Marine towed electrical resistivity survey using sequential dual-transmission and low-noise sensor

摘要

Marine towed electrical resistivity survey is widely used for various purposes such as underground resources exploration, coastal engineering, archaeological detection, and UXO detection. To improve data quality and resolution, we propose enhanced in-house developed marine towed electrical resistivity survey system. First, hollow-type carbon fiber submersible electric field sensors were developed; second, sequential dual-transmission routine implemented by three-phase bridge power circuit. To implement sequential dual-transmission routine, our new streamer cable has three graphite current electrodes, and they are connected to the three-phase bridge power circuit. The sensor was made by a bundle of carbon fibers, generally 7 micro meter diameter. The routine was verified using the numerical experiment, and the sensors were verified using comparison tests in the water tank filled with seawater. Through the field surveys in the sea, we confirmed that our whole system worked properly and the dual transmission routine was effective to distinguish separated objects in the seabed. We expect that this system can contribute to improve detection probability and efficiency in the field.