Download Rivers Revision - Wellsway School

The Restless Earth
Unit 1: section B
In the physical paper you will have to answer 3 questions; 1 on
water on the land, 1 on the restless earth and 1 on the coastal
zone. The paper is 1:30hrs long therefore you should aim to spend
30 minutes on each question.
The Syllabus
Opposite is a copy of
the syllabus for this unit
of work.
It should help you to
highlight any gaps in
your notes and
learning.
MEDCs - Seattle, USA, 2001
or California, USA, 2003, or
Kobe, Japan, 1995 and
LEDCs - Gujarat, India, 2001
or Bam, Iran, 2003 or
Sichuan, China, 2008
A case study of an
earthquake in a rich part of
the world and one from a
poorer area –
their you use
The case studies
specific
causes;upon
primary
will depend
yourand
teacher.
Misseffects;
Bendon’s
secondary
class shouldand
focus
on term
Bam
immediate
long
and
California;
Mr Mann’s
responses
– the
need
class
should focus
on and
Kobe
to predict,
protect
and Sichuan;
and Mrs
prepare.
Contrasts
in
Frost’sand
classresponses
should focus
effects
willon
be
Bam clear.
and Kobe.
The Alps
A case study of one range of fold mountains.
The ways in which they are used – farming,
Hydro Electric Power, mining, tourism and how
people adapt to limited communications,
steep relief, poor soils.
Asian
2004
You may
also Tsunami,
want to use
elements
A case
of a tsunami
– its cause,
fromstudy
the Japan
2011 Tsunami
as
effects
and the
responses.
well
although
long term
responses have yet to be known
Main Case
Studies
Soufrière Hills Volcano, Montserrat
A case study of a volcanic eruption – its
cause; primary and secondary effects;
positive and negative impacts; immediate
and long term responses
Key idea no.1
The Earth’s crust is unstable, especially at plate
margins.
You must know:
•Distribution of plates; contrasts between
continental and oceanic crust.
•Destructive, constructive and conservative
plate margins.
The structure of the Earth
The Earth’s crust is not a continuous
layer, but is split up into seven large
tectonic plates and many smaller ones.
2 types of plates…
• Oceanic plates – the crust is thin (5-15km), but
dense (heavy) as it is made of basaltic (igneous rock
formed from quick cooling lava/magma) rock.
• Continental plates – the crust is much thicker (up to
100 km), but lighter as it is made of granitic
(igneous rock formed from slow cooling
magma/lava) rocks.
Plate margins
Constructive plate
margins
• When plates move in
opposite directions e.g.
the North American
and Eurasian plates.
• Usually occurs under
the oceans (e.g. the
Mid-Atlantic Ridge).
• A the plates move
apart the gap is filled
with rising magma
from the mantle, which
create shield volcanoes
– which in turn can
become volcanic
islands such as Iceland.
Plate margins
Destructive plate
margins
• When plates move in
together e.g. the Nazca and
South American plates.
• Occurs when the denser
oceanic crust is subducted
under the lighter
continental crust (at a
subduction zone, an oceanic
trench)
• In the subduction zone,
energy builds and is
sometimes released as an
earthquake. Composite
volcanoes an be formed
when magma rises causing
a volcanic eruption.
• Fold mountains may occur
along these boundaries (e.g.
The Andes along the west
coast of south America.
Plate margins
Conservative plate
margins
• When plates slide
past each other
e.g. the Pacific and
North American
plates along the
San Andreas Fault.
• Pressure builds
from the friction
and may cause a
‘jerk’ which causes
an earthquake.
Key ideas no. 2 & 3
• Unique landforms occur at plate margins.
and
• People use these landforms as a resource
and adapt to the conditions within them.
You must know:
• Location and formation of fold mountains,
ocean trenches, composite volcanoes and
shield volcanoes.
• A case study of one range of fold mountains.
Formation of landforms on plate
boundaries
1. Fold Mountains
2. Ocean Trenches
3. Shield Volcanoes
4. Composite Volcanoes
The majority of Ocean
Trenches are located around
the edges of the Pacific
Ocean. They are associated
with destructive plate
boundaries. At these
margins, the subduction
zone is the ocean trench.
These trenches are
inaccessible to humans and
so have no human use. It is
the continental shelf where
the greatest human activity
occurs – mainly fishing and
drilling for oil and gas.
Shield Volcanoes
Plate Margin
Constructive
Formation
As the plates move apart, magma rises upwards from the mantle to
fill the gap. This adds new rock to the spreading plates. Some of
the magma may also be forced out to the surface through a vent.
Some volcanoes grow high enough to form volcanic islands.
Form of volcano
Shield volcano (made from BASIC lava – low silica content – very
runny and travels long distances).
Characteristics
It has a wide base and gentle slopes.
Made of lava only.
Regular and frequent eruptions.
Lava pours out with little violence.
Examples
Hekla and Surtsey in Iceland.
Mauna Loa and Kilauea in Hawaii.
Composite Volcano
Plate Margin
Destructive
Formation
When the plates collide, the denser oceanic plate is pushed down
into the mantle. Here the plate melts and is destroyed in the
subduction zone. In the subduction zone the plate forms a pool of
magma. The great heat and pressure may force the magma along a
crack where it erupts at the surface to build a volcano.
Form of volcano
Composite cone volcano (made from ACID lava – high silica content
– very viscous and travels short distances before it cools).
Characteristics
Tall cone with a narrow base and steep sides.
Made of alternate layers of lava and ash.
Irregular with long dormant periods.
Violent explosions possible.
Examples
Etna, Vesuvius and Stromboli in Italy.
Krakatoa in Indonesia.
Can you draw a diagram of a composite volcano and label it to show its main
features?
Exam Question
State two differences between composite and
shield volcanoes (2 marks)
The examiner says… when stating differences, make sure that
you mention both – not just one of the them.
Differences could be any two relating to –
• Lava
• Eruption
• Shape
• Composition
• Plate boundary
A case study of one range of fold
mountains
• Name: The Alps
• Location: Europe (Italy, France, Switzerland,
Austria and Slovenia).
• Highest peak: Mont Blanc (4810 m)
• Formed:35 million years ago
• Created by: The African plate pushing north
against the Eurasian plate.
• Made up of: sediments deposited in the
geosyncline of the Tethys Sea
Key idea no. 4
Volcanoes are hazards resulting from tectonic activity.
Their primary and secondary effects are positive as well
as negative. Responses change in the aftermath of an
eruption.
You must know:
• Characteristics of different types of volcanoes.
• A case study of a volcanic eruption – its cause;
primary and secondary effects; positive and
negative impacts; immediate and long term
responses.
• Monitoring and predicting volcanic eruptions.
Characteristics of different types of
volcanoes
Shield Volcano
Characteristics
It has a wide base and gentle slopes.
Made of lava only.
Regular and frequent eruptions.
Lava pours out with little violence.
Composite Volcano
Characteristics
Tall cone with a narrow base and steep sides.
Made of alternate layers of lava and ash.
Irregular with long dormant periods.
Violent explosions possible.
Case study: Soufrière Hills Volcano,
Montserrat
• Cause (plate boundary)
• Primary effects (people injured and killed; buildings, property
and farmland destroyed; communications and public services
disrupted)
• Secondary effects (shortages of drinking water, food and
shelter; spread of disease from contaminated water;
economic problems (cost of rebuilding and loss of economic
activities); social problems (family losses and stress).
• Immediate and long term response (evacuations; monetary
aid; rebuilding etc).
This is the case study in UGG which you would have
done with your teacher. You also did a different case
study when Miss Humphrey’s came in. As long as you
can apply each of these points to a case study it will be
fine to use in the exam.
Monitoring and predicting volcanoes
Predicting and preparing for volcanic eruptions can help reduce
the damage that they cause. Poorer countries cannot afford to
monitor volcanoes properly and may have less effective
emergency plans.
• When magma is on the move it causes small
earthquakes and these can be measured by
seismometers.
• In the days before an eruption, the hot magma moves
towards the surface which causes ground
temperatures to rise – this can be picked up by heat
seeking cameras on satellites.
• Tiltmeters measure volcanoes moving (caused by the
rising magma). GPS also detects movement.
• Immediately before an eruption the volcano will expel
an increased amount of gas and steam.
Key idea no. 5
Super-volcanoes are on a much bigger scale
than other volcanoes and an eruption would
have global consequences.
You must know:
• The characteristics of a super-volcano and the
likely effects of an eruption.
The term "supervolcano" implies an
eruption of magnitude
8 on the Volcano
Explosivity Index (VEI) ,
meaning that more
than 1,000 cubic
kilometres (240 cubic
miles) of magma
(partially molten rock)
are erupted. They
usually occur under hot
spots or at subduction
zones.
Global locations
•
•
•
•
•
Toba, Indonesia;
Taupo, New Zealand; North Island
Long Valley, California, USA;
Longridge, Oregon, USA;
Yellowstone National Park, Wyoming
Yellowstone, Wyoming, USA
•
•
•
•
Previous eruptions –
640,000 years
1.3 millions years
2.1 million years ago (the biggest eruption)
An eruption is (over)due!
The effects of ash from
Yellowstone
•
•
•
•
•
•
•
•
Likely to cover ¾ of the USA
90% of the people killed within 1000km
Most deaths by inhaled ash turning to cement
East coast of USA could have 1 cm depth of
ash
Reduces sunlight + triggers rainfall
Communication links disrupted
30cm can crush a roof
Kill crops + contaminate water supplies
The last super-volcano to erupt was
Toba (Indonesia) 74,000 years ago
• The last super-eruption plunged the world
into a freezing, volcanic winter that lasted a
decade, and threatened the human
population with extinction.
• While ordinary volcanoes can kill thousands of
people and destroy entire cities, it's thought a
super-volcano could claim up to a billion lives
and devastate continents.
Key idea no. 6
Earthquakes occur at constructive, destructive
and conservative plate margins.
You must know:
• Location and cause of earthquakes.
• Features of earthquakes – epicentre, focus,
shock waves and the measurement of
earthquakes using the Richter and Mercalli
Scales.
Location of earthquakes
Earthquakes occur at constructive, destructive and conservative
plate boundaries
The cause of earthquakes
• Over 90% of earthquakes occur where plates are
colliding at destructive plate boundaries. The
pressure and energy which builds in the
subduction zone as one plate is subducted under
another is released in an earthquake.
• The point at which the earthquake happens
below the surface is called the focus.
• The point on the surface directly above the focus
is called the epicentre. This is where the greatest
force of the earthquake is felt.
Exam question
1 (a) (ii) Draw a labelled diagram(s) to explain
why earthquakes occur at conservative plate
boundaries. (4 marks)
What is the examiner looking for?
1 (a) (ii) Diagram should show plates moving in
similar directions (but not the same); should label
to show sliding past each other; or same
direction, but at different speeds; the pressure
building up as the plates stick and the sudden
release causing the jerking movement which is
the earthquake.
An example may be used – likely to be San
Andreas Fault. Diagrams may be plan view, cross
section or a combination of both.
Key idea no. 7
The effects of earthquakes and responses to them
differ due to contrasts in levels of wealth.
You must know:
•A case study of an earthquake in a rich part of the
world and one from a poorer area – their specific
causes; primary and secondary effects; immediate
and long term responses – the need to predict,
protect and prepare. Contrasts in effects and
responses will be clear.
The factors that control the effects of
an earthquake
Physical
Physical
•High magnitude on Richter scale
•Low magnitude (below 5)
•Shallow focus (near the surface)
•Focus deep underground
•Sands and clays vibrate more (e.g.
Mexico City)
•Hard rock surface (e.g. Seattle)
Human
Great (or total) damage
High number of deaths and injuries
Mercalli Scale VII-XII
•High density of population
•Residential area of a city
•Self-built housing
•Lack of emergency procedures
(e.g. Gujarat in India)
Superficial damage to buildings
Few casualties
Mercalli Scale I-VI
•Low density of population
•Urban area with open spaces
•Earthquake-proof buildings
•Regular earthquake drills
Human
Effects of an earthquake
Primary effects
Collapsing buildings, roads and bridges.
People being killed by being trapped in their
homes, places of work and cars.
THESE ARE DETERMINED BY A MIXTURE OF
THE PHYSICAL AND HUMAN FACTORS
OUTLINED ON THE PREVIOUS SLIDE. THE
CHANCE ELEMENT IS THE TIME OF DAY.
Secondary effects
These are the after effects, such as fires,
tsunamis, landslides and disease.
•Fires are caused by earthquakes fracturing
gas pipes & bringing down electricity wires.
Firs spread quickly in areas of poor quality
housing.
•Tsunamis are giant sea waves caused by an
earthquake on the sea floor & are really
dangerous for people living along low lying
coasts.
•Landslides are most likely on steep slopes &
in areas of weak rocks such as sands and
clays.
•Diseases such as typhoid & cholera spread
easily when burst pipes lead to shortages of
fresh water & to contamination from sewage.
Responses to earthquakes
• Immediate emergency aid is needed everywhere where a
strong earthquake strikes.
• Specialist rescue teams with sniffer dogs & lifting equipment,
and medical teams with field hospitals can be expected to be
airlifted within hours to rich countries, thanks to advance
preparations.
• The poorer the country the greater its reliance upon shortterm aid from overseas.
• In the medium term, the need is for a quick return to normal
life (or as near normal as possible) by repairing and replacing
what has been lost & restarting economic activity. The focus
needs to be switched from disaster aid to development aid.
Predict, prepare, protect
Predict
Prepare
Protect
•Seismometers measure
small fore-shocks that
occur before the main
earthquake. They also
show increases in
temperature, pressure and
release of radon gas.
•Preparing disaster plans
& carrying out regular
practices. (In Japan
Earthquake preparation is
part of the curriculum).
•Building regulations should
ensure that buildings are
earthquake resistant and provide
protection rather than causing
danger in an earthquake. They
should also restrict building on
unstable surfaces like clay &
reclaimed land where earth
movement is greatest & building
collapse is most likely.
The ‘3 Ps’ are used to try and reduce the effects
of earthquakes.
•Mapping previous
earthquakes and looking
for gaps where earthquakes
are likely.
•Plotting regularity helps to
show if there is a
recognisable time-length
pattern.
•Unusual animal and fish
behaviour can indicate an
earthquake is imminent.
•Training emergency
services such as police,
fire and ambulance crews.
•Organising emergency
food, water, medical &
power supplies.
•Setting up an efficient
earthquake warning and
information system using
TV & radio.
•Strict building
regulations.
•Earthquake resistant buildings
are built with:
•Foundations sunk into bedrock;
•Rubber shock absorbers;
•Fore resistant building
materials;
•Steel frames which ‘sway’.
A case study of an earthquake in a rich part
of the world and one from a poorer area
MEDCs - Seattle, USA, 2001
or California, USA, 2003, or
Kobe, Japan, 1995 or L’Aquila
2007 and
LEDCs - Gujarat, India, 2001
or Bam, Iran, 2003 or
Sichuan, China, 2008
–
their
specific causes; primary and
secondary effects;
immediate and long term
responses – the need
to predict, protect and
prepare. Contrasts in
effects and responses will be
clear.
The case studies you use
will depend upon your
teacher. Miss Bendon’s
class should focus on Bam
and California; Mr Mann’s
class should focus on Kobe
and Sichuan; and Mrs
Frost’s class should focus
on Bam and Kobe.
Key idea no. 8
Tsunamis are a specific secondary effect and can
have devastating effects in coastal areas.
You must know:
•A case study of a tsunami – its cause, effects
and responses.
Can you draw a diagram showing the cause and process of a
tsunami?
Case Study: Asian Tsunami 2004
You may also want to use
elements from the Japan 2011
Tsunami as well although the
long term responses have yet to
be known
The USGS (United States Geological Survey) record of the earthquake
The waves spread out on their voyage of destruction
Within half an hour the waves had reached Sumatra and Malaysia
and swept ashore in Thailand.
Two hours later they reached Sri Lanka and India.
Within four hours they had crossed the ocean to the east coast of Africa
The killer wave strikes Kalutara Sri Lanka
The Asian Tsunami
Yr 9
What…
…was the magnitude / strength of the Earthquake on the Richter Scale?
…occurred as a result of the Earthquake?
…is a Tsunami?
…region and countries were affected?
Who…
…did it affect most (which types of people)?
…was killed in the Tsunami (how many people) and who was affected?
…gave aid to the affected areas? (What kind of aid and how much)
…(what feelings, emotions and losses did these people experience)
When…
…did it occur? (date, time)
…did the Tsunami hit different coastlines?
You should
confidently be able to
answer these
questions.
Why…
…did the Earthquake occur? (Which tectonic plates were involved and what type were they?)
…did the earthquake cause a Tsunami?
…was the Tsunami so devastating in the areas that it hit?
What next…
…what aid is needed to help people recover in the long term?
…how will the tourist industry recover?
…can these people’s lives ever return to how they were before the Tsunami?
?
Past paper questions
• Explain why volcanoes are found at
destructive plate boundaries. (3 marks)
• Describe the ways in which a super-volcano
is different from a volcano. (4 marks)
• Study the table which shows information
about frequency and magnitude of
earthquakes between 2000 and 2007.
Describe the relationship between the
magnitude of earthquakes and their
frequency. (4 marks)
• Describe a method, other than the Richter
Scale, of measuring earthquakes. (4 marks)
This answer is worth 4 marks -the examiner would
be looking for the following…
Using case studies of earthquakes in rich and poor
parts of the world, compare and
describe the immediate responses. (8 marks)
What does the examiner say?
Actual content will depend on the case study being used.
Immediate – Rich parts – response will be rapid; often practice emergency
drills; these will be put into effect / Emergency services mobilised,
including helicopters, emergency departments of hospitals, fire service etc.
Contingency plans for ensuring supplies of clean water, medical supplies,
blankets, shelters.
Poorer areas - There will be reference to the need to rescue people – may
be done by relatives and basic equipment or just by hand initially, a need
to put out fires, to provide medical help, to ensure there is clean water (and
food). All of this may require international aid and teams of sniffer dogs,
heavy equipment, medical staff, provision of water purifying tablets,
blankets, setting up shelters, tents etc.
What should a level 3 style answer
include?