Geomagnetically Induced Currents (GIC) which flow in technological systems such as power transmission grids, are a consequence of the geoelectric field induced at the surface of the Earth during geomagnetic storms. We use an electrical model of the power network, measured GIC data and geomagnetic data from Eskdalemuir observatory to estimate the MT parameters apparent resistivity and phase. The long period MT responses are generally smooth and stable over a period range which extends from about 200-40,000s. We invert the apparent resistivity and phase for a smooth 1D resistivity model using an Occam algorithm
