The Torvizcón, Spain, landslide of February 1996: the role of lithology in a semi-arid climate

Abstract

The analysis of a shallow landslide in las Alpujarras, a metamorphic terrain of semi-arid Spain is presented. The extensive outcropping of phyllites and mica-schist is one of the most important keys in the understanding of mass failure. The degree of schistosity offers planes of weakness where water can penetrate and cause mass movement processes by increasing pore water pressures. A shallow slope movement occurred during extreme events, causing damage to the local and regional infrastructure and increasing the likelihood of natural disasters. By using the infinite slope model of Skempton and DeLory, a back analysis of an observed shallow landslide was carried out. The results of the sensitivity analysis indicated that material properties play a signifi- cant role in controlling slope processes and that the slope angle should not be considered as the only parameter to define instability threshold.