*2.2.3.5 Karst structures*

They pose a threat to people and structures or to agriculture and water areas in and near settlement areas in places where karst-type structures such as fractures/cracks, dissolution caves, and dissolution channels develop [28, 40] (**Figures 2–5b,c**). In the regions with intense collapses, hazardous areas that cause a safety problem for human and other living things emerge. Furthermore, agricultural areas, water resources, road routes, as well as settlement areas are also damaged. Therefore, a safety problem exists not only in settlement areas and in the immediate vicinity of them but also outside of them, and it affects the lives of all living beings. Furthermore, these problems also pose risks to national economies.
