High-resolution Mapping of Seismic Structures in the Lower Mantle

下地幔地震结构的高分辨率测绘

• 批准号: 0609717
• 负责人: Lianxing Wen
• 金额: $ 25万
• 依托单位: SUNY at Stony Brook
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-09-01 至 2010-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0609717&HistoricalAwards=false
• 关键词: resolution; Mapping; Seismic; Structures; Lower

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".

首席研究员继续进行“非洲异常”和“太平洋异常”的绘图工作，并将研究扩大到核幔边界的其他区域。对这两种异常现象的持续研究包括：分段填图“非洲异常”在下地幔的地理范围，约束“非洲异常”基底的各向异性行为，填图“太平洋异常”基底的地理范围，约束“太平洋异常”在下地幔的结构、速度特征及其与基底的构造联系，绘制了“太平洋异常”基底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。扩展研究的重点是菲律宾，南海和中国中部的CMB附近的地震结构。首席研究员还在地幔成分、温度、动力学以及与其他学科观测的关系的背景下，探讨了地震结果的可能解释和影响。该提案的智力价值包括收集、识别、解释高质量异常地震数据并建立波形和旅行时间模型，其科学目标是绘制CMB若干区域的详细结构特征和速度结构，以及下地幔两个突出低速异常的结构特征和速度结构。除了培养研究生外，该建议对我们进一步了解地球热演化、地幔热化学对流、地幔热化学柱、两个突出异常的动力学和组成、地幔地球化学储层的起源和分布、以及地幔地震不均匀性与地球表面观测到的地球化学特征（包括“DUPAL异常”）之间的关系。