Japan Geoscience Union Meeting 2018

Presentation information

[EE] Poster

M (Multidisciplinary and Interdisciplinary) » M-TT Technology & Techniques


Sun. May 20, 2018 3:30 PM - 5:00 PM Poster Hall (International Exhibition Hall7, Makuhari Messe)

convener:Yuichi S. Hayakawa(Center for Spatial Information Science, The University of Tokyo), Christopher A Gomez (Kobe University Faculty of Maritime Sciences Volcanic Risk at Sea Research Group), Shigekazu Kusumoto(富山大学大学院理工学研究部(理学))

[MTT35-P05] High-resolution seafloor DEM of World War II wreck site by combining multibeam bathymetry and SfM photogrammetry

*Hironobu Kan1, Chiaki Katagiri2, Yumiko Nakanishi3, Shin Yoshizaki4, Masayuki Nagao5, Rintaro Ono6 (1.Graduate School of Integrated Sciences for Global Society, Kyushu University, 2.Okinawa Prefectural Archaeological Center, 3.Osaka Prefectural Board of Education, 4.Kyoto City Archaeological Research Institute, 5.Research Institute of Geology and Geoinformation, AIST, 6.School of Marine Science and Technology, Tokai University)

Keywords:SfM, MBES, seafloor geomorphology, underwater archeology

The high-resolution digital elevation model (DEM) generation using Structure-from-motion (SfM) photogrammetry is challenging for underwater objects and geomorphology because global positioning systems-based mapping techniques cannot be applied to the seafloor. We eliminate this problem by incorporating precise control points obtained from high-resolution multibeam echosounding bathymetry to generate 3D models using SfM photogrammetry.

A World War II wreck USS Emmons, a 106-m US Navy Benson-class destroyer minesweeper sank in ~40 m of water off Okinawa Island, Japan, is used as a case study for this project. The Sonic 2022 was used for multibeam bathymetry which has a variable ultrasonic frequency of 200 to 400 kHz, 256 ultrasonic beams and selectable swath coverage of 10 to 160 degrees. An ultrasonic frequency of 400 kHz is selected for this study. An ultra-high-resolution DEM with a grid size of ~5 cm was generated for a 120 m × 30 m area covering the entire wreck site using geographical coordination using 1,716 images of the wreck obtained during scuba expeditions.

The USS Emmons stalled from damages incurred during an attack by Japanese kamikaze planes on April 6, 1945. The ship was abandoned and intentionally sunk. The wreckage of the kamikaze planes is also scattered on the seafloor. More than 70 years after the end of the Second World War, documentation of the war through material evidence beyond first-person accounts is increasing in significance. The model provides a primary record of the current state of the wreck, and allows for the establishment of various measures for its conservation.