Sensitivity Analysis of Multiple Modes Rayleigh Waves Phase Velocity by Low-Velocity Interlayer Model

The sensitivity of multiple modes Rayleigh waves phase velocity are analyzed based on a low-velocity interlayer model. The results show that the wave phase velocity of multiple modes is very sensitive to the shear velocity of low-velocity interlayer and thickness of the layer. The wave phase velocity is more sensitive to the shear velocity than thickness of the layer. The sensitive band of fundamental model is concentrated in a narrow band of low frequency. Inverting Rayleigh waves of fundamental and higher modes can effectively improve the accuracy of inverted S-wave velocities. The sensitivity of multiple modes Rayleigh waves phase velocity to the shear velocity of low-velocity interlayer and thickness of the layer show that Rayleigh surface wave method is suitable for low-velocity interlayer survey.