Answer
Two components of glacial movement are basal sliding and internal deformation.
Basal sliding: Basal sliding occurs when a glacier slides over its underlying bedrock or sediment. It happens primarily in regions where the glacier's base is meltwater-saturated or where a thin layer of water forms between the ice and the bed. The overlying ice's pressure and the water's lubricating effect facilitate the sliding motion. Basal sliding is responsible for the faster movement of glaciers and can account for a significant portion of their overall flow.
Internal deformation: Internal deformation refers to the movement of ice within a glacier caused by the pressure and stress applied to the ice mass. Under the immense weight of the glacier, the ice deforms and flows plastically, similar to a very slow-moving fluid. This internal movement occurs due to the crystal structure and properties of ice, which allow it to deform under pressure. Internal deformation is more significant in the deeper parts of the glacier, where the pressure is higher, and the ice can deform and flow over longer periods.
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