Formation of Sea Arch
At headland, wave erosion is most concentrate because of wave refraction.
Destructive waves erode along the line of weakness, e.g. fault line or joint, that lies across the headland. Repeated hydraulic action and abrasion widen and deepen the line of weakness. Sea caves are formed at the two sides of the headland.
Further erosion enlarge the sea caves and finally joint together. A sea arch is formed.
Back Natural arch at Tai O Wan