Dynamic loads induced by earthquakes are often major factors in the design of earthrndams. Earthquake induced stresses are major factors in determining the angles of therndam slopes and significantly influence the selection of materials, the zoning of the dam,rnand the construction method. Awareness about more rigorous seismic stability analysis isrnalso growing during recent years.rnIn Ethiopia dams are being constructed for various purposes. The analysis and design ofrndams has been carried out by taking many factors in to account. Among these factorsrnearthquake effect is considered mainly for major dams. One of these dams is the SibilurnDam, which is under design for the Addis Ababa water supply. Until the present, inrnEthiopia, seismic effect is commonly considered by the pseudo-static analysis method.rnBut representation of the complex, transient and dynamic effects of earthquake shakingrnby constant pseudo-static forces is obviously not accurate. In this thesis an attempt wasrnmade to compare the pseudo-static and dynamic response analysis by taking the SibilurnDam as a case study. The main purpose of the study is to show the shortcomings of thernpseudo-static analysis method as compared to the dynamic response analysis whenrnapplied to the analysis of earth/ rock fill dams.rnThe thesis is organized as follows: initially a background is given on seismicity andrnseismic hazards in general and Ethiopia in particular. The second chapter coversrnsummary of previous works related to this study. In the third chapter some description isrngiven about the Sibilu Dam, the dam under the case study. In chapter four, the definitionrnof the expected seismic excitation for the dam site is presented. The historical records ofrnearthquake events are collected and geotechnical data of the dam site are reviewedrn2rnpaying special attention to the location of active faults. The obtained data set is analyzedrnto give the required earthquake parameter for two different return periods.rnIn fifth chapter, the pseudo-static slope stability analysis is done with the conventionalrnlimit equilibrium method by using the design ground motion as an input. The analysis isrnperformed for the upstream and down stream slopes of the dam by varying the possiblerncritical cases. In chapter six, analysis and design is done based on permissiblerndeformation. The dynamic response analysis is done by varying the material behavior.rnNon-linearity is considered by the Equivalent Linear Method. Finally, comparison of therndifferent analysis methods is made and conclusions and recommendations are drawn.