1D Time Domain Electromagnetic Interpretations Over 2D / 3D Structures

Time domain electromagnetic soundings have been calculated over 2D / 3D structures in a layered halfspace and<br>hereafter inverted using a 1D least squares time domain code. The forward calculations are done in the frequency domain<br>and the subsequent transform to time domain is performed using fast digital filters. The study focuses on typical<br>hydrogeological models. The investigated models include a resistive dyke, a resistive beam and resistive block structure with<br>edges with varying slopes in a conductive layered halfspace with an overburden. The 1D interpretations of the 2D / 3D<br>responses show that the vertical resolution is reduced and the resistivities are smeared out. The 2D / 3D responses over<br>models with a resistive body in a conductive host is easily fitted with the 1D models whereas it is not possible to fit the<br>responses from good conductors in a resistive host very well.