The Interpretation of Shear‐Wave Splitting Parameters In the Presence of Two Anisotropic Layers
The Interpretation of Shear‐Wave Splitting Parameters In the Presence of Two Anisotropic Layers
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DOI：
10.1111/j.1365-246x.1994.tb04027.x
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发表时间：
1994-12
影响因子：
2.8
通讯作者：
P. Silver;M. Savage
中科院分区：
文献类型：
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作者：
P. Silver;M. Savage
摘要我们考虑在单层各向异性材料假设下的剪切波分裂参数的行为，而实际上存在两层不同的各向异性性质。结果表明，由此得到的视分裂参数仍然是有意义的量，实际上可以(在固定频率下)写成各层分裂参数的三角函数。这些表达式揭示了表观分裂参数的许多性质。例如，视快偏振4和延迟时间6T表现出作为以r/2周期的入射偏振的函数的系统变化。在许多情况下，派生的表达式可用于对两个层的各个属性进行倒置。结果表明，沿圣安德烈亚斯断裂系统的几个台站具有两层性质，顶层平行于圣安德烈亚斯断裂的局部走向。最后，导出的表观分裂参数的表达式可以很容易地推广到多层。
SUMMARY We consider the behaviour of shear-wave splitting parameters that are made under the assumption of a single layer of anisotropic material when in fact two layers of differing anisotropic properties are present. It is shown that the resulting apparent splitting parameters are still meaningful quantities and in fact can (at fixed frequency) be written as trigonometric functions of the splitting parameters of the individual layers. These expressions reveal many properties of the apparent splitting parameters. For example, the apparent fast polarization 4, and delay time 6t, exhibit systematic variations as a function of incoming polarization with r/2 periodicity. The derived expressions can be used to invert for the individual properties of the two layers in many circumstances. We show that several stations along the San Andreas fault system display the properties of two layers, with the top layer being parallel to the local strike of the San Andreas fault. Finally, the derived expressions for the apparent splitting parameters are shown to be easily generalized to multiple layers.