Transcript Oxford University Press 2001

CE - Mountain-building processes
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S2 - The unstable earth
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Mountain-building
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Vs
Unstable earth
The unstable earth
What makes up the earth’s crust
Where are the unstable zones on the earth?
Why does the crust move?
What are the causes of volcanic eruptions & earthquakes?
Volcanic
eruptions
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Earthquakes
Fold
mountains
What makes up the earth’s crust?
 The earth is made up of 3 layers:
crust
mantle
core
 The earth’s crust is made up of __________
and
rocks
continents and
__________.
They form the __________
soil
ocean
__________
floors.
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Where are the unstable zones on the earth?
 There are 3 major zones of earthquakes and
volcanic activities:
Mediterranean
belt
Mid-Atlantic
zone
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CicumPacific belt
Why does the crust move?
 The earth’s crust is made up of __________.
plates
 Name the plates marked 1 to 7 in the map below.
Eurasian
Plate
African
Plate
North
American
Plate
Pacific
Plate
Indo-Australian
Plate
Antarctic Plate
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South
American
Plate
Why does the crust move?
 The plates are moving very slowly along
_________________.
plate boundaries
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Why does the crust move?
 The movement of plates is caused by the _______________
convection of
magma in the mantle.
Destructive plate boundary
Two plates move __________
towards each other
Constructive plate boundary
Plates move __________
apart
magma
Convection of __________
 This process is explained in the theory of _________________.
plate tectonics
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What are the causes of volcanic eruptions?
magma
Hot __________,
volcanic
__________
and __________
are
ash
gases
thrown out to the earth surface.
When there is a line of __________
weakness
in the earth’s crust, magma escapes
to the surface from the mantle.
This is called volcanic __________.
eruption
Magma in the mantle is under great heat and high pressure.
__________
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What are the causes of earthquakes?
The earth will shake. This is called _______________.
earthquake
The plates will break and
energy is released.
__________
When the plates move, __________
pressure builds up in them.
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What are the harmful effects of earthquakes?
Collapse of dams may
flooding
cause __________
Landslide
__________
Fire
__________
may
break out
Big waves —
tsunamis
__________
Buildings, bridges,
roads and railways
collapse
__________
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killed
People are __________
and injured
How to reduce the negative impact of
earthquakes?
__________
Prediction
Scientific methods have been developed to predict
when and where hazards will occur.
Protection measures
Build earthquake-__________
buildings.
proof
wider
parks
Build __________
roads and open ________.
Preparation
drills
Carry out earthquake __________.
Relief
__________
work
Better planning for emergency work.
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What are fold mountains?
The rocks may be folded up into high mountains.
fold
They are known as __________
mountains.
When plates move together, some rocks in between are
folding
compressed and bent. This is called __________.
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Where are the fold mountains?
1. Name the fold mountains 1 to 4.
plate boundaries
2. Fold mountains are usually found at _______________.
Alps
Himalayas
Rockies
Andes
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How are fold mountains formed?
The weight changes them into __________.
rocks
Sand and mud are left between two plates.
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How are fold mountains formed?
The rocks are folded up into high __________
fold
mountains.
The fold mountain formed
Himalayas
here is the ____________.
plate
The rocks in between are compressed by __________
movement.
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