Long-term electromagnetic field observational network in Russian Primorye

An electromagnetic field observational network is being constructed in Russian Primorye. The method employs a commercial telephone network to measure voltage differences with long dipole lengths ranging from 10 to several dozens of kilometers. For better understanding of the spatial and frequency behavior of transfer functions a prognostic model of 3D conductivity structure has been constructed and the numerical modeling has been carried out. The particular aim is to check the hypothesis that the lithospheric mantle is much more resistive that is was estimated using a homogeneous model of the lithosphere and the low values of effective integral resistivity were obtained due to the influence of the sub-vertical conducting zones associated with subduction system.