Experimental Research on Seafloor Mapping and Vertical Deformation Monitoring for Gas Hydrate Zone Using Nine-Axis MEMS Sensor Tapes

Seafloor mapping and vertical deformation monitoring are important for a gas hydrate exploitation. Due to the complexity of the marine environment and the difficulty of the seafloor operation, an in situ seafloor mapping and high-resolution vertical deformation monitoring simultaneously are big challenges. This paper describes an experimental research on an in situ system for a seafloor mapping and vertical deformation monitoring based on an elastic steel tape, along which an array of nine-axis microelectromechanical system (MEMS) sensors is arranged. The tape can measure both the motion of the bend and the twist. The MEMS sensor consists of an accelerometer, a gyroscope, and a magnetometer. The Euler angles obtained from the nine-axis MEMS sensor can be converted to a relative rotation matrix, showing the amount of the bend and the twist, and the curved shape of the tape can be calculated. Based on this concept, multitapes are used for the seafloor mapping and vertical deformation monitoring. To assess the monitoring system, a lab scale experiment in a water tank is carried out. The results demonstrate the feasibility of the proposed system for the seafloor mapping and deformation monitoring.