Erosion along our coastline is the result of abrasive action
of sand and gravel, moved by the waves and currents, by wind, rain, undercutting like at
cliffs, and to a lesser extend from seismic activities.Beach is defined in Essentials
of Oceanography as: A zone of
unconsolidated (loose) particles extending from below waterlevel to the edge of the
coastal zone.
Most shores undergo vigorous erosion, understandable the loose material on beaches is
easier moved than rocky shore. Earth Dynamic Systems calls beaches "a river of
sand".
The rate at which beaches erode depends on the forces applied. Therefor a sheltered
beach, like the beach near the wharf in Monterey
will show less of a sign of erosion than the beach and sandy cliffs below Stilwell Hall
see picture above.
Coastal erosion is considered to be natural process that has altered the world's
shorelines ever since the ocean were first formed. Erosion has been at work for more than
4 billion years.
Examples of how the beaches change can be found within the series of pictures about Asilomar Beach.