1. Ground fissures: Different types of ground fissures may occur in karst areas. Apart from ground fissures formed by neotectonic movement that may occasionally be seen, the more common ones are ground fissures produced in red clay in karst areas due to its swelling-shrinking property (expanding when wet, shrinking when dry), which often cause buildings to crack and be damaged. Another type of ground fissure is caused by land subsidence and appears and is distributed along with land subsidence. The stronger the subsidence, the denser the ground fissures, with extension lengths ranging from tens of meters to more than one hundred meters. For example, during a water release test at the Huating Manganese Mine in Leping, Jiangxi, more than 150 ground fissures appeared along with the drawdown, with a maximum length of 160 meters and a visible maximum depth of 2 meters.

　　2. Land subsidence:

　　Different types of land subsidence may occur in karst areas. One common type is "dewatering-compaction subsidence." For example, at Cuihu Park in Kunming, due to drainage from the civil air defense project at nearby Yuantong Mountain, the karst groundwater level dropped considerably. In the overlying loose saturated soil layer there, in addition to 39 collapses, obvious settlement and cracking phenomena such as pier settlement, building cracking, and cracking on the outer side of the lake embankment were also commonly seen in the park. This is the result of dewatering and compaction of the soil layer. The overburden at the Huating Manganese Mine in Leping, Jiangxi, consists of red clay 5–35 m thick and a sand-gravel layer about 5 m thick. In February 1970, a water release test was conducted in a 40 m pit, with a drawdown of 32.5 m and a water inflow of 268 L/s. In addition to 82 collapses, land subsidence and cracking also occurred within about 1 km inside the drawdown cone, with a maximum settlement of 360 mm, and a subsidence area with settlement exceeding 30 mm of about 3 square kilometers. This is also the result of dewatering and compaction of the sand-gravel layer and consolidation and compaction of the cohesive soil layer after dewatering. Another type of subsidence is caused by densely distributed small karst fissures and cavities beneath the soil layer, causing the soil layer to be lost relatively uniformly downward. This phenomenon is most typical in gypsum karst areas.