Regularized joint inversion of magnetotelluric and gravity data based on inequality and Gramian constraints
CHEN Xiao1,2(), ZENG Zhi-Wen3(), DENG Ju-Zhi1,2, ZHANG Zhi-Yong1,2, CHEN Hui1,2, YU Hui1,2, WANG Yan-Guo1,2
1. State Key Laboratory of Nuclear Resources and Environment, East China University of Technology, Nanchang 330013, China 2. School of Geophysics and Measurement-control Technology, East China University of Technology, Nanchang 330013, China 3. College of Geoexploration Science and Technology, Jilin University, Changchun 130026, China
Regularized joint inversion based on Gramian constraints is a hot research topic in the field of geophysical joint inversion. Given the difficulty in selecting weighted factors of the regularization and constraint items, it is necessary to introduce inequality constraints into the regularized joint inversion. To investigate the regularized joint inversion of magnetotelluric (MT) and gravity data based on Gramian constraints, this study compared the application effects of the penalty function method and the transform function method in the joint inversion and processed the measured data of a survey line in Xiangshan, Jiangxi Province. According to the results from model experiments, both methods can effectively constrain petrophysical parameters, and the penalty function method has higher flexibility but requires the artificial setting of the weighted factors. Moreover, the processing of the measured data shows that the joint inversion based on inequality and Gramian constraints is highly practical and can improve the precision of geophysical interpretation.
Xiao CHEN,Zhi-Wen ZENG,Ju-Zhi DENG, et al. Regularized joint inversion of magnetotelluric and gravity data based on inequality and Gramian constraints[J]. Geophysical and Geochemical Exploration,
2023, 47(3): 575-583.
Joint inversed results of different projects for the model test 1 a—designed residual density model;b—designed resistivity model;c—residual density result of project 1;d—resistivity result of project 1; e—residual density result of project 2;f—resistivity result of project 2;g—residual density result of project 3 ;h—resistivity result of project 3;i—fitting curves of gravity anomalies
Joint inversed results of different projects for the model test 2 a—residual density result of project 1;b—resistivity result of project 1; c—residual density result of project 2;d—resistivity result of project 2;e—residual density result of project 3;f—resistivity result of project 3;g—fitting curves of gravity anomalies
Position map of a profile in the Xiangshan volcanic basin
岩性
σ平均/(g·cm-3)
ρ/ (Ω·m)
碎斑熔岩
2.63 (2.61~2.65),低
6000 (400~400000),大部分>5000
流纹英安岩
2.69 (2.65~2.72),中等
2685,大部分<5000,偏低
变质岩
2.77 (>2.72),高
低阻样本为3451,高阻样本为31092
Statistical results of petrophysical properties of Xiangshan volcanic basin
3D inversed resistivity result of a MT profile
Joint inversed results of different projects a—joint inversed residual density result of project 1;b—joint inversed residual density result of project 2; c—gravity anomaly fitting curves of project 1;d—gravity anomaly fitting curves of project 2;e—coupling relationship for joint inversed results of project 1;f—coupling relationship for joint inversed results of project 2
Comparison diagram of 3D MT inversed result and joint inversed residual density result a—3D MT inversed result;b—joint inversed residual density result
[1]
Sun J J, Li Y G. Joint inversion of multiple geophysical data using guided fuzzy c-means clustering[J]. Geophysics, 2016, 81(3):ID37-ID57.
Chen X, Yu P, Deng J Z, et al. Joint inversion of MT and seismic data based on wide-range constraints[J]. Chinese Journal of Geophysics, 2016, 59(12),4690-4700.
[3]
Gallardo L A, Meju M A. Characterization of heterogeneous near-surface materials by joint 2D inversion of dc resistivity and seismic data[J]. Geophysical Research Letters, 2003, 30(13):11-14.
[4]
Molodtsov D M, Kashtan B, Rostov Y. Joint inversion of seismic and magnetotelluric data with structural constraint based on dot product of image gradients[C]// SEG Expanded Abstracts, 2011:740-744.
[5]
Zhdanov M S, Gribenko A, Wilson G. Generalized joint inversion of multimodal geophysical data using Gramian constraints[J]. Geophysical Research Letters, 2012, 39:L09301.
[6]
Zhu Y, Zhdanov M S. Gramian constraints in the joint inversion of airborne gravity gradiometry and magnetic data[C]// SEG Expanded Abstract, 2013:1166-1170.
[7]
Lin W, Zhdanov M S. The Gramian method of joint inversion of the gravity gradiometry and seismic data[J]. Pure and Applied Geophysics, 2019, 176(4):1659-1672.
[8]
Zhu Y. Joint inversion of airborne magnetic and electromagnetic data:Case study in the Northwest Territories of Canada[C]// SEG Expanded Abstract, 2015:864-868.
[9]
Jorgensen M. Joint 3D inversion of gravity and MT data using Gramian constraints:A case study from Yellowstone[C]// SEG Expanded Abstract, 2018:2307-2311.
[10]
Ogunbo J N. Dotting the i and crossing the T of the entire MiT resistivity community by the Gramian constrained joint EM/electrical inversion[C]// SEG Expanded Abstract, 2018:2587-2591.
[11]
Zhdanov M S. Joint inversion of multimodal data using focusing stabilizers and Gramian constraints[C]// SEG Expanded Abstracts, 2018:1430-1434.
[12]
Carter-McAuslan A, Lelievre P G, Farquharson C G. A study of fuzzy c-means coupling for joint inversion,using seismic tomography and gravity data test scenarios[J]. Geophysics, 2015, 80(1):W1-W15.
[13]
Moorkamp M, Roberts A W, Jegen M, et al. Verification of velocity-resistivity relationships derived from structural joint inversion with borehole data[J]. Geophysical Research Letters, 2013, 40(14),3596-3601.
[14]
Lin W, Zhdanov M S. Joint multinary inversion of gravity and magnetic data using Gramian constraints[J]. Geophysical Journal International, 2018, 215(3),1540-1557.
[15]
Li Y G, Oldenburg W D. Fast inversion of large-scale magnetic data using wavelet transform and a logarithmic barrier method[J]. Geophysics Journal International, 2003, 152(2):251-265.
[16]
Commer M, Newman G A. New advances in three-dimensional controlled-source electromagnetic inversion[J]. Geophysical Journal International, 2008, 172(2):513-535.
Wang Z, Pan H P, Luo Y L, et al. 3D hole-to surface resistivity inversion with nonlinear conjugate gradients method under the constraint of inequality[J]. Progress in Geophysics, 2016, 31(1):360-370.
[18]
Hu W, Abubakar A, Habashy T M. Joint electromagnetic and seismic inversion using structural constraints[J]. Geophysics, 2009, 74(6):R99-R109.
Liu X, Deng J Z, Chen X. Three-dimensional focusing inversion to gravity data based on inequality constraints[J]. Science Technology and Engineering, 2020, 20(30):12332-12341.
Yu H. Three-dimensional fine structure and geodynamics setting of transcrustal magmatic system beneath the Xiangshan volcanic basin[D]. Nanchang: East China University of Technology, 2021.
Wang B Z, Xu S Z, Liu B H, et al. An example of aeromagnetic anomaly separation using multi-interpolation division[J]. Oil Geophysical Prospecting, 1997, 32(3):431-438,462.
[23]
Deng J Z, Yu H, Chen H, et al. Ore-controlling structures of the Xiangshan volcanic basin,SE China:Revealed from three-dimensional inversion of magnetotelluric data[J]. Ore Geology Reviews, 2020, 127(0):103807.
Guo Y H. Study on regularized joint inversion of magnetotelluric and gravity based on Gramian constraints[D]. Nanchang: East China University of Technology, 2020.
