Tectonic geomorphology and seismicity of the Osmaniye Basin

This study is based on the investigation of the tectonic geomorphology and seismicity of the Osmaniye Basin. Despite the existence of studies related to the field, the absence of a study covering both tectonic geomorphology and seismicity has led us to conduct such research. The aim is to examine in detail the tectonic geomorphology and seismicity of the "Osmaniye Basin," which is located in the Mediterranean Region and stands out with its complex tectonic structure. The basin has developed under the influence of active fault systems due to its location in the interaction zone of the Arabian and Anatolian plates, and this situation has brought about distinct geomorphological features as well as high seismic activity potential. In this context, the geological history, current tectonic movements, and their effects on the surface morphology of the basin will be comprehensively addressed in the study. The geological situation of the Osmaniye Basin includes the formations of various formations extending from the Paleozoic to the Quaternary. The region is under the influence of significant fault systems such as the East Anatolian Fault Zone (EAFZ) and the Karataş-Osmaniye Fault Zone. These faults have deeply affected the tectonic evolution and current structural characteristics of the basin. In particular, the role of the EAFZ in the region and its interaction with other faults are of critical importance for understanding the seismicity of the basin. Tectonic activity has played a fundamental role in the development of landforms in the Osmaniye Basin. The formation and geomorphological evolution of the Düziçi Plain are closely related to tectonic subsidence and sedimentation processes. The uplift of the Amanos Mountains and the effect of faults such as the Karataş-Osmaniye Fault have played a significant role in the emergence of the current morphology of the plain. In addition, rivers such as the Ceyhan River and Horu (Hamis) stream have been effective in determining the morphology. The Osmaniye Basin and its surroundings have been the scene of significant earthquake activities in historical and instrumental periods. According to historical records, large earthquakes have occurred in the region, and numerous seismic events have also been recorded in the instrumental period. In particular, the fact that the Osmaniye city center and nearby settlements are located directly on active fault lines keeps the earthquake risk in the region high. Recent earthquakes have clearly demonstrated the seismic sensitivity of the region. In the study, existing research on the identification, characterization, and seismic potentials of the active faults affecting the Osmaniye Basin has been examined in detail. The contributions of the Karataş-Osmaniye Fault Zone, the İskenderun-Düziçi Fault Zone, and the EAFZ to the earthquake potential of the region are evaluated. In light of the data obtained, inferences have been made about future earthquake probabilities and seismic hazard assessment. In conclusion, this thesis aims to reveal the complex relationship between the tectonic geomorphology and seismicity of the Osmaniye Basin by comprehensively analyzing the geological structure and seismic risks of the region. The findings obtained will provide an important scientific basis for disaster risk management, land use planning, and sustainable development strategies. Furthermore, it is also intended to guide future research.