The Impact of Earthquake Induced Landslides on the Terrain Predicted by Means of Landslides Susceptibility Maps. The Case of the Lefkada Island.

Περίληψη

The occurrence of landslides is frequent in Greece. The current study focuses on Lefkada Island presenting the highest landslide occurrence among the Ionian Sea islands, on the west coast of Greece. The Ionian Islands have suffered from many destructive earthquakes and Lefkada holds a key position among them. The main failure mechanism occurring is rock fall. The most common preparatory factors of these events are the steep morphology and the type of the geological formations, while their triggering event is the seismic activity. Although landslides cannot be predicted accurately, many attempts have been made to compile susceptibility maps on a global or continental scale. Mapping areas susceptible to landslides is essential for the strategic planning and management of the land-use. In the present study, diverse data such as geological formations, tectonic structures, pre- and post- earthquake landslides, geomorphologic and topographic features were compiled for the preparation of the susceptibility map. The above data was digitized and imported in a Geographic Information System (GIS). Afterwards, thematic layers of lithology, slope angle, slope aspect, tectonic lineaments, drainage network and road network were developed. After the creation of the these layers, GIS techniques were applied, in order to produce the maps by means of the weighted linear combination - W.L.C., semi quantitative method.