大地电磁与接收函数结构约束联合反演  

Structure constrained joint inversion of magnetotelluric data and receiver function

作　　者：甘露 吴庆举[1] 黄清华[2] 张慧茜 唐荣江 GAN Lu;WU QingJu;HUANG QingHua;ZHANG HuiQian;TANG RongJiang(Institute of Geophysics,China Earthquake Administration,Beijing 100081,China;School of Earth and Space Sciences,Peking University,Beijing 100871,China)

机构地区：[1]中国地震局地球物理研究所,北京100081 [2]北京大学地球与空间科学学院,北京100871

出　　处：《地球物理学报》2022年第11期4460-4470,共11页Chinese Journal of Geophysics

基　　金：国家自然科学基金重点项目(42030310)资助.

摘　　要：本文基于拟牛顿法对大地电磁与接收函数进行联合反演,提出了新的联合约束算子,实现了电阻率模型和速度模型之间的相似度约束.该方法给予两种模型足够的变化自由度,同时又约束两种模型向耦合方向演化.根据联合约束算子在反演迭代中的变化趋势,以及两种模型的空间梯度分布,可以判断电阻率模型和速度模型是否耦合.合成数据和野外实测结果表明,联合反演相对于单独反演可以提高电阻率和速度模型之间耦合程度,同时也能保持较好的数据拟合.联合反演提高了大地电磁的纵向分辨率,一定程度降低了大地电磁的非唯一性.Using the quasi Newton method,we jointly invert the magnetotelluric and receiver function data to obtain resistivity model and velocity model with similarity constraint,and a new joint constraint operator is defined to control spatial gradients.Our method accommodates the two models with different properties to evolve towards coupled and similar structure,but still provides enough freedom to model all essential features.The evolution of joint operator and spatial gradient distribution indicates the coupling degree of two different models.The synthetic data and field measurement results show that the joint inversion can improve the coupling degree between resistivity and velocity models compared with the single inversion,and maintain a good misfit at the same time.We also find that the joint inversion significantly improves the resolution of magnetotelluric and reduces the non-uniqueness of magnetotelluric.

关 键 词：接收函数 大地电磁 结构约束 拟牛顿法 联合反演 

分 类 号：P315[天文地球—地震学] P319[天文地球—固体地球物理学]