报告地点：腾讯会议：555-920-791
报告时间：2023-05-26 从 10:00 到 11:30
报告人：庞冠宁（康奈尔大学）
报告人简介：
2015年于中国科学技术大学取得本科学士学位，2021年于犹他大学取得博士学位。2021年八月开始在康奈尔大学从事博士后研究。主要研究方向包括地震序列震源结构分析，板块内地震时空性质分析，地球内核小尺度散射结构成像，以及俯冲板块构造等相关工作。
报告题目：New Discoveries of the Fine-Scale Heterogeneity of the Earth's Solid Inner Core
报告内容简介
Evidence for the existence of fine-scale (<10 km) heterogeneity within the Earth’s inner core (IC) has been reported over the last 20 years. However, the detailed structures and origins of the fine-scale heterogeneity are poorly constrained. Continued seismic mapping of the IC fine-scale heterogeneity is important because it provides a complementary picture of IC fabrics, which records the history and evolution of Earth’s core. Here, we observe and model seismic energy scattered from the IC and create a 3D model of inner core fine-scale heterogeneity. Our model shows that inner core scattering is ubiquitous and provides fresh insight into the growth history of the inner core. We explore IC differential rotation by studying the changes in forward scattering within the IC of P waves of earthquake doublets. We find that the inner core experienced a burst of differential rotation during 2001–2003. This fleeting bit of differential rotation helped excite an inner core rotational oscillation, consequently exciting the six-year oscillation in the length of day.