Earthquake Safety Evaluation for Dams in Upper Aras Basin, Turkey

The Aras basin, which covers an area of 102,000 km2, has the Aras river and many tributaries. The Aras river rises from eastern Turkey and drains the south side of the Lesser Caucasus Mountains, then joins the Kura River, which drains the north side of those mountains and joins Caspian sea after 1 072 km. It is a transboundary river, which flows in and along the countries of Turkey, Armenia, Azerbaijan, and Iran. There are so many small and large dams in the basin. However, eighteen of large dams, which are located on Upper Aras basin, were considered for this study. The heights of dams range from 25 to 157 m. The twelve of them are under operation stage while others are under construction and final design stages. Main part of this basin is located on active seismic region. It is clear that earthquake safety of dams is an important aspect in dam engineering and requires more comprehensive seismic studies for understanding the seismic behavior of dams subjected to severe earthquakes. This study evaluates the main concept of seismic hazard analysis and introduces results of analyses executed for dams of Upper Aras basin, Turkey. The analyses indicate that 75 percent of dams pose moderate hazard ratio and two of them are under near source effect when considered the updated seismic data.