Spatiotemporal reorganization of global earthquake disaster impacts within coupled human-Earth systems

Abstract. Understanding how earthquake disaster impacts reorganize across space and time is essential for interpreting seismic hazards within coupled human-earth systems. Using global disaster records from EM-DAT spanning 1980–2024, this study examines multi-scale spatiotemporal patterns of earthquake disaster impacts and their socio-environmental associations at global and national scales. Temporal analyses show a pronounced decoupling between seismic occurrence and disaster consequences: while earthquake frequency, exposed population, and cumulative economic losses increased overall, mortality rates declined markedly after the early 2000s. Spatial analyses reveal strong heterogeneity across continents, countries, and major tectonic plates. Asia accounts for a substantial share of global earthquake occurrences, affected populations, fatalities, and economic losses, yet national-level impacts vary considerably even under comparable tectonic settings. Standard deviation ellipse and centroid analyses further indicate an eastward to southeastward migration of the global earthquake disaster centroid over time, accompanied by relatively stable orientation and a modest contraction in spatial dispersion. To explore factors associated with national differences in fatalities, a Geographical Detector model is applied using cumulative fatalities as the dependent variable and a set of natural, climatic, socioeconomic, governance, infrastructure, and health-related variables as explanatory factors. Results show that population density and development- and governance-related indicators exhibit relatively high explanatory power, while interactions among factors generally strengthen spatial associations through bilinear or nonlinear enhancement. Overall, the findings suggest that global disparities in earthquake disaster impacts reflect the spatial co-configuration of hazard exposure, development conditions, and institutional capacity, contributing to a system-level understanding of how seismic disaster impacts evolve within coupled human-Earth systems.