Total risk analyses for large dams in Kizilirmak basin, Turkey

Abstract. Dams located near urban areas have a high risk potential for life and property in downstream. Turkey is one of the most seismically active regions in the world and has at least 1200 large dams with different type. Major earthquakes with the potential of threatening life and property occur frequently here. Kizilirmak basin studied in this article is located in a seismically very active part of Turkey. The northern part of basin is structurally cut by a significant fault system. The shear zone, which is frequently jointed, fractured and faulted at the central part of basin increases total risk of dams within the zone. Consequently, there are so many large dams, which are located close to these faults in the basin. In this paper authors summarize the methods used for the analysis of total risk, discuss the seismic hazards of 36 large dams constructed in the Kizilirmak basin on the basis of the seismic activity of the dam site and their total risk as based on physical properties and the position in the basin. The seismic hazard analyses have indicated that peak ground acceleration changes within a wide range (0.09 g and 0.45 g) for the dam sites of basin. The total risk analyses depending on the seismic hazard rating of dam site and risk rating of the structure have concluded that 23 large dams have high-risk class in the basin.