TRANSFORMATION OF THE SPECTRUM OF LOVE WAVES IN THE PRESENCE OF A RIGID LAYER AND A COMPLIANT HALF-SPACE

The variation of the spectrum of Love waves in the presence of a rigid layer and a compliant half-space is predicted. Only the slightly inho mogeneous first Love mode, characterized by a somewhat lower transvers e sound velocity in the half-space and by square-law dispersion, exist s at low frequencies in the given situation. The spectrum undergoes tr ansformation as the frequency increases, and transverse normal modes p ropagate at above-critical frequencies. The phase velocity of such wav es in the long- and short-wavelength regions is somewhat higher than t he transverse sound velocity in the layer. The dispersion law changes at the same time. The dispersion varies inversely as the frequency in the long-wavelength region, whereas for short wavelengths the dispersi on law acquires terms that vary inversely as the frequency to the firs t, second, and third powers. The waves can be categorized as quasisymm etrical and quasiantisymmetrical. The modified transverse normal modes are strongly inhomogeneous in the long- and short-wavelength regions.