Avdeeva, Anna, Jegen, Marion , Moorkamp, Max and Franz, Gesa (2016) Three-dimensional resistivity image of off-shore magmatism at the Walvis Ridge and Rift Basin. [Poster] In: EM Induction Workshop 2016. , 14.-20.08.2016, Chiang Mai, Thailand .

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Abstract

We present a three-dimensional resistivity model derived from a large-scale magnetotelluric experiment offshore
Namibia. To obtain the model we use the inversion code "mtinv" based on an integral equation approach
(see Avdeev&Avdeeva, 2009, Avdeeva et al., 2012 and Moorkamp et al., 2010). The code allows positioning of
MT sites at the sea-floor and inclusion of bathymetry. However, the bathymetry is approximated with a rectilinear
mesh, which is not optimal as a large portion of the computationally feasible grid is used up by bathymetry, at
the same time reducing the resolution of the upper region. Nevertheless, we observe a good correlation of the
boundaries of large-scale resistive anomalies with seismically identified lower crustal high-velocity structures.
This gives us confidence in the large-scale features of the resistivity model. Together with information from 2-D
seismic profiles and on-shore geology the resistivity model provides valuable insight into the spatial distribution
of increased magmatic activity.

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