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Coastal erosion is the wearing away of land or the removal of beach
sediment by tidal and wave currents. On rocky coasts, coastal erosion
results in dramatic rock formations contain rock layers with different
resistances to erosion. Softer areas become eroded much faster than
hard ones, which result in landforms such as tunnels, bridges, columns and
pillars. On sedimentary coasts, coastal erosion typically poses more of a
danger to human settlements than it does to nature itself. Human
interference can also increase coastal erosion: Hallsands in Devon,
England, was a coastal village that was washed away overnight, an event
possibly made worse by the removal of shingle in the bay in front of it. The
California coast, which has soft cliffs of sedimentary rock and is heavily
populated, regularly has incidents of housing damage as cliffs erode. The
Holderness coastline on the east coast of England, just north of the
Humber Estuary, is the fastest eroding coastline in Europe due to its soft
clay cliffs and powerful waves. Groynes and other artificial measures to
keep it under control has only sped up the process further down the coast,
because long shore drift starves the beaches of sand, leaving them more
Types of erosion
Abrasion- Abrasion is the scraping of a rock surface by friction between
rocks and moving particles during their transport by wind, glacier, waves,
gravity, running water or erosion. After friction, the moving particles
dislodge loose and weak debris from the side of the rock.
Hydraulic action- Hydraulic action is a form of erosion caused by the force
of moving water rushing into a crack in the rockface. It is strong enough to
loosen sediment along the river bed and banks. The water compresses the
air in the crack, pushing it right to the back. As the wave retreats, the highly
pressurised air is suddenly released with explosive force, capable of
chipping away the rockface over time.
Corrosion- Corrosion is the way which rivers use the rocks that they carry to
batter and erode the land.
Attrition- Attrition is the way rocks in glaciers or rivers scrape and erode the
rocks that they are moving over. This breaks them into smaller pieces.