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[O] Geography(Pure) Smart Guides

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  1. Topic I: Coasts(Physical)

    1. How and why are coastal environments different and dynamic?
    5 Topics
  2. 2. Why are coastal areas valuable?
    4 Topics
  3. 3. How can we manage coastal areas in a sustainable manner?
    2 Topics
  4. Topic II: Living with Tectonic Hazards(Physical)
    4. Why are some areas more prone to tectonic hazards?
    2 Topics
  5. 5. What landforms and associated tectonic phenomena are found at plate boundaries?
    3 Topics
  6. 6. How do people prepare for and respond to earthquakes?
    3 Topics
  7. Topic III: Variable Weather and Changing Climate(Physical)
    7. Why do different places experience different weather and climate?
    7 Topics
  8. 8. What is happening to the Earth’s climate?
    5 Topics
  9. 9. Is the weather becoming more extreme?
    4 Topics
  10. Topic IV: Global Tourism(Human)
    10. How does the nature of tourism vary from place to place?
    2 Topics
  11. 11. Why has tourism become a global phenomenon?
    3 Topics
  12. 12. Developing tourism at what cost?
    2 Topics
  13. Topic V: Food Resources(Human)
    13. How and why have food consumption patterns changed since the 1960s?
    6 Topics
  14. 14. What are the trends and challenges in the production of food crops?
    4 Topics
  15. 15. How can the problem of food shortage be addressed?
    1 Topic
  16. Topic VI: Health and Diseases(Human)
    16. What are the global patterns of health and diseases?
    3 Topics
  17. 17. What influences the spread and impact of infectious diseases?
    3 Topics
  18. 18. How can we manage the current and future spread of infectious diseases?
    4 Topics
  19. Topic VII: Geography Skills and Investigations
    19. Map Reading
    11 Topics
  20. 20. Tourism Fieldwork
    1 Topic
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COASTAL EROSION (Acronym: CASH)

  1. Corrasion / abrasion
    As waves break, sediments carried by the waves such as sand and rocks are hurled against the coast. The loosened sediments knock and scrape against the coastal cliffs. This weakens the surface and breaks down the coast. Over time, the impact of corrasion is powerful enough to erode resistant rocks and undercut a cliff.
  2. Attrition
    When rock particles carried by waves rub or hit against one another, they break down into smaller pieces and become more smoother and more rounded over time.
  3. Solution / corrosion
    Sea water reacts chemically with water-soluble minerals in coastal rocks and dissolves them. For example, limestone rocks are easily eroded by carbonic acid. When solution of minerals occurs, rocks are weakened and eventually disintegrate.
  4. Hydraulic action
    When waves strike against a rock surface, the waves trap air in the rock joints. This air is compressed by the oncoming waves, exerting pressure in the joints. As the air is repeatedly compressed, the joints weaken and the rocks shatter.

SEDIMENT TRANSPORT

Sediments are transported along coasts through two related processes: beach drift and long shore drift. These processes are the result of waves approaching the coast at an angle. As waves approaching the coast at an angle break on the beach, the sediments move up the beach as swash and move perpendicularly down the beach as backwash. The resultant zigzag movement along the beach is known as beach drift.

When waves approach the coast at an angle, they generate longshore currents in the nearshore zone and move sediments along the shore. Long shore currents are ocean currents that flow parallel to a coast. The combined effect of sediment movement by longshore currents and beach drift is known as longshore drift. Longshore drift is most
rapid when waves approach a straight coast at an angle of 40° to 50°

SEDIMENT DEPOSITION

Sediments eroded from the coast are transported away and deposited elsewhere. When wave energy decreases, the waves are unable to carry these sediments. Large sediments are deposited first, followed by smaller sediments. Deposited sediments vary in type and
size, resulting in a variety of beaches.

The location of Coasts influences the deposition of sediments. In areas where coasts are sheltered from strong winds, destructive waves are less common. Fine sediments are deposited along sheltered coasts with calm waters such as mangrove coasts. In large sheltered bays, sandy beaches are common. On the other hand, coarser sediments are likely to settle in small bays.