Title: Large scale resistivity surveys combining magnetic and magnetotelluric observations
Abstract: Electromagnetic methods allow investigations of subsurface conductivity structures. This work focuses on electromagnetic array data (38 measuring sites) covering an area of 900x600 square kilometres in central Australia. From the dataset three-dimensional conductivity models (forward and inversion models) are developed. These allow the identification of the major geological structures as well as implications for the tectonic history of central Australia.The good spatial coverage of the data allows conversions of magnetic to magnetotelluric transfer functions. Based on the comparison of measured and converted results the conversion approach leads to a better understanding of electromagnetic transfer functions. Using synthetic and measured datasets we show that the conversion can be used to clarify similarities and differences in magnetic and magnetotelluric results. In addition the conversion allows the separaration of electric and magnetic modes in magnetotelluric data and can therefore be used to remove galvanic distortion from long period magnetotelluric transfer functions.