On the physical vulnerability of buildings exposed to landslide hazards in the Lisbon Metropolitan Area

Abstract

This study assesses the physical vulnerability of buildings (PVB) in the Lisbon Metropolitan Area (LMA) exposed to landslides triggered by both rainfall and earthquakes. Firstly, a statistical model (Information Value), validated with a ROC curve, was adopted to assess susceptibility to landslides caused by rainfall. Secondly, an Analytic Hierarchy Process was adopted to assess the susceptibility to landslides caused by earthquakes. In this case, the model was validated with an inventory of historical landslides in the LMA. The vulnerability assessment included all residential buildings surveyed in the 2011 Census, considering a set of vulnerability parameters, namely: the presence of reinforced structure, number of floors, conservation status, and need for repairs in the structure and finishes. These parameters, and their respective weights, were based on expert opinion and literature. Through this analysis, it was possible to identify meaningful regional interactions between the earthquake and rainfall-triggered landslides, leading to complex damage scenarios for residential buildings. It was also possible to identify risk hotspots and potential risk adaptation and mitigation measures.