Hillslopes and hillslope processes features on edges of karst poljes of the southern part of Vis Island, Croatia

The morphology of surrounding hillslopes of karst poljes of Vis Island reflects past and present tectonic, climatic and biologic processes that drive soil production, mobilization, and transport. Rock mass and soil transport results in modelling of hillslopes and positioning of inflexion points. Today, Vis Island is characterized by the lack of water, so intense formation of hillslopes occurred during more humid period in the geologic past, when the rainfall amount was greater than the potential evapotranspiration. To get more detailed insight into morphogenesis of the hillslopes, a number of profiles of the surrounding slopes of the poljes were analysed. The shape analysis was based on the digital elevation model. Convex slopes indicate younger uplifts and are dominated by destructive processes, while concave slopes are genetically older and are dominated by accumulation processes. In this area, younger uplifts occurred in Neogene-Quaternary Neotectonic tangential phase characterised by stress of N-S direction. This stress regime leads to a transformation of hillslope landscape, refolding of the existing structures and the formation of new ones. Reactivation of the existing discontinuity during neotectonic phase is a consequence of the fact that each new tectonic cycle, with the new regime of the main stress direction, uses existing discontinuities (that take a part of directed pressure). If the hillslope profiles and tectonics are compared, it can be seen that the hillslope shapes and existing faults and fracture systems are in correlation and in an almost "ideal position" for the reactivation in neotectonic cycle. Analysis of hillslope shapes and correlation with tectonics can be used to explain evolution stages, related processes and relative age differences between hillslopes, related karst poljes, and, consequently, the relief features of southern part of Vis Island. Also, it can be used to predict future stages of evolution, which is of great importance for numerous practical purposes.