A multi-hazard and multi-risk assessment methodological approach to support Civil Protection planning in wide areas

Abstract

The paper presents a study having as objective the development of an operational methodology to perform a multi-hazard and multi-risk assessment, including cascading hazards, to support Civil Protection planning in wide areas in Lombardia region. Natural hazards are mainly considered. A semi-quantitative, deterministic approach is adopted in a complete procedure, despite the awareness of current methodological and data barriers. The procedure is implemented in a GIS project, providing a flexible tool. Data are elaborated and represented in minimum cartographic units defined as hexagonal cells. Multi-hazard levels measure the number of spatial overlays and interactions among possible hazards in each cell. Due to lack of data and applicable methodologies, the value of vulnerability to multiple and to multi-hazard, is fixed as a conventional constant equal to 1. Exposure levels measure the presences in each cell of different elements: population, built environment, mobility systems, strategic and relevant facilities for Civil Protection purposes. The combination of multi-hazard and exposure levels, through a specifically designed matrix, gives as result the multi-risk levels (high, medium, low) in each cell. The methodology has been applied in different areas of Lombardia region and the case study of the Brembana valley is presented in this paper. Being a novel approach, this study sets the basis for further developments, enabling, due to its structure, enhancements through integrations and refinements in each phase.