Thermal Distribution and Chemical Compositions of Discolored Waters Derived from Submarine Volcanic Activities

Abstract

The Hydrographic Department actively participates in the national programme for prediction of volcanic eruption since the beginning of this programme in 1973. This paper shows a review of the analytical results of thermal distribution and chemical compositions of several volcanic discolored waters observed and collected by the Hydrographic Department. Thermal distribution of discolored water by the airborne thermal infrared radiometer makes clear the complicated thermal distribution pattern around the spouting point of the Kaitoku Seamount and the Hukutoku-Oka-no-Ba submarine volcanoes. Relative temperature differences between the sea surface temperature and the volcanic discolor” ed water temperature are in harmony with the submarine volcanic activitites. Total Fe is decreasing and pH value is increasing according to the distance from the spouting point of volcanic discolored water. Triangular diagram on Fe-Al-Si and/ or (Fe+ Al)/Si from chemical analysis of volcanic discolor～ ed waters indicate the degree of submarine volcanic activities and make possible to compare about volcanic activities of submarine volcanoes in different time and/ or at different places.