Analysis of the Role of Precipitation and Land Use on the Size of the Source Area of Shallow Landslides

Abstract

Rainfall-induced shallow landslides cause damage to human activities and infrastructureseach year, and although the size of a landslide correlates to the damage that it causes, very few studies have previously investigated the factors that influence the size of a shallow landslide. The aim of this work was to assess the role of precipitation and land use in controlling the size of the source area of rainfall-induced shallow landslides. After ruling out the impact of the slope angle and bedrock lithology in the two selected catchments, the role of land use was investigated: the statistical tests showed that woodlands and vineyards had statistically different source area size distributions, possibly due to the different hydrological behaviours between the two. A correlation was additionally found between the size of a source area and the amount of cumulated rainfall in the three days prior to each analysed event. In both cases, an increase in source area size was linked to an increase in pore pressure. This study aimed to fill the existing gap in the research to help implement policies aimed at reducing the size, and consequently the impact, of shallow landslides.