geo

• Waves


  Form when wind blows over the sea, causing friction with the surface of the water and creating ripples that grow into waves
• Fetch


  The distance the wind blows across the water, the longer the fetch the more powerful the wave
• Tsunamis


  Form when earthquakes or volcanic eruptions shake the seabed
• Wave action at the coast

  1. Waves approach the shore, breaking up and surging up the beach (swash)

  2. Water then comes back down the beach (backwash)
• Constructive waves


  • Low waves that surge up a beach with a powerful swash, usually formed by distant storms
• Destructive waves


  • High-energy waves with a larger backwash than swash, formed by local storms
• Coastal erosion processes


  • Hydraulic power
  • Abrasion
  • Attrition
  • Corrosion
• Coastal weathering processes


  • Chemical weathering (carbonation, hydration)
  • Mechanical weathering (freeze-thaw)
• Mass movement processes


  • Sliding landslides
  • Slumping
• Longshore drift


  The movement of sediment along the coast by waves approaching at an angle
• Deposition


  Occurs when waves lose energy and drop sediment, e.g. in sheltered bays
• Erosional coastal landforms


  • Cliffs and wave-cut platforms
  • Headlands and bays
  • Caves, arches, stacks, stumps
• Depositional coastal landforms


  • Beaches
  • Sand dunes
  • Spits
  • Tombolos and sandbars
• Seawalls


  • Concrete barriers placed at the coast to reflect waves, often with a promenade
• Groynes


  • Timber or rock structures built out from the coast to trap sediment and prevent longshore drift
• Rock armour


  • Large boulders dumped at the coast to break and absorb wave energy
• Gabions


  • Wire cages filled with rocks, used to support cliffs and buffer against waves
• Beach nourishment


  • Adding sand or shingle to beaches to make them wider or higher
• Dune regeneration


  • Replanting marram grass and using fences to protect and rebuild sand dunes