鹿児島湾における大正大噴火以前と現在の潮流に関する数値シミュレーション

概要

論文の詳細を見る
Kagoshima Bay, which is located at the southernmost part of Kyushu Island, Japan, is composed of innermost and central basins. These two basins are separated by Sakura-jima Island, which is an active volcano that had erupted heavily in 1914 in the Taisho era (so called the Taisho eruption). Before this eruption, the innermost and central basins were connected with two channels, which are named Sakura-jima Channel and Seto Strait. This eruption, however, filled in the Seto Strait with a large amount of lava flows, and mainly formed the present geometry only with Sakura-jima Channel. During 100 years after the Taisho eruption, coastal developments due to economic activities have also changed the coastal and bottom topography. This study aims to reveal the tidal currents for the two geometries in the Meiji era before the Taisho eruption and the present period, using a numerical model based on simple assumptions. Both the simulated current fields showed the similar oscillating pattern. The tidal current before the Taisho eruption indicates that the phase of the oscillating flow in Seto Strait precedes that in Sakura-jima-Channel. This means that Seto Strait may be responsible for the balance of the current velocity intensities in the two channels. Moreover, it also influences the residual current pattern which is characterized by an anticlockwise rotation in the central basin.
鹿児島大学の論文
2007-12-25