Generalized Inversion Technique application in the Marmara Region, Northeast Turkiye, to determine seismic source, path, and site parameters

The Marmara region of northwestern Türkiye is characterized by high seismic hazard due to the presence of the western section of the North Anatolian Fault system and its proximity to the densely populated Istanbul metropolitan area and other densely populated cities. The 2019 and 2025 Silivri earthquakes, along with historical earthquakes such as the 1999 Izmit and 1912 Murefte earthquakes, are recent examples of the region's earthquake risk. Those events showed complicated source characteristics. The Marmara region also has complex geology and diverse site characteristics that amplify its earthquake risk and require further analysis to better understand both site effects and earthquake sources. In this study, we apply the Generalized Inversion Technique (GIT) to separate and quantify seismic source, path, and site effects using earthquakes with moment magnitudes M≥3 recorded by regional strong‐motion and broadband networks. The dataset consists of earthquakes that occurred during the 2019 and 2025 Silivri sequences and their aftershocks, recorded across a dense regional network surrounding the Sea of Marmara. The GIT is applied to the dataset of 101 earthquakes recorded by more than 300 stations in the study area. Both parametric and nonparametric approaches are implemented to retrieve frequency‐dependent source spectra, attenuation characteristics, and station site amplification factors. This dual approach is used for cross-validation of the retrieved parameters and provided a comprehensive characterization of seismic wave propagation in the Marmara region. The results provide new constraints on regional attenuation properties and station‐specific amplification patterns in the Marmara region, as well as improved estimates of earthquake source parameters. These findings contribute to a better understanding of ground‐motion variability in the region and provide input for future ground‐motion prediction and seismic hazard assessment studies in the vicinity of the Marmara Fault system and the Istanbul metropolitan area.