Here are some sample questions from the Extreme Natural Events assessments and some sample answers with their grades.
1.Read the following Geographic Concept. Include
specific references to it, as well as to the extreme natural event and
to the environment of the case study (studies) you have named on page 2,
to support your answers to this question.
Fully explain how your named extreme natural event has affected the natural environment.
Volcanic
eruptions can have many effects on natural environments. The natural vegetation
is stripped bare and trees lose their leaves. Forests may be burnt. Often all
the trees fall in the direction of the blast. New landforms are created and
others destroyed. New cones can appear or craters fill with rainwater to create
new lakes. Sometimes the eruption is so large that the top of a mountain is
blown off so that its height is reduced or the sides collapse as they are
unstable to form a caldera. Soils are also affected. Straight after an eruption
the ash covers the ground making it hard to grow anything. However, over time the
soils become more fertile. Waterways are changed by debris from lahars. If
there are lots of lava flows they may fill up a river valley and change the
shape of the land. Coastlines are only affected if the eruption occurs near to
the sea when they can change the shape of the coastline.
Overall
Mark – Not Achieved
Main
Reason: No reference to a case study
2.
Read the following Geographic Concept. Include
specific references to it, as well as to the extreme natural event and
to the environment of the case study (studies) you have named on page 2,
to support your answers to this question.
Fully explain how your named extreme natural event
has affected the natural environment.
When
Tarawera erupted in 1886 it had a major impact on the environment. It was a
huge eruption, measuring a 4 on the Volcanic Explosivity index (VEI). This was
so large that it was recorded by the ancient Chinese who saw strange red skies.
The eruption started just after midnight with a series of small earthquakes.
The first eruption happened about 1.30am with a huge cloud of ash. At this time
most people were in their houses hiding as they were scared and did not know
what to do. When the ash fell on the roofs of the houses they collapsed under
the weight. 153 people were killed in 3 Maori villages such as Te Wairoa. This
could have been avoided if people had been evacuated. Today scientists are much
more able to predict if an eruption is likely. When Pinatubo erupted in 1991
this was also a large eruption measuring a 5 on the VEI scale. However, an
effective evacuation by the government saw 370,000 people in the 30km radius of
the volcano moved to safety elsewhere. This shows that volcanic eruptions can
have big impacts on environments.
Overall
Mark: Not Achieved
Reason:
Is all on impacts of cultural environments not natural.
3.
Read the following Geographic Concept. Include
specific references to it, as well as to the extreme natural event and
to the environment of the case study (studies) you have named on page 2,
to support your answers to this question.
Fully explain how your named extreme natural event
has affected the natural environment.
When
Tarawera erupted in 1886 it had a major impact on the environment. This
eruption was very large measuring a 4 on the volcanic Explosivity Index meaning
that it could do a lot of damage to the natural environment. One impact that it
had was that it changed lake Rotomahana.
Before the eruption this lake was fairly small and well known as the site of
two silica terraces called the Pink and white terraces that were a major
tourist attraction at the time. When the eruption occurred just after midnight
on June 10th 1886 the hot lava hit the cold water of the lake and
caused a massive explosion. The water was turned into hot mud that rained down
across the whole region and buried it. A large hole was left where the lake
stood. Over time this hole filled with rainwater to form the present lake. This
is now more than double its original size and is 40m higher than before the
eruption. This shows that volcanic eruptions can cause big changes to the shape
of the environment.
Overall
Mark: Not Achieved
Reason:
Only one impact on the natural environment is mentioned.
4.
Read the following Geographic Concept. Include
specific references to it, as well as to the extreme natural event and
to the environment of the case study (studies) you have named on page 2,
to support your answers to this question.
Fully explain how your named extreme natural event
has affected the natural environment.
When
Pinatubo erupted in June 1991 it caused many effects on the natural
environment. The vegetation that covered the mountain sides was stripped bare.
The soils were made infertile causing a food shortage. The rivers that had
their source on Mt Pinatubo such as the Maloma were all changed as they were
unable to flow along their original path. Most dramatic of all was that a new
caldera was formed that was 2.5km wide. The highest point of the caldera rim
stood 260m lower than the pre-eruption summit. This shows that volcanic
eruptions can change natural environments.
Overall
Mark: Achieved
Reason:
Has several impacts on natural environments and case study specifics. However,
this is descriptive only and does not give reasons for the effects needed to
lift to Merit.
5.
Read the following Geographic Concept. Include
specific references to it, as well as to the extreme natural event and
to the environment of the case study (studies) you have named on page 2,
to support your answers to this question.
Fully explain how your named extreme natural event
has affected the natural environment.
Volcanic
eruptions can have many effects on natural environments as can be seen by the
case studies of Tarawera (1886) and Pinatubo (1991). Both of these eruptions
were very large and explosive measuring 4-5 on the VEI (Volcanic Explosivity
index). Because of the size of the eruption they had major effects on relief.
On Tarawera the top of the mountain split open along a 17km long line. This
went through a nearby valley and as the hot magma came into contact with cold
lake water it turned it to steam, ash and mud. This rained down over the area
burying valleys and destroying forests. The ground was covered in up to 8m of
mud that made the soils infertile for the next 10 years. Features such as the
Pink and White terraces were destroyed while the holes left by the explosions
later filled with rain creating new lakes such as Lake Rotomahana. In the
Pinatubo eruption the explosion was so vast that it created a caldera 2.5km
wide. The river systems were all altered
as they were clogged with volcanic sediment. Minerals such as lead were brought
to the surface making soils infertile.
Overall
Mark: Merit
Reason:
Has several impacts on natural environments that are explained with good case
study evidence. Lacks reference to change needed for excellence.
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