Geomorphological responses of rivers to active tectonics along the Karahayıt Fault, Western Türkiye

Abstract

Understanding the topography in active tectonic areas and assessing the rates and models of active deformation in the upper crust are primary objectives in tectonic geomorphology studies. The drainage pattern of river systems is highly sensitive to tectonically induced changes, and it often preserves the records of the formation and progression of most tectono-geomorphic processes within its boundaries. Therefore, the evolution of landforms is a consequence of the evolution of individual drainage basins in which they are formed. Assessing the rates of tectonic deformation using geomorphic data is a traditionally adopted method to characterize the nature of active faults. Globally, the Digital Elevation Model (DEM) is widely used as a crucial tool to analyze the morphotectonic features of drainage basins. In this study, some geomorphic indices were applied to investigate the impact of tectonism on landscape along the Karahay & imath;t Fault and its associated drainage areas. These geomorphic indices are mountain front sinuosity (Smf values between 1.17-1.52), valley floor width-to-height ratio (Vf values between 0.25-1.46), basin asymmetry factor (AF values between 15-72), drainage basin shape (Bs values between 3.18-6.01), hypsometric integral and curve (HI values between 0.32-047), channel sinuosity (S values between 1-1.6), normalized steepness index (Ksn values between 1-390) and Chi integral (chi values between 200-4400). The development of drainage areas on the hanging wall and footwall block of the Karahayit Fault differs depending on the uplift. The drainage areas developed on the hanging wall present different patterns depending on the regional uplift caused by the fault. This reveals that the fault contributed significantly to the development of drainage areas and regional uplift in the region. In addition, the maximum earthquake magnitude that may occur in the future on the Karahayit Fault, whose activity is supported by geomorphic indices, is calculated as 6.23. Since an earthquake of this magnitude may cause loss of life and property in the region, precautions should be taken.