用接收函数Ps转换波研究地壳各向异性——以哀牢山—红河断裂带为例

倾斜界面与各向异性介质均可使接收函数的切向分量产生明显的能量.通过对不同模型的理论接收函数的研究，可以发现倾斜界面产生的接收函数切向分量与各向异性介质产生的接收函数切向分量具有显著的差异，主要表现在到时差与周期性上.利用各向异性和倾斜界面造成的切向分量不同的周期性，可以通过加权叠加的方法突出各向异性或倾斜界面的影响，并可对接收函数径向、切向分量进行波形互相关计算，获取各向异性分裂参数.通过对布设于红河断裂附近的4个三分量宽频带流动台站的接收函数莫霍面Ps震相的研究，获得红河断裂附近的地壳各向异性快波方向为132°，快慢波时间延迟为024s.地壳各向异性快波方向与红河断裂带构造走向一致，与上地幔各向异性的快波方向相差近90°，表明红河断裂地区地壳与上地幔构造可能存在解耦现象.

A study on crustal anisotropy using P to S converted phase of the receiver function: Application to Ailaoshan-Red River fault zone

Both a dipping boundary and anisotropy can cause significant energy in the transverse component of receiver functions. But the obvious differences still can be distinguished from the study of synthetic receiver functions. The main distinctions are presented in arrival time and periodicity. The characteristics of anisotropy or dipping can be enhanced by the weighted stacking method according to different periodicities. And splitting parameters can be derived from the waveform cross correlating method. As an example, we studied crustal anisotropy near the Red River Fault using P to S converted phase of the receiver function derived from four broadband digital seismic stations near the Red River Fault and obtained a fast polarization direction of 132° and time delay of 024s. The fast polarization direction in the crust is consistent with tectonic zones of this region but nearly perpendicular to the fast polarization direction of the upper mantle, implying that the crust and upper mantle may be de coupling near the Red River Fault.