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Montfort Secondary SchoolSec 3Normal AcademicCommon Test 2 2014

Elective Geography

15

2194/2

30 MINUTES

Name:Date:

Class:()

Write your answers in the spaces provided.

1(a)Study Figure 1A which shows the movement of some plates at a plate boundary.

http://facweb.bhc.edu/academics/science/harwoodr/GEOL101/Study/Images/DetachmentFault.gif

Figure 1

(i)Identify the type of plate boundary shown in Figure 1.[1]

Continental-continental divergence plate boundary.

(ii)Name specific examples for the two types of landforms that arise due to the plate movement shown in Figure 1. [2]

Valleys: Rhine Valley, Hutt Valley, East African Rift Valley, Dead Sea Rift Block mountains: Vosges, Sierra Nevada, Black Forest1 mark each for each landform. Any other examples accepted.

(iii)Describe the formation of the two landforms formed by the plate movement shown in Figure 1. [4]

- The two landforms are rift valleys and block mountains- They are formed when tensional forces pull plates apart, giving rise to faults.- A rift valley is formed when sections of the crust extend along those fault lines and the central block of land subsides between two parallel faults.- The sections which are left standing higher than the rift valleys are the block mountains.

1 mark each for one point.

1(b)Study Figure 2 which shows the distribution of some of the worlds deep oceanic trenches (thick lines) and the Pacific Ring of Fire (shaded coastal and offshore regions).

http://www.geography.org.uk/resources/indonesiantsunami/Figure 2

(iii)Using the map in Figure 2, describe the distribution of the deep oceanic trenches in relation to the Pacific Ring of Fire.[2]

Most of the deep oceanic trenches like the Philippine Trench and Middle America Trench arefound within the Pacific Ring of Fire around the edges of the Pacific Ocean.

A few trenches like the South Sandwich Trench and Puerto Rico Trench however are found faraway from the Pacific Ring of Fire.

1 mark each

2People should stay away from volcanoes because they will be killed and their properties destroyed by volcanic eruptions. To what extent do you agree with the statement?[6]

Level 1 (0-2 marks)Does not answer the question or gives general statements that reflect little understanding of the question for example Volcanoes cause pollution and have negative effects on weather.

Level 2 (3-4 marks)Relates to the question briefly.Explanation of only the harms of volcanoes OR brief explanation of both the benefits and harms of volcanoes. No relevant case studies or examples given.

Level 3 (5-6 marks)Answers the question directly.Detailed explanation of both benefits and harms of volcanoes.

Sample Level 6 answer

I agree to a large extent that people should stay away from volcanoes because there are risks to people who live near volcanic areas. Although these people can also enjoy benefits of living near volcanoes like the availability of fertile volcanic soil, they are vulnerable to destruction by volcanic materials and the occurrence of landslides during an eruption.

There are benefits to living near volcanic areas. The lava and ash from volcanic eruptions break down to form fertile volcanic soil which are favourable to agriculture. The presence of minerals in these soils become available to crops after the rocks have been weathered and broken down for thousands of years, thus only people living in these areas are able to enjoy the benefits of the fertile soil. For example, the volcanic soils of Java and Bali are able to support a large cultivation of tea, coffee and rice over many decades.

However, volcanic materials like rock fragments and lava which can reach temperatures of up to 1400C can cause widespread damage to human property. A pyroclastic flow containing hot fragments like ash and boulders travelling at speeds greater than 80km/h destroys everything in its path. Even inhaling the hot ash and gases can result in serious injury or death.

Besides destruction by volcanic materials, landslides which occur due to the structural collapse of a volcanic cone during a volcanic eruption have the potential to obstruct the flow of rivers causing floods and burying entire villages and farmlands. For example, the eruption of Nevado del Ruiz in Colombia caused landslides of wet volcanic debris called lahars which killed more than 20,000 people.

Thus, I agree to a large extent that people should stay from volcanoes even though they may receive certain benefits from volcanic areas like the availability of fertile soil for agriculture.