A study of integrated seafloor visualization and geological characteristics for habitat mapping around the nearshore area of Dokdo in the East Sea

Abstract

We obtained precise seabed geomorphology and analysed submarine conditions for understanding habitat seafloor characteristics around the nearshore area of Dokdo in the East Sea. The field survey was carried out in the southern nearshore area of Dongdo(East Islet) and Seodo(West Islet) of Dokdo. We have been acquired the precise topography map using multibeam echosounder system(EM 3001, Kongsberg). Side scan sonar(EdgeTech 4125) survey for producing seafloor backscattering images was carried out. High-resolution underwater video images were obtained by scuba dive survey. As a result of bathymetry survey, the southern nearshore area of Dokdo has shallow water depth range(Dongdo : ~ 30m, Seodo : ~ 50m). And extended bedrocks from land of Dongdo and Seodo are laid on the nearshore islets. From the near islets to 15~20m, there are irregular underwater rocks with a little steep slope. Below 20m, the slope became gradual and surface sediments consist of gravelly sand and sandy gravel. We fulfilled an integrated visualization technique with topography map, seafloor backscattering images and underwater video images of the survey area. The integrated visualization results present more information than separate geological products for seabed environmental mapping study. They are useful to understand the relation between seafloor characteristics and topographic environments for habitat mapping of Dokdo.a of Dongdo(East Islet) and Seodo(West Islet) of Dokdo. We have been acquired the precise topography map using multibeam echosounder system(EM 3001, Kongsberg). Side scan sonar(EdgeTech 4125) survey for producing seafloor backscattering images was carried out. High-resolution underwater video images were obtained by scuba dive survey. As a result of bathymetry survey, the southern nearshore area of Dokdo has shallow water depth range(Dongdo : ~ 30m, Seodo : ~ 50m). And extended bedrocks from land of Dongdo and Seodo are laid on the nearshore islets. From the near islets to 15~20m, there are irregular underwater rocks with a little steep slope. Below 20m, the slope became gradual and surface sediments consist of gravelly sand and sandy gravel. We fulfilled an integrated visualization technique with topography map, seafloor backscattering images and underwater video images of the survey area. The integrated visualization results present more information than separate geological products for seabed environmental mapping study. They are useful to understand the relation between seafloor characteristics and topographic environments for habitat mapping of Dokdo.