Cross gradient based joint inversion of EM-LIN and DC resistivity data

Document Type : Research Paper

Authors

1 Institute of Geophysics, University of Tehran, Tehran, Iran.

2 Department of Engineering Geology, School of Geology, College of science, University of Tehran, Tehran, Iran.

10.22059/ijmge.2026.399972.595285

Abstract

Non-uniqueness and instability of single geophysical approaches may be reduced by utilizing constraints and a priori information in terms of regularization, but deriving enough information about subsurface sources generally demands integration of two or more geophysical data sets. Cross gradient based joint inversion is one of the most widespread ways of geophysical data integration where involved methods share their information for each other through cross gradient function. In this paper, the joint inversion of DC resistivity and EM34 data was applied to the measured data at Morgenzon Farm site in South Africa, where the reconstruction of a dolerite dyke or sill is the principal target indicating the presence of groundwater. The separate inversion of DC resistivity data highlights a two layered medium as an interface and a small weak anomaly in the middle of the profile, while EM34 inverse model indicates a resistive dyke in the middle of the profile with a depth range from 5 to 15 m. Join inversion allows the involving methods to propagate their characteristics to each other, and it was found that joint inverse model of the DC resistivity is the best result to reconstruct the subsurface structure. In addition, joint inversion results were compared with the cooperative inversion of these approaches. Ultimately, the measured magnetic and gravity data were also inverted, allowing their joint interpretation with the separate and joint resistivity models.

Keywords

Main Subjects

References

[1] Pilkington, M. (1997). 3-D magnetic imaging using conjugate gradients. Geophysics, 62(4), 1132-1142.
[2] Fedi, M., Hansen, P. C., & Paoletti, V. (2005). Analysis of depth resolution in potential field inversion: a tutorial. Geophysics, 70, A1-A11.
[3] Fedi, M. (2007). DEXP: A fast method to determine the depth and the structural index of potential fields sources. Geophysics, 72 (1), I1-I11.
[4] Fedi, M., & Pilkington, M. (2012). Understanding imaging methods for potential field data. Geophysics, 77(1), G13-G24.
[5] Baniamerian, J., Oskooi, B., & Fedi, M. (2017). Source imaging of potential fields through a matrix space-domain algorithm. Journal of Applied Geophysics, 136, 51-60.
[6] Wang, H., Li, M., & Shang, X. (2016). Current developments on micro-seismic data processing. Journal of Natural Gas Science and Engineering, 32, 521-537.
[7] Koteleva, N., & Frenkel, I. (2021). Digital processing of seismic data from open-pit mining blasts. Applied Sciences, 11(1), 383.
[8] Mousa, W. A., & Al-Shuhail, A. A. (2022). Processing of seismic reflection data using MATLAB. Springer Nature.
[9] Varfinezhad, R., Oskooi, B., & Fedi, M. (2020). Joint inversion of DC resistivity and magnetic data, constrained by cross gradients, compactness and depth weighting. Pure and Applied Geophysics, 177, 4325-4343.
[10] Najaftomraei, M., Moghadam, S., Varfinezhad, R., Goudarzi, A., & Faghih, A. (2024). Subsurface characterization in southeastern Asaluyeh using DC resistivity and ground penetrating radar. International Journal of Mining and Geo-Engineering, 58(4), 423-429.
[11] Milano, M., Varfinezhad, R., Bizhani, H., Moghadasi, M., Kalateh, A. N., & Baghzendani, H. (2021). Joint interpretation of magnetic and gravity data at the Golgohar mine in Iran. Journal of Applied Geophysics, 195, 104476.
[12] Ghari, H., Varfinezhad, R., & Parnow, S. (2023). 3D joint interpretation of potential field, geology, and well data to evaluate a salt dome in the Qarah‐Aghaje area, Zanjan, NW Iran. Near Surface Geophysics, 21(3), 233-246.
[13] Singh, A., Mishra, PK, & Sharma, S.P. (2019). 2D cooperative inversion of direct current resistivity and gravity data: A case study of uranium bearing target rock. Geophysical Prospecting, 67 (3), 696-708.
[14] Varfinezhad, R., Parnow, S., Florio, G., Fedi, M., & Mohammadi Vizheh, M. (2023). DC resistivity inversion constrained by magnetic method through sequential inversion. Acta Geophysica, 71(1), 247-260.
[15] Ghose, R., & Slob, E.C. (2006). Quantitative integration of seismic and GPR reflections to derive unique estimates for water saturation and porosity in subsoil. Geophysical Research Letters, 33 (5).
[16] Varfinezhad, R., Hafizi, M. K., & Hashemi, H. (2016). Application of different inverse methods for combination of vS and vGPR data to estimate porosity and water saturation. Journal of the Earth and Space Physics, 41(4), 89-94.
[17] Haber, E., & Oldenburg, D. (1997). Joint inversion: a structural approach. Inverse problems, 13(1), 63.
[18] Gallardo, L. A., & Meju, M. A. (2011). Structure‐coupled multiphysics imaging in geophysical sciences. Reviews of Geophysics, 49(1).
[19] Legault, J.M., Carriere, D., & Petrie, L. (2008). Synthetic model testing and distributed acquisition dc resistivity results over an unconformity uranium target from the Athabasca Basin, northern Saskatchewan. The Leading Edge, 27 (1), 46-51.
[20] Varfinezhad, R., Ghari, H. and Rafiei, R., 2022. Topography incorporated inversion of DC resistivity data using integral equation vs. Res2dinv software. Bulletin of Geophysics & Oceanography (BGO), 63(3).
[21] Chambers, JE, Kuras, O, Meldrum, PI, Ogilvy, RD, & Hollands, J (2006). Electrical resistivity tomography applied to geologic, hydrogeologic, and engineering investigations at a former waste-disposal site. Geophysics, 71 (6), B231-B239.
[22] Rucker, DF, Loke, MH, Levitt, MT, & Noonan, GE (2010). Electrical-resistivity characterization of an industrial site using long electrodes. Geophysics, 75(4), WA95-WA104.
[23] Ghari, H., Parnow, S., Varfinezhad, R., Milano, M., Fourie, F.D. and Tosti, F., 2024. Cross-Gradient Joint Inversion of DC Resistivity and Gravity Gradient Data: A Multi-Disciplinary Approach for Geoscience, Heritage, and the Built Environment. Remote Sensing, 16(23), p.4468.
[24] Wilson, S. R., Ingham, M., & McConchie, J. A. (2006). The applicability of earth resistivity methods for saline interface definition. Journal of hydrology, 316(1-4), 301-312.
[25] Tsokas, G.N., Tsourlos, P.I., Vargemezis, G., & Novack, M. (2008). Non‐destructive electrical resistivity tomography for indoor investigation: the case of Kapnikarea Church in Athens. Archaeological prospection, 15(1), 47-61.
[26] Varfinezhad, R., & Oskooi, B. (2020). 2D DC resistivity forward modeling based on the integral equation method and a comparison with the RES2DMOD results. Journal of the Earth and Space Physics, 45(4), 43.
[27] Parnow, S., Oskooi, B., & Florio, G. (2021). Improved linear inversion of low induction number electromagnetic data. Geophysical Journal International, 224 (3), 1505-1522.
[28] Pérez-Flores, M. A., Antonio-Carpio, R. G., Gómez-Treviño, E., Ferguson, I., & Méndez-Delgado, S. (2012). Imaging of 3D electromagnetic data at low-induction numbers. Geophysics, 77(4), WB47-WB57.
[29] Parnow, S., Oskooi, B., & Florio, G. (2021). Improved linear inversion of low induction number electromagnetic data. Geophysical Journal International, 224 (3), 1505-1522.
[30] Varfinezhad, R., & Parnow, S. (2022). 3D Electromagnetic low induction number modeling using integral equations. Journal of the Earth and Space Physics, 47 (4), 99-110.
[31] Ghari, H. and Varfinezhad, R., 2022. 2D Linear inversion of ground-based controlled-source electromagnetic data under a low induction number condition.
[32] Ghari, H. and Mahdavi, M., 2024. Dyke detection as the main target of groundwater exploration using Magnetometry and Electromagnetic data. International Journal of Mining and Geo-Engineering, 58(3), pp.257-262.
[34] Makhokha, D., & Fourie, F. (2016). A systematic approach to the interpretation of conductivity anomalies across intrusive dolerite dykes and sills in the Karoo Supergroup (Doctoral dissertation, MSc thesis. University of the Free State, Bloemfontein).
[35] Ghari, H., 2025. Joint Interpretation of Electromagnetic in Low Induction Number and Electrical Resistivity Tomography: A Case Study on Data from an Area in South Africa. Journal of Analytical and Numerical Methods in Mining Engineering, 15(42), pp.15-23.
[36] Pérez-Flores, M. A., Méndez-Delgado, S., & Gómez-Treviño, E. (2001). Imaging low-frequency and dc electromagnetic fields using a simple linear approximation. Geophysics, 66(4), 1067-1081.
[37] Aster, R. C., Borchers, B., & Thurber, C. H. (2018). Parameter estimation and inverse problems. Elsevier.
[38] Tikhonov, AN, & Arsenin, VIAK (1977). Solutions of ill-posed problems.
[39] Li, Y., & Oldenburg, D. W. (1992). Approximate inverse mappings in DC resistivity problems. Geophysical Journal International, 109(2), 343-362.
[40] Loke, M.H., & Barker, R.D. (1996). Rapid least‐squares inversion of apparent resistivity pseudo-sections by a quasi‐Newton method1. Geophysical prospecting, 44 (1), 131-152.
[41] Auken, E., & Christiansen, A. V. (2004). Layered and laterally constrained 2D inversion of resistivity data. Geophysics, 69(3), 752-761.
[42] Günther, T., Rücker, C., & Spitzer, K. (2006). Three-dimensional modeling and inversion of DC resistivity data incorporating topography—II. Inversion. Geophysical Journal International, 166 (2), 506-517.
 [43] Gündoğdu, N. Y., & Candansayar, M. E. (2018). Three-dimensional regularized inversion of DC resistivity data with different stabilizing functionals. Geophysics, 83(6), E399-E407.
[44] Li, Y., & Oldenburg, D. W. (1996). 3-D inversion of magnetic data. Geophysics, 61(2), 394-408.
[45] Li, Y., & Oldenburg, D. W. (1998). 3-D inversion of gravity data. Geophysics, 63(1), 109-119.
[46] Boulanger, O., & Chouteau, M. (2001). Constraints in 3D gravity inversion. Geophysical prospecting, 49 (2), 265-280.
[47] Cella, F., & Fedi, M. (2012). Inversion of potential field data using the structural index as weighting function rate decay. Geophysical Prospecting, 60 (2), 313-336.
[48] Ghari, H., Varfinezhad, R., & Parnow, S. (2023). 3D joint interpretation of potential field, geology, and well data to evaluate a salt dome in the Qarah‐Aghaje area, Zanjan, NW Iran. Near Surface Geophysics, 21(3), 233-246.
[49] Gallardo, L. A., & Meju, M. A. (2004). Joint two‐dimensional DC resistivity and seismic travel time inversion with cross‐gradients constraints. Journal of Geophysical Research: Solid Earth, 109(B3).
[50] Rubidge, T. M., 2005. The story of earth and life. 1st ed. Cape Town: struik Nature.
[51] McCathy, T., & Rubidge, B. (2005). the Story of Earth and Life, a South African Perspective on a 4.6-billion-year Journey. Struik, Cape Town, South Africa, 184-211.
[52] Geel, C., 2014. Brief geologic overview of the Cape Fold Belt and Karoo Basin: Field excursion to Matjiesfontein, 10th Inkaba yeAfrica conference. Matjiesfontein, Inkba yeAfrica.
[53] Murray, R., Baker, K., Ravenscroft, P., Musekiwa, C., & Dennis, R. (2012). A groundwater-planning toolkit for the main Karoo basin: Identifying and quantifying groundwater-development options incorporating the concept of wellfield yields and aquifer firm yields. Water SA, 38(3), 407-416.
International Journal of Mining and Geo-Engineering
Volume 60, Issue 1
March 2026
Pages 9-15

Files

Share

How to cite

Statistics