Norihito OOSAWA

Modeling of Pyroclastic Flow and Powder Snow Avalanches Considering 3-Dimensional Topography and Development of Numerical Simulator

Yusuke FUKUSIMA

Large part of country in Japan is mountains area. Many villages and large structures have the potential of damage by pyroclastic flow or powder snow avalanche. In order to prevent these disaster, the understandings on characteristic of pyroclastic flow and powder snow avalanche are necessary. A hazard map can be made based on such knowledge. Also, the constructions of facilities preventing these disasters are possible.
The flow mechanisms of pyroclastic flows and powder snow avalanches are similar to the thermal flow on the inclined boundaries. The models and the numerical simulator on such flows are developed considering the three dimensional topography. These models were originally proposed by Fukushima (1986). This numerical simulator can analyze the route of flow and lateral spreads of pyroclastic flows and powder snow avalanches in addition to the travel speed, the concentration of particles, the kinetic energy of turbulence. The simulator for the pyroclastic flows and powder snow avalanches on the three dimensional topography can estimate the actual behaviors of these flows.