中文摘要：

笔者给出了一种能够模拟弹性波在任意各向异性介质中传播的二维三分量高阶有限差分算法。相对于常规交错网格有限差分方法，旋转交错网格有限差分方法在介质具有强差异性时能更精确地模拟地震波的传播，避免常规交错网格中因对弹性系数进行插值而带来的误差。采用高阶旋转交错网格有限差分方法模拟并分析了零偏移距横波分裂现象随裂缝介质方位角和倾角变化的响应特征。结果表明：结合完全匹配层（PML）吸收边界条件的高阶旋转交错网格有限差分方法能获得高精度的地震波场模拟数据，并且在边界具有良好的吸收效果；横波分裂现象主要受裂缝走向与波的极化方向之间的夹角影响，受裂缝倾角影响较小，且快慢横波的能量也跟裂缝走向与波极化方向间的夹角有关。具有倾斜对称轴的横向各向同性（TTI）介质倾角的变化可能会导致记录中波到达时的变化，影响快慢横波的时差。利用横波分裂的能量分布和方位各向异性特征，可以帮助检测裂缝的方位角和倾角。横波在多层TTI介质中传播时会发生多次分裂的现象。

英文摘要：

A high-order rotated staggered grid scheme （RSG） has been implemented to simulate the shear-wave splitting in tilted transversely isotropic （TTI） media. The high-order RSG can simulate wave propagation in media that contain high-contrast discontinuities like cracks more precisely than the standard staggered grid scheme （SSG） by avoiding the unstableness of the staggered grid scheme （SSG）. The authors conducted a study of zero-offset S-wave splitting with the high-order RSG. The S-wave splitting study was mainly focused on fractured media which, on the scale of seismic wavelength, could be regarded as transversely isotropic （TI） media. The resuits of numerical modeling show that the high-order RSG scheme can be used to simulate waves＇propagation in general anisotropic media. The perfect matched layer （PML） absorbing boundary condition combined with the high order RSG scheme can well attenuate reflections from the artificial boundary. The S-wave splitting is mainly affected by the angle between polarization direction of incoming wave and strike of the TTI media, and the energy of fast and slow shear waves is also associated with this angle. The dipping angle of TTI media may affect time lag between the fast and slow waves, which may result in variation of arrival time of waves from the same interface. Thus, the analysis of energy distribution of the fast and slow waves and the variation of arrival time may help detect the strike and dipping angle of the fracture. Besides, when propagating in the media that contain more than one layer of TTI media, the S-wave splitting will occur more than once.