Coasts

Cards (45)

  • How do waves form?
    Waves form when wind blows over the sea
  • What is fetch in relation to waves?
    Distance wind blows across the water
  • What causes tsunamis?
    Earthquakes or volcanic eruptions shaking the seabed
  • What is swash in wave dynamics?
    Water that moves up the beach
  • What is backwash in wave dynamics?
    Water that comes back down the beach
  • What are the characteristics of constructive waves?
    • Low waves that surge up the beach
    • Stronger swash than backwash
    • Carry in deposits of sand and pebbles
    • Formed by storms far away
  • What are the characteristics of destructive waves?
    • Higher waves with larger backwash
    • Steep profiles
    • Plunge downwards and pull sediment back
    • Formed by local storms close to the coast
  • What are the four main types of coastal erosion processes?
    1. Hydraulic power
    2. Abrasion
    3. Attrition
    4. Corrosion
  • What is hydraulic power in coastal erosion?
    Water enters cracks, compressing air and exerting pressure
  • What is abrasion in coastal erosion?
    Rocks in water bash against cliffs, wearing them away
  • What is attrition in coastal erosion?
    Rocks and pebbles hit each other and break down
  • What is corrosion in coastal erosion?
    Weak acids in seawater dissolve coastal rocks
  • What are the two types of weathering processes?
    1. Chemical weathering
    • Carbonation
    • Hydration
    1. Mechanical weathering
    • Physical breakdown of rocks
  • What is carbonation in chemical weathering?
    Weak carbonic acids attack rocks
  • What is hydration in chemical weathering?
    Water swells the structure of rocks
  • What is freeze-thaw in mechanical weathering?
    Water freezes in rock cracks, exerting pressure
  • What is mass movement in coastal processes?
    • Movement of weakened rocks into the sea
    • Types include landslides, slumping, and rock falls
  • What is longshore drift?
    Movement of sediment along the coast by waves
  • How does longshore drift affect pebbles on the beach?
    Pebbles are moved at an angle by waves
  • What causes deposition in coastal areas?
    Waves lose energy and drop sediment
  • What are the erosional landforms created by coastal processes?
    1. Cliff and wave-cut platform
    2. Headlands and bays
    3. Caves, arches, and stacks
  • How is a wave-cut notch formed?
    By erosion at the base of a cliff
  • What forms a headland and a bay?
    Hard rock remains while soft rock erodes
  • What happens to waves entering a bay?
    They lose energy and deposit material
  • What is the process of cave formation on a headland?
    Erosion creates caves that can become arches
  • What are the types of deposition landforms?
    1. Sandy beaches
    2. Pebble or shingle beaches
    3. Sand dunes
    4. Spits
    5. Tombolos
    6. Sandbars
  • How do sandy beaches form?
    In sheltered bays with constructive waves
  • How do pebble beaches form?
    On exposed parts of the coastline
  • What are the stages of sand dune development?
    1. Embryo dune
    2. Fore dune
    3. Yellow dune
    4. Grey dune
    5. Mature dune
    6. Dune slack
  • What is a spit in coastal geography?
    A deposition landform formed by longshore drift
  • What is a tombolo?
    An old island connected to a headland by a spit
  • What are the hard engineering coastal defenses?
    1. Seawall
    2. Groins
    3. Rock armor
    4. Gabions
  • What is the purpose of a seawall?
    To protect the coast from wave action
  • What is a disadvantage of seawalls?
    They can be expensive and obtrusive
  • What do groins do?
    They trap sediment to prevent erosion
  • What is a disadvantage of groins?
    They can cause erosion further along the coast
  • What is rock armor used for?
    To break and absorb wave energy
  • What is a disadvantage of rock armor?
    They can be expensive to transport
  • What are gabions used for?
    To support cliffs and act as buffers
  • What is a disadvantage of gabions?
    They can rust and become ineffective