Local Anomaly of Earth Currents
Shiraki, M. & Yanagihara, K.
Abstract
Magnetotelluric analysis is a simplified method to deduce the conductivity distribution under the ground. However anisotropy of earth currents makes it difficult to apply the method for practical problems.
The case when the anisotropy was symmetric was solved by Yanagihara previously using a single elliptical model at Kakioka. Here we use a double elliptical model to explain the asymmetric anisotropy which is the real case at Kakioka.
Inner ellipse may represent the region of high resistivity rocks surrounded by sediments and the distribution of sea and land may be equivalent to outer ellipse.
Eliminating the local effect of earth currents，the apparent resistivity for S２ of daily variations is obtained to be 14Ωm.
