Geohazards in karst, and amplification of the related effects due to land mismanagement

Karst is a highly fragile setting, due to peculiar geological and hydrological features, and the strict connection between the surface and the sub-surface. It presents spectacular landforms, often exploited as natural parks and show caves, and hosts very important natural resources. Karst covers 20% of the Earth's surface and provides 30-35% of drinking water, with high-quality groundwaters. However, the direct connection between surface morphology and the underlying aquifer make karst waters extremely vulnerable to pollution. Occurrence of geohazards in karst strongly differs from other natural settings. Subsidence and sinkholes originated by presence of cavities, slope movements favoured by conduits and caves, flash floods related to inability of the system to manage water from heavy rainstorms, are the main types of geohazards observed. Even though mostly related to natural processes, their occurrence and consequent damage to the anthropogenic environment are often caused or exacerbated by human activities. Management of karst territories cannot be carried out without taking into account the peculiar features and behaviour of karst terrains and aquifers. The delicate and fragile equilibrium reached by nature in the course of millennia can be easily threatened by man, with catastrophic consequences to the society in terms of casualties and economic losses.