NUMERICAL SIMULATION OF PYROCLASTIC FLOW BASED ON THE THERMAL THEORY

THE CASE OF MT. FUGEN, UNZEN VOLCANO

Abstract

Large scale pyroclastic flow occured at Mt. Fugen, Unzen volcano, on June 1991. The pyroclastic materials are suspended in air, so that the pyroclastic flow runs fast with relatively low resistance on the slope. In this paper, the fluid dynamical model of the pyroclastic flow is presented. The model is based on the thermal theory on the inclined wall, in which the effect of the of the air temperature is taken into account. The model can predict variations of the height, the speed of pryoclastic flow and the concentration of pyrocalstic materials.