DEVELOPMENT OF A SIMULATION MODEL FOR OIL DISPERSION FOLLOWING DAMAGE TO OIL STORAGE TANKS CAUSED BY A TSUNAMI

Abstract

 A new tsunami oil dispersion simulation was developed by including an oil storage tank disaster scenario.

 The numerical tsunami analysis used linear long wave theory and the numerical fluxes are calculated by approximate Riemannian solver. The presence of dykes is also taken into account and if the tsunami height is greater than the embankment, the embankment is considered to be destroyed.

 The time variation of the tsunami forces acting on the storage tank is estimated from the tsunami velocity and inundation depth. The oil diffusion is then calculated when the tsunami forces are greater than the permissible values determined from the weight of the storage tanks.

 The oil diffusion behavior is calculated using the Lagrangian method. The behavior of oil particles is determined by the tsunami velocity and the collision with the embankment. The Lagrangian method allows the oil particles to be labelled based on the storage tank from which they originate. This allows the origin of the diffused oil to be identified and effective countermeasures to be taken. The distribution of maximum oil concentrations can be used to identify areas at high risk of tsunami fires.

 To demonstrate the simulation, a case study is conducted for the Port of Osaka area. Tsunami conditions are those of a Nankai Trough earthquake, which are used for estimated tsunami inundation maps. The placement of the storage tanks is determined based on satellite imagery. The oil fill volume is set by the maximum amount by which the storage tank can be destroyed, as determined by the time variation of the tsunami forces. The oil dispersion behavior changes significantly depending on whether the embankments are presented.