Attrition
Attrition is also called weathering, in which rock particles are worn against other rock particles so they break up and wear each other down into smooth, round pebbles. This is usually caused by a combination of tidal action and coastal winds.
Abrasion
Also called corrasion, this action is how sea cliffs erode. Various sizes of rock are carried by fast-moving waves that break against cliffs, wearing them down like sandpaper. Large pieces of the upper cliff face break or fall off because of gravity.
Hydraulic Action
In hydraulic action erosion, air is forced into tiny fissures and cracks in large rocks by the breaking of large waves. This air pressure exerts enough force on these rocks that they eventually weaken enough to collapse.
Corrosion
The process of corrosion occurs when materials with a low pH chemically weather cliff rocks with a high pH. Combined with the action of abrasion and hydraulic action, the chemical composition of seawater significantly contributes to the way sea cliffs break apart.