The effect or result of a constructive force is that new land, such as a mountain or a landmass, is built. This can occur via natural situations such as silt from a river being eroded and deposited in a new location, or lava from a volcanic eruption cooling and forming new land in an area. Crustal deformation is another constructive force. Crustal deformation changes the shape of Earth’s surface via the pressure caused by tectonic plate movements. Folds and faults are two ways that Earth can experience crustal deformation. A fold is a bend in Earth that is caused by the compressional forces. On the other hand, faults occur along a crack (fault line) in Earth’s surface. Faults undergo compressional and/or tensional forces, causing the two sides along either side of the fault line to be displaced.