The difference between a sinkhole and a sinkhole is that one is naturally formed, and the other is that there are more human factors in it. Tiankeng is a natural geographical phenomenon, and subsidence is a manifestation of natural and man-made disasters. Tiankeng is a special terrain in karst area. This kind of terrain generally appears in the form of deep pits. The walls are steep, with a diameter and depth of several hundred meters. The bottom is usually connected to an underground river. Even if there is no underground river, there should be traces of it. Generally speaking, this terrain used to be called karst funnel. 0 1 year was named tiankeng by geography experts in China, which was unanimously recognized by the international geography community, and was later regarded as a general term for this kind of terrain. There are two reasons for the formation of sinkholes, one is collapse, and the other is erosion. Collapsed sinkholes account for most of the known sinkholes, which must be related to underground rivers. Due to the strong dissolution and kinetic energy of underground river, the rock stratum collapses continuously, which leads to the surface collapse and forms a unique karst landform. Erosive sinkholes are even rarer and need special hydrogeology and long historical evolution to form. As far as quantity is concerned, the reference value of the reason is too small, so I won't go into details. Generally speaking, tiankeng is a unique geographical phenomenon, which is unique and non-renewable, and its formation is quite regular. Sinking and sinkhole are two phenomena. Sinking is a geographical disaster, which is largely caused by man-made, and only a few are caused by groundwater eroding the soil layer. Most of the land subsidence is caused by human engineering and economic activities, and it is only a simple physical phenomenon, which is not the joint action of physics and chemistry like tiankeng. Even the scale of collapse is far smaller than that of tiankeng, and the occurrence of collapse is irregular, which is largely an accidental disaster phenomenon. In modern society, frequent engineering activities, overloading of highways and over-standard exploitation of underground resources such as groundwater lead to frequent ground subsidence. ?

Therefore, tiankeng and subsidence are two completely different geographical phenomena in terms of formation reasons and scale. Tiankeng plays a great role in geographical research, and subsidence reminds human beings to protect the earth.