Page - 920 - in Book of Full Papers - Symposium Hydro Engineering

requirements. Other one is Bureau method, which considers various risk factors and weighting points to quantify the total risk factor (TRF) of any dam [11]. In this methods the TRF depends on the dam type, age, size, downstream risk and vulnerability, which depends on the seismic hazard of the site. For all analyses throughout this study, the peak ground acceleration was determined by two methods discussed above, only the results obtained by DSHA. All procedures mentioned above can be executed by the DAMHA program that is working on the basis of geographic information system (GIS). For total risk of dams, two different methods mentioned above are used for all dams considered for this study. 3. ANALYSES AND RESULTS Dam designers in Turkey believe the fact that embankment dams, which are well compacted according to the specification, are suitable type for regions having high seismic activity. Whereas it is a well-known fact that strong ground shaking can result to instability on embankment and loss of strength at the foundations. Additionally, active faults, which are very close to the foundation of dams, have the potential to cause damaging displacement of the structure. Most of the existing dams considered for this study are under near source effect [12]. ICOLD defined the near-field motion, which is ground motion recorded in the vicinity of a fault [8]. In this specification, a correlation between radius of near field area and earthquake magnitude is suggested as based on the cases on West United States. Author established limits of near-field motion for the investigation area. According to this model, the maximum magnitude of the earthquakes ranges from 5.7 to 6.7 and the minimal distance to fault segment is between 1.1 and 3.1 km for five dams (Table 2). The last one, namely Alacati Kutlu Aktas dam, is not under near field motion with minimal distance to fault segment is 10.1 km. The 83.3 percent of dams considered for this study has a minimal distance, which is less than 3.1 km to an active fault. In other word, all dams with exception of Alacati Kutlu Aktas dam, are not far away 10 km to active faults. Table 2. The results of deterministic seismic hazard analyses No Dam Deterministic Method * Maximum earthquake Mmax Minimum distance, Rmin Mean PGA + 50 % Mean PGA + 84 % 1 A.Kutlu Aktaş 6.1 10.1 0.116 0.189 2 Balcova 6.1 2.4 0.288 0.450 3 Gordes 6.7 1.1 0.442 0.702 4 Guzelhisar 6.7 3.1 0.409 0.642 5 Tahtali 5.7 1.9 0.277 0.431 6 Urkmez 5.7 1.7 0.310 0.482 The results of the DSHA are given in table 2. In this table, Mmax is the maximum earthquake magnitude in Mw and Rmin is the minimum distance to fault 920