Practical marine TDEM systems using ROV for the ocean bottom hydrothermal deposits

摘要

The new Time Domain EM technologies for the exploration of the ocean bottom hydrothermal mineral deposits have been developed. The two measuring systems of moving-type and fixed-type were introduced in 2012. In the moving-type measuring, the real time monitoring of the signals at the ROV control room is possible and this is one of the big advantage of the moving-type system. The fixed-type measuring system enables us the noise free measurements from the ROV and tidal currents. In 2015, new time domain system towed by the ROV was developed. The towed-type system promotes highly efficient operation and shows as low noise levels as the fixed-type. These measuring system were tested at the Okinawa hydrothermal areas, as the results, the mineral deposits are clearly detected by the obtained apparent resistivity anomalies over the known seafloor massive sulphide areas.