UNRAVELING THE CONNECTION BETWEEN SUBSURFACE STRESS AND GEOMORPHIC FEATURES (Invited Presentation)

The stress field within the lithosphere plays an important role in shaping surface features such as topography, faulting, and non-brittle deformation. These stress fields, at long wavelengths, stem from variations in crust and lithospheric mantle thickness and density, as well as tractions from the convecting mantle acting on the lithosphere's base. However, how these stress sources manifest in surface features remains largely unclear. In this study, we investigate the alignment between principal horizontal compressive lithospheric stress directions, fault traces, and river flow across the globe. Our analysis reveals a correspondence among these three features. The orientations of fault traces and observational stress largely align with expectations based on Anderson's fault theory. However, the level of correspondence varies spatially based on the stress regime and stress sources. Extensional fault regimes are primarily influenced by variations in lithospheric density and thickness, while compressive fault regimes are more affected by stresses arising from mantle flow. We introduce a metric to quantify the relative influence of mantle flow or lithospheric heterogeneity on surface features, offering insights into variations in lithospheric strength. Additionally, we observe that river networks tend to align with fault directions in areas with active faults, particularly high-order rivers. This study highlights the significant influence of subsurface mechanisms on surface deformation and provides insights into the interplay between subsurface stress and surface features.