报告题目：Seismic Detection and Dynamic Implications of Prevalent Asthenospheric Partial Melt
报告人：花君临 美国德克萨斯大学奥斯汀分校
报告人简介：花君临博士于2021年在美国布朗大学获得博士学位，目前在美国得克萨斯大学奥斯汀分校从事博士后研究。主要研究方向为地震散射波成像，地震波全波形反演成像，地幔动力过程分析，地球物理地球化学数据联合分析，环境地震学等。已在EPSL，JGR，GJI等刊物发表多篇文章。
报告内容：The asthenosphere plays a fundamental role in present-day plate tectonics as its low viscosity controls how mantle convection is expressed at the surface. However, the origin of the asthenosphere and in particular the role of partial melt in reducing viscosity and facilitating deformation remains debated. By analyzing scattered seismic waves sampled at globally distributed stations, here we found the first globally widespread evidence for a positive seismic velocity gradient at depths of ~150 km. This velocity boundary is most commonly detected in regions with elevated upper mantle temperatures and is best modelled as the base of a partially molten low seismic velocity zone within the asthenosphere. However, the presence of the boundary does not correlate with accumulated mantle strain as expressed in seismic wave anisotropy patterns, indicating that it does not significantly affect large-scale viscosity. Rather, this implies a partially molten zone embedded within an asthenosphere whose low viscosity is primarily controlled by gradual pressure and temperature variations with depth.
报告时间：2022年9月21日 10:00-11:30
报告形式：腾讯线上会议，会议号：688-920-809
邀请人：马知途 教授