A scalar audiomagnetotelluric survey across an outcropping dike

This work presents a modeling study of the shallow electric signature of an outcropping dike of the Guapiara Lineament in the Parana Basin, Brazil. Th e forward geoelectrical model was constructed on the basis of the response functions obtained with a scalar AMT data set along a profile perpendicular to the strike of the dike. The objective was to assess the shallow electri cal signature of a typical dike in Parana Basin, which is beyond the spatia l sampling of a typical long period tensor MT survey. The geoelectrical mod el presented in this paper identified the dike, a Permian sedimentary seque nce and a quaternary alluvial deposit. The dike intruded through a normal f ault, which was characterized by its vertical offset and the identification of the hanging and foot walls. The dike is strongly anisotropic with a res istivity value along the strike that is two orders of magnitude smaller tha n along the perpendicular direction. The hypothesis of an anisotropic dike is supported by an independent data set.