Kinematic and morphometric evidence for recent reactivation of the Kale-Yeşilyurt fault zone within the East Anatolian Fault System

Abstract

The Kale-Ye & scedil;ilyurt Fault Zone (KYFZ) exhibits recent tectonic reactivation, which is critical for understanding regional seismicity and the geodynamic evolution of the East Anatolian Fault System (EAFS). This study integrates kinematic and morphometric analyses to explore the reactivation processes along the fault. Kinematic analysis, incorporating fault-slip data and stress inversion, reveals complex deformation patterns characterized by strike-slip and extensional movements, with NE-SW trending minimum stress axes. February 6, 2023, earthquake sequence highlighted significant stress accumulation along the Kale-Ye & scedil;ilyurt and G & ouml;ksun segments. Fieldwork and morphometric analyses, including mountain front sinuosity (Smf) and drainage basin analysis, suggest variable uplift rates and tectonic forces, with an asymmetric westward-directed uplift along the KYFZ. HI-HC index analysis underscores rapid uplift, particularly in the western basin, signaling ongoing tectonic and geomorphic activity. The normalized channel steepness index (Ksn) values reveal variations in erosion rates, providing insight into regional uplift patterns and knickpoint distribution. While morphometric indicators collectively point to high tectonic activity along the Ye & scedil;ilyurt segment, the Kale segment exhibits particularly intense activity with a dominant normal fault component. The 2020 Sivrice earthquake and the 2023 earthquake doublet further emphasize the structural complexity of the fault system and underscore the KYFZ's pivotal role in the active tectonics of the EAFS. Future research incorporating advanced geospatial technologies is vital for improving our understanding of tectonic processes, mitigating earthquake hazards, and enhancing seismic risk assessments.