past eruption site / seismic reflection equipment / /
NaturalFeature
Sea Bottom Topography / Hachijojima Island / Aogashima Island / Izu-Shichito Islands / /
Organization
Naval Hydrographic Office / Hydrographic Department of Japan / Hydrographic Department / Japan Coast Guard / Azusa Nishizawa Hydrographic Department / Yasuo Ootani Hydrographic Department / United States Navy / Maritime Safety Agency / Cartography Division / Kunio Yashima Hydrographic Department / /