Quasi-three-dimensional seabed sounding problem using a horizontal electric dipole

摘要

We consider the quasi-three-dimensional problem of seabed sounding with a horizontal magnetic dipole. The three-dimensional problem is reduced to a parametric family of two-dimensional problems. The Double Exponential method of Fourier transform evaluation suggests the conjecture that the same harmonics are required to reconstruct the total and the normal field from their spatial spectra. The computer experiment confirms this conjecture and it is shown that solving about 14 two-dimensional problems is sufficient to compute the total field on a single profile. We assess the sensitivity of different electromagnetic field components to the presence of a weakly conducting anomaly above the seabed given observations at the seabed. The highest sensitivity is observed for the component E z, which can be used to determine both the boundaries and the conductivity of the anomaly. The horizontal components also respond to the anomaly, but more weakly.