Submarine Volcanic Activity and Its Surveillance in the Adjacent Seas of Japan

Abstract

The Hydrographic Department of Maritime Safety Agency has been conducting surveillance and investigation about the activity of submarine volcanoes in the adjacent seas of Japan. There are three active submarine volcanoes belonging to Middle Mariana ridge; Fukutoku oka-no-ba about 4 miles mrtheastward, Minami-Hiyosi Kaizan about 50 miles south-south eastward and Fukuzin Kaizan about 180 miles southeastward from Minami-Io Sima Is. respectively. Discolored water around them is found at irregular intervals, which should be caused by submarine volcanic eruption. The Hydrographic Department conducts to research their activity using remote sensing techniques such as aerial photogrammetry, multiband photographs and thermal camera by an airplane. A survey ship also is used to research bathymetry, geological structure, geomagnetism and gravity in the submarine volcanic areas at the rest time of the volcanic activity. In this paper, wedescribe about the system of surveillance and investigation to them together with the record of recent submarine volcanic eruptions in the adjacent seas of Japan.