Publication Date:
2020-02-12
Description:
Within the framework of the German - South African geo-scientific research initiative Inkaba yeAfrica several magnetotelluric (MT) field experiments were conducted along the Agulhas- Karoo Transect in South Africa. This transect crosses several continental collision zones between the Cape Fold Belt, the Namaqua Natal Mobile Belt and Kaapvaal Craton. Along the profile we can identify areas (〉 10km) with phases over 90◦. This phenomenon usually occurs in presence of electrical anisotropy. Due to the dense site spacing we are able to observe this behaviour consistently at several sites. In this presentation we focus on the profile section between Prince Albert and Mosselbay. With isotropic 2D inversion we are able to explain most features in the MT data but not the abnormal phase behavior. With several anisotropic forward modelling studies we have tested the influence of anisotropy parameters on the MT responses. In a first step we use simple 2D models with embedded zones of electrical anisotropy to get a basic understanding of anisotropic responses. In a second step isotropic 2D inversion results serve as background models in which we included anisotropic zones, e.g. to fit the abnormal phase curves. These resolution tests are necessary and important for the future development of a 2D inversion with spatially constraint anisotropy.
Keywords:
550 - Earth sciences
Type:
info:eu-repo/semantics/conferenceObject
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