Abstract
Some investigations are applied to the surface waves in the three dimensional elastic medium. At first, after formulating a thin-layered element and discrete wave number method, the validity of the method is examined from an analytical point of view. It is found that the present method, which represent the solution for the elastic wave motion in terms of normal modes, is equivalent to the analytical solution, when the elastic medium exists on the rigid basement. The present solution and the analytical solution complement each other for the undestandings of these solutions. Next, the characteristics of the surface wave modes of the negative group velocity are investigated using the present method. Impulsive responses, which only have the negative group velocity modes, are synthesized, and compared with the complete solutions. It is found that the effect of the negative group velocity modes on the complete solutions is very small.
