Climate-driven surface mass loading and stress modulation in global subduction zones

Surface mass redistribution driven by hydrological, oceanic, and atmospheric processes produces time-varying loads on the solid Earth, generating stress perturbations that may influence seismicity. Quantifying how these surface processes interact with tectonic stress accumulation in subduction zones, where the largest earthquakes and associated cascading hazards occur, requires an interdisciplinary integration of Earth system and solid Earth observations, yet remains insufficiently understood. The periodic nature of surface mass loading provides a natural probe of fault sensitivity to modest stress perturbations, enabling the detection of spatially coherent and seasonally varying stress modulation patterns across major subduction zones. Here, we present a global, data-driven framework that integrates GRACE/GRACE-FO satellite gravimetry–derived mass variations, global earthquake focal-mechanism catalogs, and tectonic stress models to investigate how time-dependent surface loads modify fault stress states across subduction margins in the upper 50 km and near the seismogenic plate interface. Using openly available and independently curated datasets within a high-performance computing framework, we compute load-induced stress perturbations at depth and evaluate their orientations relative to the prevailing tectonic stress field to identify conditions under which surface-driven stresses may promote or inhibit fault failure. Our results reveal systematic spatial and temporal patterns linking climate-driven surface processes with megathrust and upper-plate fault behavior, while demonstrating that the seismic response to loading is strongly controlled by tectonic setting. This study also highlights both the opportunities and challenges of interdisciplinary research based on heterogeneous open datasets.