Sensitivity analysis of multilayer earth models

An accurate electrical model of the earth is useful for many applications related to electric traction and distribution systems: stray currents, step voltages, lightning phenomena. There exist methods to correlate apparent resistivity measurements with a multilayer earth model, generally based on iterative optimization algorithms, but all suffer from a general sensitivity to the starting point. In this work, after a general presentation of the problem and of the experimental method to obtained measured values of the apparent resistivity, some reference problems are considered to evaluate the robustness of the solution methods.