The latest the Niigata Chuetsu offing Earthquake (2007) gave big damages on large thin shell structures such as oil storage tanks, and Tokachi offing Earthquake (2003) also gave a big damage on the oil storage tanks. The sloshing phenomenon of oil in tanks takes place during earthquake excitations and the roof of the tank is destructed. In this study the sloshing of fluid in tanks are investigated for cylindrical tanks and the methods for reduction of sloshing motions are studied.
