Earth Planets Space, 54, 743–752, 2002 Numerical simulation of volcanic plume dispersal from Usu volcano in Japan on 31 March 2000 using PUFF model

In this study, a volcanic ash tracking model called “PUFF ” is applied to the actual eruption of Usu volcano on 31 March 2000 in order to infer the movement of airborne ash clouds for aviation safety. The PUFF model was developed and operated by the Alaska Volcano Observatory since the eruption of Redoubt volcano in 1989. The performance of the PUFF model is examined in this study based on the ground truth of the observed distribution of tephra on the ground. According to the model simulation, the ash plume erupted from Usu volcano first moved eastward for the New Chitose International Airport. As the upper air westerly wind gradually shifted to southerly wind, the ash front traveled from Chitose to Nemuro while the subsequent eruption plume directed toward the northeast over Sapporo area. The vertical cross sections and 3-D perspective image of the ash clouds are presented as a function of time. The model simulation was justified by the agreement between the modeled and observed distributions of tephra on the ground. The PUFF model with accurate wind information can simulate the location and the direction of the moving airborne ash cloud on a realtime basis, which may provide crucial information to aviation industry. 1