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Test
1 Feedback
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Earthquakes
and volcanoes
Here
is the feedback and answers to the Test
in Unit 01.
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| 1 |
(a)
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Your
answer must start by saying that the crust is the solid surface
layer of the earth. This will gain one mark, but there are
two marks available. So you must elaborate or develop your
answer. For example, you could say that the crust is the least
dense layer of rock or that it floats on the mantle rocks.
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(b) |
You
could start by describing the mantle. Say that it is a semi-solid/
semi liquid layer of rock, or that it is hot and 'plastic'
i.e. it can flow slowly. However, you must explain that convection
currents are formed when heated rock becomes less dense, flows
towards the surface, then cools and sinks back again.
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(c) |
Again,
you could start by saying that the plates are sections of
the earth's crust, or that they are blocks of solid rock which
float on the mantle. The main part of your answer must state
that the plates can be pulled apart or pushed together, and
a plate margin is where two plates touch. |
| 2 |
(a) |
If
you cannot do this simple task then you have not started to
revise properly! You must learn details like this.
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(b) |
The
most common examples used in exams are: |
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(i) |
Constructive
- Mid Atlantic plate |
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(ii) |
Destructive
- Pacific plate/ Eurasian plate (off Japan); Philippines plate/
Eurasian plate (just south of Japan); Nazca plate/ South American
plate (coast of South America). |
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(iii) |
Conservative
- North American plate/ Pacific plate (California)
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If
you were not sure of this answer you should have been able
to check by looking at the arrows showing the direction of
plate movements. Remember:
• Constructive plate margin
- plates move apart.
• Destructive plate margin
- plates move together.
• Conservative plate margin
- plates move side by side. |
| 3 |
(i)
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When
a question starts like this, with 'name an area …' , you must
read through the whole question before you start to answer
any of it. Choose an example that you have learnt about in
detail, not just the first volcano that comes into your head.
If you make your choice without thinking through your whole
answer, you may end up in trouble!
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(ii) |
There
are three marks available for this question. Make sure that
your answer shows at least three stages in the process. For
instance, you could write:
Mount Pinatubo erupted because the Pacific plate was being
forced down beneath the Eurasian plate. Friction between the
plates caused heating. This made rocks melt to form magma,
and the magma rushed to the surface because it was under high
pressure.
1 mark for the movement at the plate margin.
1 mark for the heating caused by friction.
1 mark for the melting of the rock to form magma.
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The point about the pressure may well have
been worth a mark too, but there were only three
marks available for this question.
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(iii) |
There
are 6 marks available. That probably means that this
question will be marked using three levels. You cannot get
to the highest level by just giving a list of points. Your
answer must make connections between different aspects of
the answer. For instance:
The eruption released steam, and this condensed to form
clouds. This led to heavy rainfall, which turned the volcanic
ash to mud, which flowed downhill, swamping property and drowning
people.
Here the connections are:
eruption » steam »
condensation » rainfall »
mudflows » death and destruction
This is clearly part of a high-level answer. If the candidate
had remembered that the streams of volcanic mud are called
'lahars', she could well have reached the top of the level.
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The other essential part of a high-level answer
is reference to both short and long-term consequences. When
you get a two-part instruction like this it may well be
worth underlining or highlighting the two key words. This
will help you to make sure you answer the whole question
well. That is far better than writing a brilliant answer
to only half the question. Probably the mark scheme will
say something like:
If either short or long term consequences are missing,
Max mark = Mid Level.
Be warned!
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| 4 |
There
are three parts to this question. The first part asks you
to describe the preparations. That means you need some quite
straightforward facts and ideas.
The second part tells you to make sure you use real examples.
Name the place(s), and then show that you know what makes
your named place(s) special.Be
as precise as you possibly can.
The third, and most difficult, part asks you to say how successful
the preparations were. Try to avoid very vague phrases like
'They were quite successful' or 'They were not really very
successful.' Make statements like this:
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In
the San Francisco earthquake some old buildings collapsed because
they were built before the building regulations were brought
in. Many of the collapsed buildings were built on poor foundations,
along the edge of the Bay. However, most of the modern buildings
survived the shock. Unfortunately one freeway collapsed, killing
several people, but without the building regulations many thousands
may well have died. |
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