Development and validation of the Terrain Stability model for assessing landslide risk during heavy rain infiltration

Abstract. Slope stability is a key topic, not only for engineers but also for politicians, due to the considerable monetary and human losses that landslides can cause every year. In fact, it is estimated that landslides have caused thousands of deaths and economic losses amounting to tens of billions of euros per year around the world. The geological stability of slopes is affected by several factors, such as climate, earthquakes, lithology and rock structures, among others. Climate is one of the main factors, especially when large amounts of rainwater are absorbed in short periods of time. Taking into account this issue, we developed an innovative analytical model using the limit equilibrium method supported by a geographic information system (GIS). This model is especially useful for predicting the risk of landslides in scenarios of heavy unpredictable rainfall. A hydrological steady-state assumption was incorporated into this approach. The model, called Terrain Stability (TS), was developed and programmed in MATLAB. This model allows a simulation of the slope stability in a 2D spatial distribution. Many variables measured in the field – topography, precipitation, type of soil – can be added, changed or updated using simple input parameters. To validate the model, we applied it to a real example, that of a landslide which resulted in human and material losses (collapse of a building) at Hundidero, La Viñuela (Málaga) in February 2010.