Abstract
Bathymetric surveys using a multibeam echo sounder (MBES) were conducted northwest of Kyushu, Japan, during cruises GS23 and GB23 to create marine geological maps. High-resolution seafloor bathymetry was obtained during these surveys, although the characteristics of the multibeam system made it difficult to cover large areas with shallow water depths during the surveys. As a result, the surveys did not yield sufficient spatial data to advance geological interpretations of the region. This report focuses on the methods used for depth data acquisition and processing, as well as the results, while omitting detailed descriptions of the seafloor topography.