A method for the hydrodynamic analysis of large bottom-fixed offshore structures under earthquake action is presented. The investigation deals with arbitrarily shaped vertical bodies of revolution, to which the so-called macroelement method can be applied. The structure is considered here as rigid, the compressibility of the surrounding water has been taken into account. Numerical results for several bottom-mounted structures give information on the earthquake-induced hydrodynamic forces and their parts (added mass and damping). The effectiveness of the macroelement method is demonstrated. The influence of geometrical shape, relative dimensions, water depth and water compressibility is shown.