Lunchtime revision class powerpoint for 1.1 exam

1. Year 11 Geo
September Exam 2013

2. When
 Tuesday 17th September
 1pm

3. What do I need ?
 PenS (more than one)
 Coloured pencils
 Ruler
 Calculator

4. 1.1 Extreme Natural Events
 How have natural processes led to your
natural event
 Explain the effects of the natural event on
the cultural environment
 Explain the effects of the natural event on
the natural environment

5. Chosen extreme natural event
 Our chosen extreme natural event is ………
VOLCANIC ERUPTIONS
 You need to know about volcanic eruptions
and you also MUST bring name at least one
case study example in your answer
 E.g. Mt Tarawera in 1886 or Mt Pinatubo in
1991 or Nevada del Ruiz in 1985

6. How have natural processes
led to your natural event?
 This question is asking about the
sequence of events that cause a
volcanic eruption.
 What processes do you remember that
cause volcanic eruptions?

7.  The earth is
made up of 12
major plates
that float on
the earth’s
semi liquid
mantle layer.
NZ sits
between the
Pacific plates
and Australian
plates

8.  Plates can be
either
CONTINENTAL
(mostly land) -
these are thicker
but less dense or
OCEANIC (mostly
sea) – these are
thinner but more
dense/heavier

9.  The earth’s plates
move
independently of
one another at
rates of 1-15 cm
per year as
convection
currents occur in
the mantle. The
mantle is heated
by the core
causing it to rise
and fall

10.  When an oceanic
and continental
plate are pushed
together by
convection
currents, subductio
n occurs. This is
when the
denser, oceanic
plate is forced
below the
lighter, continental
plate
e.g. this happens off the east coast of the North Island of NZ
where the Pacific plate subducts below the Australian plate at a
rate of 8cm a year

11.  As the oceanic
plate is forced
beneath the
continental plate,
intense friction and
heat is caused as
the plates rub
together. This heat
then melts the
plate as it sinks into
the mantle,
creating magma
which collects in a
magma chamber
e.g. Mt Ruapehu’s magma chamber sits 100km below the earth’s
surface

12.  Pressure builds up
in the magma
chamber as
gases are
produced like
carbon dioxide
and sulfur dioxide

13.  This pressure
builds up then
forces the
magma to make
its way up to the
earth’s surface
through weak
spots or cracks
known as fissures
in the earth’s
crust

14.  Before an
eruption can
begin, sometimes
a plug (old,
solidified lava in
the vent) must be
blasted out of the
way first.

15.  When magma
reaches the earth’s
surface, gases like
carbon monoxide are
released first, this
means magma has
become lava. Lava
and rocks are erupted
into the air and will fall
around the crater to
eventually form the
volcano’s cone. The
more gas and silica
contained in the lava,
the more viscous (less
runny) the lava will be
e.g. Mt Ruapehu was formed from rhyolite lava meaning the
lava was very viscous and this has given it a very
uneven, jagged shaped cone with a height of 2797m

16. Hints for EXCELLENCE
 Include case study detail THROUGHOUT your
answer instead of in a clump in the end
 Draw a well labelled diagram that sums up
the overall process and refer to it in your
written answer
 Include the definition of the CONCEPT given to
you in your answer. E.g. A process is a series
of related events. The natural process of
subduction works as a series of steps to
create volcanic eruptions

17. Explain the effects of the natural
event on the cultural environment
 We can divide the effects of a volcanic
eruption on a cultural environment into
TWO different categories.
 SOCIAL this means people’s daily
lives and feelings are
impacted
 ECONOMIC this means businesses and
money are impacted

18.  Remember effects can be both POSITIVE
and NEGATIVE
 You MUST refer to at least ONE case study
example in your answer.
 Ideally, for each effect you will have a
piece of case study detail to back up
what you are saying

19. Negative Social Effects could
include….
 Loss of life from ash inhalation, pyroclastic flows or
lahars occurring during the volcanic eruption
 Houses destroyed and people injured, this makes
people feel angry and upset as they will become
homeless
 Ashfall from volcanic eruptions can damage and
destroy crops meaning people will go hungry
 Motorways can become blocked and
communications cut off so people feel isolated as
they are unable to travel

20. Positive Social effects could
include……
 Communities come together to help in
the recovery process after a volcanic
eruption

21. Negative Economic effects
could include……
 Livestock may become sick or die after
eating ash covered grass so farming
businesses will lose money
 Skifields maybe forced to close during an
eruption costing them a loss in profit
 The cost to repair the infrastructure
damaged can be extensive, increasing
tax for the rest of the population

22. Positive Economic Effects
could include….
 New tourist destinations, like crater lake
tours and geothermal valleys can be
created which means businesses can
develop bringing money to the region
 Increased geothermal activity can lead
to increased profits for local electricity
companies

23. Hints for EXCELLENCE
 Try to give a piece of case study information
for each effect
e.g. A negative economic effect is that natural
landscapes like the Pink and White terraces that
brought tourists to the area can be destroyed
by volcanic activity. This occurred during the
June 1886 eruption of Mt Tarawera when the
Pink and White terraces were lost during the
eruption under 22 metres of ash. This meant a
loss of tourism and money to the Rotorua area.

24. Hints for EXCELLENCE
 If you are given a CONCEPT definition in
the question USE THIS IN YOUR ANSWER
 Organise your answer into categories – 1
paragraph on social effects (positive and
negative) and 1 paragraph on economic
effects (positive and negative)

25.  We can divide the effects of a volcanic
eruption on the natural environment into 4
categories
 Relief (shape of the land)
 Soil
 Vegetation
 Drainage patterns (lakes and rivers)
 You should learn a map of your case study
area that you can locate these effects on
Explain the effects of the natural
event on the natural environment

26. e.g. This is a case study area map of MT TARAWERA – this
would be useful for both NATURAL and CULTURAL effects on
the environment

27. Relief effects could include…
 The shape of the land is changed as
features like volcanic cones are
destroyed by explosive volcanic
eruptions, new cones are built up by build
up of new lava or chasms/splits in the
landscape are created during the
eruption

28. Soil effects could include….
 Excess ash deposits can make the soil more
acidic and this results in it being infertile
BE CAREFUL HERE that you DO NOT talk about
crops as this is an effect on PEOPLE not the
natural environment
 Soil can be eroded from the landscape as
lahars move quickly down the volcano

29. Vegetation effects could
include…
 Ash covers trees and vegetation which
limits the regrowth of the young trees
 Forests surrounding a volcano can be
burnt or flattened by pyroclastic flows
 Lahars can strip vegetation off the sides of
volcanoes as the move quickly down the
landscape

30. Drainage effects could
include…
 Lakes can be enlarged during the
eruption or created if it is an active vent
 Rivers can become discoloured by ash
and pathways can change as they
become clogged by volcanic sediment

31. Hints for EXCELLENCE
 Again, try to give a piece of case study
information for each effect
e.g. An effect on the relief of the natural
landscapes can be seen when an eruption
creates and destroys new landform features
from the force of the explosion. This occurred
during the 1991 Mt Pinatubo eruption when the
top of the volcano was replaced by a new
caldera 2.5km wide and the height of the
volcano was decreased by 260m.

32. Hints for EXCELLENCE
 If you are given a CONCEPT definition in
the question USE THIS IN YOUR ANSWER
 Organise your answer into categories – 1
paragraph on relief effects, 1 paragraph
on soil effects, 1 paragraph on drainage
patterns and 1 on vegetation

33. Whats going to be in it ?
 1.2
 Explain how natural and cultural factors
have led to population distribution
 The Migration Model with Specifics from
India or New Zealand
 The Effects that migration has had on
india
 The sustainability of the Indian Population