Static and cyclic triaxial tests on isotropically and anisotropically consolidated specimens of core and filter/rockfill material, with diameters between 228 and 308 mm, were performed to determine parameters for the earthquake response analysis of the existing 155 m high Goescheneralp earth core-rockfill dam in Switzerland in its present state, and also after heightening it by 8 m. The analysis included a 2D equivalent linear response analysis using the FE-method and the assessment of stability using Newmark's block sliding method. The resulting displacements of selected blocks along the crest are within about 0.5 to 1.0 m, which is an acceptable range. Hence, the Goescheneralp dam was assessed to be safe against the relevant seismic events.