瀑布由地球内力和外力作用形成,如断层、凹陷等地质构造运动和火山喷发、流水侵蚀等造成地表变化后,流动的河水近于垂直地跌落,即形成瀑布。此外,冰川对岩石的刨蚀也可造成瀑布。构成瀑布的三要素为:落差、宽度和水量。在河流的时段内,瀑布是一种暂时性的特征,它最终会消失。侵蚀作用的速度取决于特定瀑布的高度、流量、有关岩石的类型与构造以及其他一些因素。在一些情况下,瀑布的位置因悬崖或陡坎被水流冲刷而向上游方向消退;而在另一些情况下,这种侵蚀作用又倾向于向下深切,并斜切包含有瀑布的整个河段。随着时 The waterfall is formed by the effect of internal forces and external forces on the earth. After geological changes such as faults and dents and volcanic eruptions and water erosion cause surface changes, the flowing river drops nearly vertically and forms a waterfall. In addition, glazing on the rock can also cause waterfalls. The three elements that make up a waterfall are: drop, width and amount of water. The waterfall is a temporary feature during the river’s time and it will eventually disappear. The rate of erosion depends on the height of a particular waterfall, the flow rate, the type and texture of the rock concerned, and other factors. In some cases, the location of the waterfall recedes from the upstream due to the scouring of the cliff or scarp; in other cases, this erosion tends to be deep down and bevel the entire reach containing the waterfall . With time