Separation of wavefronts of qS1 and qS2 waves in general anisotropic medium
Studying the shear wave splitting can provide another way to understand the characteristics of seismic wave propagation in anisotropic media and image the underground anisotropic parameters.Although there are various methods for calculating the group velocities of three seismic wave modes(qP,qS1,qS2)of general anisotropic media,it is still a challenge to separate the wavefronts of qS1 and qS2 waves.Based on the recently given analytical formula for calculating the group velocities of three seismic wave modes(qP,qS1,qS2),the qS1 and qS2 waves in adjacent directions can be identified under the assumptions as continuous phase velocities.To avoid being misled by the numerical calculation errors,a confidence function and the idea of fast marching method are introduced to identify the two qS waves point by point,and the independent wavefronts for the three waves(qP,qS1,qS2)are obtained.The numerical simulation results show that the algorithm is suitable for different types of anisotropic media and can stably obtain the separated wavefronts even for complex cases.This work can provide algorithmic support for multiple ray tracing,multi-phase traveltime tomography,and shear wave splitting in general anisotropic media.
General anisotropic mediumGroup velocityShear wave splittingWavefront separation
万方数据
维普
