Tracking cliff activity based on multi temporal digital terrain models – an example from the southern Baltic Sea coast

Abstract

A multi-temporal digital terrain models [DTM] study of a coastal cliff section at Kaszuby Coast (northern Poland) is presented in this paper. The analytical study was based on five LiDAR-derived DTM acquired between 2010 and 2016. The main idea was to compare changes year by year or every two years (depending on the available material). The DTM were analysed using various geoprocessing techniques, and as a result the map of slope and the gradient of maximum changes in z-value were prepared. The analysis of the temporal variations of these parameters were also prepared and allowed to visualize and track the landslides that occurred within the cliff. What is more, the areas of sediment increasement and decreasement, as well as the average rates of vertical displacement within the landslides and sediment balance on the beach were estimated. The studies allowed also to discuss the interrelation between the mass wasting processes and the protective infrastructure on the seashore. The information gathered allows us to find the mechanisms and development of landslides on the steep cliff coast.