Global occurrence models for human and economic losses due to earthquakes (1967–2018) considering exposed GDP and population

In moderate-to-low seismic hazard regions, estimating the socio-economic consequences of an earthquake on the regional 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 (e.g. fatalities and injuries) and economic losses (e.g. direct and indirect costs, number of buildings destroyed or damaged). In this study, exposed population and GDP at the date of the earthquake complete the flat file information, estimated thanks to the exposed area computed with an empirical relationship derived from the ground motion footprint provided by USGS ShakeMap. Earthquake consequences have increased since 1967 and follow a non-stationary Poisson distribution with rate proportional to exposure. In order to assess the stationarity of the consequences, we assumed stationary losses and fatalities by normalizing consequences by the exposed wealth and population verified on a sub-set of earthquakes for which exact population is given by national census. The completeness of the flat file catalogue is compared to the international seismological catalogue, and we compute the annual rate of exceedance of human and direct economic losses relative to the exposed population and the associated GDP per capita. We show that, although the number of casualties and the absolute magnitude of losses increase as consequence of urban concentration, global losses, relative to effective exposure corresponding to macroseismic intensity of at least V, decrease. (Access to the flat file: https://www.isterre.fr/philippe-gueguen/earthquake-losses-database/ ).