利用地震背景噪声探测下地幔散射体

以地震干涉理论为基础，探索和发展利用地震背景噪声互相关技术提取下地幔散射体波信号的方法。以我国东北地区高密度地震台站连续波形记录为数据基础，应用这种“去源化”方法探究东北亚大陆下方下地幔散射体的空间分布、尺度特征和物性异常，结合地震波层析成像及岩石矿物高温高压实验结果，探讨散射体存在的机理；结合太平洋板块演化历史重构研究，探讨散射体的动力学成因。

The heterogeneities interior the Earth is important for understanding the scale of mantle convection, efficiency of mantle stirring, mantle rheology and geochemical reservoirs. Based on the theory of seismic interferometry, we will apply seismic ambient noises cross-correlation technique to retrieve the body waves scattered from the heterogeneities in the mid-lower mantle at depth around 800-1300 km, and investigate the scatterers with fine-scale in the lower mantle. We will develop the novel method based on the continuous records of seismic arrays deployed densely in Northeast China, and investigate systematically the spatial distribution, scale characteristics, and the velocity structure of the scatterers. We will integrate recent progresses obtained from seismic tomography studies and experimental results from mineral physics, to explore the thermal, phase change or chemical mechanism of those detected scatters, and attempt to trace the dynamic reasons for the existence of the heterogeneities in the mid-lower mantle.