利用背景噪声研究壳幔结构发展综述

An overview of development of ambient noise's application on crust and upper mantle's structure

利用背景噪声研究地下结构即对两个台站长时间的地震噪声记录进行互相关计算提取台站间的格林函数,获取面波频散特征,并进一步层析成像或测量面波走时变化.通过该方法可获得壳幔速度结构和对地下介质监测.近些年,该方法在理论上和实践上都有长足进展.首先介绍地震背景噪声应用的发展历史,进而重点论述利用背景噪声对壳幔进行群速度和相速度结构成像、三维剪切波速度结构成像、与其他方法联合成像和对地下介质监测的应用.最后分析了目前背景噪声应用面临的问题,并展望了其发展前景.

The methodology of applying ambient noise to research on structure of underground is that extracting the Green’s Functions between seismic stations from long-time cross-correlation calculation of ambient noise recorded by these two stations, obtaining characteristics of surface wave dispersion,and inverting for surface wave tomography,or observing travel time shifts of surface wave.Ambient noise tomography can obtain velocity structure of crust and upper mantle with high resolution,and travel time shifts of surface wave can be useful indicators to changes of underground medium.In recent years,this methodology has gained lots of advances both in theoretical derivations and practical applications.This paper introduces the developing background and process of the applications based on ambient noise firstly,and then mainly summarizes its tomography applications：structure tomography of the group velocity and phase velocity,structure tomography of three dimensional shear wave velocity,tomography combined with other methods and observing the internal structure of underground.The paper analyzes the problems of applications on ambient noise and discusses the prospects in further applications finally.