On the subterranean Electric Conductivity near Memambetsu deduced by the Magneto-telluric Method
The theory of Niblett and Sayn-Wittgenstein is applied to data of geomagnetic and earth-current variations at Memambetsu as the first step of investigation to estimate the subterranean electric conductivity. Ratio of amplitude Ex/Hy only are used to estimate the subterranean electric conductivity, because the earth-current at Memambetsu shows intense anisotropy. The vertical distribution of electric conductivity at Memambetsu is estimated. It is found out that the subterranean electrical structure near Memambetsu may be made of 3 layers for the depth from 8 km to 170 km. The first layer lies in the depth from 8k m to 20 km, t he second one from 20 km to 90 km, and the third one from 90 km to 170 km. The electric conductivity in each layer varies from 3×10・-13 to 1×10・-13 e.m.u. in the first layer, from 1×10・-14 to 2×10・-15 e.m.u. in the second one and from 3×10・-14 to 2×10・-14e.m.u. in the third one, respectively.