Mapping Small-Scale Structure Above the Core-Mantle Boundary

该项目的目的是通过研究与地幔基底D”相互作用的剪切波的小尺度区域变化，提高我们对核心-地幔边界（CMB）区域的地球物理学理解。具体来说，研究人员将寻找地幔柱、化学边界层和CMB俯冲板块基础的直接证据，并利用不断增长的宽带阵列数据数据库提供的更高分辨率。CMB的复杂性和可变性在地下岩石圈内是无可比拟的。作为岩石地幔和液体外核之间的主要化学和热边界层，CMB可能在质量循环以及地幔与地核内部和之间的热量传递中发挥重要作用。研究人员将具体解决以下问题：1)地幔柱是否在D ‘ ’中形成？2) D”内是否存在横向离散的化学边界层？3)板块到达CMB吗？D”结构的一维模型将使用反射率合成材料生成，但最终模型也将使用Komatitsch和Tromp（2001）的光谱元素方法进行全3D合成测试，该方法已安装在华盛顿大学的SGI并行处理机上。

WysessionEAR-0207751 The aim of this project is to advance our understanding of the geophysics of the Core-mantle boundary (CMB) region through examination of small-scale regional variations in shear waves that interact with D", the base of the mantle. Specifically, the investigators will look for direct evidence of the foundations of mantle plumes, chemical boundary layers, and subducted slabs at the CMB with the increased resolution provided by the growing database of broadband array data. The CMB displays complexity and variability unequalled within the sub-lithospheric earth. As a major chemical and thermal boundary layer between the rocky mantle and liquid outer core, the CMB likely plays significant roles in the circulation of mass, as well as the transfer of heat both within and between the mantle and core. The investigators will specifically address the following questions: 1) Do mantle plumes form in D"? 2) Are there laterally discrete chemical boundary layers within D"? 3) Do slabs reach the CMB? One-dimensional models of D" structure will be generated using reflectivity synthetics, but final models will also be tested with fully 3D synthetics using the spectral-element method of Komatitsch and Tromp (2001), which has been installed on Washington University's SGI parallel processing machine.