balance and
flair.
Quality of
argument – the
degree to which
an argument is
constructed,
developed and
concluded
Language is
basic;
arguments are
partial, over
simplified and
lacking clarity.
Little or no
sense of focus
of task.
37
The Essay questions
June 2010
'The hazards presented by volcanic and seismic events have the greatest impact on the world’s
poorest people'. To what extent do you agree with this view?
Answer 1.
Tectonic hazards such as earthquakes and volcanic eruptions occur across the surface of the globe,
but many argue that they have the greatest impact on the poorest people – the inhabitants of
LEDCs. However, there are many different factors which contribute to the severity of a tectonic
event, both physical and human.
Firstly I do not agree with this view because the severity of an event and the impact it has obviously
depends on the magnitude of the event. For example, the Bandah Aceh earthquake of 26th
December 2004 off the coast of Indonesia measured 9.1 on the Richter Scale whereas L’Aquila
earthquake in Abruzzo, Italy of 2009 only measured 6.3R. Volcanic eruptions also differ in
explosivity. Mount Etna on Sicily erupted in 2008 with only Strombolian activity whereas the
Soufriere Hills eruptions 1995-97 on Montserrat varied from Pelean to Plinean activity.
Also obviously the type of event also determines the impact it has on people – rich or poor. With
the L’Aquila earthquake the only primary effect it produced was ground shaking for 20 seconds
whereas the Bandah Aceh earthquake was submarine and produced tsunami waves. There were
several waves varying from 20m to 30m in height. This made the impact of the tsunami far more
widespread as the waves travelled a great distance across the Indian Ocean affecting countries as
far apart as South Africa and Indonesia, India and Burma. Volcanic eruptions also come in different
forms – volcanoes found on destructive margins often lie dormant for long periods of time, then
produce explosive and violent eruptions of acidic lava, pyroclastic flows, ash and larger lava bombs.
The eruptions on Montserrat were of this nature. Constructive margins and hot spots produce
gentle eruptions of lava which are more continuous. Although on Etna on Sicily has uncertain
tectonic conditions and lies near a destructive margin, the eruptions here are of this nature.
Finally the length of the event also determines the severity of its impact. The Boxing Day tsunami
was thankfully short-lived as was the L’Aquila earthquake. However the Soufriere Hills complex on
Montserrat erupted for 2 years and eruptions on Mount Etna are on-going.
These three factors, magnitude, type and length do have a large effect on its impact. However I
mainly agree with the view that human geography has the greatest impact on whether a tectonic
event becomes a ‘natural disaster’. Mostly this is dependent on the level of economic development
of a country.
Firstly the population density of the area as well as the land use and infrastructure determines the
input of the event. The countries bordering the Indian Ocean are mainly LEDCs with many fishing
communities living on the coast. The coastal geography in places like Thailand and Indonesia is lowlying. However, it is also densely populated often with mainly poorly built houses and poor roads
and communications. This contributed to the destruction of the area by the tsunami and made it
more difficult for remote communities to receive aid. The same is true for Montserrat as an LEDC
(although it is a UK colony), the infrastructure was not of the same standard as is an MEDC – 50% of
the water supply network was destroyed by the eruption and the capital Plymouth was covered in
ash. However the lack of roads and communications on other parts of the island made it again
difficult to obtain aid. On the other hand, the medieval city of L’Aquila had good communications
by road and rail and although it was built on lake sediments which amplified the shaking, aid was
able to be delivered.
A, or even the, major determinant of the impact of a tectonic event is the level of protection,
prediction and preparation a country has against tectonic hazards. For example, Japan has an
38
excellent tsunami warning system which can relay public warnings within 3 minutes of the seismic
event. It has also built tsunami walls to aid tsunami shelters along the coast. As a consequence, a
30m tsunami in 2005 killed only 240 people. The Boxing Day tsunami killed an estimated 230000
people. One of the main reasons for this is that the countries bordering the Indian Ocean are LEDCs
and so could not at that time afford a warning system. One has subsequently been installed.
On the other hand it is not just LEDCs which suffer from poor hazard management. A Californian
scientist commented of the L’Aquila earthquake ‘an earthquake of this magnitude in California
wouldn’t have killed a single person’. The major reason L’Aquila was lethal was because of the
collapse of old medieval buildings and more modern buildings with poor workmanship and poor
land-use planning. Italy is an MEDC and still suffered considerably.
The next major difference between LEDCs and MEDCs in their response to natural disasters is their
ability to give aid. In the 2008 Etna eruptions £5.6 million in tax breaks was granted by the
government and in the L’Aquila earthquake emergency crews were at the scene within minutes and
international aid arrived within 24 hours. By contrast, LEDCs are almost completely dependent on
foreign aid to respond to tectonic hazards. The foreign aid given for the tsunami was $7 billion but
this pales into insignificance next to the aid given for natural disasters by MEDC governments when
they have occurred in MEDCs (eg Hurricane Katrina - $62.3 billion). In Montserrat aid took several
days to come and when it did some was inappropriate. It was reported that some organisations
refused local knowledge and the sums given out were uneconomical. The water supply and sewage
disposal was also inadequate and so gastro-intestinal disease spread. In this way, poorer people in
LEDCS suffer more from earthquakes and eruptions because foreign aid so often is not enough and
is substandard.
Finally in my opinion, the reason volcanic and seismic events do have the greatest impact on poorer
people is because the ability to recover from a natural disaster is so different in LEDCs compared to
MEDCs. Insurance losses suggest that disasters in MEDCs are more costly eg £1 billion for
Montserrat eruptions and £16 billion for L’Aquila). However this hides the fact that LEDCS have very
little insurance cover – people simply can’t afford it. Furthermore people in LEDCs generally have
fewer possessions – perhaps a few livestock or a fishing boat are the most important. So, when
these are lost in a natural disaster they lose more than possessions – they actually lose their
livelihoods. For example, during the 2004 tsunami, 60% of Sri Lanka’s fishing fleet was destroyed.
Fish had just become an important export and the industry had to start all over again. What is even
more damaging is the fact that LEDCs are dependent on foreign aid to recover and this is unreliable.
The government of Sri Lanka reported 6 months after the event that it had received no foreign aid.
The Soufriere Hills eruption threw the Montserrat economy back into dependency on the UK and
just as it had reached independence for its economy. One of the reasons for this is that Montserrat
is dependent on its primary sector, particularly farming. The volcanic slopes are the most fertile and
so provide most of the food supply. When these were covered in ash, the crops failed.
So, overall, although physical factors have an extremely important role to play, natural disasters are
often not that, but in fact are ‘human-made’ disasters. As a consequence, the poorer countries are
indeed the ones which suffer the most. (40 marks) (1239 words)
Answer 2
Firstly I believe that this statement is true but only to a partial extent. Hazards presented by
tectonic activity can be managed and controlled so their impacts are lessened and even not felt.
However such management involves planning, prediction and action, all of which may cost
considerable amounts of money, unavailable to the poorest people.
For example, ever since its primary eruption in 1968 Mount Etna has been constantly erupting
every year. Though these eruptions are not always violent sometime volcanic bombs can be fired
from the composite volcano and since its eruption in 1968 it has killed around 77 people, most of
39
these unwitting tourists who did not take enough care. However due to the volcano being located
in the fairly rich area of Sicily the impacts of its hazards have been managed and fairly efficiently.
For example, explosives were first used to relocate the andesitic lava flows away from settlements,
protecting people’s housing and property. More recently, Sicily has had the funds to construct
artificial lava tunnels to conveniently drain the lava away when Etna erupts.
Moreover Sicily has managed to accurately predict the size and frequency of the eruptions of Etna
by using remote sensors which measure the bulge of the volcano, a tell tale sign of the imminent
eruption. In combination to this, they sample the gas concentration of the gas released by Etna,
using this to predict when an eruption will occur and how large it will be. This allows the Sicilian
government to take appropriate action whether that is closing off the site to tourists or evacuating
the surrounding areas. This will reduce the impact of the volcano on the surrounding area but such
schemes cost money for machinery and employment, money poorer countries may not have.
For example, Mount Pinatubo is an ash cinder volcano located in the Philippines, 90 km away from
the capital, Manilla. Lying on the subductive plate margin between the subducted Philippines plate
and continental Eurasian plate, Pinatubo is quite an explosive, violent volcano. After being reignited
in 1990 due to a magnitude 8 earthquake, Pinatubo went on to erupt in 1991. The effect of this
eruption was enormous. 30 million tonnes of sulphur dioxide was released, reducing average global
temperatures by up to 0.5C. Much ash and cinder was released which combined with the water
vapour heavy in the air to form tephra which covered nearby buildings in layers up to 33cm thick
making them collapse. Pyroclastic flows and hot gas rolled down the mountain. As an impact of this,
800 people died, 10 times the amount killed by Etna. Most of these people died in collapsed
buildings due to the weight of the tephra. Also $500000 worth of damage was made to
infrastructure and business.
Even though it is obvious that the volcano which had the greatest impact was Pinatubo, it is difficult
to ascertain whether this is due to the Philippines being economically poorer than Sicily, or simply
because the eruption of Pinatubo in 1991 was more powerful and of a greater scale.
Seismic events also present many hazards to rich and poor countries alike. For example the well
developed city of Kobe in Japan was hit by a magnitude 7 earthquake early one morning at 5am in
1995. A heavily industrialised fishing port, the ground beneath Kobe rose by 20cm and shifted
horizontally by 12cm. The impacts were great. Of the 150 quays present 120 were destroyed.
Furthermore the Hanshin expressway and bullet train route were damaged and overturned for one
mile in length. A total of 6000 people died and many were left homeless. A great fire started by
leaking gas consuming thousands of wooden houses in the old quarter.
Though seismic hazards seemed to have caused a great impact, it may have been more so if Kobe
did not have the resources or the money to react in time. Kobe quickly enlisted up to 1.2 million
volunteers to help with excavating people and distributing aid and privatised its Hanshin
Expressway for aid vehicles only, making sure aid got to its destination quickly.
As well as this Japan was able to afford to invest in earthquake proof infrastructure after the event
and continues to carry out earthquake drills in schools and work places every year on the
anniversary.
As shown Japan’s wealth allowed Kobe to quickly recover from the earthquake and reduce the
impacts of the hazards while it could, as well as being well prepared for future events.
However, the relatively poor country of Iran was even badly affected by an earthquake during 2003.
At 5.00am also, an earthquake of magnitude 6.6 shook the city of Bam. Its 2000 year old citadel and
town made out of straw, mud and clay, 90% of the city was razed to the ground trapping many
under the rubble.
A total of 30000 died, medical treatment scarcely being given due to Bam’s two hospitals also
collapsing killing most of its medical staff with it. Most of the city’s officials were also killed, making
decision making and action difficult. Only 4 rescue teams turned up within the first 48 hours after
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the quake which is abysmal when compared to Kobe’s 1.2 million volunteers. The effects were
made even worse by the earthquake occurring on a Friday, the Moslem day of rest so most people
were still sleeping. If Iran were a richer country, would the poor infrastructure which killed so many
have been replaced with sturdier building materials, allowing medical treatment to be given and aid
called in and easily transported?
In conclusion, I agree with the statement to a large extent. The less money a country has the less
prepared and efficient it can be when dealing with seismic or volcanic hazards. However I believe
that the wealth of the people is only one factor affecting the impacts of hazards and that the nature
of the seismic activity, such as whether P waves or S waves affect the area, or the volcanic event,
such as whether it is a violent composite volcano or a gentle shield volcano have more importance
in determining the impact of its hazards. Many other factors such as people’s culture, religion and
ideology may also play a part. (1035 words)
K – 3 (up); U – 2; CS – 3; Syn – 3 (down); Q – 3. Overall Level 3 (down) 24
January 2011
'Volcanic and seismic events are major pieces of evidence towards proving that plate tectonics
theory is valid'. Discuss the extent to which you agree with this statement.
Candidate A
The theory of plate tectonics has been widely accepted but there are those who don’t fully agree.
The theory says that the plate tectonics are moving. The crust of the Earth is also called the
lithosphere. It is made of solid and semi-molten material. The asthenosphere is a molten layer
underneath the lithosphere. The lithosphere is split into 7 large plates and a number of smaller
ones. It is less dense then the asthenosphere so floats and moves over it. There are two types of
plate: oceanic and continental. Continental crust is older (1,500 million years old) and less dense
than oceanic crust which is under 20 million years old and more dense.
There are three types of margins where plates meet. One type is a constructive margin. This is
where two plates move away from each other, and cause either ridges or rift valleys. The most
famous examples are the mid-Atlantic ridge (two oceanic plates moving away from each other) and
the African rift valley. The mid-Atlantic ridge is associated with a number of undersea volcanoes
and the African rift valley is associated with Mt Kenya and Mt Kilamanjaro. As the plates move away
from each other they are filled with lava which cools to create more land. As new land is being
created it would suggest that the Earth is getting bigger but this is not the case so land must be
being destroyed somewhere. This occurs at trenches which are some of the deepest points of the
ocean.
Another type of margin is destructive margins. These are where plates are moving towards each
other. When an oceanic plate converges with another oceanic plate, subduction occurs. This is
where one plate is pushed under another. When this occurs the subducted plate begins to melt into
magma and where this happens is called the Benioff zone. This magma is less dense that the
asthenosphere so it rises causing plumes of lava which in turn creates volcanoes. When this
subduction occurs it is likely that a trench will be formed. When the Pacific plate subducted under
the South American plate the Peru-Trench was formed.
When an oceanic plate converges with a continental plate subduction also occurs. Because the
oceanic plate is more dense it is the one that subducts. This also creates trenches and volcanic
activity also occurs. When the Pacific plate subducts under the Philippine plate the Marianas trench
was formed. Volcanic islands were also formed and these were Guam and the Marianas Islands.
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When subduction occurs there is likely to be friction so earthquakes are likely.
At continental/continental convergence there is no subduction so there will be no volcanic activity.
However the plates will meet and sediments will be folded and faulted to form mountain ranges.
When the Indo-Australian plate converged with the Eurasian plate the sediments from the Sea of
Tethys were folded and pushed upward to form the Himalayan mountain range. The mountain
range is continuing to rise so this suggests that the plates are still moving towards each other.
Mt Nyriragongo is related to the African rift valley. In 2002 Mt Nyiragongo erupted and killed 147
people. The eruption caused 350000 people in the town of Goma to evacuate the town and flee
into its neighbouring country Rwanda. Rwanda at the time was dealing with its population pressure
which had led to a civil war. This sudden influx of people meant there was even more pressure on
resources and space.
Eyjayjallakull in Iceland is related to the mid-Atlantic ridge. In 2010 it erupted and 1000C of lava was
spewed 150m into the air. No-one was killed but travel was severely disrupted. Heathrow airport
was shut for over a week and caused businesses all over the world to come to a standstill.
At conservative margins the plates are moving parallel to each other. As the plates rub against each
other pressure and stresses are built up. When this pressure is suddenly released an earthquake
occurs. When the Pacific plate was rubbing against the Eurasian plate there was a sudden rise in the
Eurasian plate. This caused an earthquake on the 26th December 2004 which was 9.0 on the Richter
Scale. This earthquake generated a tsunami that was over 25m in height. The epicentre of the
earthquake was on the northern tip of Sumatra. Over 200,000 people were killed with thousands
more being injured by the waves and the debris they were carrying.
Another example of an earthquake that occurred on a conservative was the Gujarat earthquake in
January 2001. It was 7.9 on the Richter Scale and the epicentre was in a small town called Bhuj. The
earthquake could be felt in neighbouring countries of Nepal and Bangladesh. 20000 people died
with tens of thousands injured.
The Northridge earthquake in Los Angeles, USA occurred in January 1994. This earthquake is linked
to the San Andreas fault. This is where two plates are moving parallel to each other (conservative
margin) but at different speeds. Pressure was created and was released in the form of an
earthquake that was 6.4 on the Richter Scale. 57 people died and the cost of repair was estimated
at over $30 billion.
Hot spots are another piece of volcanic evidence that prove the plate tectonic theory. Hot spots
occur when plumes of lava eat away at the crust above and form a volcano. A famous example is
the Hawaiian Islands. The Hawaiian Islands consist of an arc of volcanoes. The hot spot created the
first island as the volcano erupted continuously and the lava cooled to form land. The plate above
the hot spot is moving and the hot spot stationary. This created an arc of islands. Only the volcano
above the hot spot is active. The other volcanoes on other islands are extinct. This would lead to old
volcanoes being turned into seamounts.
However, volcanic and seismic events are not the only evidence to support the plate tectonics
theory. The paleomagnetic theory also supports the theory. For this the mid-Atlantic ridge was
studied. It was found that on either side of the ridge were stripes of rock of reversed polarity and
they were symmetrical on both sides. Every 400,000 years the polarity of Earth reverses. As new
land was being formed at the ridge its polarity was the same as the Earth’s at the time. This proves
that new land is being, which proves the theory of plate tectonics.
A further piece of evidence is fossils found in different parts of the world. The fossils for the
dinosaur mesosaurus were found in southern Africa and South America. It is unlikely that the same
organism could have formed in different parts of the world or that the animal could have travelled
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across oceans. Therefore the only logical explanation would be that the two parts of the world were
joined at one point but then moved away from each other.
While volcanic and seismic events provide evidence for the plate tectonics theory, they are not the
only evidence available. Evidence such as rock polarity and fossil distribution support the idea that
tectonic plates are moving and that plate tectonics theory is correct.
(1189 words) K - 3, C/U – 3↓, C/S - 3↓, Syn – 3, Q – 3↓. Overall Level 3 = 24
Candidate B
Over many years many ideas surrounding the formation of the Earth as we know it today have been
put forward and discussed. Alfred Wegener put forward his theory based on the physical
appearance of continental boundaries noticing a jigsaw fit between Africa and South America. The
same rock stratiography in south eastern America has been found in western Africa suggesting that
these continental masses separated by the large expanse of water that is the Atlantic Ocean were
once joined as one. The presence of mesosaurus fossils in these two areas alone also support the
theory that these great masses once formed one large land mass called Pangaea.
The theory behind Pangaea is also helped by lysosaurus fossils found in Antarctica and Africa
suggesting these two land masses must also have been conjoined.
The presence of coal reserves in Britain and the Arctic and marine fossils half way up Mount Everest
and other Himalayan peaks suggest that both of their current locations have at times been
different. Coal forming in more tropical conditions suggests Britain once lay closer to the equatorial
regions of the world. The marine fossils indicate that the slopes of these Himalayan giants once lay
as sea floor on ocean beds.
Sea floor spreading, noticeable under the Atlantic Ocean can now be measured using advanced
laser measurements. The spreading displays a changed land mass location as also maps their
movement and the magnetic changes in the Earth’s field.
All of these theories provide supporting evidence of a once conjoined landmass and their
subsequent movement. They provide little insight into actual plate tectonic theory, more just
supporting the existence of a force changing the look of the Earth.
Volcanic and seismic activity provide a different sort of evidential proof for plate tectonics theory.
Rather than circumstantial evidence, they provide physical, monitored alterations around the Earth
that prove tectonic theory.
Excluding hot spot activity, seismic and volcanic events occur along ocean ridges, continental
divides and ocean edges. The most active area of volcanic and seismic activity is around the Pacific
Ring of Fire in the Pacific Ocean – named due to it volcanic activity – and between Europe and Asia
along north Africa and the Himalayas. These are both lined by fold mountains, high peaks and
volcanoes both in the sea and on land. The activity around these areas, along with those along the
mid-Atlantic Ridge and in east Africa suggest a strong underlying force causing these events to
happen. As volcanic activity occurs when plumes of magma rise through the Earth’s layers and
erupt on to the Earth and cool, their location and movement is important in proving tectonic
theory. Magma rises through the mantle crust and lithosphere and so logically takes the easiest
path. This suggests fissures and cracks in the solid crust and lithosphere. This directly leads to the
presumption that the lithosphere is in pieces. These pieces are what we suggest are tectonic plates
and so the theory is established. The linear volcanic formations suggest shapes and sizes for these
plates, and track their subsequent movement.
Seismic activity coincides with the areas that receive high levels of volcanic activity. Tectonic theory
promotes the idea that plates are converging and diverging at different locations. Seismic activity is
43
created by sudden movements, suggesting that the pieces of broken lithosphere move according to
tectonic theory.
Islands such as Iceland and Surtsey along the mid-Atlantic Ridge help to prove tectonic theory. High
tech measurements using lasers show sea floor spreading and the volcanic activity and uprising
magma suggest a large fissure is present allowing plumes of magma through, creating underwater
ridges, sea mounts and volcanic islands.
Volcanic hotspots best display the movement of the plates according to tectonic theory. Hawaii is
situated in the Pacific Ocean over a super plume of magma. This causes magma to erupt from
under the sea creating a chain of sea mounts and volcanic islands. As the plate moves in a north
easterly direction at 6cm a year, eventually volcanic activity dies on these islands leaving a land
mass whilst a new land mass is created. This causes a visible chain of islands such as Kaui and Maui
in Hawaii. They track the plate movement and provide evidence for tectonic theory.
Volcanic and seismic activity provide the strongest physical evidence for plate tectonic theory, and
are major pieces of evidence in its support. However, other fossil and stratiographical evidence are
equally as important in showing the movement and alterations in continental shaping. The map
provided by hot spots, fossils and stratiographical evidence are compounded by the physical
seismic and volcanic evidence to prove plate tectonic theory and as result are equally strong pieces
of evidential proof.
(780 words) K - 4↓, C/U – 4↓, C/S - 3↑, Syn – 4, Q – 4. Overall Level 4 = 33
June 2011
Discuss the view that the impact of earthquake hazards depends primarily on human factors.
Candidate A
Earthquakes are an example of seismic activity created by plate boundaries. They can be caused by
the subduction of oceanic crust which is densest at 2.9 g/cm3 under continental crust which weighs
2.7g/m3 at destructive plate boundaries. Earthquakes can also occur along conservative plate
boundaries such as that shared by the Pacific and North American plates which move at 5-9
cm/year and 2-3 cm/year respectively causing the 1994 Los Angeles earthquake along the San
Andreas fault alongside which lies the San Gregorio and Hayward faults. Earthquakes have different
impacts dependent on the location of their foci, the point at which they originate from
underground, the presence of land in the surrounding areas, but also the human factors such as
land use, population density and the use of earthquake proofing technologies to limit earthquake
impacts.
The Boxing Day tsunami in 2004 was created due to an earthquake along the 3 plate junction where
the Philippine, Pacific and Eurasian plates all meet. The 15-20 m slip along a 1600km slip plane
created an earthquake measures at 9.1 on the logarithmic Richter scale making it one of the most
intense earthquakes in history. It caused a tsunami wave which resulted in the deaths of 180000
people according to a UN report, though other sources suggested it reached 300000. The Kobe
earthquake which devastated the port of Osaka Bay resulted in 6300 deaths and 35000 serious
injuries. This earthquake measured 7.1 on the Richter scale meaning that it was less powerful as
each step up the scale is a 10 fold increase in power and a 30 fold increase in intensity. The impacts
in terms of death were vastly different as a result of the lower reading on the scale and therefore it
can be argued that natural factors such as the origin of the earthquake and its force are important
factors in determining the impact of earthquakes.
44
Further, the differing locations of the foci of the earthquakes were another natural factor that
causes a difference in the impact of the two earthquakes. The Boxing Day tsunami could not have
occurred if the foci of the earthquake had not been 160km south west of the Sumatran city of
Banda Aceh in the Indian Ocean. If it had been further towards the land then the tsunami waves are
unlikely to have been able to reach 28m in height and thereby cause the devastation they did when
encroaching 800m inland. Although sizeable damage would have been inflicted by an event of its
size if located under or nearer to land, this is not possible due to the location of the plate
boundaries which are entirely a natural occurrence. Similarly, the foci of the Kobe earthquake was
20km off Osaka Bay and subsequently its shockwaves led to great damage resulting in 20% of the
buildings in Kobe’s CBD becoming unusable. If it had been further out to sea, the power of the
seismic waves may have depleted due to the distance travelled and so less damage inflicted.
One could argue however that these points do not have merit due to the human use of the land
that is known to be in the locale of the earthquake zones. If no one inhabited Sumatra there would
not have been deaths, nor would there have been the 6300 in Kobe had it not been so densely
populated. Simply by living one could argue that human factors are causes of impacts, especially
when assessing fatalities.
Further, the human factors can be criticised for not doing enough to limit impacts or earthquake
hazards especially events such as death as a result of not enough fresh water being supplied
following water contamination of drinking water following the tsunami. Despite generous
donations of $0.96 billion from the USA and $0.84 million from Australia, as well as £300 million
raised by UK based charities, the provision of food for 1.3 million by the World Food Programme
was not sufficient as many died from water-borne diseases such as cholera and typhoid. Similarly in
Kobe, the 5 hour delay in mobilising the self defence force meant that only 200 soldiers were
immediately mobilised, possibly resulting in further preventable deaths. The Japanese authorities
realised that more needed to be done and by 21st January, 4 days after the event, 30000 troops
were in action. For some however, it was too late.
Land use in the two areas, a further human factor, was another cause of further deaths. The idyllic
coastal resorts of the many islands that were destroyed by the tsunami in Thailand and Sri Lanka
resulted in the deaths of 9000 foreign tourists. If an alternative land use had been present such as
agriculture, this number is likely to have been lower. In Kobe the population density and close
proximity of buildings in the cramped and crowded CBD is arguably another factor that resulted in
an increased death toll. Indeed, 64 high rise buildings were destroyed by the earthquake, and only
19 were planned to be rebuilt under tighter planning laws that enforce wider thoroughfares and
more open space to limit the impact of subsequent earthquakes in this sense. The 630m section of
the Great Hanshin Expressway that collapsed could be blamed solely on human factors as some
thought that engineers hadn’t done enough to reinforce the supporting columns. After being
rebuilt by October 119, the Expressway had been strengthened.
Prevention methods are also human factors that can be utilised to limit the impact of earthquake
hazards. For example, Kobe has new planning legislation which ensures that buildings are
reinforced suitably and many are designed to crumble inwards to prevent a domino effect of falling
buildings occurring. Springs, cables and moving foundation techniques are used in the construction
of all new buildings to minimise the risk of collapse. Homes in the Nagata district, where 60% of
those over 60 who died as a result of weak wooden framed houses with heavy slate tiles, have been
rebuilt to prevent further damage. Finally in Japan, September 1 st is National Earthquake Day when
children are educated on how to minimise the risk of injury following an earthquake and are taught
to use earthquake packs containing radios, torches and first aid kits.
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To prevent a death toll in the Indian Ocean as in 2004, 25 sensors have been embedded into the
sea floor to relay information back to 26 National Tsunami Centres to create an early warning
system similar to that in the Pacific. Sensors take readings at 15 minute intervals to detect tsunami
activity and limit the impact is such an event were to occur again.
In conclusion therefore, human factors play a sizeable part in the impact of earthquake hazards.
However, one cannot ignore the root cause of such events as being natural and the strength of
them cannot be altered by any human factors. (1137 words)
K – 4; C/U – 4; C/S – 4; Syn – 4; Q – 4 (down) = 38 marks
Candidate B
Earthquakes are tremors in the Earth’s crust which are caused mainly by tension between the
tectonic plates. Earthquakes are particularly prevalent along destructive and conservative plate
margins where plates can stick together for a time before slipping and releasing large amounts of
destructive energy. Earthquakes can vary in strength and can cause buildings to fall, pipes to crack
and completely devastate built up areas. They are deadly as people can be killed by falling debris or
by secondary consequences such as famine or disease.
Although more powerful earthquakes will tend to more destructive, the impact of earthquake
hazards depends primarily on human factors.
Earthquakes will provide a far greater hazard in urban areas than in rural areas as there are more
people living in these areas and more buildings are at risk. In addition, settlements located on or
near plate boundaries will be more likely to be hit by an earthquake meaning that where humans
choose to live is an important factor in how big an impact the earthquake has.
Another human factor which dictates the severity of an earthquake hazard is the level of
development than an area has. In more developed countries, earthquake prediction and
preparation will be far superior than in less developed countries.
Although earthquakes are very tough to predict, preparations can be made if an area is susceptible
to such a hazard. For example in the USA, school children are taught how to respond to an
earthquake and each household is instructed to prepare an earthquake emergency kit to use in
case of such an event. Other ways that earthquakes can be prepared for is by building ‘earthquake
proof’ buildings which are less likely to fall in the event of an earthquake. Retro-fitting old buildings
can also lessen the hazards. Such measures are however expensive to implement and less
developed countries will as a result be unlikely to take such steps. Therefore these nations will be
more at risk from earthquake hazards. As many of the hazards presented by earthquakes are
secondary effects to the ground-shaking, the degree to which a nation is equipped to respond to
earthquakes also affects how much of a hazard it can be considered.
This point can be illustrated by contrasting two specific earthquake events. The Northridge
earthquake in Los Angeles in 1994 killed around 120 people and left several thousand injured.
However, the relief effort was effective and the hundreds of damaged buildings were soon
replaced.
The Gujarat earthquake which occurred in India, and LEDC, resulted in nearly 20000 deaths, the
majority of which were due to the after effects of the earthquake such as disease and famine. The
relief effort in this case was not as effective with the country having to rely predominantly on
foreign aid for help. This shows drastically the development of a nation can affect how much of a
hazard an earthquake event presents.
Some would argue that earthquake hazards depend on the magnitude of the earthquake in that
more severe earthquakes will inevitably cause more destruction. It is also the case that earthquakes
can have an effect on people living relatively far from a tectonic boundary and that it therefore
46
does not depend on whether people choose to live on a tectonic plate boundary. In 2004 on 26 th
December an underwater earthquake in the Indian Ocean caused devastation thousands of miles
from the epicentre. The earthquake triggered a tsunami which struck Indonesia, Sri Lanka and even
Kenya to name a few countries. The tsunami caused in total 250000 deaths and is the largest
natural disaster on record. This shows how the impact of an earthquake hazards can depend on its
magnitude.
Although the magnitude of the earthquake will inevitably affect the impact it has, the primary
factor will be human activity in that area. If an earthquake occurs in a remote area, it will not be
considered a major hazard, but in areas where there are high densities of people there are more
lives at risk and therefore the earthquake will have a greater impact.
The demographics of a population can also have an effect the impact of a hazard. For example, if an
area has predominantly elderly or very young residents, the earthquake will have a greater impact
as such sectors of society will be less equipped to deal with the effects of the disaster. The same is
true of all tectonic hazards with the impact of a volcanic eruption depending on the population of
the surrounding country.
In conclusion, the impact of earthquake hazards will always depend primarily on human factors.
Even powerful earthquakes would be less hazardous if the area had a low population and few
buildings. The impact will be more severe in a heavily built up and populated area. The way we
define a phenomena as a hazard is by how much risk it presents to us as humans. Although more
powerful earthquakes can cause more destruction, the danger to humans will correspond to the
population and structure of the area, rather than the magnitude of the quake. Not only the size but
the population and demographic of a region will also affect the impact of such events as we have
seen. With more developed countries suffering less of an impact than less developed countries.
(877 words)
K – 2 (up); C/U – 2 (up); C/S – 3 (down); Syn – 3 (down); Q – 3 = 22 marks
January 2012
To what extent can preparedness and planning mitigate the effects of volcanic hazards?
Preparedness and planning can mitigate the effects of volcanic hazards. However there are many
other factors that can influence the effects, such as volcano type, severity of eruption, length of
eruption, third party influences of which no country can prepare totally for. However these are
methods which will reduce the impact. In this essay I will discuss the impacts of a Chilean volcanic
eruption which devastated the town of Chaiten and how its poor preparation influenced this. Also I
will discuss the 1991 eruption of Mount Etna in Sicily and how its preparedness and planning has on
it as one of the world’s best monitored and controlled volcanoes.
On the 2nd May 1991 a Chilean volcano that had laid dormant for nearly 9000 years exploded into
eruption. Due east winds carried the huge ash column east. However due to the size of the column
(20-30 km in height) the town of Chaiten, 10km south west of the volcano, was largely affected.
Due to its 9000 years of dormancy, the Chilean volcanic society had not deemed it dangerous
enough to be actively monitored prior to the eruption as limited research and funding was available
to their one volcanic acquisition centre even though there was documented history of dome
column building and collapse. The rhyolitic nature of the volcano (commonly found on destructive
margins) meant that the volcano’s eruption has increased by 500000m 2 and created 50 million m3
of new material. The subsequent collapse of the column caused pyroclastic flows down the
volcano’s slopes. It was only on the 16th May when the USGS arrived was the volcano actively
47
monitored. However due to the extensive eruption creating thunderstorms due to high execution
of gases and the passing of a storm, rainfall mixed with the ash fall (15cm in some places)
generated lahars which flowed down into the town of Chaiten.
UN government officials reported that 90% of the town was damaged and 20/30% of the town was
completely destroyed. Despite this only 1 person died in this event. Due to poor planning the town
of Chaiten was almost destroyed. If effective and appropriate land zoning techniques were
enforced prior to the volcano the town wouldn’t have been in the path of destructive pyroclastic
flows and lahars. However despite not having implemented appropriate planning and not being
prepared for the disaster the quick decisive action of the Chilean government saved thousands of
lives. By the 3rd of May 3900 people had been effectively evacuated by the Chilean navy.
Furthermore quick and strict safety regulations and methods were implemented on the town.
Protective masks and bottled water was handed out of water reservoirs had been contaminated by
ash. Small business had been granted a 90 day payment freeze on existing debts while almost every
family affected was granted $1200-2200 a month to help set back up the houses and lives. Despite
poor planning and preparedness for this particular volcano, the history of volcanic events in Chile
allowed for the government to act quickly and effective procedures used. This had a big influence
on the casualty list of only one.
Mount Pinatubo in the Philippines is a classic example of how other factors of preparedness and
planning can mitigate the effects of a volcanic hazard. Although classed as developing country prior
to the eruption, Mount Pinatubo had been heavily monitored by The PhilippInes Institute of
volcanic and seismic activity and by international players such as USGS. Both teams had collectively
predicted the scale and eruption point of the eruption which enabled 56000 people to effectively
be evacuated. However what the scientists didn’t predict was the unfortunate mixing of typhoon
Yanga. Heightened winds and heavy rainfall mixed with the eruption forming devastating lahars
reaching speeds of 90 km/hour down four river valleys adversely affecting many other villages
downstream causing over 200 deaths. The heavy ash fall and precipitation mixed with heightened
wind meant buildings well outside of the 30km evacuation zone were punished. Roof collapsing led
to a further 390 deaths.
The eruption of Mount Pinatubo is a good example of despite having the world’s best analysis
(USGS) monitoring the volcano, other factors such as the mixing of typhoon Yanga caused 100s of
deaths which no one could have seen coming. This also implies that countries who have the best
preparation and planning for volcanic hazards, often MEDCs, are still just as vulnerable to those
countries who have little planning and preparation. However they have past knowledge of events
and can implement effective management schemes.
Mount Etna’s eruption in 1991 Sicily however is a good example of how effective preparation and
planning can have tremendous positive effects on a volcano’s hazards. Mount Etna, Europe’s
highest volcano at 3200 m above sea level, and most active volcano, is one of the world’s best
managed. Mount Etna is lined with a field of sensors to detect an eruption with a combination of
magnetic, geodetic, seismic and video sensors actively linked to a monitoring station in real time.
This is most necessary as Mount Etna supports rich agricultural ground supporting 25% of Sicily’s
population. Including the constant monitoring there are other factors that favour the volcano
despite being classed as a decade one. Being a composite strato volcano when eruptions do occur
its low effusion rates of lava favour managing methods despite the lava being able to travel large
distances. The volcano has no explosive traits. Therefore pyroclastic flows, lava bombs and heavy
ash fall are not a threat.
When in 1991 Mount Etna did erupt, its management, preparation and planning techniques
showed themselves to help in one of the best managed eruptions. Prior to the event huge earth
48
barriers had been set up on the slopes some tens of metres tall and several hundreds of metres
long. This was not implemented as a permanent solution but to simply delay the onset so other
methods could be brought in. Army helicopters dropped huge concrete blocks through the tops of
the lava columns to block some vents in order to aid the redirection of lava flow. To further change
the direction of lava flow, engineered blasting took place to produce new vents through which lava
could be taken away from the populated and rich agricultural areas. These methods helped save
millions of dollars of damage – environmental and structural.
There was however other factors that did aid the success of the preparation and planning. The
vents that were eruptive were high above populated areas – therefore not as hazardous as if lower
down. Furthermore low emission rates of lava made it possible to manage. Although these aided, it
was the preparation and planning of the agencies involved that proved most effective in mitigating
the effects of the volcano.
Although there are other factors that can favour the effects of volcanic hazards such as the mixing
of typhoon Yanga severely developing the unpredicted hazards of Mount Pinatubo eruption, that is
down to sheer unfortunate circumstances. Despite this I feel effective preparation and planning
such as the case of Mount Etna’s 1991 eruption and the quick decision of the Chilean government
regarding the town of Chaiten due to experience of previous hazards has the biggest effect on a
volcanic hazard.
1195 words. K - 4↓, C/U - 3↑, C/S – 3↑, Syn - 4, Q – 4↓. Level 4 – 35
June 2012
Evaluate how plate tectonics theory helps our understanding of the distribution of seismic and
volcanic events.
Candidate A
The theory of plate tectonics is a relatively new idea – only conceived and developed within the last
100 years and is now generally accepted as the explanation for the causation of earthquakes and
volcanoes and where they occur. It has now replaced the theory that tectonic events are caused by
god in most western countries.
The theory of plate tectonics was first developed by Alfred Wegener in 1912. He saw that the
continents seem to have a jig-saw fit eg Africa and South America coastlines fitting together,
suggesting that they were at one time joined together as part of a super continent called
Gondwanaland and the other super continent Laurasia was in the north. Later evidence supported
this – the fossilised remains of a dinosaur, the mesosaurus, was found on the coasts of Brazil and
Gabon. There were also the same fossilised pollen species and rock sediments on these coastlines.
Wegener’s ideas, though simple, were proved further right and built upon which further increased
our understanding of tectonic events. Sea floor spreading was discovered showing that rock is being
created and destroyed, leading us to believe in the existence of plates and plate boundaries. Sea
floor spreading was shown in the Atlantic, where it is believed the Eurasian and North American
plates are moving apart, at what is called a constructive plate boundary. Here magma rises through
a rift and cools rapidly on the surface creating new plate material and a ridge of volcanoes called
the mid-Atlantic ridge. This has created Iceland which also contains rift valleys showing the plates
are moving apart. The eruption of Surtsey in 1963 created a new island which further proved that
land and plate were being constructed along this margin. More modern technology has helped to
prove this theory. Carbon dating of the oceanic crust has shown that the crust nearer to the UK is
far older than crust along the mid-Atlantic ridge. Deep sea exploration has discovered ‘black
49
smokers’ and palaeomagnetism. Palaeomagnetism is where metallic elements in the crust are
aligned in opposing layers. Every several 100000 years the poles flip – this means that every such
time the metallic elements align themselves in the opposite direction ie facing the pole they are
attracted to. This means that each band of the opposingly aligned elements in the crust represent
several hundred thousand years of crust that was created in that time. All this evidence combined
to prove sea floor spreading but this means if a plate is being created at one end, it must be being
destroyed somewhere else.
This was once again proven by deep sea exploration. Many earthquakes and volcanoes are found
along the Pacific Ring of Fire. Running close by parallel to these boundaries were very deep ocean
trenches eg the Marianas trench, which were the deepest parts of the ocean. Scientists realised
that the ocean trenches showed that some plates are subducted – this being where they are
destroyed. Here an oceanic plate which is denser would subduct a continental plate, the plate
would melt inside the mantle creating a pool of magma which would rise through the cracks in the
rock forming a volcano. This addition to the plate tectonic theory explained why volcanoes are
always found along plate boundaries which are constructive – due to rising magma – and
destructive – due to plate melting.
However plate boundaries are different. Many earthquakes are distributed along the
Eurasian/Indo-Australian plate boundary where there are no volcanoes. There are very high
mountains here such as the Himalayas. The theory of plate tectonics explains that oceanic plates,
because they are denser, always subduct continental plates. Here two continental plates meet – so
scientists developed a theory that fold mountains were created. The two plates converge, neither
subducts the other, they both push sediments up together creating very high fold mountains.
Pressure builds and eventually the plates fault upwards, breaking and adding to the creation of the
mountains so this explained the other way that plates could be destroyed – by fracturing. The build
up of pressure and sudden faulting explained why so many earthquakes occurred along this
boundary, such as in Bam, Iran in 2003. The earthquakes found along destructive plate boundaries
such as the Japan earthquake in 2011 were caused by a similar build up of pressure, because the
subducting (Pacific) plate would ‘stick’ to the subducted (Eurasian) plate, pulling it down and then
eventually releasing the ‘stuck’ plate creating an earthquake.
So the plate tectonic theory had explained why volcanoes and earthquakes were formed along socalled imaginary lines – because there were actually a variety of different plate boundaries.
However there were some issues. The volcanoes of Hawaii and Yellowstone are found in the middle
of plates (intra-plate) and so did not correlate with the idea that volcanoes were found along plate
boundaries. However Tuzo Wilson was able to explain this with the Hawaiian hot spot theory. He
said hot spots were formed by magma plumes in the mantle which created melting of the crust at a
particular point forming a volcano. He stressed that the plume was stationary and the crust moved
over it. This created a series of volcanoes called the Emperor sea mountain chain. The plume would
create a volcano – the crust would move so the plume would no longer build a volcano there and
would start a new one alongside. The old volcano would be eroded by wind and wave until it went
under the sea creating a coral reef around it – eg the Midway Islands. Eventually the seamount
would be destroyed at a destructive plate boundary near Russia. So in fact the troubling issue of an
intra-plate hot spot actually helped to prove plate movement and therefore the theory of plate
tectonics.
Another issue was that there was evidence of volcanoes in areas away from plate boundaries.
Examples include Arthur’s Seat in Edinburgh (an extinct volcano) and the Whin Sill dyke in northern
England. But in fact these also proved plate tectonic theory because they showed temporal change
ie they were once at plate boundaries but have move away because of plate movement. All the
50
evidence, sea floor spreading, hot spots and subduction proved the plates moved. The theory
behind this was later developed: that convection currents in the mantle drove movement and slab
pull at subduction zones drag the plate across the fairly liquid mantle.
The theory proved that there was a general correlation between earthquakes/volcanoes locations
and their proximity to a plate boundary. However they only explain where tectonic events generally
occur, not specifically plate tectonic theory cannot tell us where along a boundary an earthquake
will occur just that an earthquake will occur somewhere along that boundary. In addition, the
effects of an earthquake can be felt far away from a boundary. The Boxing Day tsunami in 2004
affected the Maldives which are located intra-plate. Also seismic waves travel and can be felt over a
wide area. A very important point to note is that plate tectonic helps the understanding of the
educated, particularly in the West. People in LEDCs with poor education will be unaware of plate
tectonic theory and many of these are religious, so they will say tectonic events are from god and
so plate tectonic theory does not help that understanding because they are not privy to it.
In conclusion the recent conception and development of plate tectonic theory has greatly aided our
understanding of the distribution of seismic events. We now understand that plates are continually
moving and earthquakes and volcanoes are found along these boundaries. Exceptions to this rule
such as Hawaii also help prove tectonic theory due to their unique creation. Whilst this has helped
our understanding we also recognise the fact those in LEDCs with poor access to education are
unaware of plate tectonic theory so the theory will not yet have helped their understanding.
(1304 words)
K- 4↑; C/U – 4; CS – 4↓; Syn – 4↑; Q – 4 Total 38
Candidate B
Plate tectonic theory can help our understanding of the distribution of volcanic and seismic events
by helping us outline where they may occur but not all seismic or volcanic activity occurs at plate
boundaries.
Nova Zembla island in northern Russia is a declared nuclear zone. They used a machine to see how
much seismic energy was caused by their controlled explosions but while the seismometer was
recording this, it was also recording seismic activity around the globe producing a map of where the
most activity happened in the world. This map showed an outline of where the plate boundaries
were and therefore supported plate tectonic theory.
The mid-Atlantic Ridge supports the theory also. Here the plates move away from each other at a
constructive margin where new crust is constantly being formed where the sea cools down the
magma coming up to the surface. We know that new rock is being formed as scientists can date
how old rock is by its magnetic pull and direction. At the top of the mid-Atlantic Ridge is Iceland
which happens to be a volcanic zone. There are a series of underwater volcanoes as well as full
islands like Surtsey which were created as a direct result of volcanic activity. The eruption of the
Icelandic volcano Ejafajallajokull in 2010 caused massive disruption internationally as the ash plume
it created was picked up by the jet stream, grounding planes. No commercial planes were damaged
but a few non-commercial jets and military planes were damaged. This cost airlines billions of
dollars as people were displaced in the UK and Europe for almost a week in March. In this case
people thousands of miles away from the volcano were affected. So knowing the distribution of this
volcanic zone did not help, but local people were evacuated from the area and some tourism was
also gained as people travelled to view the eruption.
The area on the western American coast is part of the major volcanic zone called the ‘Ring of Fire’.
This outlines the Pacific plate boundary supporting plate tectonic theory. Mt St Helens is a part of
this ring. It erupted in the 1980s. It was a dormant volcano which was awakened by a magnitude 4
51
earthquake. A bulge was seen on the north flank of the volcano at about 5m per day. The local
government and authorities evacuated the area and created exclusion zones to protect people
from the volcano. When it erupted it killed around 1000 people as some local people refused to
leave their homes. It cleared an area of woodland killing deer, elk, moose and some black bears. So
this was a disaster not only for humans but also animals. Local businesses were buried under the
lava and ash from the eruption.
Not all volcanic eruptions are on or near plate boundaries. These are caused by ‘hot spots’. Hot
spots can occur right in the middle of plates so this goes against plate tectonic theory and does not
help with the understanding of the location of volcanic and seismic events. The small islands of
Hawaii are formed over a hot spot, currently Kilauea is sitting on top of a very active volcano. From
its top to its underwater bottom it is a rival to be the biggest volcano such as Kilimanjaro in Africa.
Other volcanic hotspots are Mauritius and the Maldives.
Hot spots can also cause a threat to people as they can form super-volcanoes. Yellowstone’s
caldera is sitting on a hot spot in western USA. If this erupted it would cause global problems and
would devastate almost half of the USA. It would explode at a rate that anyone close enough would
die and it would distribute ash in all 50 states of the USA. It could even change global temperatures
and cause the next ice age. This is an important example of why we should understand the
distribution of volcanoes and seismic activity even if they are not supportive of plate tectonic
theory.
By using plate tectonic theory and understanding the distribution of tectonic hazards we could help
scientist predict tectonic threats. In 1998 scientists produced a prediction of an earthquake which
devastated the city of Izmit in Turkey. The scientists looked at the Anatolian fault which is an
unusually straight fault line. They noticed a pattern of earthquakes along the fault line and decided
they would try to predict where the next earthquake would happen. They analysed that stress
moves along the fault line. In this case the stress is moving westwards. It was predicted the
earthquake would hit Izmit and despite the warning people did not adhere to the advice and in
August 1999 a magnitude 7.4 earthquake hit Izmit killing 25000 and injuring more than 30000
people.
Earthquakes in Greece and ancient times destroyed many wonders of the world such as the
Colossus of Rhodes and Mausoleum of Hercules, and even the Hanging Gardens of Babylon, and the
lighthouse in Alexandria are suspected to have fallen to earthquakes. But not all earthquakes, like
volcanoes happen at plate boundaries. So their distribution may not only be based on plate
tectonics theory. In Lapland, Sweden, there is a fracture where part of the land has jolted about 3m
upwards in parts. The fracture is about 150m long and was assumed to be caused by an earthquake
caused by the melting of ice from the Ice Age. The weight was lifted from the land causing it to jolt
upwards. But could this type of seismic activity happen again but due to the melting of the ice caps
caused by global warming? If so plate tectonics won’t be able to help predict this distribution of
this.
Fracking is another non plate tectonic type of seismic activity. In the UK in Lancashire tremors were
felt of up to 3 on the Richter Scale as a result of the extraction of natural gases from shale near
Blackpool. So, human activity can cause this type of seismic activity. Building dams can also cause
earthquakes.
In conclusion plate tectonics can help to identify where a seismic or volcanic event may happen but
not all activity can be predicted this way. So, the theory of plate tectonics is useful but other
methods need to be looked at to fully understand the distribution of these events. (1049 words)
K- 2↑; C/U – 3; CS – 3↓; Syn – 2; Q – 3↓ Total 22
52
Plate tectonics materials that can be used for statistical skills activities
1. Italian earthquakes that caused fatalities of > 10 (1905 – 2009)
Date of earthquake
Location
2009
2002
1991
1980
1976
1971
1968
1930
1920
1915
1908
1905
L’Aquila
Molise
Umbria
Irpinia
Friuli
Lazio
Sicily
Vulture
Toscana
Avezzano
Messina
Calabria
Moment Magnitude
Scale
6.3
5.9
6.1
6.9
6.2
4.5
6.4
6.5
6.4
6.8
7.2
6.9
Deaths
308
28
11
2570
989
31
236
1400
171
32610
120000
557
Investigate the relationship between the strength of the earthquake and the number of deaths. You
can do this by either a scatter graph, or by a Spearman’s Rank correlation exercise (see below)
Italian earthquakes that caused fatalities of >10 (1905 – 2009)
Location
L’Aquila
Molise
Umbria
Irpinia
Friuli
Lazio
Sicily
Vulture
Toscana
Avezzano
Messina
Calabria
Moment
Magnitude
Scale
6.3
5.9
6.1
6.9
6.2
4.5
6.4
6.5
6.4
6.8
7.2
6.9
Rank (Scale)
Deaths
Rank (Deaths)
d
d2
308
28
11
2570
989
31
236
1400
171
32610
120000
557
Σ d2 =
Calculate the Spearman’s Rank correlation coefficient using the formula:
Rs =
Now test the significance of your result using the following table:
53
Conclusion:
2. Repeat for Japanese earthquakes that caused fatalities of >10 (1933 – 2008)
Date of earthquake
2008
2007
2004
1995 (Kobe)
1978
1968
1964
1948
1946
1945
1943
1933
Moment Magnitude
Scale
6.9
6.6
6.9
6.8
7.7
8.2
7.6
7.1
8.1
6.8
7.2
8.4
Deaths
12
11
40
6434
28
52
26
3769
1362
2306
1083
3000
Japanese earthquakes that caused fatalities of >10 (1933 – 2008)
Date of
earthquake
2008
2007
2004
1995 (Kobe)
1978
1968
1964
1948
1946
1945
1943
1933
Moment
Magnitude Scale
6.9
6.6
6.9
6.8
7.7
8.2
7.6
7.1
8.1
6.8
7.2
8.4
Rank (Scale)
Deaths
Rank
(Deaths)
d
d2
12
11
40
6434
28
52
26
3769
1362
2306
1083
3000
Σ d2 =
54
3. An investigation into the variability in the size of earthquakes at two different plate margins:
Italy and Japan.
This can be investigated using the Mann Whitney U test, using the data given above.
Null hypothesis: that there is no difference between the sizes of earthquakes at the two plate
margins
Alternative hypothesis: there is a difference between the sizes of earthquakes at the two plate
margins
Italy
x
Japan
Rank (rx )
y
6.3
6.9
5.9
6.6
6.1
6.9
6.9
6.8
6.2
7.7
4.5
8.2
6.4
7.6
6.5
7.1
6.4
8.1
6.8
6.8
7.2
7.2
6.9
8.4
No in sample (NX) =12
Total of rank scores
(Σrx) =
Rank (ry)
No in sample (Ny) =12
Total of rank scores
(Σr y) =
Complete a Mann Whitney U test to see if there is a difference between the sizes of earthquakes at
the two areas of plate boundary.
NB. Rank each item of data in terms of its position within the sample as a whole; start with the
lowest rank first.
55
Formula:
Ux =
Uy =
Now test the significance of your results using the following table:
Conclusion:
56
Plate tectonics materials that can be used for statistical skills activities
Answers
Italian earthquakes that caused fatalities of >10 (1905 – 2009)
Location
L’Aquila
Molise
Umbria
Irpinia
Friuli
Lazio
Sicily
Vulture
Toscana
Avezzano
Messina
Calabria
Moment
Magnitude
Scale
6.3
5.9
6.1
6.9
6.2
4.5
6.4
6.5
6.4
6.8
7.2
6.9
Rank (Scale)
Deaths
Rank (Deaths)
d
d2
8
11
10
2.5
9
12
6.5
5
6.5
4
1
2.5
308
28
11
2570
989
31
236
1400
171
32610
120000
557
7
11
12
3
5
10
8
4
9
2
1
6
1
0
2
0.5
4
2
1.5
1
2.5
2
0
3.5
1
0
4
0.25
16
4
2.25
1
6.25
4
0
12.25
Σ d2 = 51
Rs = 1 – (6 x 51 / 1728-12) = 1 – 306/1716 = 1 – 0.178 = 0.822
Conclusion:
For n=12, this Rs is greater than 0.777, and hence the relationship is positive and significant at the
0.01 level. Therefore there is a less than 1% probability that the relationship occurred by chance. It
is highly significant.
2. Japanese earthquakes that caused fatalities of >10 (1933 – 2008)
Date of
earthquake
2008
2007
2004
1995 (Kobe)
1978
1968
1964
1948
1946
1945
1943
1933
Moment
Magnitude Scale
6.9
6.6
6.9
6.8
7.7
8.2
7.6
7.1
8.1
6.8
7.2
8.4
Rank (Scale)
Deaths
8.5
12
8.5
10.5
4
2
5
7
3
10.5
6
1
12
11
40
6434
28
52
26
3769
1362
2306
1083
3000
Rank
(Deaths)
11
12
8
1
9
7
10
2
5
4
6
3
d
d2
2.5
0
0.5
9.5
5
5
5
5
2
6.5
0
2
6.25
0
0.25
90.25
25
25
25
25
4
42.25
0
4
Σ d2 = 247
Rs = 1 – (6 x 247 / 1728-12) = 1 – 1482/1716 = 1 – 0.864 = 0.136
Conclusion:
For n=12, this Rs is not greater than 0.591, and hence the relationship is not significant at any level.
There must be other factors influencing the death toll.
57
3. An investigation into the variability in the size of earthquakes at two different plate margins:
Italy and Japan.
Italy
x
Japan
Rank (rx )
y
Rank (ry)
6.3
5
6.9
14.5
5.9
2
6.6
9
6.1
3
6.9
14.5
6.9
14.5
6.8
11
6.2
4
7.7
21
4.5
1
8.2
23
6.4
6.5
7.6
20
6.5
8
7.1
17
6.4
6.5
8.1
22
6.8
11
6.8
11
7.2
18.5
7.2
18.5
6.9
14.5
8.4
24
No in sample (NX) =12
Total of rank scores
(Σrx) = 94.5
No in sample (Ny) =12
Total of rank scores
(Σr y) = 205.5
Ux = 127.5
Uy = 16.5
Conclusion:
For a sample size of 12, the table shows that the critical value at the 0.05 level of significance is 37.
As the smaller value of U (16.5) is less than the critical value, the null hypothesis can be rejected.
We can accept the alternative hypothesis. We can be 95% certain that the result obtained did not
occur by chance, and that there is a significant difference between the sizes of earthquakes at the
two plate margins.
58
The Bay of Naples Issue Evaluation Exercise
Naples: the city
Background
Naples (Italian: Napoli) is an historic city in southern Italy, the capital of the Campania region and
the province of Naples. The city is noted for its rich history, art, culture and gastronomy, playing an
important role throughout much of its existence; it is over 2,500 years old. Naples is located
halfway between two volcanic areas, the volcano Mount Vesuvius and the Phlegraean, situated on
the coast in the Bay of Naples. Founded by the Ancient Greeks, it held an important role in ‘Greater
Greece’ and then as part of the Roman Republic in the central province of the Empire. Naples was
the capital city of a kingdom which bore its name from 1282 until 1816, then in union with Sicily it
was the capital of the ‘Two Sicilys’ until the Italian unification. In the area surrounding Naples are
the islands of Procida, Capri and Ischia, which are reached by hydrofoils and ferries. Sorrento and
the Amalfi Coast are situated south of Naples. The Roman ruins of Pompeii, Herculaneum and
Stabiae, which were destroyed in the eruption of Vesuvius in 79 AD, are also within the area.
Modern day Naples
In the modern day, the historic centre of the city is listed by UNESCO as a World Heritage Site. The
metropolitan area of Naples is the second most populated in Italy, with around 3.8 million people.
In the central area, the city itself has a population of around 1 million people; the inhabitants are
known as Neapolitans. Its greater metropolitan area, sometimes known as Greater Naples has an
additional population of 2.8 million. The demographic profile for the Neapolitan province in general
is quite young: 19% are under age 14, while 13% are over 65, compared to the national average of
14% and 19%, respectively.
Unlike many northern Italian cities there are far fewer immigrants in Naples, 98.5% of the people
are Italians. In 2006, there were a total of over 19000 foreigners in the actual city of Naples; the
majority of foreigners are Eastern European, coming particularly from the Ukraine and Poland. NonEuropeans in general are very low in number; however there are some small Sri Lankan and East
Asian immigrant communities. Statistics show that the vast majority of immigrants are female; this
is because male workers tend to head north.
The geography of the Naples area
Naples enjoys a typical Mediterranean climate with mild, wet winters and warm to hot, dry
summers. The mild climate and the geographical richness of the Bay of Naples made it famous
during Roman times, when emperors chose the area as a favourite holiday location.
The regional economy in Italy is measured on a provincial level; the province of Naples is placed
94th out of the total of 103 provinces in Italy in terms of economic wealth. However, government
statistics do not include wealth generated by the black market or untaxed wages. It is not
uncommon for Neapolitan workers to move North because unemployment is at around 28%. In
recent times, there has been a move away from a traditional agriculture-based economy in the
province to one based on service industries.
Employment in different sectors in the province of Naples breaks down as follows:
Public
services
Manufacturing Commerce
Construction Transportation
Financial
services
Agriculture
Hotel
trade
Other
activities
30.7%
18%
9.5%
7.4%
5.1%
3.7%
3.4%
14%
8.2%
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Naples is well connected in regards to major motorways, known in Italy as autostrada. From Naples
all the way north to Milan is the A1 known as autostrada del Sole (motorway of the sun), the
longest motorway on the peninsula. There are other autostrada from Naples too, such as the A3
which goes southwards right down to Reggio Calabria, as well as the A16 which goes across east to
Canosa. The latter is called the autostrada dei Due Mari (motorway of the Two Seas) because it
connects the Tyrrhenian Sea to the Adriatic Sea. Most of the sections of these motorways are dual
carriageway.
Typically narrow road in Naples.
Within the actual city itself there are many public transport services, including trams, buses,
funiculars and trolleybuses. Naples also has its own Naples Metro, the underground rapid transit
railway system of the city which has several metro stations. The main general train station of the
city is Napoli Centrale, which is located in Piazza Garibaldi. Naples has lots of narrow streets, so the
general public commonly use compact hatchback cars and scooters are especially common.
The port of Naples has several ferry services open to the general public, most of which are to places
within the Neapolitan province such as Capri, Ischia and Sorrento, or the Salernitan province, such
as Salerno, Positano and Amalfi. Within the scope of suburb San Pietro a Patierno is the Naples
International Airport, the most important airport in southern Italy, which serves millions of people
each year with around 140 flights daily.
There is one other issue that is of major concern in the area – litter. As The Lonely Planet Guide to
Italy states “Litter conscious visitors to the peninsula will be astounded by the widespread habit of
Italians who dump rubbish when and where they like”. This is particularly evident throughout the
Bay of Naples area.
Climate statistics for Naples
Month Jan
Temp 12
oC
Ppt
90
(mm)
Feb
12
Mar
15
Apr
17
May June July
22
26
29
Aug
29
Sept Oct
26
21
Nov
16
Dec
13
80
70
70
50
30
70
120
110
30
20
130
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Vesuvius.
Mount Vesuvius (Italian: Monte Vesuvio) is a stratovolcano east of Naples. It is the only volcano on
the European mainland to have erupted within the last hundred years, although it is not currently
erupting. The two other volcanoes in Italy (Etna and Stromboli) are located on islands.
Vesuvius is on the coast of the Bay of Naples, about nine kilometres east of Naples and a short
distance from the shore. It is conspicuous in the beautiful landscape presented by the Bay of
Naples, when seen from the sea, with Naples in the foreground.
Vesuvius is best known for its eruption in AD 79 that led to the destruction of the Roman cities of
Pompeii and Herculaneum. It has erupted many times since and is today regarded as one of the
most dangerous volcanoes in the world because of the population of 3 million people now living
close to it and its tendency towards explosive eruptions. It is the most densely populated volcanic
region in the world.
The most recent eruption took place in March 1944. A number of villages and orchards were
partially destroyed, and 26 people were killed, although it is thought that most of those died from
heart attacks. Residents put pots on their heads to protect against rocks shooting down through the
air. However, the rumblings soon stilled. The volcano has been quiet since. While Vesuvius is not
thought likely to erupt in the immediate future, the danger posed by future eruptions is seen as
very high in light of the volcano's tendency towards sudden extremely violent explosions and the
very dense human population on and around the mountain.
What happens if/when Vesuvius erupts again?
The emergency plan for an eruption assumes that the worst case will be an eruption of similar size
and type to the AD 1631 eruption. In this scenario the slopes of the mountain, extending out to
about 7 kilometres from the vent, may be exposed to pyroclastic flows sweeping down them, whilst
much of the surrounding area could suffer from tephra falls. Because of prevailing winds, towns to
the south and east of the volcano are most at risk from this, and it is assumed that tephra
accumulation exceeding 100 kg/m² - at which point people are at risk from collapsing roofs - may
extend out as far as Avellino to the east or Salerno to the south east. Towards Naples, to the northwest, this tephra fall hazard is assumed to extend barely past the slopes of the volcano.
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The plan assumes between two weeks and 20 days notice of an eruption and foresees the
emergency evacuation of 600,000 people, almost entirely comprising all those living in the zona
rossa ("red zone"), i.e. at greatest risk from pyroclastic flows. The evacuation, by trains, ferries,
cars, and buses is planned to take about seven days, and the evacuees will mostly be sent to other
parts of the country rather than to safe areas in the local Campania region, and may have to stay
away for several months.
However the dilemma that would face those implementing the plan is when to start this massive
evacuation, since if it is left too late then many people could be killed, whilst if it is started too early
then the precursors of the eruption may turn out to have been a false alarm. In 1984, 40,000
people were evacuated from the Campi Flegrei area, another volcanic complex near Naples, but no
eruption occurred.
Ongoing efforts are being made to reduce the population living in the red zone, by demolishing
illegally constructed buildings, establishing a national park around the upper flanks of the volcano
to prevent the erection of further buildings and by offering financial incentives to people for
moving away (up to 30000 euros per family). The underlying goal is to reduce the time needed to
evacuate the area, over the next 20 or 30 years, to two or three days.
The volcano is closely monitored by the Osservatorio Vesuvio in Naples with extensive networks of
seismic and gravimetric stations, a combination of a GPS-based and satellite-based radar to
measure ground movement, and by local surveys and chemical analyses of gases emitted from
fumaroles. All of this is intended to track magma rising underneath the volcano. So far, no magma
has been detected within 10 km of the surface, and so the volcano was, in 2007, at worst only in
the very early stages of preparing for an eruption.
Tourism to Pompeii
The Roman town is one of the best known sites in the world - and also one of the most threatened.
Visitor numbers have shot up from 863,000 in 1981 to around two million today. But many of the
houses that were open in the 50s are now closed and Pompeii was included on the World
Monuments Watch List of 100 Most Endangered Sites in 2000. Consequently, there are proposals
to restrict the number of tourists to the site.
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Further materials.
Item 1. Italians trying to prevent a modern Pompeii
(Adapted from the ‘USA Today’ website: 20th October 2003)
SAN SEBASTIANO AL VESUVIO, Italy - Carlo Tarallo lives in the last house on one of the last streets of
this village with a view to die for. So close does he sleep to the most dangerous volcano in the world
that when he looks out his bedroom window he can't see all of it. "There are great benefits to living
under Vesuvius," jokes Tarallo, 32, whose family home lies in the zona rossa , the area at highest risk
from the volcano. "You smoke as much as you want, drink as much as you want. Why not?"
Another elderly resident, Giuseppe, believes he would have plenty of time to leave when the next
eruption occurs. His memories of the last eruption in 1944 are of a lava flow that moved at 5km/h.
"Last time it all happened very slowly," he says. "And then it stopped. We are not afraid. We left
briefly and then we came back to our houses."
It's only a matter of time before it does erupt, scientists say. "It won't be tomorrow, it won't be next
month, and maybe it won't be next year. But it is overdue," says Giovanni Macedonio, director of
Vesuvius Observatory, the institute responsible for monitoring the volcano. When it blows,
Macedonio warns, it could be with the power of "tens of hundreds of atomic bombs."
During the volcano's 60-year slumber, however, sprawl from nearby Naples has spilled out; nearly
600,000 people now live in the 18 villages in the shadow of the volcano. Combined with Vesuvius'
volatile nature - its eruptions are characterised by explosions that rocket out deadly gas and dust,
not just slow-moving floods of lava - this population density makes the volcano the most dangerous
in the world, scientists say.
About 800 structures - from restaurants and resort villas to house additions such as balconies - have
been built in the park without permission, estimates Amilcare Troiano, president of National Park of
Vesuvius. So far, 30 have been removed. In early October, the country's highest court struck down a
popular appeal to award amnesty to those who have constructed illegally in the park and in towns
in the high-risk "red zone" of the volcano. More than 50,000 people sought the amnesty, which
would have made their constructions legal. (Officials estimate at least twice as many people have
constructed illegal homes, hotels and other buildings without permits or on land they don't even
own.)
The amnesty appeal was backed by the national government. That's an indication, local planners
say, of how controversial their efforts are to crack down on population growth in the area and also
of the divisions between Italy's national government and the regional government in Naples. "It can
be very dangerous. They all hate us," Troiano confesses. After receiving a few death threats at the
start of the demolition program, Troiano and his staff were assigned carabinieri (police) to protect
them. The threats have since diminished as local residents have begun to accept the program.
But by far the most ambitious aspect of the Vesuvius emergency plan is the effort to relocate many
of the area's residents. The goal is to reduce the population by as much as 150,000 within 15 years,
according to Marco Di Lello, director of urban planning for the Campania Region, home to Vesuvius.
"We're not saying everyone should leave," Di Lello stresses. "This is mainly aimed at young people,
even renters, to get them to set up households elsewhere. Or to older retired people who might
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want to move anyway." It would take two weeks to evacuate the 580,000 people now living in the
highest risk zones, according to Di Lello.
Getting everyone out safely and quickly may not be the biggest headache the government faces,
though. Scientists now know that volcanoes send out signals - rumblings and magma fractures
among other symptoms - that warn of a potential eruption in time to evacuate threatened
residents. But if the precursors can signal an eruption, they don't guarantee one. In fact, there's a
50% chance an eruption won't occur. And therein lies the hitch: what if everyone is evacuated and
Vesuvius doesn't erupt. "Imagine evacuating 580,000 people and nothing happens," Macedonio
says. "Get it wrong, and it's the end of a career."
Item 2: View of Professor Michael Sheridan (US National Academy of Sciences)
He states that the next eruption of Vesuvius could be much more deadly than the Italian authorities
are planning for. He said he had been motivated by the US experience of Hurricane Katrina, when
authorities failed to prepare adequately for a well-understood weather disaster. "The current
planning doesn't consider the maximum probable event," explained Professor Sheridan. "There
have been notable cases recently where disaster planners have not taken into account the worstcase scenario and this eruption would certainly be one of those. It actually has a fairly high
probability of occurring if we consider there have been eight large eruptions of this kind in the
history of Vesuvius with a separation in time of 2-3,000 years, and it's been nearly 2,000 years since
the last one." Professor Sheridan recognised the difficulty of evacuating three million people from a
major urban centre such as Naples. He noted that, as was the case after Hurricane Katrina,
distribution of water, food, and housing for the survivors and the nature of the escape routes must
also be carefully considered with an evacuation of such magnitude.
Waste disposal
Item 3. Riches in rubbish for Naples Mafia
(Adapted from the BBC News website: 29th July 2004)
In the Italian city of Naples, a refuse crisis has been seized upon by the local Mafia, who have
identified a lucrative business opportunity. Naples is drowning in its own waste. The situation
reached a crisis point recently when piles of rotting rubbish filled the streets and caused an
environmental and public health emergency. Angry Neapolitans even took the law into their own
hands by setting fire to mounds of refuse on street corners. "The city produces thousands of tonnes
of rubbish each week and the landfill sites are full," said Marco Colombo, an Italian journalist who
has been investigating the problem. "There are no incinerators to deal with the problem because
no one wants them in their own backyard. The concept of recycling is a foreign one to most
Neapolitans."
Goldmine
Rubbish is a headache for the local authorities, but it is proving a goldmine for the local Mafia or
"Camorra" who have had a stranglehold on the waste disposal industry for years. According to a
parliamentary commission, the business generates around £4 billion a year. "Around 50% of Italy's
household and industrial waste industry is controlled by the eco-Mafia," said Magistrate Donato
Ceglie, who is spear-heading the battle against waste trafficking. The Camorra disposes of
household and industrial waste at very competitive rates, but have allegedly dumped it in rivers,
fields and caves all over the Campania region. More seriously, it has even been claimed that
64
industrial waste has been disguised by mixing it with tarmac and asphalt, and made into bricks used
to build houses.
Contamination
Farmer Annibale Salerno has an olive and wine farm in the village of Montecorvino Pugliano, an
hour south of Naples. He claims he is one of the eco-Mafia's victims, because his land and water
have been contaminated by toxic waste. "This land is all I have got. It is the land of my father and
my grandfather," said Mr Salerno. "I am sandwiched between a massive quarry and a public
dumping site so my land is not worth anything any more. "I cannot sell my produce and my sons
have all gone up north because there is no work for them."
Environmental police force
The authorities have started to crack down on the eco-mafia. Until three years ago, Italy's waste
traffickers were untouchable. Fly-tipping - even of toxic waste - was simply treated as a
misdemeanour. Now it is a criminal offence which carries a maximum six year sentence. There is
also an environmental police force, a branch of the Carabinieri which has recently carried out four
major operations. But despite these advances, the slow judicial system means the courts have yet
to secure any major convictions.
Item 4: Stinking Naples only tip of EU's rubbish heap
(Adapted from The Independent (Europe) website: 25th May 2007)
With no end in sight to Naples' rubbish crisis, fresh questions are being raised across Europe over
the continent's crippling reliance on overflowing and unhealthy land-fills.
The European Commission is currently undertaking legal action against 14 member states for failing
to enforce landfill regulations, with large fines expected to follow. Similar waste disposal crises have
led to strikes and riots in Greece and Bulgaria this year, while Britain was recently warned that
landfill capacity will be exceeded by 2016.
Naples' rubbish crisis may worsen tomorrow with the planned closure of the only remaining working
landfill in the area. The southern Italian city has been turned into a stinking dump this week as
rubbish collectors have gone on strike complaining that they have nowhere to take it. Angry
residents have burnt refuse piled up in the streets. Italy's President Giorgio Napolitano, in a letter
published this week, appealed for a quick solution, warning that further delay would "precipitate an
ecological and health disaster, with serious economic and labour repercussions."
Collectors have stopped hauling the rubbish away because they have nowhere to take it. The
government has approved construction of more dumps but there have been delays in getting them
working because of opposition from local communities.
Tomorrow, authorities plan to shut the dump at Villaricca, north of Naples, exacerbating the
situation, according to the office of the government-appointed "garbage tsar", Guido Bertolaso. The
Villaricca dump has collected Campania's rubbish for months and is now full.
The southern Campania region - home to the luxurious Amalfi Coast but also the slums of Naples has been plagued by a number of rubbish crises in recent years. Dumps fill up, and local
communities block efforts to build new ones or create temporary storage sites. In 2004, a rubbish
crisis prompted weeks of protests.
65
Item 5: Naples battles with rubbish mountain
(Adapted from the BBC News website: 28th February 2008)
There is a sense of desperation in Naples, a teeming Mediterranean metropolis of nearly four
million. They have run out of landfills - usually former quarries - traditionally used to dump their
rubbish. And they have failed to implement orders from Rome and Brussels to sort their waste for
recycling. The European Commission's deadline for Naples to solve its rubbish problem expired on
Thursday.
Many families do not know which way to turn to keep their children healthy.
Naples, with its stupendous bay and harbour, was once a popular winter tourist destination
because of its mild climate. In February, its hotels are practically empty. Tour operators are worried
about the appalling image of the city projected internationally by the rubbish crisis.
'Rubbish tsar'
More than 250,000 tons of stinking, putrefying household waste lies uncollected along the streets
of many of the outlying areas of the city. Thousands of acres of land are filled with mountainous
stacks of "ecoballs" - unsorted compressed rubbish, in which toxic waste is often mixed with
ordinary household refuse and the remains of old cars. Municipal workers gave up rubbish
collections in December, and although the city centre has now been cleaned up and had most of its
waste removed with the help of the army, the emergency continues. Firemen answer an average of
20 calls each night as blazes of rubbish light up the countryside. From the military headquarters
where he has taken up residence since being appointed the new Naples' "rubbish tsar", Giovanni Di
Gennaro surveys the very limited progress he has made.
"I have to get waste disposal moving again. I have been given until 7 May, before the hot weather
arrives," the former chief of Italy's national police says. "But Naples is still creating rubbish faster
than it can dispose of it," he adds.
Concerned citizens
This week, he has been meeting with the Cardinal Archbishop of Naples to try to get the Catholic
Church involved. One-tenth of the city's 281 parish priests are already giving lessons to their
parishioners on how to sort their rubbish into different containers for plastic, paper, glass and
compost. The trouble is that most households in this sprawling city have never seen on their streets
any of the new coloured plastic rubbish bins now common in other parts of Italy.
Luigi Berghantino is a member of a group of concerned citizens - doctors, ecologists, physicists,
judges, geologists, journalists - who monitor the waste crisis by holding regular weekly meetings in
their spare time. He seems satisfied by some of the decisions taken by Commissioner Di Gennaro.
"He has stopped the reopening of old landfills," Luigi says. "He has created some new temporary
storage facilities for waste, and he has understood that it is cheaper and more efficient to cart away
Naples' waste by ship rather than by freight train to Germany as at present."
Ferdinando Laghi, another member of the group, is a hospital doctor who specialises in
environmental medicine. "Waste disposal here has run out of control, with illegal dumps being
created and rubbish being left by the side of the road," Dr Laghi says.
"Incineration is not a solution, it neither disposes of the waste, nor does it remove the health
hazards. It simply creates toxic dust and ash and attacks people's health in another way." The
rubbish crisis has been out of control for at least 15 years, he said.
66
"Big business all over Italy has profited by paying the Camorra, local organised crime, at extremely
low cost, to dispose of their industrial waste by dumping it in the Naples area. "Unfortunately the
Camorra chose one of the most fertile and agriculturally profitable parts of Italy".
Useful websites
Nova Online
http://www.pbs.org/wgbh/nova/vesuvius/
Summary of a range of volcano monitoring methods and technologies and disaster mitigation
USA Today
www.usatoday.com/news/world/2003-10-20-vesuvius-usat_x.htm
Article about Italian government plans regarding the possible eruption of Vesuvius, and the
attitudes of the local population
Eye Witness to History
http://www.eyewitnesstohistory.com/pompeii.htm
Text based on accounts of survivors or the AD 79 eruption and writers of the period
United States geological service
http://vulcan.wr.usgs.gov/home.html
A large and authoritative site with information on all aspects of the webquest including an overview
description of Vesuvius and its eruptions
Educational web search engine
http://www.eduseek.com/Search.aspx?Keywords=volcano
Educational information source including all things volcanic
Smithsonian Museum of Natural history
http://www.volcano.si.edu/world/volcano.cfm?vnum=0101-02=&volpage=sources
High-level source of detailed scientific survey work on Vesuvius
Naples tourism site
http://www.portanapoli.com/Eng/naples/naples.html
Excellent site including maps, images and satellite imagery of Naples, Vesuvius and the surrounding
area
Wikipedia
http://en.wikipedia.org/wiki/Naples,_Italy
Huge range of background information including demographic data
Tulane university lecture
www.tulane.edu/~sanelson/images/vesuvius.gif
Summary of the 79 AD eruption
67
Questions.
1. Using all of the resources provided explain why the Bay of Naples area, including Naples, is a
popular destination for tourists.
10 marks
2. Analyse the main issues for the local authorities that may arise if/when Vesuvius erupts again.
15 marks
3. Your A level geography group has been asked to conduct a research enquiry into the issue of
waste management in the Naples area. Design an appropriate enquiry to meet the objectives of the
task by identifying:
 an appropriate hypothesis
 appropriate primary and secondary data sources
 appropriate methods of data collection, presentation and analysis.
15 marks
4. The task of local governments is to supervise the spending of the funds made available to them,
and to prioritise the ways in which those funds are allocated.
The authorities of the Bay of Naples area have a number of issues to manage:
 The provision of effective public services, including transport and waste management
 The provision of evacuation procedures following of a major volcanic eruption
 Supporting a thriving tourist industry
How would you prioritise the funding for these three issues? Justify your choice.
20 marks
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Mark scheme.
Question 1.
Level 1: Several causes of tourism in the area are stated. However, the answer is basic with no
cause/reason explained clearly and thoroughly. At this level much of the answer relies on data lifted
from the resources.
1-4
Level 2: The answer takes at least two of the causes/reasons for high levels of tourism and explains
in detail why they are important factors, and with clear understanding. Clear links are made
between information from the resources and the candidate’s own knowledge and understanding.
5-8
Level 3: The answer is thorough and detailed, and a wide range of reasons/causes is analysed in
detail and with thorough understanding. The answer is clearly synoptic showing good all round
understanding of the topic.
9-10
Question 2.
Level 1: The answer contains simplistic statements regarding possible issues that may arise. It is not
clear from the answer that the candidate has recognised/understood the restraints re. the location
of the area - it could apply to any similar area. At this level much of the answer relies on data lifted
from the resources.
1–6
Level 2: The answer contains detailed statements about the possible issues. There is a clear
understanding of the factors leading to the possible issues, together with recognition that there will
be some difficulties associated with them. The answer is clearly linked to named and located areas.
There is some recognition that the attitudes of the local people will vary – the authorities may have
to have a range of alternatives in terms of strategies. There is recognition of conflict within the
management of the issues. There are elements of synopticity – the interrelationships between a
range of factors.
7–12
Level 3: The answer contains a thorough and detailed account of the possible issues, including
background/contextual material on the area and/or participants. There is some recognition of the
variation in the basis of attitudes within each set of participants affected. There is also some
consideration of the short- and long-term implications of the issues. There is evidence of critical
understanding of geographical concepts, principles and issues. The answer is fully synoptic. 13–15
Question 3.
Level 1: Simple statements of enquiry, with real sense that the enquiry is feasible. Candidates at the
upper end of this level have established an appropriate hypothesis but have not sufficiently
developed methods to test the research question.
1-6
Level 2: Candidates display skill in identifying an appropriate hypothesis. They show sound
knowledge and understanding of the data to be collected and a range of techniques that are
appropriate for presenting and analysing evidence.
7-12
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Level 3: Candidates display skill, creativity and insight in identifying an appropriate hypothesis, and
in formulating and adopting effective sequences of enquiry. They show detailed knowledge and
understanding of the data to be collected and a wide range of techniques that are appropriate for
presenting and analysing evidence.
13-15
Question 4
Level 1: A basic ranking is made, but any reasons given for this are little more than unsubstantiated
assertions of pros and/or cons. The answer does not make direct reference to the strategic aim
given in the preamble and it is impossible to see any indirect recognition of their importance. 1–6
Level 2: A clear ranking is made, together with some appropriate justification supported by clear
arguments. The justification tends to be constructed simplistically. For example, the reasons for
supporting the first issues outweigh the reasons for the other two, or only the negative aspects of
support for the other two issues are given. There is clear use of and reference to the strategic aim
given in the preamble.
7–12
Level 3: The answer is detailed and developed. The ranking is justified thoroughly. The positives and
negatives for supporting (or not) each of the three issues are examined in depth and compared with
each other. There is clear use of and reference to the strategic aim throughout the answer. There is
recognition that the decision-making process in such cases would be very complex. A variety of
considerations is dealt with in detail. Each of the issues is considered at different scales and from
differing viewpoints. The answer is developing a high level of synopticity - the connections within
and between the information given both at the outset, and for each of the three issues, are
developed.
13–18
Level 4: The candidate has completed the task thoroughly. The answer critically evaluates the task
that has been given in relation to the context of the exercise. There is evidence of critical
understanding of geographical concepts and principles. There is a clear acknowledgement that
there is going to be disagreement when the outcome of the ranking process is
announced/published. There may be recognition that each of the different proposals for support
would satisfy the strategic aim but in different ways and that it is the relative ranking of these that
could influence the decision-making process to a greater extent. The answer is care-fully structured,
shows real geographical insight, a clear sense of place and an understanding of a variety of different
needs. Synopticity is shown throughout the answer.
19–20
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