Probabilistic Seismic Hazard Analysis for Andalusian Dams in Southern Spain Using New Seismogenic Zones

Abstract

The importance of developing accurate seismic analysis for dams becomes crucial, especially in active seismic zones. In this research, a probabilistic seismic hazard analysis (PSHA) for 48 Spanish dams in the Andalusian region (southern Spain) has been carried out. The selected dams (25 concrete + 23 embankment dams) fulfill the double requirement of being higher than 61.0 m and having a reservoir capacity greater than 13.60 hm3. Seismogenic parameters have been retrieved from the new seismogenic zones established in 2015, considering the soil homogeneously as rocky. Furthermore, return periods and structural periods range from 500.0 to 5,000.0 years and from 0 to 4.0 s, respectively. Results are plotted in terms of peak grand accelerations (PGAs) and pseudospectra accelerations (PSAs) for each dam. A disaggregation analysis was carried out to provide the contribution of hazard for magnitude and distance pair. The results allowed a possible PGA and return period in any point in Andalusian region to be obtained by linear interpolations. A double dimension for results is provided: first, uniform hazard spectra (UHS) are provided indicating the probability of exceeding the spectral acceleration in each spectral period is constant at a certain site; then, disaggregated results indicate the right combination of magnitude and distance that contribute the more to the seismic hazard at a specific site, for a given intensity measure, and at a certain level of intensity.