Characteristics, Dynamic Analyses and Hazard Assessment of Debris Flows in Niumiangou Valley of Wenchuan County

Niumiangou valley, the epicenter of 12 May 2008 Wenchuan earthquake (MS 8.0), became an area with frequent and dense debris flow disasters post-earthquake. Based on in situ investigations after 14 August 2010 a series gathered data, characteristics dynamic analyses post-earthquake flows valley were conducted, then their hazard degree was assessed. Some research conclusions are obtained: (1) these have some typical characteristics, such as rainstorm viscous-type flow, happening usually between 11 p.m. 5 a.m., broken out main channel well six branch gullies at same time also induced branches good vegetation; (2) parameters (including volumetric weight, velocity, peak discharge, impact force, total amount solid materials washed by single maximum height rises super elevation bend) relatively significant, due to which it can be indicated that great destructive power harmfulness; (3) is very high, compared occurred years 2013 post-Wenchuan earthquake, comparison result shows higher, consistent current situation. Therefore, according results, development phase large-scale rainfall-induced disasters, greater damage stronger wallop, will easily occur rainy seasons 20 earthquake.