The effect of topography and geology on telluric currents

Abstract

The electric field vectors associated with telluric currents are known to vary in relative magnitude and principal direction at different locations. A number of temporary recording sites were occupied in the College, Alaska, region, where telluric currents have been recorded routinely since 1955. The results of this study show that the relative magnitude may change by a factor of 5 and that the principal direction may range over 33° and in one extreme case 70°, in the area of radius 10 miles from the Geophysical Institute. Model studies using a two-dimensional resistor network were made to determine the effects of some simple topographic and conductivity configurations on the telluric field.