Morphometric constraints on tectonic activity and landscape evolution in the Uludağ Range, NW Türkiye

The Uludağ Range of northwest Türkiye forms a key tectonic boundary between the North Anatolian Fault Zone and the Western Anatolia Extensional Region, where active deformation is expressed across a network of strike-slip and normal faults. To investigate how fault segmentation and kinematics control landscape evolution in this complex orogen, we integrate high-resolution morphometric analysis with paleoseismological data. We extracted key morphometric indices—including Δ-relief, Δ-elevation, Δ-gradient, Δχ, hypsometric integral, channel concavity (m/n), normalized channel steepness (k_sn), and knickpoint distribution—from 10-meter DEMs using open-source geomorphic toolkits. Our results demonstrate pronounced spatial variability in geomorphic signatures and tectonic activity across four divide segments (DS). DS01, associated with the right-lateral Ulubat Fault, exhibits exceptional morphometric stability and minimal disequilibrium, in line with long earthquake recurrence intervals and low Holocene slip rates. In contrast, DS02 and DS03—bounded by the Bursa and Soğukpınar faults—display χ-based divide migration and subtle landscape adjustment. DS04, influenced by the İnegöl and Oylat faults, is characterized by elevated channel steepness, dense knickpoint clustering, and southward divide migration, collectively indicating ongoing uplift and transient drainage adjustment. The strong correspondence between morphometric disequilibrium and documented earthquake recurrence patterns highlights the critical value of integrating geomorphic and paleoseismological datasets. Our findings demonstrate that only through the convergence and cross-validation of multiple independent metrics can the segmented imprint of active deformation be reliably detected—particularly where landscape response is temporally offset from fault activity. The methodological framework developed here provides a robust template for quantifying active structures and their geomorphic consequences and can be widely applied to other tectonically complex mountain belts for seismic hazard assessment and landscape evolution studies.