Velocity Calculation of Lahar in Changbai Mountain Region

Lahar as one of most serious volcanic hazards, threats people's lives and property securities of volcanic region. Velocity is the most important parameter for lahar hazard assessment and prevention. The calculation result of lahar velocity can provide reference materials for making hazard prevention plan, and make the hazard relief measure of lahar transition from passive to active. Selected the area near the Tianchi as the research region, and divided the research region into forming region, circulation region and accumulation region. In order to establish the calculation model, divided the circulation region and accumulation region into many meshes, which were small enough to meet the calculation accuracy. The calculation time step length was also identified very small as-0.001 min. Calculated the average and peak velocity of lahar, triggered by the assuming medium and small eruption of Tianchi volcano. The longitudinal variation of lahar frontal average and peak velocity was acquired by the numerical simulation result. Although there is some different between the assumption of this research and the actual condition, flow velocity and accumulation situation of lahar are calculated in quantity and extension by numerical simulation, these result has reference value for preventing and reducing lahar disaster.