Assessment of physical vulnerability of buildings and analysis of landslide risk at the municipal scale: application to the Loures municipality, Portugal

摘要

This study offers a semi-quantitative assessment of the physicalvulnerability of buildings to landslides in a Portuguese municipality(Loures), as well as the quantitative landslide risk analysis computed asthe product of the landslide hazard by the vulnerability and the economicvalue of the buildings. The hazard was assessed by combining thespatiotemporal probability and the frequency–magnitude relationship of thelandslides. The physical vulnerability assessment was based on an inquiry ofa pool of European landslide experts and a sub-pool of landslide experts whoknow the study area, and the answers' variability was assessed withstandard deviation. The average vulnerability of the basic geographicentities was compared by changing the map unit and applying thevulnerability to all the buildings of a test site, the inventory of whichwas listed on the field. The economic value was calculated using anadaptation of the Portuguese Tax Services approach, and the risk wascomputed for different landslide magnitudes and different spatiotemporalprobabilities. As a rule, the vulnerability values given by the sub-pool ofexperts who know the study area are higher than those given by the Europeanexperts, namely for the high-magnitude landslides. The obtainedvulnerabilities vary from 0.2 to 1 as a function of the structural buildingtypes and the landslide magnitude, and are maximal for 10 and 20?m landslidedepths. However, the highest risk was found for the landslides that are 3?m deep,because these landslides combine a relatively high frequency in the Louresmunicipality with a substantial potential damage.