Fault-controlled uplift segmentation and crust–mantle heterogeneity in the topographic evolution of the Sındırgı Segment (Western Anatolia) ruptured during the 2025 M6.1 earthquake sequence

Abstract

Topographic evolution, particularly in extensional tectonic regimes, stems from fault activity and crust–mantle heterogeneity, both of which coordinate long-term rock uplift. Understanding how surface topography records the interaction between fault activity and deep lithospheric processes is essential for explaining the extension of continental regions. In this study, Moho variations were adopted as a core element to examine landscape evolution along the Sındırgı Segment in Western Anatolia through a multimodal analysis of geomorphic indices, drainage-network metrics, knickpoint distributions and the inversion of river longitudinal profiles. Morphometric parameters and normalized channel steepness showed along-strike segmentation and spatially variable uplift patterns. $\chi$ and Gilbert metrics indicated uneven drainage-divide behaviour, namely, the drainage system is still adjusting. River-profile inversion showed that rock uplift got underway during the Late Pliocene and accelerated during the Early to Middle Pleistocene. This migration produced continual topographic markers preserved in the present-day relief and knickpoints. Moho depth varied along the fault and matched the cumulative uplift and landscape segmentation. So upper-crustal faulting alone is not enough to explain surface deformation and long-wavelength topography. Note that the Moho data gave a regional-scale lithospheric constraint; the observed relationship should only be interpreted as partial lithospheric modulation rather than direct causality. In conclusion, the Sındırgı Segment has not been shaped by a sole process. Instead, an intertwined system is active, in which fault-controlled surface processes interact with deeper lithospheric heterogeneity. Spatially variable tectonic forcing, coupled with ongoing drainage adjustment within an active extensional setting, drives the landscape evolution.