Estimation of Probabilistic Seismic Hazard for Marine Structures: A Case Study for Haydarpaşa Port

The size and importance of maritime transportation in world trade are well known. The number of ports, which is one of the most important elements of maritime transportation, is increasing day by day not only in our country but also throughout the world. Many active fault systems in our country are located at sea. In the Marmara Region in particular, most active branches of the North Anatolian Fault system pass through the Sea of Marmara. When offshore structures such as ports are constructed in high-seismicity zones such as the Sea of Marmara, conducting site-specific seismic hazard studies is necessary to reduce the seismic risk of offshore structures. In 2007, the first Turkish Seismic Design Code for Port Structures was published, which introduced new design concepts in the seismic design of offshore structures. According to this code, the design can be finalized in three basic steps: assessment of regional seismicity, estimation of geotechnical hazards, and soil-structure interaction analysis of offshore structures. Nowadays, the first Turkish Seismic Design Code for Port Structures is on the verge of a major update, which was published as a draft report in May 2019. In this manuscript, site-specific probabilistic seismic hazard analysis is needed to determine the seismic hazard associated with typical port sites. Considering this new draft code as a guideline document, we developed consistent seismic hazard studies for offshore structures within the Haydarpaşa Port sites. Unlike the old one, this new document identifies four different levels of ground motion: minimum damage level earthquake (T_R=72), limited damage level earthquake (T_R=144), controlling damage level earthquake (T_R=475), and maximum considered earthquake (T_R=2.475).