Coastal zone

Coastal zone

Waves are formed by tsunamis, wind blowing over the sea, or friction. 

The seabed interrupts the circular, orbital motion of the water. The motion becomes more elliptical as the water becomes shallower. This causes the crest to rise up and topple onto the beach. There is little horizontal transfer of water but forward motion of water as waves approach the coastline.

Constructive waves surge up the beach with a strong swash and they carry a lot of sediment so they build the beach. Constructive waves have a weak backwash. They are formed by distant storms.

Destructive waves are formed by local storms and they destroy the beach with a strong backwash. They have a weak swash.

Weathering affects rocks exposed at the coast. 

Mass movement is the downhill motion of material under the influence of gravity:

•  Rockfall is when fragments of rock break away from the cliff face.
•  Mudflow is when saturated soil and weak rock flow down a slope.
•  Landslide is when blocks of rock slide downhill.
• Rotational slip is when slumps of saturated soil and weak rock are along a curved surface.
  

Examples of coastal erosion include:

• Hydraulic action involves trapping air into the cracks of the rock, causing the rock to break apart. 
• Corrasion involves picking up fragments of rock and hurling them at the cliff by the sea.
• Abrasion involves grinding pebbles over a rocky platform.
• Attrition involves carrying fragments of rock in the sea knocking them against one another.
  

River transportation processes include:

• Solution is when rocks are dissolved by seawater.
• Traction involves rolling down large pebbles along the seabed.
  
• Saltation involves heavy particles 'bouncing'.
  
• Suspension involves carrying particles within the water.
  

Waves arrive at the coast moving…