Study of China lithosphere by receiver function and surface wave tomography

岩石圈的高分辨率地震观测由于许多因素而受到阻碍。(1)岩石圈-软流层边界作为一个梯度过渡带和低速带（软流圈）的上边界，体波或广角地震反射难以探测到;（2）面波研究由于台站分布稀疏，分辨率有时会受到影响。然而，已经表明，表面波层析成像的分辨率可以通过包括更高模式的表面波而大大提高（Priestley等人，2005年）。最近开发的S接收器函数方法似乎提供了观察LAB的另一种手段（Li等人，2004; Kumar等人，2005 a，B，c）。在过去几年中，中国将永久地震网络大幅扩展到80多个宽带台站。本文提出将P波和S波接收函数方法与多模式面波层析成像方法联合收割机应用于中国岩石圈结构研究。面波模型可用于以两种方式改进接收器函数估计：首先，它们可直接用于联合反演，其中它们去除与单独的接收器函数的反演相关联的一些模糊性;其次，它们可提供用于接收器函数的时深转换的适当模型。对整个岩石圈而不仅仅是地壳的认识，将大大提高我们对中国板块构造、印度-亚洲碰撞和大的板内地震的认识。

High-resolution seismic observation of the lithosphere is hampered due to a number of factors. (1) As a gradient transition zone and as an upper boundary of a low-velocity zone (asthenosphere), the lithosphere-asthenosphere boundary (LAB) is hard to be detected by body waves or wide-angle seismic reflections; (2) Surface wave studies sometimes suffer from low resolution due to sparse station distribution. It is, however, shown that the resolution of surface wave tomography can be greatly improved by including higher mode surface waves (Priestley et al., 2005). The recently developed S receiver function method appears to provide another means to observe the LAB (Li et al., 2004; Kumar et al., 2005a,b,c). In the last several years China significantly expanded the permanent seismic network to more than 80 broadband stations. We propose here to combine applications of P and S receiver function methods with multi-mode surface wave tomography to study the lithospheric structure of China. Surface wave models might be used to improve the receiver function estimates in two ways: firstly they can straightforwardly be used in a joint inversion, where they remove some of the ambiguities associated with inversions of receiver functions alone; secondly they can provide appopriate models for time-depth conversion of the receiver functions. Knowledge about the the entire lithosphere, not only the crust, will significantly improve our understanding of plate tectonics of China and the Indo-Asian collision and of large intraplate earthquakes.