High-resolution Mapping of Seismic Structures in the Lower Mantle

首席调查员继续绘制“非洲异常”和“太平洋异常”的地图，并将研究扩大到核幔边界的其他区域。对这两个异常的继续研究包括：分段填图下地幔“非洲异常”的地理范围，约束“非洲异常”底部的各向异性行为，填图“太平洋异常”底部的地理范围，约束下地幔“太平洋异常”的构造和速度特征及其与底部的构造联系，填图“太平洋异常”底部和下地幔异常的构造特征、长度-尺度和速度折减的横向变化。扩大的研究重点是菲律宾海底、南中国海和中国中部附近的中巴地震构造。首席调查员还从地幔成分、温度、动力学以及与其他学科观测结果的关系等方面探讨了对地震结果的可能解释和影响。该建议的智能优点包括高质量异常地震数据的收集、识别、解释和波形和走时模拟，其科学目标是绘制CMB多个区域的详细构造特征和速度结构图，以及下地幔两个突出的低速异常的结构特征和速度结构图。除了研究生的培训外，该提议还对我们进一步了解地球的热演化、地幔中的热化学对流、热化学地幔羽流、两个突出异常的动力学和组成、地幔中地球化学库的起源和分布，以及地幔地震非均质性与地球表面观测到的地球化学特征(包括DUPAL异常)的关系产生了广泛的影响。

The Principal Investigator continues the work on mapping the "African anomaly" and the "Pacific anomaly", and expands the study to other regions of the core-mantle boundary (CMB). The continued studies of the two anomalies include: mapping the geographic extent of the "African anomaly" in the lower mantle section by section, constraining the anisotropic behaviors of the base of the "African anomaly", mapping the geographic extent of the base of the "Pacific anomaly", constraining the structural and velocity features of the "Pacific anomaly" in the lower mantle and its structural connection to the base, and mapping the lateral variations of structural feature, length-scale and velocity reductions of the base of the "Pacific anomaly" and the anomaly in the lower mantle. The expanded study focuses on the seismic structures near the CMB beneath Philippines, South China Sea and central China. The Principal Investigator also explores possible interpretations and implications of the seismic results, in the context of mantle composition, temperature, dynamics and the relationship to the observations in other disciplines. The intellectual merits of the proposal include collection, identification, interpretation and waveform and travel time modeling of high-quality anomalous seismic data, with a scientific goal of mapping detailed structural features and velocity structures in several regions of the CMB, and structural features and velocity structures of the two prominent low-velocity anomalies in the lower mantle. Besides the training of a graduate student, the proposal has broad impacts on our further understanding of the thermal evolution of the Earth, thermal-chemical convection in the mantle, thermal-chemical mantle plume, dynamics and composition of the two prominent anomalies, the origin and distribution of geochemical reservoirs in the mantle, and relationship of mantle seismic heterogeneities to the geochemical signatures observed at the surface of the Earth including "the DUPAL anomaly".