ASSE-ASsessment of shallow landslides SEdiment sources and delivery hazard at catchment scale

The occurrence of intense and, occasionally, concentrated-in-time rainfall events on slopes can lead to the formation of shallow landslides, which in the past have been to blame for both damages to infrastructures and activities and for the loss of human lives. Overall this work aims to identify different existing gaps in literature regarding the characteristics, occurrence and development of shallow landslides with the goal of providing some possible solutions. This work aims to fill some of the existing gaps in literature regarding shallow landslides by addressing four main questions: i) How can the natural variability of the inputs be taken into account when modelling shallow landslides?; ii) How can land use and land management be exploited as inputs in modelling?; iii) How can the runout be estimated and which factors influence it?; iv) Which factors influence the size of the source area? The first and second questions were addressed through the implementation of the existing physically-based landslide susceptibility model LAPSUS-LS into a probabilistic model to take into account the natural variability of the inputs, improving the reliability of the modelling strategy in identifying the source areas of shallow failures at catchment scale. The third question, regarding how the runout can be estimated and which factors influence it, was tackled, along with the second question, through the development of a methodology to predict the length of the runout in heterogeneous areas, using as inputs a limited amount of remotely-collected data and geological and land use factors. Lastly, given the proven importance of the source area in determining the length of the runout of a shallow landslide, an analysis of the factors which influence its size was carried out, discovering a link between both the land use and the cumulated rainfall and landslide size.