CAREER: Geodynamics of subducting slabs in the Earth's deep mantle from seismic anisotropy

俯冲带是地球表面最重要的构造特征之一，是地震、火山和海啸灾害的主要地点。俯冲对于了解地球内部也是至关重要的；地球的长期演化是由地幔的动力学驱动的，而通过俯冲将海洋板块循环回到地幔是地幔过程的主要驱动力。了解板块如何从地表下沉到地幔底部--以及它们如何与周围的地幔相互作用--对于理解地幔作为一个动态系统至关重要。这个职业项目旨在解决的科学挑战是，通过地震波的测量，了解俯冲板块在穿过深部地幔时如何变形周围的地幔。地震各向异性的观测和建模将用于探测三个区域的俯冲动力学：深部上地幔、过渡带和最下部地幔。我将研究俯冲板块下深部上地幔中各向异性和流动的模式，使用详细的横波分裂数据集来测试控制板块下地幔流动的假说。我将探讨俯冲板块如何变形过渡带和最高下地幔，以及变形方式是否与“停滞”与“非停滞”板块的动力学行为有关。最后，我将询问D“层地幔底部各向异性的几何形状，目的是了解撞击核幔边界(CMB)的板片残骸如何驱动流动，以及流型如何与CMB上方的其他结构(如低剪切速度区)相关。该项目的研究部分将得到一项教育和外联工作的补充，这项工作的重点是通过一项名为FEST(科学教师实地体验)的试点计划，向高中教师提供宽带野外地震学部署方面的研究经验。将对地球深层结构和动力学的研究转化为公众的一个主要战略是让教师参与地球深层研究，实地项目将提供高度身临其境和有意义的研究体验。

Subduction zones are among the most important tectonic features on the Earth's surface and represent prime sites for earthquakes, volcanoes, and tsunami hazards. Subduction is also vitally important for understanding the Earth's interior; Earth's long-term evolution is driven by the dynamics of the mantle, and the recycling of oceanic plates back into the mantle through subduction is a major driver for mantle processes. Understanding how slabs sink from the surface to the base of the mantle - and how they interact with the mantle around them - is crucial for understanding the mantle as a dynamic system. The scientific challenge that this CAREER project aims to address is to understand how subducting slabs deform the mantle around them as they descend through the deep mantle using measurements of seismic waves.Observations and modeling of seismic anisotropy will be used to probe subduction dynamics in three regions: the deep upper mantle, the transition zone, and the lowermost mantle. I will examine the pattern of anisotropy and flow in the deep upper mantle beneath subducting slabs, using detailed shear wave splitting data sets to test hypotheses for controls on sub-slab mantle flow. I will explore how subducting slabs deform the transition zone and uppermost lower mantle and whether the style of deformation is related to the dynamic behavior of "stagnant" vs. "non-stagnant" slabs. Finally, I will interrogate the geometry of anisotropy at the base of the mantle in the D" layer, with the goal of understanding how slab remnants impinging on the core-mantle boundary (CMB) drive flow, and how flow patterns are related to other structures above the CMB such as low shear velocity provinces. The research component of this project will be complemented by an education and outreach effort which will focus on providing high school teachers with research experience on broadband field seismology deployments through a pilot program to be called FEST (Field Experiences for Science Teachers). A prime strategy for translating research into the structure and dynamics of the deep Earth to the general public is to involve teachers in deep Earth research, and field-based projects will offer a highly immersive and meaningful research experience.