Karst Collapse Landscape

This is a landform that forms by ground collapse in karst areas. It can be divided into bedrock collapses and overlying strata collapses. The former are caused by the collapse of a cave roof due to cave enlargement, and the latter form by sinking of the overlying rock layer due to a loss of balance induced by natural or artificial factors. Bedrock collapse caves are always associated with bore-like collapse dolines with depths of tens to hundreds of metres. A cave is called a ‘tiankeng’ or ceiling pit if the width and depth are more than 100 m. When a collapse occurs in soil layers, circular, saucer-shaped, pot-shaped or cone-shaped collapse dolines can form. Karst collapse landforms are widespread in China and include tens of thousands of sunken pits. They can be either ancient or modern and may have formed under natural conditions, but some are caused by human economic and engineering activities (Fig. 4).

Fig. 4

Karst collapse landscape – Hezhou, Guangxi Province