Abstract:

The core model of LAHARZ is a semi-empirical numerical model based on the hydrodynamics model and combination with the analysis on the lahars of nine volcanoes. The lahars in four high easy-happening rivers, Erdaobai River, Songhua River, Yalu River and Tumen River, are simulated by the LAHARZ based on the 1∶250000 digital elevation model. The threshold of the energy cone is set to 0.07 according to historical plume height and the average slope. By comparing and matching the simulated river with the real river, the river threshold value is determined to be 5 000. And the volume thresholds are defined as 10⁸m³, 10⁹m³, 10¹⁰m³,and 10¹¹m³ by their historical lahar volumes. The simulated results show that the flow distance and the damage scale were influenced by the different thresholds, which is similar with the historical lahars’ extent. The damage grades are divided into four levels as 40 km, 70 km, 80 km and 100 km. It is important for the planning and construction in the Changbai Mountain area. In addition, this disaster zoning model and method can be used to be the reference of other volcanoes.

Key words: Changbai Mountains, numerical simulation, lahar, LAHARZ, energy cone