Comparative Analysis On Sensitivities of Love And Rayleigh Waves
Comparative Analysis On Sensitivities of Love And Rayleigh Waves
复制标题
DOI：
10.1190/1.2792611
复制
发表时间：
2007
期刊：
影响因子：
--
通讯作者：
C. Zeng;J. Xia;Q. Liang;Chao Chen
中科院分区：
文献类型：
--
作者：
C. Zeng;J. Xia;Q. Liang;Chao Chen
在近地表剪切波（S波）调查中，Love波通常比Rayleigh波更少使用，因为获取S波数据不像获取P波数据那么容易。Love波的频散与泊松比无关。这一特征可为提高横波速度成像质量提供有价值的依据。地球性质对面波（Love波和Rayleigh波）频散曲线的敏感性是确定横波速度模型精度的基础。通过对比分析Love波和Rayleigh波对频散曲线的敏感性，可以在反演过程中合理选择面波频散数据的模式和频率范围，从而提高横波速度剖面的精度。对于层状地球模型，灵敏度由百分比变化而不是偏导数定义。基于规则模型和不规则模型的分析表明，对于地球的属性，如S波速度和每层的厚度，Love波比瑞利波在大多数频率范围内更敏感。虽然低速层可以显着影响的灵敏度的洛夫波和瑞利波，洛夫波的灵敏度变化的横波速度是在低频率高得多。Love波对半空间中S波速度的变化比Rayleigh波更敏感。这意味着Love波可以更容易地恢复半空间的横波速度。这表明多模Love波与Rayleigh波联合反演可以获得更精确的横波剖面。
Love waves are generally less employed than Rayleigh waves in near-surface shear-wave (S-wave) investigations because acquiring S-wave data is not as easy as acquiring P-wave data. The dispersion of Love waves, however, is independent of Poisson’s ratio. This character can be the valuable basis to improve the S-wave velocity imaging. The sensitivity of earth properties to the dispersion curve of surface waves (Love and Rayleigh waves) is fundamental to determining the accuracy of an S-wave velocity model. By analyzing sensitivities to the dispersion curves of Love and Rayleigh waves comparatively, modes and frequency ranges of surface-wave dispersion data can be chosen appropriately during the inverse procedure, which helps to improve the accuracy of S-wave velocity profiles. For layered earth models, the sensitivities are defined by the percentage changes instead of partial derivatives. Analysis based on a regular model and an irregular model shows that, for earth properties such as the S-wave velocity and the thickness of each layer, Love waves are more sensitive than Rayleigh waves in most frequency ranges. Although the low velocity layer can dramatically influence the sensitivities of both Love and Rayleigh waves, the sensitivity of Love-wave to changes in S-wave velocity is much higher at low frequencies. Furthermore, Love waves are more sensitive than Rayleigh waves to the change of Swave velocity in half-space. That means Love waves can recovery the S-wave velocity of the half-space more easily. All these indicate that the joint inversion of multimode Love waves with Rayleigh waves would obtain a more accurate S-wave profile.