How the ability of detecting and characterizing elongated structures using small-loop EMI systems depends on measurement configuration

MARTINELLI, PATRICIA; BONOMO, NÉSTOR; DUPLAÁ, CELESTE

Beijing, China

Congreso; IAGA WG 1.2 on Electromagnetic Induction in the Earth, 19th Workshop; 2008

Fixed-boom small-loop frequency domain electromagnetic induction systems (SLEM) allow for rapid detection of a great variety of near-surface buried structures. One coil generates a controlled primary magnetic field and the other records the variations of the induced field while the instrument is moved over the studied area. The most usual acquisition configuration is such that the coils are horizontal and the instrument axis is parallel to prospecting lines. Data is generally interpreted by direct visualization of the plan-views of the in-phase (IP) and quadrature (Q) components of the induced field measured at each frequency. In addition, 1D inversion methods are applied to characterize subsoil structure indepth. The scope of this work is to analyze how the employed SLEM system orientation affects the ability of the method to detect small elongated structures, buried at shallow depths, and the possibility of later recovering appropriate subsoil models from 1D inversions of the corresponding data.