A severity index to assess technological and natural risks in a study area

The paper addresses the problem of assessing the overall risk in a given area properly taking in account the contribution of each technological and natural risk sources present, such as industrial activities subject to Seveso directives, transportation of dangerous goods, earthquakes, volcanic eruptions, flooding, landslides, etc., based on the available quantitative or qualitative data. To this end, a "severity index", which is a dimensionless measure of the risk level, is defined for each risk source and the corresponding severity maps are obtained dividing the study area into meshes and calculating the values of the severity index for each mesh. Hierarchical prioritization techniques based on expert judgement are then applied to determine the weights associated to technological and natural risk sources, which are then combined to obtain global severity maps for the study area, which can be compared with vulnerability maps to achieve an accurate picture of the risk in the study area. The methodology has been implemented in a GIS (Geographic Information System) tool, which assists the users along the procedure. © 2006 Taylor & Francis Group