This document provides an overview of natural hazards caused by tectonic plate movements, including earthquakes, volcanoes, and tsunamis. It discusses the structure of the Earth and concepts of plate tectonics such as continental drift and the three types of plate boundaries. Specific landforms associated with each boundary type are described, including fold mountains, rift valleys, and volcanoes. The document also covers volcanic eruptions and the risks of living near volcanoes or in earthquake zones.

1. Chapter 1: Living with Tectonic
Hazards
Part 1: Hazards of the world
Copy when you see the star

2. What is a Natural Hazard
• Earthquakes
• Volcano eruption
• Tsunami

3. Earthquake
• Is it possible for Singapore to experience an
earthquake?
• When tremors occur near fault lines, energy is
moved along the crust in waves.
• Such energy when sufficiently strong will
travel long distances.
• Over distance, the energy will reduce.
• If there is a massive earthquake in Indonesia,
we will feel it in Singapore.

4. What the Japanese are trained to do.
• Take a look at the next video.
• Pay attention to the specific action that the
Japanese people do in the event of an
earthquake in the following locations.
– Home
– When driving
– At the shops
• You will have to answer the worksheet after
watching the video so pay attention.

5. Let’s now attempt the exercise
• You have 10 minutes to
answer the questions on the
handout.
• Good luck!

6. What is the structure of the Earth?
•Core
•Mantle
•Crust Read up on Pg 7
in your textbook

7. Tectonic Plate
• The crust of the earth.
• Two general types
–Continental plate
• Less Dense, heavier
–Oceanic plate
• Denser, lighter

8. Continental Drift
• Theory that crustal plates are constantly
moving
• Convectional currents move in the mantle due
to the variations of temperature.
• Warmer magma near the core rises, pushing
the crust above to the sides before sinking
down upon losing the temperature.

9. Continental Drift Diagram

10. Evidence of Continental Drift Theory
• The changing shape of earth’s land
mass over earth’s history shows that
the plates are moving.
• The current location of the
continents on earth will continue to
change.

11. Continental Drift Diagram

12. SRP Work
• Watch the following video on Colliding
Continents
• Answer the questions in the SRP handout /
complete the groupwork
• http://www.youtube.com/watch?v=KCSJNBM
OjJs
• 50 mins National Geographic video

13. Types of plate boundaries
• Convergent plate boundary
• Divergent plate boundary
• Transform plate boundary
• Refer to pg 9 textbook

15. Divergent plates
Oceanic – Oceanic divergence
• Area where two oceanic plates move
away from each other
• Magma moves up to the surface and
cools to form new oceanic crust
• Mid-Atlantic Ridge
• Possible to find underwater
volcanoes at such locations.

16. Diagram of Divergent plate boundary
(insert water surface for oceanic)

17. Continental – Continental divergence
• Area where two continental plates move away
from each other
• Magma moves up to the surface and cools,
forming new land.
• Often fractures form at the plate boundary,
forming a linear depression (rift valley)
• Great African Rift Valley

18. Exercise Time
• What do you think is needed to answer this
question?
– “ With the aid of diagram (s), explain the different
types of divergent plate boundaries that you have
learnt. Give specific examples.”
– Use Foolscap paper, complete your diagrams and
short explanations with examples.
– Diagrams in pencil please.

19. Part 2: Convergent plates

20. Plate movements
• If there are plate boundaries that are
diverging, at the end of that plate, there
will be convergence.
• 3 common types of convergent
boundaries
– Oceanic vs Oceanic plate
– Oceanic vs Continental plate
– Continental vs Continental plate

21. Reasons for convergence
• Plates converge due to continental drift.
• As the plates are pushed apart, they crash into
one another.
• Generally, the denser plate will subduct (sink)
below the less dense plate.
• The plate that is riding above will buckle (fold)
and massive landforms will occur.

22. Oceanic Crusts
• Beneath deep oceans
• Between 5km and 8km
• Consists of basalt
• Very dense and heavy
• Made of young rock (200 million years ago)

23. Continental Crust
• Beneath the earth’s land masses
• Between 30-60 km
• Consists of lighter rock, like granite
• Wide range of rock ages, from recent to over 4
billion year old.

24. Oceanic-oceanic plate boundaries
• When two oceanic plates converge
• Denser plate subducts under the less dense
plate
• Area where it subducts is called the
subduction zone
• A depression in the sea floor occurs at the
subduction zone and is called a deep sea
trench. (The Mariana Trench)
• Volcanic islands can also be formed at such
boundaries

25. Oceanic-oceanic plate boundaries

26. Oceanic-Continental plate convergence
• When an oceanic plate converges with a
continental plate.
• The dense oceanic plate is forced down into
the mantle.
• A deep sea trench is often formed at the
subduction zone.
• The continental plate folds and forms fold
mountains and volcanoes
• Volcanoes tend to be a result if melted magma
is able to rise up through cracks in the crust
back to the surface.

27. Oceanic-Continental plate
convergence

28. Continental-Continental plate convergence
• When two equally dense continental plates
converge.
• There will still be a subduction occurring for
one of the plates. However there is a large
amount of friction built-up before it occurs.
• The strong force generated also causes
folding.
• At such plate boundaries, large mountain
ranges tend to form. (Himalaya)

29. Continental –continental plate
convergence

30. Transform boundary
• Occurs when plates slide past one
another horizontally.
• Huge energy released when friction is
overcome
• Large massive earthquakes experienced
• San Andreas Fault (California)

33. Exercise time
• Take a look at the handout (exercise 2).
• Using the information you have learnt so far,
answer the question to the best of your
abilities.
• Good luck

34. Review Comparison Table
Plate boundary type Associated landforms Example
Divergent
Oceanic-Oceanic
Deep sea ridge
Mid-Atlantic Ridge
Divergent
Continental-Continental
Rift Valley
Great African Rift Valley
Convergent
Oceanic-Oceanic
Deep Sea Trench, Volcanoes,
Volcanic Islands
Mariana Trench, Mariana
Islands, Pacific plate and the
Philippine plate
Convergent
Oceanic-Continental
Deep Sea Trench, subduction
zone, Volcanoes, Fold
mountains
Sunda Trench, Barisan
mountains, Australian plate and
the Eurasian plate
Convergent
Continental-Continental
Deep sea trench, subduction
zone, fold mountains
Himalayas, Eurasian plate and
the Indian plate

35. Part 3
Landforms commonly associated at
tectonic boundaries

36. Fold Mountains

37. Fold Mountains
• The rock layers on the crust are
constantly exposed to pressure
• When they are compressed, they
fold, forming fold mountains.
• To upfold is called the anticline and
downfold is called the syncline.

38. Fold Mountains
• The major ranges are along
convergent plate boundaries
• The rocky mountains
• Himalayas
• Swiss Alps
• Pg 22

39. Rift Valleys /
Grabens

40. Rift Valleys
• Near divergent plate boundaries, plates pull
apart, causing land displacement.
• The downward displacement forms rift
valleys.
• Found commonly along divergent boundaries
• Also called Graben
• East African Rift Valley

41. Rift Valley diagram

42. Block Mountains / Horst
Yosemite National Park

43. Block Mountains
• When sections of the crust are pulled
apart by tensional force, some parts are
ripped off.
• The downward displaced areas are the
rift valleys
• The blocks left behind form block
mountains with steep sides.
• Also called Horst

44. Block Mountain diagram

45. Volcanoes

46. Volcanoes
• Landform formed by magma ejected from the
mantle.
• Magma builds up in the earth’s crust to form a
magma chamber.
• With repeated layering of ejected magma, the
volcano grows in height
• Found a divergent and convergent plate
boundaries where there is subduction.

47. • Vents are openings in the earth’s surface
with a pipe leading into the magma
chamber
• When magma is ejected onto the
surface, it is called lava. There is no
change in composition.
• Vulcanicity refers to the upward
movement of magma in the crust and
onto the surface.

49. Let’s take a short Brain Break
• Take a look at the
video on Mt St
Helens in America
• Half the volcano
was blown off in the
eruption

50. Viscosity
• The stickiness of the lava
• The resistance of the lava to flowing
• High viscosity flows slowly
• Low viscosity flows quickly
• Viscosity of the lava determines the
volcano’s shape

51. 2 Key types of Volcanoes
1.Shield Volcanoes
2.Composite Volcanoes
(Stratovolcanoes)

52. Shield Volcanoes

53. Shield Volcanoes
• Gentle sloping sides and a broad
summit
• Low-silica lava (low viscosity) present
• Lava flow is fast, spreading out
quickly
• Subsequent layering leads to wide
base with low overall height.
• Mount Washington in America

54. Stratovolcanoes

55. Stratovolcano
• Developed from successive eruptions.
• Ash and lava (coarse fragment) accumulate over
time.
• Layers of ash are locked in by subsequent layers of
lava.
• Tall volcanoes with concave bases formed.
• Secondary cones may develop as magma from the
vent seeps into the sides of the cone and erupts.
• Pyroclastic flow common
– Hot rock fragments and superheated gases.
• Mount Pinatubo, Philippines

56. Mt Pinatubo

57. Distribution of volcanoes
• Pacific Ring of Fire is the most active volcanic
activity occurs
• Many earthquakes and volcanic eruptions
occur along the ring of fire
• Ring is along several converging plates (Pacific,
Nazca, Philippines, Australian and Eurasian
plates)
• Volcanoes can also form where plates diverge.
• Pg 29

58. Pacific Ring of Fire

59. Volcanic Eruptions
• Volcanoes fall into 3 states
–Active
–Dormant
–Extinct

60. Active Volcano
• Constant volcanic activity
• Currently undergoing eruption or
are expected to erupt in the
future.
• Mt Pinatubo, Philippines; Mt St
Helens, America.

61. Dormant Volcano
• Currently inactive but may erupt
in the near future
• Prolonged period of no volcanic
activity
• Inner magma chamber still hot
and active
• Mt Fuji, Japan

62. Extinct Volcano
• Volcanoes without current seismic
activity
• No geological evidence of eruption in
the past thousands of years.
• Almost no risk of eruption.
• Lake Toba, Indonesia

63. Risks of living near volcanic areas
1.Destruction by volcanic
materials
2.Landslides
3.Pollution
4.Effects on weather

64. Destruction by volcanic materials
• Lava, rock fragments, volcanic bombs (ejected
molten lava blobs)
• Extreme temperatures of projectiles and lava
flow, destroying and killing.
• Inhaling hot gases and ash can also lead to
injury and death.
• With pyroclastic flow, speeds above 80km/hr
can be achieved, making it impossible to
escape.

65. The loss people of Pompei

66. Landslides
• Collapse of a volcanic cone during eruption.
• Downward displacement of previous slide of
volcano.
• Causes large scale damage to infrastructure
and loss of life.
• Settlements near the volcano may get wiped
out totally.

67. Landslide

68. Pollution
• Ash particles and gases released disrupt
human activities over long distances.
• Some gases (Carbon monoxide, Sulphur
dioxide, etc) are harmful to humans
• Fine ash particles captured in the air endanger
planes and cause large monetary loss due to
grounding of flights.

69. Pollution

70. Effects on weather
• Sulphur dioxide reacts with water vapour in
the atmosphere.
• The particles reflect the sun’s energy back into
space.
• This leads to a cooling of surface temperatures
on earth.
• Fall in global temperature might affect plant
and animal life.

71. Let’s attempt an exercise on what we
have covered.
• 15 - 20 minutes,
• Complete all the questions in
Foolscap / space provided
• Good luck

72. Earthquakes
• Caused by sudden release of stored
energy due to movements of crustal
plates.
• Occurs along faultlines as pressure builds
up stress and when the plates slip,
earthquakes are formed.

73. Key Earthquake Terms
• Seismic waves – energy that is released
by earthquakes.
• Focus – the point in the crustal plate
where the seismic energy originates.
• Epicentre – point above the Focus on
earth’s surface. Most of the energy
released travels along the surface of the
earth.

74. • Aftershocks
– subsequent smaller earthquakes that follow
after a major earthquake.
– Could continue to occur months after the
initial earthquake.
– Some aftershocks might be as powerful as
the original earthquake.

75. Depth of Focus
• The depth of focus affects the
impact felt on the surface.
• 2 key types
1. Deep-focus earthquakes
2. Shallow-focus earthquakes

76. Depth of focus
• Deep-focus earthquake
–70 to 700km below surface
–Smaller impact on land
–Most of seismic waves lose their
energy as they reach the surface.

77. Depth of focus
• Shallow-focus earthquake
–70km and above in the crust
–Greater impact on land
–Seismic waves reach surface
quickly and with more energy.

78. Measurement of earthquakes
• Richter scale (Pg31 in textbook)
9?? Destruction impacts thousands of kilometers of land

79. Factors affecting earthquake damage
• Population Density
• Level of Preparedness
• Distance from epicentre
• Time of occurance
• Soil type

80. Population density
– High population density affects more people
– Tendency for high-rise buildings increases damage
– Higher literacy rate in cities mean higher chance
of better preparedness.
• Higher chance of survival
• Better evacuation plans, trained rescue workers.

81. Level of preparedness
• Proper public training and social
awareness leads to less panic
• Repeated practice of emergency
exercise leads to familiarity of action
• Emergency preparedness kits raise
possibility of survival

82. Earthquake Preparedness

83. Distance from the epicentre
• Seismic energy weakens as the
distance increases from the
epicentre.
• Locations further away from the
epicentre suffer less from the
earthquake.

84. Time of occurance
• Time of earthquake determines what
people are doing and whether they are
able to react.
• At night, people are asleep. There is less
time to react.
• In the day, survivors of an earthquake are
able to avoid subsequent accidents.

85. Type of soil
• Loose and unconsolidated (not packed
tightly) soil move more in times of an
earthquake.
• Impact on the buildings on the surface is
greater. Damage is often worse.
• Liquefaction – loose soil flowing like
water.
• Danger of landslides after earthquakes
cause more harm.

86. Earthquake zones
• Tendency for earthquakes to occur
along crustal plate margins.
• Tendency for earthquakes to be
caused when subduction along
destructive plates or slipping of
transform plates

87. Earthquake Zones

88. Hazards of living in earthquake zones
• Tsunamis
• Disruption of services
• Fire
• Landslides
• Loss of lives
• Loss of property

89. Tsunamis
• Tsunami – an unusually large sea wave
• Formed by sudden movement of sea floor
• Possible causes
– Earthquakes at subduction zones
– Explosive underwater volcano eruption
– Underwater landslide
– Large coastal landslides

90. Tsunamis
• As the displaced water moves, it gathers
strength and size.
• When it hits the coast, large destruction is
resulted.

91. Disruption of services
• Loss of electricity, gas and water leads to
loss of essential services.
• Broken pipelines also raise the risk of
explosions.
• Roads and railway destruction make it
harder to send aid.

92. Fire
• Earthquakes at timings where meals are
prepared raise risk of fires.
• Gas pipes and electric cables that are
broken lead to fire risk.
• Urban areas are densely populated,
hence larger fire risk.

93. Landslides
• Shaking of earthquakes loosen soil.
• Along slopes and hills, original vegetation
may no longer be able to hold soil.
• Landslides and mudflows cause large
damage.
• Heavy rainfall after earthquakes raise the
risk of landslides.

94. Destruction of property and
Loss of lives
• Earthquakes destroy homes and buildings that
are not earthquake proof.
• Large amount of money needs to be spent to
rebuild the property.
• Urban areas with more infrastructure (roads,
subways) cause even more money to repair.

95. Part 4
Benefits of living near a Volcano

96. 4 key benefits of living near volcanoes
• Fertile soil
• Precious stones and minerals, building
materials
• Tourism
• Geothermal energy

97. Fertile Soil
• Lava and ash breakdown to form fertile
volcanic soils
• The richest soils on earth, highly
favourable for agriculture
• Hawaii and Bali

100. Precious stones and building materials
• Volcanic rocks can be rich in precious stones
and minerals.
• After the top layers of volcanic rocks are
eroded, these can be extracted.
• The volcanic rocks at Kimberley, South Africa,
are the richest source of diamonds globally.
• Other useful materials like sulphur can be
collected from volcanic rocks. Sulphur is used
to refine sugar and make matches and
fertilisers.

102. Tourism
• Volcanic areas have dramatic landscapes.
• Scenery attracts tourists for hiking and
camping.
• Volcanic areas are rich in history and attract
visitors too.
• The ruins of Pompeii, Italy. The black beaches
in Bali

104. Geothermal Energy
• When groundwater comes in contact with the
hot rocks underground, it heats up and
escapes as steam.
• This can be harnessed to produce Geothermal
Energy.
• Large turbines are used to complete this
process.
• Iceland uses Geothermal energy to power
over 70% of their homes.

106. Part 5 : Responses to
Earthquakes
‘O’ Level only

107. Why do people live in such places?
• Favorable living conditions
–Fertile soil conditions for
agriculture.
• No alternative location to live in.
–Case of no choice

108. Review Question
• Turn to pg 47 of your textbook.
• Using that map, let’s answer the questions in
the handout.

109. 3 approaches to earthquakes
1.Fatalistic approach
2.Acceptance approach
3.Adaptation approach

110. Fatalistic approach
• People who accept earthquakes as
unavoidable.
• Tend to resist evacuation in the face of an
earthquake.
• Common for communities in less
developed countries with limited access
to other places.
• People who live near Mt Pinatubo.

111. Acceptance approach
• People who accept the risk of living in
earthquake-prone areas due to the
benefits of living in that area.
• Benefit outweigh the costs of moving
away.
• Mostly accepted by the developed
countries.
• People of Christchurch.

112. Adaptation approach
• People who successfully live in
earthquake-prone areas as they are well
prepared.
• Use of earthquake monitoring devices,
risk assessment, technology to increase
earthquake resistance.
• Costly approach but able to save many
lives and property.
• People in Taiwan and Japan.

113. Responding to earthquakes
• Preparedness measures
– Land use regulations
– Building design
– Infrastructure development
– Emergency drills
– Use of technology

114. Suitability of preparedness measures
• Use of specific measure / package of
measures dependent on factors
–Affordability of implementation
–Education level of population
–Availability of resources
–Suitability of application

115. Short-term responses
• The immediate responses that a country
needs to adopt upon experiencing the disaster
– Handling the status of the affected zones
– Searching and rescuing casualties
– Providing medical aid, food and water
– Setting up emergency shelters
– Calling for humanitarian aid (international aid)

116. Long-term responses
• Post disaster action to prevent / alleviate
impact of future potential disasters
– Improving infrastructure
– Compensation of land and property loss.
– Ensuring the economic recovery of the affected
region
– Managing health options (psychological impact)

117. There is no single quick fix
solution to any natural
disasters. Every situation and
condition and location is
different and the dynamic
situation needs to be dealt
with based on the resources
available at the moment of
the disaster.

118. The End