贝叶斯有限断层破裂分布模型反演研究进展  

Review of Bayesian finite-fault source model inversion

作　　者：魏国光 陈克杰 朱海 柴海山 Wei Guoguang;Chen Kejie;Zhu Hai;Chai Haishan(Department of Earth and Space Sciences,Southern University of Science and Technology,Shenzhen 518055,China;Institute of Risk Analysis,Prediction and Management(Risks-X),Academy for Advanced Interdisciplinary Studies,Southern University of Science and Technology,Shenzhen 518055,China;Guangdong Provincial Key Laboratory of Geophysical High-resolution Imaging Technology,Southern University of Science and Technology,Shenzhen 518055,China)

机构地区：[1]南方科技大学地球与空间科学系,深圳518055 [2]南方科技大学风险分析预测与管控研究院,深圳518055 [3]广东省地球物理高精度成像技术重点实验室(南方科技大学),深圳518055

出　　处：《地球与行星物理论评（中英文）》2023年第6期684-698,共15页Reviews of Geophysics and Planetary Physics

基　　金：国家自然科学基金资助项目(42074024);广东省地球物理高精度成像技术重点实验室资助项目(2022B1212010002);中国科协青年人才托举工程。

摘　　要：精确的有限断层破裂分布模型对于研究震源物理机制、评估地震灾害等具有重要意义.目前,有限断层反演通常采用线性最小二乘方法,但该方法存在一定局限性:(1)不易评估完全的参数空间,因而不利于评估非高斯分布的参数不确定性;(2)为了提高反演稳定性,在反演中通常施加断层滑移平滑约束(正则化),但平滑强度的确定具有一定主观性;(3)断层几何设置不同使得反演结果不尽相同;(4)难以顾及地球速度模型不确定等.与之对应,通过确定参数概率密度分布,贝叶斯反演提供了所有参数总体最优解,同时刻画不同参数之间协方差大小,可以有效克服上述问题.特别是过去十余年间,随着计算机算力飞速提升,贝叶斯反演得到了越来越多应用.通过阐释贝叶斯有限断层反演理论与技术,本文试图梳理近年来贝叶斯有限断层反演成果,最后展望贝叶斯有限断层反演发展趋势.A finite-fault earthquake slip model can characterize the kinematics of rupture,which is essential for earthquake mechanism studies and seismic hazard assessments.The finite-fault model of an earthquake can be inverted from a wide range of geodetic measurements and seismic recordings.The linear least squares method minimizes misfits between observations and forward modeling and is a common approach in finite-fault inversion problems.This method may not yield the most plausible finite-fault model and has four main limitations.First,total parameter spaces are challenging to explore,and non-Gaussian parameter uncertainties cannot be evaluated.Second,to improve the stability of the fault slip inversion,fault slip smoothing operators(regularization techniques)are usually applied;however,determining the strength of smoothing a fault slip distribution is subjective.Third,the fault geometry needs to be predetermined,and different fault geometry settings can result in varying inversion results.Fourth,it is difficult to account for uncertainties in forward modeling because of imprecise Earth velocity models.In contrast,Bayesian inversion determines the probability density distribution of the model parameters,providing a globally optimized solution to all model parameters and characterizing trade-offs between pairs of model parameters.Therefore,the Bayesian approach effectively overcomes the problems encountered in linear inversion.With the rapid improvement in computer technology,Bayesian inversion has become highly developed,especially in the past decade.This review reports the results of recent Bayesian finite-fault inversion studies and explains the theory and methodology of Bayesian finite-fault inversion.

关 键 词：破裂分布 线性反演 贝叶斯推断 概率密度分布 

分 类 号：P315[天文地球—地震学] P228[天文地球—固体地球物理学]