Scattering in Earth's Lower Mantle and Implications for Mantle Flow Models

这项研究涉及对地幔深处的散射体进行系统的测绘，特别是在地幔底部1000公里处，最近的高分辨率层析成像揭示了地幔不均匀平面形状的意外变化。这项研究的目标有三个。首先，将整合成像技术，以开发一种强大的偏移方法，用于研究下地幔的非均质性。其次，将寻找更多的证据来约束假设的下地幔主体化学变化。对1300公里深度的初步反转表明，上、下地幔的构造有限。这项工作将把这项工作延续到地幔底部的三分之一。第三，通过结合散射和透射层析成像，将寻求对地幔底部的结构和动力学的更好的了解。体波散射技术与透射层析成像技术的结合将更好地确定波速变化的梯度和幅度，从而产生一类新的地球模型，对我们星球的化学和热史施加更严格的限制。

9814614van der HilstThis research involves the systematic mapping of scatterers in the deep mantle, in particular in the bottom 1000 km of the mantle where recent high-resolution tomography revealed unexpected changes in the planform of mantle heterogeneity. The objectives of this research are threefold. First, imaging techniques will be integrated to develop a powerful migration method for studies of lower mantle heterogeneity. Second, additional evidence will be sought for constraints on the postulated change in bulk chemistry in the lower mantle. Preliminary inversions to 1300-km depth suggest limited structures in the upper lower-mantle. This work will continue this work into the bottom third of the mantle. Third, by means of a combination of scattering and transmission tomography, improved understanding will be sought of the structure and dynamics of the base of the mantle. The integration of the techniques of body-wave scattering with those of transmission tomography will better determine that gradients and amplitudes of wave speed variations and thus produce a new class of Earth models that place tighter constraints on the chemical and thermal history of our planet.