Modelling of the earthquake socio-economic and legal consequences at the urban scale

In moderate-to-low seismic hazard regions, estimating the socio-economic consequences of an earthquake on the urban scale is a costly and difficult task. This study analyses existing global earthquake databases to build a loss flat file of 445 earthquakes since 1967 with a magnitude greater than 4.5. The flat file includes information on the social consequences (fatalities, etc.) and economic losses (direct and indirect costs, number of buildings destroyed or damaged, etc.) of each earthquake. In this study, exposed population and GDP at the date of the earthquake complete the flat file information, estimated in relation to the ground motion footprint provided by USGS ShakeMap. TThe completeness of our catalog of social and economic losses is tested thanks to the creation of a synthetic database of losses of the 22 856 earthquakes between 1967 and 2015 affecting at least one country from the ISC-gem database. From these data, we propose a more realistic loss models. Then, occurrence models of human and direct economic losses relative to the exposed population and GDP per capita are derived showing that, although the number of casualties and the absolute magnitude of losses increase as a consequence of urban concentration, global losses relative to exposure decrease. Finally, the projection of future losses is discussed.