HWA CHONG INSTITUTION
Sec 3 IHE – Geography
T1 Class Test
Name: __________________________ (
) Class: 3O2
Date 26 /02 /14
Parent’s Signature: ________________________
Topic: Geomorphology
____/25m
Section A: Data Response and Field Techniques (10m)
Fig. 1 shows details of major plate boundaries.
A
C
B
Fig. 1
1
a)
With the aid of a well-labelled diagram, explain the formation of fold
mountains in A.
[4]
b)
Compare the characteristics of volcanoes found in B and C.
[4]
c)
Explain the formation of the Marianas Trench.
[2]
Sec 3/ IHE Geog 2014/ Chan ML
Section B: Structured and Open Ended Questions (15m)
1)
Explain the formation of the Hawaiian islands.
[3]
2)
Account for the presence of and risks of hydrothermal activity in the
Yellowstone National Park area.
[4]
“People living in volcanic areas tend to focus on the benefits and overlook
the hazards.” How far do you agree with this statement? Explain your
answer.
[8]
3)
Source Acknowledgement:
1a)
Fig. A
UCLA
Sec 3/ IHE Geog 2014/ Chan ML
Answers
1 a)
With the aid of a well-labelled diagram, explain the formation of fold
mountains in A.
Eurasian
Plate
IndoAustralian
plate





b)





Marks (1/2m) each:
 Plate movement:
convergent
 Names of plates: IndoAustralian & Eurasian
 Compression/Sediments
folded
 Fold Mtns: Himalayas
Indo-Australian (Continental) plate converges w/ the Eurasian
Indo-Australian subducts beneath the Eurasian Plate for a short distance
Both plates are of same density,
Compressing, contorting the edges / boundaries
Sediments contorted and lifted to great heights forming the Himalayan
Mtns
Compare the characteristics of volcanoes found in B and C.
B

[4]
Process
Convection currents sink,

causing the plates to collide
Nazca Plate collides with the
S. American Plate

The thinner and denser
oceanic descends beneath
the continental plate:
subduction occurs
As the oceanic plate is
subducted into the mantle,
the edges are destroyed
C
Convection currents rise,
causing the plates to move
away from each other
Magma rises through the
cracks forming volcanoes
Landforms
The melting of subducting
 Volcanoes: Nyiragongo
plate produces silica-rich
magma
It moves along cracks or
fractures and escapes
through vents to the land
surface, forming a chain of
Sec 3/ IHE Geog 2014/ Chan ML
[4]



volcanoes subduction
volcanoes
Volcanoes are steep and tall,
Viscous lava
Violent eruption
c)




Explain the formation of the Marianas Trench.
Convection currents: movement within the mantle
Material sinks into the mantle, leading the plates to collide
As the Pacific Plate (oceanic) subducts beneath the Eurasian Plate
(continental)
A deep, long and narrow trench is formed
Section B: Structured and Open Ended Questions (15m)
1)
2)
Explain the formation of the Hawaiian islands.
[3]
 In areas HOTSPOT
 Magma spreads out and melts lithosphere
 Rises though fractures, cools, solidifies and forms volcano after
building up over time
 Plates moves and carries volcano with it
 Old volcanoes become extinct, grow denser with age and
eventually sinks to form a seamount
 New volcano forms over new spot to eventually form a chain of
volcanic islands (in this case, the Hawaiian islands)
Account for the presence of and risks of hydrothermal activity in the
[4]
Yellowstone National Park area.
Presence
 Hotspot area
 Magma comes from the mantle,
 Vast amount of viscous magma moving to the surface through
fractures
 OR: Magma in the magma chamber heats up the water causing
them to escape on the surface under immense pressure
(gysers)
Risks:
 Major eruption may occur, VEI 8
 Regional and global proportions: would have an impact on the
climate (block the sunlight, lower the temperature)
Sec 3/ IHE Geog 2014/ Chan ML
[2]



3)
Animals, crops and people of immediate surrounding area
would die
Mass starvation, mass evacuation,
Great impact on the world economy
“People living in volcanic areas tend to focus on the benefits and overlook
the hazards.” How far do you agree with this statement? Explain your
answer.
[8]
Answer Scheme for Open Ended Question:
P1 Yes, people choose to live in volcanic areas due to the economic benefits
(Agriculture)
E
Elaborate your answer…
E
L
Give examples (and explain) on countries where violent eruption caused
destruction (you may have 1 or 2 examples)
 Mt Etna: ash weathers into fertile soil = ideal for farming in the
surroundings of Mt. Etna
 Nyiragongo: farmers benefit from the fertile soil – subsistence farming
 Java and Bali, Indonesia: supports the cultivation of crops: tea, coffee and
rice – due to the most fertile soil area
 Mt. Pinatubo: ideal for rice growing: the volcano has not erupted since
1380 – so it has been a long term benefit
 In the 1991 eruption destroyed all crops on adjacent farmland, water
supplies were cut off and became contaminated, buildings, roads,
factories were completely destroyed.
 Not only did the eruption ruined the harvest in 1991, it made it
impossible for 1992
 1 million farm animals died due to starvation (lack of grass)
 Displacement of thousands of farmers and family
Link back to the Qn: therefore, though the returns of good harvest attracted
farmers to settle in the area, all was destroyed after the eruption.
P2
E
E
Other economic activities, such as tourism are examples of long term benefits
Because…
Elaborate your answer…
 Geysers and volcanoes in Yellowstone Nat Park generates tremendous
amount of revenue through tourists who visit the park every year (both
local and foreign)
 Hot springs – are good for health, very popular in Korea and Japan
(tourism)
 Precious stones: Kimberley in S. Africa (diamond trade)
Sec 3/ IHE Geog 2014/ Chan ML






L
The ruins of Pompeii, Italy (popular tourist attraction): more than 3 million
people visit the site every year
Geothermal energy: Iceland – alternative energy: 70% of homes are
heated by volcanic steam
Warnings of volcanic eruptions will keep tourists away
Ashes and lahars will destroy the infrastructure and roads, making it
inaccessible and unsafe for tourists
The after-effect may be long term as it takes time to rebuild the area or
attractions
Ash cloud from the Icelandic and Chilean volcanoes prevented / disrupted
flights within the region – not only locals were affected, flights to
neighbouring countries were also hindered
Link back to the Qn: therefore, though the returns to the economy attracted
many people to settle in the area, together with their buildings and industries, to
be destroyed by the eruption.
Environmental impact is important because the eruption can emit a tremendous
amount of gases and particles which will be suspended in the atmosphere for a
P3 long time, affecting not only the local area, but the region.
E
E
L
Elaborate your answer…
 The long term effect of ash in the atmosphere can also be observed in the
weather
 Temperature measure after Mt. Pinatubo’s eruption showed that the
average global temperature declined, causing a cooling effect. Though
Pinatubo delayed global warming for several years, it is interesting to note
that is may have a negative impact on the ozone layer
 The particles containing sulphur remains suspended in the atmosphere for
several years
 They are important / contributes to the destruction of the ozone; enhancing
ozone loss
Link back to the Qn: Many people overlook the impact of eruptions on the
environment.
Conclusion: The long term benefits of living near volcanic areas far
outweigh the risks and destruction caused by an eruption, which may not
happen. Ironically the feature which benefits the population and area may
also bring destruction.
Sec 3/ IHE Geog 2014/ Chan ML
Sec 3/ IHE Geog 2014/ Chan ML