Destructive Waves: •operate in storm conditions. •are created from big, strong waves when the wind is strong and has been blowing for a long time. •occur when wave energy is high and the wave has travelled over a long fetch. •tend to remove material from the coast and are associated with erosion. •backwash is stronger than the swash. •have a short wave length and are high and steep
Constructive Waves: •operate in calm weather. • are less powerful waves. • break on the shore and tend to deposit material, building up beaches. • are responsible for transporting material. • swash is stronger than the backwash. •have a long wavelength, a low height and are less steep than destructive waves.
The sea changes and shapes the coastal landscape. Coastal erosion is the wearing away and breaking up of rock and beach material found along the coast. Destructive waves will erode the coastline in the following ways. •The constant force of waves crashing on the shore damages it. In addition air may become trapped in joints and cracks on a cliff face. When the wave breaks the air becomes compressed, weakening the cliff and causing erosion. This is called hydraulic action. • Waves bring with them bits of rock and sand. These grind down cliffs like the action of sandpaper. This is called abrasion. • Waves cause rocks and pebbles on the shore to smash into each other and break down and become smaller and smoother. This is called attrition. • Acids contained in sea water will slowly dissolve certain types of rock such as chalk or limestone. This is called corrosion or solution.