Download Year 9 Revision

Year 9 Revision
May 2014
RESTLESS EARTH
Structure of the Earth
• The Earth is made
up of 3 main
layers:
– Core
– Mantle
– Crust
Crust
Mantle
Outer core
Inner core
World Plates
What are earthquakes and where do they occur?
DESTRUCTIVE
CONSERVATIVE
Earthquakes are vibrations caused
by movements at plate margins
and at fault lines (cracks in the
earth’s surface).
They can occur at all 4 major plate
boundaries but the most severe
earthquakes are normally found at
CONSERVATIVE and
DESTRUCTIVE plate margins.
Why do earthquakes happen?
How can we measure earthquakes?
The Richter Scale
This measures the magnitude of a tremor (how
powerful it is) using an instrument called a
seismograph.
On the Richter Scale, magnitude is expressed in
whole numbers and fractions.
1
2
3
4
5
6
7
8
9
10
Richter
Scale
It is a logarithmic scale which means that a size
‘6’ on the Richter Scale is 10 times larger than a
size ’5’ and 100 times larger than a size ‘4’.
The largest earthquake
ever recorded was in
Chile. It measured 8.9
on the Richter Scale.
Mercalli Scale
Mercalli Scale
This measures
how much
damage is
caused by the
earthquake
based on
observations. It
is measured on a
scale between I
and XII.
Epicentre and focus
How can we limit earthquake damage?
predict
plan
a tiltmeter can check any movement
within the rocks
protect
water levels can rise in wells and
lakes because of cracks in the
rock
1. predict
foreshocks before the main quake
can be detected by a seismometer
animals can act strangely before
the earthquake
How can we limit earthquake damage?
advise people to plan for an
earthquake (eg tell them to turn off
the gas, find a ‘safe’ place in their
homes, pack an emergency kit)
make an emergency plan
2. plan
enforce regulations to make
some buildings earthquake
proof
organize regular ‘earthquake
practices’ for offices and
schools
What should people pack in their emergency kit?
Design a poster reminding people what to do in an earthquake.
Impacts
Primary
Secondary
TSUNAMI
• What do you know?
What caused the tsunami?
VOLCANOES
•Volcanic bombs,
ash, lava, gases
•Magma chamber
•Parasitic cone
•Crater
•Main vent
At destructive plate boundaries the lava is viscous (thick like treacle) and it
cannot flow very far from the volcano’s vent. This makes the volcano steep
sided.
At constructive plate boundaries the lava is runny and it can flow far away from
the volcano’s vent. This makes the volcano gentle sided.
Do all volcanoes erupt?
Active volcano – liable to erupt e.g. Mt Etna.
Dormant (sleeping) volcano – a volcano which has not erupted
for many years. For example, Mt Pinatubo erupted in 1991 after
500 years of dormancy.
Extinct volcano – a volcano which has not erupted for many
thousands or millions of years e.g. Edinburgh.
However, it is often very difficult to tell whether a volcano will erupt
again…El Chichon, Mexico erupted in 1982 after being dormant for
approximately 1200 years!
Mt St Helens – the eruption
Why do people live in volcanic areas?
This lava is weathered
(broken down) to form a
fertile soil,
Can you think of any other reasons?
Tourists are attracted to areas of
volcanic activity.
Geothermal energy (heat from
the earth) can be produced in
many volcanic areas.
EXTREME WEATHER
HURRICANES
How do hurricanes form?
22
Hurricane Katrina
Hurricane Katrina hit New Orleans
on the morning of the 29th August
2005 bringing with it
terrible destruction.
Winds of over 250 kilometres
per hour were recorded as
Katrina hit the coast,
causing a storm surge
8.5 metres high.
New Orleans
23
Effects of Hurricane Katrina
80% of the city was flooded and
over a million homes were left
without electricity.
Over 1,800 deaths were
caused by the storm, around
700 of them in New Orleans.
In some areas the flood level
rose to over six metres. Those
that had decided to stay in their
homes had to either find high
ground and await rescue or
risk swimming and wading
through polluted floodwater.
24
TORNADOES
•
•
•
•
•
Why do they happen?
What states do you find in Tornado Alley?
What is Tornado Watch?
What is Tornado Warning?
What is the Fujita scale?
GEOGRAPHY OF CRIME
Crime
Geography is brilliant. It even covers
crime !
© Oxford University Press 2008
7.5 In the fight against crime
TOURISM-GOOD OR BAD?
© Oxford University Press 2010
Why has tourism grown in the UK?
improved transportation
1975
45
40
35
1978
1980
1985
1990
household income in the UK
30
25
20
15
number of cars
in the UK
(millions)
more people take early
retirement
10
5
0
1950
1975
2000
Internet
more leisure time
The Butler model of tourism
3
2
Growth of
tourism
4
1
Match the descriptions to the stages.
The local fishermen get better
prices for their seafood.
The bars and clubs
stay open until 4am.
time
It is difficult to get to your
hotel from the airport due
to poor quality roads.
Some souvenir shops start to close down.
The sea becomes too polluted to
be used for swimming.
The local government has to
find new water supplies due
to the increased demand.
New airports are built.
Rare species are no
longer found in the area.
People move to the area to work
in the construction industry.
Ecotourism
Ecotourism
GLOBALISATION
Design and brand name
Source of raw material
Manufacture and
processing of raw
materials
Making and finishing
Jeans
Country where jeans are
sold