Marine Controlled-source Electromagnetic Sounding on Submarine Massive Sulphides Using Numerical Simulation

Abstract

Recently, controlled-source electromagnetic methods are widely used for shallow sub-seafloor explorations. In this paper, we propose a new controlled-source electromagnetic method using an autonomous underwater vehicle (AUV) for the exploration of submarine massive sulphides (SMS). A numerical simulation code for 2.5-D or 3-D electromagnetic field in the frequency domain is employed in order to estimate electromagnetic responses from possible conductivity structures. As a result, we confirmed that we could detect the area of SMS effectively using Ty-Hx and Tz-Ez for transmitter and receiver. This is because the electric field is attenuated and the electric flux is concentrated to the interior of conductive zones. We also confirmed that the effects of topography were relaxed using normalized electromagnetic fields in the simulation. Based on our results, we think that the new controlled-source electromagnetic method is realizable.