The quasi-static magnetic susceptibility sounding method and application of plane wave

Magnetic susceptibility plays a crucial role in detecting magnetic materials, but traditional static magnetic exploration methods do not have the capability to physically measure depth. This study proposes a quasi-static magnetic susceptibility sounding method that utilizes the skin effect of plane electromagnetic waves. Specifically, the measuring area simultaneously observes the magnetic field in the horizontal and orthogonal directions of quasi-static plane electromagnetic waves from both the base station and the measuring station. The different trends between the measuring station and the base station are then calculated. The magnetic field difference at the skin depth is normalized by the magnetic field of the base station, resulting in the magnetic susceptibility at various depths. Moreover, by applying Ampere's law and starting from the theory of quasi-static magnetic polarization, the fundamental formula for quasi-static magnetic susceptibility sounding was derived. The response rules of the horizontal magnetic field and apparent magnetic susceptibility of a horizontal and tilted sheet were calculated. Experimental research on quasi-static magnetic susceptibility sounding was conducted in the Yemaquan mining area in Qinghai, where a comparative analysis with geological profiles and static magnetic method inversion profiles revealed that the quasi-static magnetic susceptibility information accurately reflects the spatial distribution of skarn magnet mineralization zones at different depths and enables frequency sounding of magnetization rates.