loading page

Comparison of Different Coupling Methods for Joint Inversion of Geophysical data: A case study for the Namibian Continental Margin
  • +2
  • Gesa Katharina Franz,
  • Max Moorkamp,
  • Marion Jegen,
  • Cristian Berndt,
  • Wolfgang Rabbel
Gesa Katharina Franz
GEOMAR Helmholtz Centre for Ocean Research Kiel

Corresponding Author:gfranz@geomar.de

Author Profile
Max Moorkamp
Ludwig Maximilians Universitaet
Author Profile
Marion Jegen
Author Profile
Cristian Berndt
GEOMAR Helmholtz Centre for Ocean Research Kiel
Author Profile
Wolfgang Rabbel
CAU Kiel
Author Profile


Integration of multiple geophysical methods in combined data analysis is a key practice to reduce model uncertainties and enhance geological interpretations. Electrical resistivity models resulting from inversion of marine magnetotelluric (MT) data, often lack depth resolution of lithological boundaries, and distinct information for shallow model parts. This is due to the nature of the physics i.e. diffusive method, model regularization during inversion, and survey setup i.e. large station spacing and missing high frequency data. Thus, integrating data or models to constrain layer thicknesses or structural boundaries is an effective approach to derive better constrained, more detailed resistivity models. We investigate the different impacts of three cross-gradient coupled constraints on 3D MT inversion of data from the Namibian passive continental margin. The three constraints are a) coupling with a fixed structural density model; b) coupling with satellite gravity data; c) coupling with a fixed gradient velocity model. Here we show that coupling with a fixed model (a and c) improves the resistivity model most. Shallow conductors imaging sediment cover are confined to a thinner layer in the resulting resistivity models compared to the MT-only model. Additionally these constraints help to suppress vertical smearing of a conductive anomaly attributed to a fracture zone, and clearly show that the seismically imaged Moho is not accompanied by a change in electrical resistivity. All of these observations aid interpretation of an Earth model indicating involvement of a plume impact in continental break-up during the early Cretaceous.
Dec 2021Published in Journal of Geophysical Research: Solid Earth volume 126 issue 12. 10.1029/2021JB022092