Negative Residual Topography in Global Back‐Arc Basins Scales With Slab Dip

Abstract

Dynamic topography above subduction zones is widely inferred, but its magnitude and controls remain poorly constrained at the global scale. Here, we estimate residual topography across a range of back‐arc basins by correcting bathymetry for sediment loading, crustal structure, and lithospheric age, and compare the anomalies with slab geometry and subduction parameters. Most basins show negative residual topography, and the anomalies become more negative with increasing slab dip. Continental–oceanic back‐arc basins tend to show more negative residual topography than ocean–ocean systems. Residual topography further covaries with cumulative subducted water content, consistent with a possible influence of hydration‐modified mantle rheology on slab‐driven flow. Although the number of basins with complete slab constraints remains limited, these results suggest that slab geometry is associated with negative residual topography in back‐arc regions and provide observational constraints for geodynamic models of mantle flow around subduction zones.