题目：New Insights into Mantle Convection from Finite-Frequency Tomography of the Mantle Transition Zone

时间：2018年6月22日下午4:00

地点：地球物理学院四楼多媒体教室

报告人简介：

  周莹，女，2005年获得美国普林斯顿大学地球物理博士学位，2007-2013年任美国弗吉尼亚理工大学地球科学系助理教授，2013年至今任弗吉尼亚理工大学地球科学系副教授。主要研究方向包括：非均匀介质中地震波传播，有限频地震成像理论，地壳和地幔各向异性和非弹性性质，地壳和地幔中的间断面以及核幔边界结构。

报告摘要：In this talk, I will present our recent work in imaging seismic structures in the mantle transition zone based on finite-frequency tomography of SS precursors and teleseismic receive functions. The high resolution 410-km and 660-km discontinuity maps suggest a warm mantle above cold stagnant slab beneath major subduction zones. This indicates strong near-field return flows in a superadiabatic mantle. The high-resolution images in the Western United States reveal a trail of anomalies in the mantle transition zone that closely follow the Yellowstone-Snake River Plain hotspot track. This observation contradicts the mantle plume model and suggests that the surface volcanic track is a result of reserved-polarity subduction along pre-existing fracture zones on the Farallon plate, not the long-believed mantle plume.

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地球勘探与信息技术教育部重点实验室

地球物理学院