(a) List three landforms associated with coastal erosion. (b) Explain the following processes of wave erosion: (i) hydraulic action: (ii) COrrasion

Answer Details

(a) Three landforms associated with coastal erosion

• Cliffs (and the wave-cut platform at their base).
• Caves, arches and stacks (and stumps).
• Headlands and bays (also blow holes and geos).

(b) Processes of wave erosion

(i) Hydraulic action: this is the erosion caused by the sheer force of moving water. As waves break against a cliff, water is forced into cracks and joints in the rock. The air trapped in these cracks is suddenly compressed and then released as the wave retreats. This repeated compression and expansion weakens and shatters the rock, breaking pieces away. No rock fragments are needed; it is the power of the water and trapped air alone.

(ii) Corrasion (abrasion): this is the wearing away of the coast by the load carried by the waves. Waves pick up sand, pebbles and boulders and hurl them against the cliff face and drag them over the shore platform. This grinding and scraping action, like sandpaper, chips and smooths the rock, deepening notches and enlarging caves.