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回顾了接收函数叠加成像方法的发展过程,发现现在仍被广泛用于接收函数成像的共转换点(CCP)叠加成像方法存在着一定的缺点.通过计算转换波射线路径,得到不同深度、不同震中距转换波射线参数,发现共转换点叠加方法适合于P波接收函数叠加成像,对S波接收函数叠加成像却可能产生错误.结果显示在震中距为60°左右时,真正的转换点位置与共转换点叠加方法追踪到的转换点位置在深度为140km处水平方向偏离约200km,在震中距70°-80°之间时,真正的转换点位置与传统共转换点叠加方法追踪到的转换点位置之间的偏差小于S波接收函数的水平分辨率.利用不同深度产生的转换波射线参数进行反投影,能将转换点归位到更接近于真实的转换点位置上,从而使得通过S波接收函数获取的地球内部结构更加可靠.在岩石圈厚度变化剧烈的地区,建议优先采用震中距在70°-80°之间的远震S波事件进行岩石圈结构的研究.
This paper reviews the development of the superposition method of receiver function and finds that there are some shortcomings in the method of superposition imaging of CCP, which is still widely used in receiving function imaging. By calculating converted ray paths, From the converted wave parameters, it is found that the method of co-conversion point superposition is suitable for superposition imaging of P-wave receiver function, but the error may be caused by superposition imaging of S-wave receiver function.The results show that when the epicenter distance is about 60 °, The transition points tracked by the transition point stacking method shift about 200 km horizontally at a depth of 140 km. When the epicenter is between 70 ° and 80 °, the transition point between the true transition point and the traditional transition point is the transition point The deviation between the positions is less than the horizontal resolution of the S-wave reception function.Using back-projection of the converted wave ray parameters generated at different depths can shift the transition point closer to the true transition point so that the S-wave The internal structure of the Earth obtained by the receiver function is more reliable. In areas where the lithosphere thickness varies strongly, it is recommended that the epicentral distance be between 70 ° -80 ° Between the teleconnection S wave event lithosphere structure research.