An approach from earthquake-induced landslides identification to numerical simulation of debris flow

On August 14, 2010, an intense and prolonged rainfall triggered debris flow in Hongchun Gully, Yingxiu Town, the epicenter of Wenchuan earthquake. The event transported huge sediment material to the watercourse of the Minjiang River and formed a natural dam, resulting in flash flood in the new reconstruction Yingxiu Town. In order to predict the run out distance and extent of the hazard area of such kind of debris flows, we develop an approach from earthquake-induced landslides investigation to numerical simulation of debris flow in this study. At first, we determined the loose deposits by aerial photography identification and field investigation. Six large scale landslides were found in Hongchun Gully by using the object-oriented analysis remote sensing technique. And then, a two-dimensional numerical model was used to simulate the transport process of debris flow. Raster grid network of digital elevation model generated from GIS was used for the finite difference mesh. Results from the numerical simulation showed a good agreement with actual movement and deposition distribution of Hongchun Gully debris flow.