Free surface (Rayleigh) waves in anisotropic elastic half-spaces: the surface impedance method

The questions of uniqueness and existence of free surface waves in anisotropic linear elastic half-spaces have been settled in previous investigations by appeal to the theory of uniformly moving dislocations. An alternative framework relying on the surface impedance tensor is capable of settling the same issues; that framework is developed and fully exploited in the present work. The same framework may be used to study thoroughly the existence of Stoneley waves in bonded anisotropic half-spaces, which is the subject of an accompanying paper.