A Semi-Probabilistic Seismic Hazard Assessment of Büyükçekmece Using Ground Motion Simulations

Abstract This study presents a comprehensive seismic hazard assessment for Büyükçekmece, a district in Istanbul, Turkey, situated near the seismically active North Anatolian Fault (NAF). Utilizing stochastic ground motion simulations with the validated EXSIM algorithm, the study focuses on understanding the potential impact of medium to large magnitude earthquakes (ranging from 6.3 to 7.42) on this vulnerable community. The research employs a site-specific approach, considering unique amplification factors for each location, enhancing the accuracy of ground motion modeling. By conducting 50 scenario-based simulations, the study assesses the seismic hazard, highlighting the importance of comprehending variations in ground motion, even when they are small, for a more precise hazard assessment. Furthermore, this study addresses the critical issue of uncertainty, particularly concerning stress parameters and hypocenter locations. The researchers demonstrate that variability in these factors can introduce substantial uncertainty in ground motion predictions. Through probabilistic assessments involving multiple scenarios and stress drop values, the study provides insights into the range of potential ground motion outcomes. Notably, the results indicate that ground motion levels vary with earthquake magnitudes and underscore the significance of accounting for this variability. This research emphasizes the seismic vulnerability of Büyükçekmece and the importance of accurate ground motion simulations, offering valuable insights for earthquake preparedness and mitigation efforts in the region.