报告地点：腾讯会议 853 533 807
报告时间：2021-12-17 从 14:30 到 16:30
报告人：王巍
报告人简介：
王巍，美国南加州大学博士后。2010，2013年于中国科技大学获得本科和硕士学位， 2019年于加州大学圣地亚哥分校获得博士学位。2019年9月开始在南加州大学从事博士后研究。主要研究方向包括地球内部小尺度和非弹性性质反演，多尺度地震触发现象的观测及机制解释，小地震震源物理分析。目前在Nature Geoscience, PNAS, EPSL等国际SCI期刊发表论文12篇，其中第一作者7篇。
报告题目：An initial map of fine-scale heterogeneity in the Earth’s inner core
报告内容简介
The seismological properties of Earth’s inner core are key to understanding its composition, dynamics, and growth history. Within the inner core, fine-scale heterogeneity has previously been identified from backscattering of high-frequency compressional waves. Here, we use historical earthquake and explosion data from the Large Aperture Seismic Array, USA between 1969 and 1975 to build a 3D map of heterogeneity from the inner core boundary to 500 km depth and determine the geographical distribution of the scatterers across the 40% of the inner core that is visible to the array. Our model has two regions of strong scattering, one beneath eastern Asia and the other beneath South America, both located where past local surveys have identified scattering structure. We suggest that these loci of strong, fine-scale heterogeneities may be related to random alignments of small, inner core crystals due to fast freezing. These areas, which have been identified as having high attenuation and lie beneath colder areas of the core-mantle boundary, potentially provide constraints on the dynamics of the inner core and the motions in the outer core with downwelling in the mantle and outer core possibly associated with strong scattering and inner core heterogeneity.