Amplitude Characteristics of Rayleigh-Type Waves in Horizontally Inhomogeneous Layered Media

The propagation of a Rayleigh-type surface acoustic wave (SAW) along the free boundary of a layered half-space with a smooth change in its elastic parameters horizontally is considered analytically and numerically. The change in amplitude of the SAW for the transition of a wave from a single-layer system to a single-layer, single-layer to two-layer, and two-layer to two-layer system depending on the elastic parameters, as well as the length of the sounding wave, is calculated. It is shown that as it propagates, the amplitude of SAW decreases with an increase in the velocity of longitudinal waves and density of the medium, and with an increase in the velocity of transverse waves in the medium, the SAW amplitude can both increase and decrease. The change in the SAW amplitude associated with a change in the longitudinal wave velocity is stronger; therefore, this parameter should be taken into account in applied methods. It is shown that the magnitude of the dominant wavelength depends on both the geometric and elastic parameters of the system.