Year 11 Geo1.1 Extreme Natural Events

When

Moday 17th November

9.30am

What do I need ?

PenS (more than one)

Coloured pencils

Ruler

Calculator

String (optional)

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

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

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

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

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?

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

Plates can be

either

CONTINENTAL

(mostly land) -

these are thicker

but less dense or

OCEANIC (mostly

sea) – these are

thinner but more

dense/heavier

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

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

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’ssurface

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

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

Before an eruption

can begin,

sometimes a plug

(old, solidified lava

in the vent) must

be blasted out of

the way first.

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’sandesitic magma an irregular shaped cone at a height of 2797m is formed as lava is viscous

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

Past questions

Fully explain the natural processes that

operate to produce your named extreme

natural event within the environment of your

named case study

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.

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

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

Positive Social effects could

include……

Communities come together to help in the

recovery process after a volcanic eruption

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

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

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)

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

Past questions

Fully explain how your named extreme

natural event has affected the cultural

environment. You may use diagrams to

support your answer

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

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

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

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

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

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

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

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.

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

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

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

Vulnerability diagram

This diagram requires

annotations but is a

perfect example of

how simple a diagram

can be.

Likely concepts….

Environment: Characteristics of an area that

make it more or less vulnerable

Processes: sequences of related actions that

shape and change environments

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

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

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

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

Concepts that could apply…

Perception: How different groups of people

view the area may impact how they respond

to an event.

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!

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

Possible annotated

diagram for stages of

response at Mt

Ruapehu

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

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