Earth and Space
Science 2.5
Structure of response
(order & arrangement of
ideas/ concepts)
Student work sample
Task: Question 1
Mt Ruapehu is a stratovolcano, mostly andesitic in nature, found in New Zealand’s Taupo Volcanic
Zone. The last time Mt Ruapehu erupted was in 1996. It is a typical andesitic volcano with a classic
cone shape.
Language Features
Technical Features
(subject and topic specific
words & symbols)
Explain why Mt Ruapehu erupts andesite and discuss the characteristics of such an eruption. In your answer, you
should:
 state why active volcanoes occur in New Zealand’s Taupo Volcanic Zone (TVZ)
 outline the tectonic plate processes under New Zealand’s North Island
 use plate tectonics to explain what causes Mt Ruapehu to erupt andesite (you may use and label the diagram in
the box below to support your answer).
Key Ideas/ Features
(Factual/ objective; focus
on things & processes)
The intermediate grade magma underneath Mt Ruapehu has water mixed in it (from
the ocean), because it is under pressure it remains water under ground. As the lava
erupts from the volcano the release in pressure causes the water to turn to a gas
(steam) making the eruption explosive. This means the lava and ash from the eruption
explodes out of the volcano and the reason why andesitic lava is explosive. Andesitic
magma occurs when the continental crust, which is silica rich, melts and mixes with the
Basaltic oceanic crust in a subduction zone. This creates a intermediate grade sticky
magma called andesite.
Descriptive words and
phrases (which specify
the subject and details of
the idea/ concept(s))
Style
(Impersonal, passive voice:
attention on action, not who
did it)
Connective / linking
words & phrases (which
accomplish the
explanation and/or
analysis)
Structure of response
(order & arrangement of
ideas/ concepts)
Key Ideas/ Features
(Factual/ objective; focus
on things & processes)
Style
(Impersonal, passive voice:
attention on action, not who
did it)
Task: Question 3
In the early hours of September 4th 2010 Christchurch was rocked by a magnitude 7.1
quake that caused liquefaction that lead to major damage to Christchurch city and its
surrounding districts. Christchurch city is located on alluvial plains that were
formed from ancient sediments from the Southern Alps. The plains are crossed by
multiple rivers and streams.
Language Features
Technical Features
(subject and topic
specific words &
symbols)
Discuss, with reasons, the causes of the magnitude 7.1 Christchurch earthquake and explain why
this earthquake caused liquefaction of land in many areas of the city. In your answer, you
should:
 explain the type of tectonic plate boundary in the South Island
 explain how the South Island’s tectonic plate boundary leads to earthquakes
 define liquefaction and describe its effects on land
 explain in detail the characteristics of land that is prone to liquefaction.
You may draw a labelled diagram(s) in the box provided to support your answer.
The plate boundary in the South Island is a convergent plate boundary because the Australasian & Pacific plate are both continental & have
the same density. This has resulted in the South Island’s Southern Alps & the formation of the massive transformation fault – the Alpine
fault. This fault can be considered as plate boundary of the Australasian and Pacific plates. Plates converging and moving laterally past each
other is not a smooth process & at times they get stuck and movement stops until energy is released via an earthquake. The plates move
relative to one another.
In the South Island, this release of pressure does not just result in movement of the Alpine fault, there are other fault lines that move. Lots
of fault lines are hidden because they are covered by sediments. This was the case in the 4 September earthquake as the East West
previously unknown fault line called the Green Dale Fault moved significantly to release energy. This earthquake was very shallow so shaking
was severe at the Earth’s surface.
To compound this problem, Christchurch is built on old sediments that originate from Toulesse rocks of the Southern Alps. These sediments
are different sizes & the shaking sorts them by size with the smallest (eg, sand) at the top & largest (eg, gravel) at the bottom. This is called
liquefaction. Liquefaction is most severe when you have water mixed in with sediments. When this mixture (water and sediments) is shaken
you get the solid soil turning into a mush slurry with sand sized particles at the top and bigger particles below.
So, if your house is near a river or a wet area in Christchurch you would have had more liquefaction than if the soil (sediments) was dry
like in other areas.
Descriptive words and
phrases
(which specify the subject
and details of the idea/
concept(s))
Connective / linking
words & phrases
(which accomplish the
explanation and/or
analysis)