- Hazards (Tectonic-related & Climate-related) - Internal Structure of the Earth (Core, Mantle & Crust) - Tectonic Plate Movement (Convection Currents & Slab-Pull Force)

2. Living with
Tectonic Hazards
(Plate Tectonics)
Gateway 1

3. In this chapter, you will learn…
Gateway 1:
Why are some areas more prone to TECTONIC HAZARDS?
Gateway 2:
What LANDFORMS and associated tectonic PHENOMENA
are found at plate boundaries?
Gateway 3:
How do people PREPARE and RESPOND to earthquakes?

4. In this chapter, you will learn…
Gateway 1:
Why are some areas more prone to TECTONIC HAZARDS?
Gateway 2:
What LANDFORMS and associated tectonic PHENOMENA
are found at plate boundaries?
Gateway 3:
How do people PREPARE and RESPOND to earthquakes?

5. Watch this! 
• Video 1:
https://www.youtube.com/watch?v=QnHPDp9-eNo
• Video 2:
https://www.youtube.com/watch?v=uMW8Rg2TTqs
Your task:
• Give a suggested title for each video
• Fill in table on Handout pg. 1

6. Video 1:

7. Video 2:

8. After watching… 
• What is happening in the video?
• Name a natural hazard occurring in the video
• What do you think will happen to the people and buildings?
• What do you think caused this to happen?
• How are the videos similar or different?

9. (A) What is a natural hazard?
Definition
A naturally occurring event that threatens
human lives and causes damage to
property.

10. (A) What is a natural hazard?
What are some examples
of natural hazards?
On Handout pg.1, classify the hazards into the appropriate categories.
WORD SPLASH!
Tectonic natural hazards Climate-related natural hazards

11. Distribution of Earth’s natural hazards
O level exam type questions (TB pg. 5)
2a) Describe the distribution of earthquakes and volcanoes. [4]

12. (a) Describe the distribution of earthquakes and volcanoes. [4]

13. Distribution of Earth’s natural hazards
O level exam type questions (TB pg. 5)
2b) Compare the areas that are prone to volcanic activity,
earthquakes and tropical cyclones. What is the relationship
between the three natural hazards in terms of their locations? [4]

14. (b) Compare the areas that are prone to volcanic activity, earthquakes and tropical cyclones. What
is the relationship between the three natural hazards in terms of their locations? [4]

15. Distribution of Earth’s natural hazards
Pitstop 1
2a) Describe the distribution of earthquakes and volcanoes. [4]
• Most volcanoes and earthquakes are generally located along the Pacific Ocean.
• This area stretches northwards from the Andes in South America to California in
North America, and up north along the western coast to Alaska.
• The area also stretches along the East Asian countries of Korea, Japan and China,
Southeast Asia, bypassing Australia into New Zealand.
• But there are also areas where earthquakes occur but few or no volcanoes are
present.
• This area stretches from southern Australia in the Indian Ocean to the middle of
the Atlantic Ocean.
• This area with earthquakes and few/no volcanoes also include central Asia and the
Middle East, starting from the Himalayas to the Mediterranean.

16. Distribution of Earth’s natural hazards
Pitstop 1
2b) Compare the areas that are prone to volcanic activity, earthquakes and tropical
cyclones. What is the RELATIONSHIP between the three natural hazards in terms of
their locations? [4]
• Earthquakes and volcanic activity have a CLOSE RELATIONSHIP in terms of their
locations.
• While there are some areas where there are earthquakes but no volcanoes, EQ and
volcanic activity generally occur in the same locations (e.g. along the Pacific ocean /
the Pacific Ring of Fire)
• However, there is NO RELATIONSHIP between the location of tropical cyclones and
that of earthquakes and volcanic activity.
• Tropical cyclones are climate-related so their occurrence depends on changes in
climate, whereas EQs and volcanic activity are tectonic hazards that depend on
tectonic activities.

17. Why are some areas more prone
to tectonic hazards?
(B) Internal structure of earth
 Core
 Mantle
 Crust

18. (B) Internal structure of the earth
Let’s watch! 
Drones Sacrificed for Spectacular Volcano Video | National
Geographic
https://www.youtube.com/watch?v=zFIWWM0Iv-U

20. (B) Internal structure of the earth
Let’s watch! 
Layers of the earth:
https://www.youtube.com/watch?v=Q9j1xGaxYzY
The lyrics are given in your handout pg. 1

25. Outer layer that
holds the liquid
chocolate in.
This semi-liquid
chocolate centre
The central solid
nut.
The CRUST
• Less than 1% of
Earth’s volume
The MANTLE
• 80% of Earth’s
total volume
The CORE
Ferrero Rocher
How many layers
are there?
Earth
Layered Structure

26. (B) Internal structure of the earth
Crust
Mantle
Core

27. (B) Internal structure of the earth
Let’s now have
a “slice” of earth to
see its cross-section!
Handout pg. 2
TB pg. 6-7

28. Outer
core
Inner
core
CORE
MANTLE
CRUST
Lower
mantle
Upper
mantle
Lithosphere
Asthenosphere
Oceanic crust Continental crust
Ocean
Continents
Cross-section of
Earth’s interior Highest
Lower
Temperature
Thick
Thin
Thickness

29. Outer
core
Inner
core
CORE
Ocean
Continents
Cross-section of
Earth’s interior
Liquid
Solid
- 3500km thick
- Mostly iron and nickel
- 3000°C to 5000°C

30. Outer
core
Inner
core
CORE
MANTLE
Lower
mantle
Upper
mantle
Ocean
Continents
- 2900km thick
- Mostly solid rock that
flows under high temp
and pressure
- 800°C to 3000°C
Cross-section of
Earth’s interior

31. Outer
core
Inner
core
CORE
MANTLE
CRUST
Lower
mantle
Upper
mantle
Oceanic crust Continental crust
Ocean
Continents
- A few km to
70km thick
- Crust beneath oceans/seas
- Crust beneath continents/landmasses
Cross-section of
Earth’s interior

32. Outer
core
Inner
core
CORE
MANTLE
CRUST
Lower
mantle
Upper
mantle
Lithosphere
Asthenosphere
Oceanic crust Continental crust
Ocean
Continents- Crust + uppermost mantle
- Rigid & brittle
- Uppermantle mantle
material just below
the lithosphere
- ‘weak sphere’
- Softer
- High temp & pressure
- Rocks easily
deformed
When rocks in the lithosphere
melt, hot molten rock
(i.e. magma) is formed.
Cross-section of
Earth’s interior

33. Outer
core
Inner
core
CORE
MANTLE
CRUST
Lower
mantle
Upper
mantle
Lithosphere
Asthenosphere
Oceanic crust Continental crust
Ocean
Continents
Cross-section of
Earth’s interior

34. Why are some areas more prone
to tectonic hazards?
(C) Tectonic plates:
 Oceanic
 Continental

35. (C) What is a tectonic plate?
• Tectonic plates are part of the lithosphere (which is rigid & brittle).
PLATE
large, rigid slab
of solid rock
TECTONICS
“to build”
(in Greek)
PLATE TECTONICS
earth’s surface is
built of plates
+ =

36. (C) What is a tectonic plate?
Location
Thickness
Type of rock
By observation, classify the following statements under the correct crust:
 Beneath deep oceans
 Beneath earth’s continental land masses/shallow seas close to continents
 Thinner (5-8km)
 Thicker (35-70km)
 Less dense & lighter rocks (e.g. granite)
 Denser & heavier rocks (e.g. basalt)

37. (C) What is a tectonic plate?
Location Beneath deep oceans Beneath Earth’s land masses &
under shallow seas close to continents
Thickness Thinner (5-8km) Thicker (35-70km)
Type of rock Heavy & dense (e.g. basalt)
Less than 200million y.o
Lighter & less dense (e.g. granite)
Recent to nearly 4 billion y.o

39. Jigsaw Activity!
As a group, try to piece together jigsaw puzzle
to form a world map!
Looking at your completed jigsaw puzzle,
• How would you describe the pieces of the jigsaw?
• What do the lines represent?
• Which continent do we live in?
• What observations can you make about the plate and the
related continent that we live in?

40. Jigsaw Activity!
As a group, try to piece together jigsaw puzzle
to form a world map!
Key learning points from this activity:
 Plates are NOT continents.
 Tectonic plates can be made up of: (1) oceanic crust
(2) continental crust
(3) oceanic & continental crusts
 Tectonic plates move in relation to one another

41. Continents

42. Earth’s Major Tectonic Plates

43. Earth’s Major Tectonic Plates

44. Earth’s Major Tectonic Plates

45. What do you notice?
What might have
happened?

46. Pangea Theory
pan ("all, entire, whole")
Gaia ("Mother Earth, land")

47. Pangea Theory
pan ("all, entire, whole")
Gaia ("Mother Earth, land")

48. Why are some areas more prone
to tectonic hazards?
(D) Plate movement:
 Slab-pull force
 Convection currents

49. (D) Why do plates move?

50. (D) Why do plates move?
Plate movements are caused by convection currents & slab-pull force
working together.
Convection currents =
movement of heat within
the mantle
• Material in the mantle is
heated by the core.
• The mantle material expands
and rises.
• The rising magma spreads out
beneath the plates, causing
plates to be dragged along
and away from each other

51. (D) Why do plates move?
Plate movements are caused by convection currents & slab-pull force
working together.
Convection currents =
movement of heat within
the mantle
• Then, the hot mantle material
cools slightly and sinks, pulling
the plates along.

52. (D) Why do plates move?
Plate movements are caused by convection currents & slab-pull force
working together.
Convection currents =
movement of heat within
the mantle
• The sinking mantle material
heats up again as it nears the
core and the whole process
repeats.

53. (D) Why do plates move?
Plate movements are caused by convection currents & slab-pull force
working together.
Slab-pull force = force that
causes a sinking oceanic plate to
dive beneath another less dense
continental/oceanic plate.
• This process is called
subduction.
• The subducting/sinking plate
drives the downward moving
portion of convection
currents.