| Abstrakt: |
Indonesia is a country located in a region with high level of seismicity. The seismic activities are caused by the tectonic plate interaction of Australian Plate, Eurasian Plate, Philippine Sea Plate and Pacific Plate. A number of volcanoes and active faults are also believed to be the causes of earthquakes around the country. The effect of earthquake on the infrastructure should be taken into consideration, especially for the large-scale structure built in dense population area. One of large-scale structures constructed is Kedung Ombo Dam in Central Java, Indonesia. The dam was constructed in 1976 over the borders of three regencies, namely Sragen, Grobogan, and Boyolali, of which have a relatively high population density. Considering that the dam has been operated for more than 30 years, it is necessary to evaluate the influence of earthquake hazard on the safety of the dam. For this purpose, two main data are required; firstly, the information about the updated seismicity (earthquake) of the area, and secondly the information about the geotechnical properties of the dam. This paper presents the study of seismic hazard analysis using total probability theory for the pre-evaluation of the safety of Kedung Ombo Dam. The objective of this study is to obtain peak ground acceleration in the return periods of 500; 2500; and 10,000 years. The result indicates the seismic hazard of Kedung Ombo Dam for the return periods of 500; 2500; and 10,000 years, respectively, are 0.23 g; 0.36 g; and 0.5 g. Based on deaggregation process, the most influential factor is earthquake with a magnitude between 5.78–6.7 (Mw) located between 22–44 km from the dam. The accelerogram for dynamic analyses is presented in the end part of the paper. [ABSTRACT FROM AUTHOR] |
