Landslide susceptibility analyses in flysch areas in the north-eastern part of the Adriatic coast

Abstract

Many different instability phenomena were found on flysch slopes in the past 30 years in the area of dominant geomorphological unit Rjeina Valley -Suaka Draga Valley -Bakar Bay -Vinodol Valley. This paper gives the review of present landslide appearances and the estimation of the possible landslide occurrence at the NW part of Vinodol Bakarac Valley, between the Bakarac and Kriie settlements, in the Kvarner area (north-eastern Croatian Adriatic coast). Based on longtime investigation work results for different purposes it was established that the wings and the base of the valley are made of flysch rock complex, consisting mainly of silty marl, laminated siltstones and fine grained sandstones near the contacts with karstified carbonate rock mass. Landslide susceptibility analysis of this area was made based on existing data about lithological composition and geological fabric, geotechnical properties of slope deposits and flysch bedrock, hydrological and hydrogeological conditions and existing landslides inventory map. Spatial analysis of unfavorable conditions in the investigated location resulted in landslide susceptibility map which divides the area into four classes of susceptibility.