Estimate of the deep layer resistivity near Kakioka
There was the electrification scheme of the National Railway, Joban Line, near Kakioka 10 years ago. Then in order to get some idea of the artificial electric and magnetic field due to leakage currents from the railroad, the distribution of disturbance field was measured supplying test currents of 400-600 amp through earthing electrodes. Electric fields were observed at 7 temporary earth-current stations and Kakioka which were distributed 3 to 45km apart from the earthing points. From these data the vertical distribution of resistivity is estimated down to several ten km depth. The electrification of the railway was realized afterwards using ac currents as the power. Then no effect has been detected in the normal records at Kakioka Magnetic Observatory.