Liquefaction can be described as the loss of tension that is experienced by a layer of soil or of sand. The loss of surface tension is caused by an applied stress that is usually related to seismic activity. Although sand grains support much more weight than water, in principle they can behave as if they were a liquid surface is shaken hard enough.
Moraines are some of the most recognizable features of glacial advances and retreats. They can be seen not only on the edges of current glacially covered areas, but also in regions where glaciers long ago retreated. Made up of debris dragged and pushed by the glacier, moraines are far from uniform and contain a mixture of grains, regolith and rock chunks.
The swash is the water that advances onto the beach with the onset of a wave. It is characterized by the white foam that caps the front of the wave and reaches the beach first. The swash is responsible not only for depositing sediments and debris on the beach, but also for moving the sediment around across the beachfront.
The backwash face of the wave breaking and retreating is the movement away from the beach and back towards the water. The backwash tends to have less of a swell and slide back towards the ocean instead of rushing in rapidly like the first stage of the swash. Another feature of backwash that makes it different from the incoming water is the 90° angle that it maintains with the line of the shore.
Abrasion is a type of physical weathering that occurs when the force of friction between two objects brought repeatedly into close contact are worn away and eventually broken into constituent pieces. Abrasion can occur in many settings including beachfronts, rock walls, exposed bedrock layers, and rivers.
Deposition is a result of erosion, and the two processes are inextricably linked. The debris and sediments that are broken off from their bedrock formation be erosion are deposited somewhere else and can contribute to the eventual formation of sedimentary rocks when placed under intense pressure and stress.
