Chapter Identifying cliffs morphodynamics: a 3D GIS approach for a better hazard management. Examples in Croatia

Abstract

In this paper, we present a simple method for elaborating and mapping a multivariate index for coastal cliffs. The final map aims to classify zones of low, medium and high hazards related to morphodynamics. This classification is a synthetic description that must later be explained with geological and other features. The index is calculated on regularly and closely spaced transects along the coastline. It uses three easily determined parameters: the evolution of the cliff edge, the height and the mean slope. The sites selected for this study are located in Croatia. The first coastal cliff is located on the island of Vrgada. Massive episodic rockfalls usually occur on this 90° steep cliff. The second is the coastal cliff of Duilovo in the urban area of Split. Erosion processes along this cliff include rockfalls and landslides supported by water, while weathered sediment are moved downslope by gravity during dry periods. At both sites wave action is not the key process in the formation in cliff formation, but it carries away debris and other forms of material that have accumulated downslope. The morphodynamics analysis on both sites was tested and is presented for the first time.