Outline why there are volcanoes at plate boundary Y. [4]
1 mark for each of the following points:
·
Oceanic-continental
convergence between the Nazca Plate (oceanic) and the South American plate
(continental)
·
When the oceanic
plate converges with the continental plate, the denser oceanic Nazca plate
subducts beneath the less dense continental South American plate.
·
**not necessary
(An oceanic trench is formed at the point fo subduction and fold mountains form
on the continental plate.)
·
At the subduction
zone, solid mantle material melts and forms magma.
·
The magma
rises through the crust, giving rise to volcanoes and volcanic eruptions.
P68
BEDOK NORTH SECONDARY SCHOOL
PRELIMS 2014
20
Describe
the likely effects of the earthquake on the people and the landscape in the
area. [5]
·
The tremors
would result in the destruction of the infrastructure of the area such as dam
and roads.
·
Due
to the high population density of the city, the extent of damage may be
devastating as it will cause many lives to be lost.
·
There
could also be loss of lives due to landslides from the nearby mountain.
·
Due
to the tremors, the gas pipes may be damaged and thus there might be a
likelihood of fire.
·
Electricity
cables may be also damaged and thus communication services such as television
broadcasts and telephone lines may also be affected.
·
Destruction
of homes/ settlements as the large city is very near the fault lines.
P41
P41
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Use
Fig. 9 to contrast the rainfall patterns of the two climates.
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·
TEC has higher rainfall than TMC
(total annual rainfall of 2365mm in TEC and 1490mm in TMC).
·
TEC wet throughout the year while
TMC has a distinct wet and dry season (TEC at least 100mm of rain monthly
while TMC has dry season from Jan to May, Nov and Dec but wet season from Jun
to Oct).
·
Wet months for TMC have higher
rainfall than those for TEC (>300mm in Jul and Aug in TMC while around
270mm in Apr, Oct and Nov in TEC).
·
TMC is especially wet in middle of
the year (Jun to Sep) but during the same period, TEC rainfall is the lowest.
·
End of the year is dry months for
TMC but high rainfall experienced in TEC.
[3m
for any 3 points]
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