USV explores seabed without crew, maps geology 200m below seafloor [Reading Science]

KIGAM, KIOST Successfully Test Technology Along 4-Kilometer Stretch off Pohang Coast
Receives Seismic Signals from 2 Kilometers Away... Expected to Enable Geological Surveys in Shallow Waters

A technology has been developed in South Korea to map geological structures more than 200 meters below the seafloor using an unmanned surface vehicle (USV). It is expected to enable subsea geological surveys in shallow coastal waters that are difficult for large research vessels to access.

The Korea Institute of Geoscience and Mineral Resources (KIGAM) said on October 19 that a research team led by Dr. Shin Jeonggyun at its Pohang Geology and Mineral Resources Demonstration Research Center developed marine seismic exploration technology using a USV in collaboration with the Korea Institute of Ocean Science and Technology (KIOST), and successfully tested it in waters off Pohang.

Conceptual diagram of a marine refraction seismic exploration system based on an unmanned surface vehicle and its data acquisition system. Courtesy of the Korea Institute of Geoscience and Mineral Resources.

Marine seismic exploration is a technology for mapping geological structures by analyzing how artificially generated seismic waves travel through subsea strata or are reflected and refracted at boundaries. It is used in marine resource exploration, subsea geological surveys and offshore infrastructure construction.

Previously, seismic wave generators and receivers were typically mounted on the same large research vessel. This restricted vessel access and equipment operation in shallow waters and along coastlines where land meets the sea.

The research team used a system that separates the crewed vessel generating seismic waves from the USV receiving the signals. The USV was equipped with compact, low-power seismic wave reception and recording equipment, as well as wireless communications equipment. The team also enabled the equipment to be controlled remotely from shore or a nearby vessel, with data collection monitored in real time.

The test was conducted along an approximately 4-kilometer survey area off the eastern side of Hwanjin Beach in Pohang. The team collected seismic data at five locations by moving the USV. As a result, it detected refracted signals from seismic waves generated about 2 kilometers away and successfully imaged the seismic velocity structure of strata more than 200 meters below the seafloor.

In particular, in the shallow waters to the west, the team identified a geological structure where seismic waves travel faster than in the surrounding area. The team thereby confirmed that geological structures beneath the seafloor can be surveyed using a USV deployed at a distance.

However, this study only confirmed the feasibility of automating the seismic wave reception process. The vessel generating the seismic waves still needs to carry crew, and further development is needed for a survey system that can operate multiple USVs simultaneously.

"Compared with other fields of marine research, marine seismic exploration has been relatively slow to transition to unmanned operations," said Dr. Shin Jeonggyun of KIGAM. "This study is significant because it applied unmanned operations in stages, starting with the receiver, to address the spatial limitations of conventional survey systems and demonstrate the potential of unmanned exploration."

The research team plans to expand the technology's applications to vertical cable seismic surveys and long-range reflection surveys, and to develop a survey system that can operate multiple USVs simultaneously.

This content was produced with the assistance of AI translation services.