GREENDALE SECONDARY SCHOOL HUMANITIES DEPARTMENT Geography Elective

Transcription

1 GREENDALE SECONDARY SCHOOL HUMANITIES DEPARTMENT Geography Elective Name: ( ) Class: Secondary Date: Revision for EOY Exam ) Study Fig. 1 which shows a satellite image of the East African Rift Valley. African Plate (Nubian boundary) African Plate (Somalian Boundary) Indian Ocean Fig. 1 Using Fig. 1 and your own knowledge, explain the formation of rift valleys. [4] They are formed at a divergent plate boundary when two plates move apart. The central block of land subsides (sinks) between two parallel faults due to tensional forces. A rift valley, which is a valley with steep sides is formed. An example shown in Fig. 1 is the East African Rift Valley which is formed when the African Plate diverge at the Nubian and Somalian Boundary. 1

2 2) Fig. 2 shows a landform formed as a result of continental convergence. Identify Landform A formed as a result of this movement. Explain the formation. [5] Himalayas fold mountain At convergent plate boundaries, India subcontinent and Eurasian Continent converge and collide. The compressional force creates immerse pressure Rock layers buckle and fold. (folding) Result in the uplifting and compression of Earth s crust forming the Himalayas fold mountain 3) Fig. 3 shows the death toll and magnitude of earthquakes in different parts of the world. Year Location Death Toll Magnitude (Richter Scale) 2001 Gujarat, India 16, Sumatra, Indonesia 230, Pakistan 75, Haiti 316, Sendai, Japan 15, Fig. 3 Based on the information in Fig. 3 and studies you have made, discuss the [3] 2

3 other factors that affect the extent of earthquakes apart from magnitude. One factor that affects the extent of earthquakes is level of preparedness. In countries where countries are prepared, they have evacuation drills and people know exactly how to evacuate when earthquakes strike. This reduces the number of deaths, such as in Sendai, Japan where only people died from an earthquake of magnitude 9.0. Another factor is population density. A country with large population density will most probably have higher death toil when an earthquake strikes. The earthquake in Haiti which killed people could be due to this factor. Time of occurrence is another factor. When an earthquake strikes at night, people could be sleeping and they may not have sufficient time to react and escape. As a result, the death toll will be higher as compared to one that strikes in the daytime. 4) Fig. 4 provides some information on a tectonic feature. Fig. 4 Identify features A and B shown in Fig. 4. Explain how features A and B are formed with well-labeled diagrams. [10] B: Rift Valley A: Block Mountain B: 3

4 They are formed at a divergent plate boundary when two plates move away from each other. The central block of land subsides (sinks) between two parallel faults due to tensional forces. A rift valley, which is a valley with steep sides is formed. A: 4

5 It is formed at a divergent plate boundary when two plates move away from each other. When the crusts on either side of the normal faults move apart, they sink and leave the central block standing higher than the rest. This forms a block mountain, which is a block of land with steep sides. 5) Immediate post-earthquake responses are more crucial than long-term measures. [8] How far do you agree with this statement? Support your answer using evidence. I agree to this statement to a large extent. Some of the immediate postearthquake responses are searching for and rescuing casualties and providing medical aid, food and water. However, there are long-term measures that are effective as well, such as improving infrastructure. Searching for and rescuing casualties involve quickly locating and freeing people who are trapped under collapsed buildings. This is important as the faster survivors can be found and rescued, the lesser the number of deaths. For example, after the earthquake in Tohoku, Japan in 2011, sniffer dogs and heat sensors were deployed and successfully rescued many who were trapped. However, rescue workers only have a limited number of time, of 72 hours or 3 days to find trapped survivors. Without food and water, trapped people are unlikely to survive after 3 days. Nevertheless, this immediate post-earthquake response is effective in minimising the impacts of earthquake as it can greatly reduce the number of deaths. 5

6 Another immediate post-earthquake response is providing medical aid, food and water. The injured are treated and clean drinking water is provided to survivors to prevent dehydration and the spread of diseases. This provision of immediate aid helps survivors to continue with their lives, which is greatly effective in reducing the impacts of earthquake. For example, after the earthquake in Afyon in 2002, the Turkish Red Crescent Society immediately responded by delivering tents, blankets and 3000 heaters to the region. This helped greatly in reducing the number of deaths. However, there could be situations where the medical supplies, food and water may not be sufficient and this may lead to social unrest, which adds on to the problem caused by the earthquakes. Nonetheless, this response is still crucial in minimising the impacts of earthquake. However, apart from immediate post-earthquake responses, long-term measures like improving infrastructure can be critical in ensuring that the impacts of future earthquake are minimal. Usually, infrastructure and amenities are rebuilt and improved upon after an earthquake. Authorities often develop stricter building codes to ensure infrastructure is restored at a higher safety level than before. This will help ensure that buildings do not collapse easily in the event of an earthquake, reducing the number of deaths. An example is the buildings in Japan, which are mainly earthquake-proof. Thus, the number of people killed as a result of the earthquake is greatly reduced. However, reinforced buildings are only good in protecting against earthquakes but in times of tsunamis, these buildings could still be destroyed. Nonetheless, this response is still crucial in minimising the impacts of earthquake. In conclusion, I feel that immediate post-earthquake responses are more effective as they are the immediate help given to the victims and these aids could be the main life-savior. 6