• 固体地球物理及空间物理学（大气、行星、地球动力学、重磁电及地震学、地热学） •

重震联合反演方法及其应用进展

1. 1. 中国地震局地球物理研究所, 北京 100081
2. 中国地震局第二监测中心, 西安 710054
3. 武汉大学测绘学院, 武汉 430079
• 收稿日期:2018-11-04 修回日期:2019-06-21 出版日期:2019-10-28 发布日期:2019-10-28
• 作者简介:张佩,男,1989年生,博士研究生,主要从事地震学成像方法与地球内部结构方面的研究.(E-mail: zhpec15@163.com)
• 基金资助:
国家自然科学基金面上项目(41774056);国家重点研发计划“基于断层带行为监测的地球物理成像与地震物理过程研究”(2018YFC1503405)

Advancement of joint inversion of gravity and seismic data and its application

ZHANG Pei1,2,SONG Xiao-dong3,4,XIONG Ao-lin3

1. 1. Institute of Geophysics, China Earthquake Administration, Beijing 100081, China
2. Second Monitoring and Application Center, China Earthquake Administration, Xi’an 710054, China;
3. School of Geodesy and Geomatics, Wuhan University, Wuhan 430079, China
• Received:2018-11-04 Revised:2019-06-21 Online:2019-10-28 Published:2019-10-28

Abstract:

Geophysical inversion is one of the best ways to explore underground structures. As seismic waves can penetrate deep down to have local sampling, Seismology has been a primary method for human to probe the deep interior of the earth. While gravity is volumetric integral effect of density and distance, which is generally more sensitive to shallower structure than seismic data. Complemented and constrained with each other, joint inversion of seismic and gravity data can improve the spatial resolution, which make the inversion result more stable and reliable. This paper, firstly, introduces the velocity-density empirical relationship between seismic and gravimetric data. Then three commonly used methods for joint inversion are described separately, which are sequential inversion, synchronous inversion and cross-gradient inversion. A brief introduction to the application of the joint inversion methods worldwide is conducted subsequently. It is considered that sequential inversion can calculate different kinds of data separately and independently, which is simple in principle and easy to implement. However, this method depends on the prior model and the empirical relationship between velocity and density, and there may be an error amplification effect in lower resolution region (such as model boundaries). Synchronous inversion adopts the strategy of simultaneous inversion of seismic and gravity data in the same equation system, which reduces the impact of the single data prior model on the results, but the simultaneous application of two data is bound to introduce the problem of data weight allocation. While the cross-gradient method seeks structural similarity of different physical parameter models, and makes the least hypothesis about the potential rock physical relationship, which reduces the non-uniqueness of the inversion algorithm to some extent. However, the structure of the mandatory matching model does not necessarily conform to the physical parameters distribution of underground media. Therefore, when using cross-gradient joint inversion, it should be noted that the derivation of the model needs to follow objective criteria to control their structural similarity and data fit. Finally, as the empirical relationship between velocity and density and the weight distribution of the data have a significant impact on the inversion, more attention should be paid to them.