1D complete calculation for electrostatic soundings interpretation

Soundings achieved with the electrostatic method cannot be interpreted corr ectly with 1D electrical programs if the extension of the array or the cond uctivity of the ground are too large. A complete calculation taking into ac count the induction effect due to the frequency must be performed. This pap er presents the solutions for overcoming the difficulties encountered in th is calculation: the iterative processes which make it possible to determine the kernel functions of the Hankel transforms and the analytic integration of the terms of the electric field. Application to practical cases first i llustrates the distortion of the electrostatic curves by reference to DC so unding curves. The limitation in depth of investigation is then emphasized: in practice, the investigation is limited by the skin depth corresponding to the frequency used. The examples of the soundings obtained in the city o f Alexandria (Egypt) demonstrate the importance of using the complete calcu lation for very conductive grounds.