When the seaquake acting on a floating structure is discussed, the effect of free-surface waves is usually ignored. However, when sea-bed vibrates due to earthquake, the compressional waves ; i.e.the sound waves ; in sea water and the water waves on the free-surface occure at the same time. If the interaction between both waves may exist, the combined theory of the sound and water waves should be considered. This paper gives the investigating results of the interaction between free-surface waves and underwater sound waves in frequency domain.
