Anisotropic effects of non‐axial seismic wave propagation in foliated crustal rocks
Anisotropic effects of non‐axial seismic wave propagation in foliated crustal rocks
复制标题
片状地壳岩石中非轴地震波传播的各向异性效应
DOI：
--
复制
发表时间：
2002
期刊：
影响因子：
--
通讯作者：
N. Christensen
中科院分区：
文献类型：
--
作者：
D. Okaya;N. Christensen
地震波在地壳内的传播方向通常不平行于固有的岩石对称轴，这是由于地质构造的倾角和/或倾斜到弓形的射线路径。我们使用Christoffel方程和岩石物理学测量的地壳变质岩的速度来检查各向异性速度和走时效应作为非轴向传播的函数。P波和S波速度在快轴向速度和慢轴向速度之间进行三角加权。在一个非轴向角度范围内求平均值，得到了贯穿地壳射线路径所遇到的有效速度。轴向速度不能简单地用来量化地壳各向异性效应。P波延迟和剪切波分裂的角度行为对材料对称轴对角测量的VP敏感;该对角速度控制非轴向剪切波奇异性的存在或不存在。这些行为有助于量化地壳岩石对地震各向异性观测的贡献，地震各向异性可以作为地壳变形的代理。
Seismic wave propagation within the crust is usually in directions not parallel to inherent rock symmetry axes due to geologic dips of structures and/or oblique‐to‐arcuate raypaths. We use Christoffel equations and petrophysically measured velocities of crustal metamorphic rocks to examine anisotropic velocities and traveltime effects as functions of non‐axial propagation. P‐ and S‐wave velocities are trigonometrically weighted between fast and slow axial velocities. Averaging over a range of non‐axial angles yields effective velocities as encountered by through‐going crustal raypaths. Axial velocities cannot be simply used to quantify crustal anisotropic effects. The angular behavior of P‐wave delay and shear wave splitting are sensitive to VP measured diagonal to the material symmetry axes; this diagonal velocity controls the presence or absence of non‐axial shear wave singularities. These behavior help quantify the contributions of crustal rocks to observations of seismic anisotropy which can serve as proxies for crustal deformation.