交叉梯度约束的地震走时与重力联合反演方法研究  

Joint Inversion Method for Seismic Body Wave Traveltime and Gravity Data Based on Structural Constraint

作　　者：谭智 姜金钟[1,2] 石磊 李永华[3,4] TAN Zhi;JIANG Jinzhong;SHI Lei;LI Yonghua(Yunnan Earthquake Agency,Kunming 650224,Yunnan,China;Kunming Institute of Prediction,China Earthquake Administration,Kunming 650224,Yunnan,China;Institute of Geophysics,China Earthquake Administration,Beijing 100081,China;Key Laboratory of Earthquake Source Physics,China Earthquake Administration,Beijing 100081,China;Xiaguan Earthquake Monitoring Center Station,Yunnan Earthquake Agency,Dali 671000,Yunnan,China)

机构地区：[1]云南省地震局,云南昆明650224 [2]中国地震局昆明地震预报研究所,云南昆明650224 [3]中国地震局地球物理研究所,北京100081 [4]中国地震局震源物理重点实验室,北京100081 [5]云南省地震局下关地震监测中心站,云南大理671000

出　　处：《地震研究》2025年第4期550-560,共11页Journal of Seismological Research

基　　金：国家自然科学基金项目(42274118,42274080);云南省地震局地震科技专项(2024ZX03).

摘　　要：不同地球物理数据参与的联合反演,可有效减少反演的多解性,为地球内部结构研究提供多参数约束。重力与地震联合反演的开展常基于速度-密度经验关系,但由于地下结构复杂,部分地区岩石物理关系难以准确确定。针对这一问题,提出了一种基于交叉梯度约束的地震走时与重力联合反演方法。该方法将频率域重力反演和近震体波走时反演相结合,采用优化的顺序策略,实现了速度模型与密度模型的相似性耦合。理论模型和青藏高原东北缘实际观测数据试验都显示,联合反演有效提高了密度结构的垂向分辨率。重力数据的引入,更好地约束了地壳浅层(地下5 km以内)P波速度结构,明显改善了体波射线分布稀疏地区的横向分辨能力。Joint inversion of different geophysical data can effectively reduce the non-uniqueness of results and provide more constraints for studying the Earth's interior structure.Joint inversion of gravity and seismic data is usually carried out based on velocity-density relationships.However,the actual subsurface structures are complex,making it difficult to accurately determine the velocity-density relationships in certain areas.To address this issue,we have developed a joint inversion method for seismic traveltime and gravity based on cross-gradient constraints.This method combines frequency-domain gravity inversion and body wave tomography,and uses an optimized sequential strategy to achieve the structural similarity coupling between the velocity model and the density model.Synthetic tests and real data tests of the Qinghai-Xizang Plateau suggest that this joint inversion can effectively enhance the vertical resolution capabilities of the density structure.Furthermore,incorporating gravity data better constrains the P-wave velocity structure in the shallow Crust(5 km underground)and significantly improves the horizontal resolution capabilities in areas with sparse body wave ray coverage.

关 键 词：重震联合反演 结构耦合 交叉梯度 顺序策略 

分 类 号：P315.726[天文地球—地震学]