Coastal Erosion and Landforms

Your coastline is constantly changing, and it all starts with wave erosion. Waves are incredibly powerful forces that wear away rock through three main processes you need to know.

Hydraulic action happens when waves crash into cliffs and compress air into tiny cracks in the rock. This pressure builds up and literally blows the rock apart from the inside - think of it like nature's demolition work. Abrasion is when waves pick up stones and sand, then hurl them against cliffs like a giant sandblaster. Finally, attrition occurs when all those broken rock pieces smash into each other in the water, grinding down into smaller and smaller fragments.

Headlands and bays form because not all rocks are equally tough. Where you have alternating bands of hard and soft rock, waves erode the weaker sections faster, creating curved bays. The harder rock remains sticking out as headlands - those dramatic cliff points you see along coastlines.

As waves continue their relentless attack on headlands, they create an amazing sequence of landforms: cracks widen into caves, caves break through to form arches, and when arches collapse, they leave isolated stacks standing in the sea.

Quick Tip: Remember the sequence - cracks → caves → arches → stacks. It's a classic exam question!

Meanwhile, wave erosion at the base of cliffs creates a wave-cut notch that eventually causes the cliff above to collapse. Over time, this process creates a wave-cut platform - that flat rocky area you sometimes see exposed at low tide. Mass movement also plays a role through slides $straight-line movement$, slumps (rotational movement), and rockfall (material breaking and tumbling down slopes).