Frequence domain electromagnetic source polarization investigation in case of a 2-D seafloor trench

In the course of seafloor EM survey the topographical changes of the seafloor can have influence on the EM components. These topographical inhomogeneities are 3-D ones. However, they are frequently elongated in one direction and can be treated as 2-D inhornogeneties. The aim of this model study is to present a numerical method for frequency domain marine controlled-source electromagnetic measurements using horizontal electric dipole sources on the seafloor and illustrate how the EM responses are affected by a 2-D trench. The horizontal electric dipole source is parallel and perpendicular to the struetural strike and the EM field components are computed along an in-line horizontal seafloor profile perpendicular to the axis of the trench at two frequencies.