This document provides information and guidance for a Year 11 Geo exam on extreme natural events. It outlines the exam date, required materials, and examiner expectations. Volcanic eruptions are chosen as the natural event, with case studies of Mt. Tarawera in 1886 and Mt. Pinatubo in 1991 recommended for study. The document provides detailed descriptions of the natural processes leading to volcanic eruptions and the effects on cultural and natural environments. It also discusses characteristics making environments vulnerable and how different groups have responded over the short and long term. Diagrams are suggested to help explain concepts. Students are advised to thoroughly learn facts about two case studies.

1. Year 11 Geo
1.1 Extreme Natural Events

2. When
 Moday 17th November
 9.30am

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

4. What has the examiner said?
 NOT A LOT!
 For each paper you need to refer to your case
study, use maps/diagrams and apply
geographic concepts
 For 1.1 make sure your answer refers to
DIFFERENT PLACES within an environment
(1 case study) that are effected by a volcanic
eruption OR DIFFERENT ENVIRONMENTS
(2 case studies) that are effected by volcanic
environments

5. 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
 Natural and cultural characteristics (features) of the
environments that make them vulnerable to the
extreme natural event(s)
 How different groups of people have responded to the
effects of the extreme natural events

6. Chosen extreme natural event
 Our chosen extreme natural event is ………
VOLCANIC ERUPTIONS
 You need to know about volcanic eruptions and you
also MUST name at least one case study example in
your answer
You must learn 1 NZ case study AND 1 overseas case
study
 E.g. Mt Tarawera in 1886 AND Mt Pinatubo in 1991 or
Nevada del Ruiz in 1985

7. DISCLAIMER
 Most of these slides are written as general
effects or processes NOT specific to an
eruption
 YOU MUST ANSWER EVERY QUESTION
SPECIFIC TO A VOLCANIC ERUPTION

8. 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?

9.  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

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

11.  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

12.  NZ sits on the Pacific
and Australian plate.
When an oceanic and
continental plate are
pushed together by
convection currents,
subduction occurs.
This is when the
denser, oceanic Pacific
plate is forced below
the lighter, Australian
continental plate at a
rate of 5-8cm a year in
an area off the east
coast of the North
Island known as the
Hikurangi trench

13.  As the Pacific plate
is forced beneath the
Australian 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 100km
below Mt Ruapehu’s
surface

14.  Pressure builds up in
the magma chamber
as gases are
produced like carbon
dioxide and sulfur
dioxide. Magma
below Mt Ruapheu is
created at an
intermediate depth,
with moderate
amounts of silica and
gases, known as
andesitic magma.

15.  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

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

17.  VOLCANISM: 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. During
the September 1997
eruption, ash clouds of
10km height were
produced and lahars
were created due to the
presence of the crater
lake. Due to Ruapehu’s
andesitic magma an
irregular shaped cone at
a height of 2797m is
formed as lava is
viscous

18. Concepts that could apply…
 Process: A series of related actions that work
on and change the characteristics of the
surrounding environment
 Environments: have particular characteristics
and features, which can be a result of
processes. Some environments have been
changed because of an extreme natural event

19. Past questions
 Fully explain the natural processes that
operate to produce your named extreme
natural event within the environment of your
named case study

20. 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 different categories.
 SOCIAL this means people’s daily
lives and feelings are
impacted
 ECONOMIC this means businesses and
money are impacted
 INFRASTRUCTURE damage to buildings and
services like power, water etc.

21.  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
 If it asks for the CULTURAL environment,
effects must be on stuff that people have built

22. 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

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

24. 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

25. 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

26. Negative Infrastructure (cultural
environment) impacts
 Damage to water supply for surrounding
towns which can be costly to repair
 Road networks are destroyed, cutting off
townships
 Hospitals, military bases may be destroyed
 Communication grids are destroyed (phone
lines etc)

27. Concepts that could apply…
 Change: involves any alteration to the natural
or cultural environment. As people interact
with their environment, both are changed.
 Perspectives: may influence how people
interact with environments and the decision
and responses that they make

28. Past questions
 Fully explain how your named extreme
natural event has affected the cultural
environment. You may use diagrams to
support your answer

29. Explain the effects of the natural
event on the natural environment
 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

30. 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

31. 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

32. 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

33. 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

34. 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

35. Concepts that could apply…
 Change: an alteration of the natural or cultural
environment. It occurs at varying rates, at
different times, and in different places
 Processes: a sequence of related actions that
changes the surrounding environment

36. Past questions
 Full explain how your named extreme natural
event has affected the natural environment.
 Include a combination of notes and
diagram(s) to support your answer.

37. Vulnerability of the environment
 This aspect is asking you about natural and
cultural characteristics of an area that makes
it MORE or LESS in danger when a volcanic
eruption occurs

38. Vulnerability- Natural factors
 Location, close to plate boundary means
more at risk
 Location, if earth’s crust is thin more at risk
 Rivers running down mountainside and crater
lakes increase risk of fast flowing lahars

39. Vulnerability – Cultural factors
 Preparedness; evacuation plans in place,
strong emergency responses systems mean
they are less at risk
 Large numbers of people living nearby
 Monitoring of volcano can decrease their
vulnerability

40. Vulnerability diagram
 This diagram requires
annotations but is a
perfect example of
how simple a diagram
can be.

41. Likely concepts….
 Environment: Characteristics of an area that
make it more or less vulnerable
 Processes: sequences of related actions that
shape and change environments

42. Past questions
 Draw an annotated (labelled) diagram in the
box below to clearly show the major natural
characteristics (features) of the environment
in your named case study (studies) that make
it vulnerable (likely to be affected) by your
named extreme natural event

43. Response of different groups
 This aspect is asking you about how different
groups of people react to a volcanic eruption
 Groups can react in the SHORT TERM(straight
after the eruption has finished, up to a couple of
months) and in the LONG TERM (clean up over a
period of months, years. Can involve preparation
for another eruption)
 Responses can also be classified as BEFORE,
DURING or AFTER the event

44. Short term responses
 Evacuating those most affected by volcanic
hazards
 Sweeping roofs, cutting off water supplies and
using masks over face when outside
 Supplying emergency provisions after
eruption finished (water, shelter, food,
vaccinations etc)
 Dealing with injured and dead

45. Long term responses
 Rebuilding infrastructure e.g. water supply,
town centres, sewage system
 Put in place evacuation systems for future
emergencies
 Educate people
 Monitoring of volcano e.g. seisometers,
tiltometers etc
 Relocation of indigenous peoples

46. Concepts that could apply…
 Perception: How different groups of people
view the area may impact how they respond
to an event.

47. NOTE ABOUT CASE
STUDIES
 For this particular question it IS NOT
appropriate to write about Mt Tarawera
 Stick to Mt Ruapehu or Mt Pinatubo for this
one!

48. Past questions
 When an extreme natural event occurs,
individuals, groups or organisations, respond in
different ways. These responses may occur
immediately after the event, or they may be long
term responses.
 Name TWO individuals, groups or organisations
AND fully explain how EACH has responded to
the effects of your named extreme natural event at
a selected time period

49. Possible annotated
diagram for stages of
response at Mt
Ruapehu

50. Overall tips for Excellence
 Use case study detail (this is called specifics) THROUGHOUT
your answer not just in a clump at the end.
 In short answer questions, back up each point you make with a
specific. This should be a number or name of something
 Use the definition of the CONCEPT given in the question in your
answer so the examiner sees you clearly understand it
 PLAN your answer. Break your main points into paragraphs so
your thoughts are clear and to the point
 Learn a diagram for each of your case studies and USE this in
your answer. Don’t forget to refer to it

51. 1.1 Final Tips
 Learn TWO case studies. One for NZ and one
for overseas
 Know at least 10 facts about each that include
a name or a number
 Be able to draw a diagram for each case
study environment that you can annotate
 Be able to draw an annotated diagram of
subduction