Field observations of debris-flow initiation processes on sediment deposits in a previous deep-seated landslide site

作     者：Fumitoshi IMAIZUMI Satoshi TSUCHIYA Okihiro OHSAKA 

作者机构：Department of Environment and Forest Resources ScienceFaculty of AgricultureShizuoka University 

出 版 物：《Journal of Mountain Science》 (山地科学学报（英文）)

年 卷 期：2016年第13卷第2期

页      面：213-222页

核心收录：

学科分类：081803[工学-地质工程] 08[工学] 0818[工学-地质资源与地质工程] 

基　　金：supported by the Grant-in-Aid for Scientific Research of Japan Society for the Promotion of Science (JSPS KAKENHI) (Grant Nos.80378918 26292077) 

主　　题：Debris flow Initiation zone Field monitoring Ohya landslide 

摘      要：Although information regarding the initiation processes of debris flows is important for the development of mitigation measures,field data regarding these processes are *** conducted field observations of debris-flow initiation processes in the upper Ichinosawa catchment of the Ohya landslide,central *** 19 June 2012,our videocamera monitoring systems recorded the moment of debris-flow initiation on channel deposits(nine surges) and talus slopes(eight surges).The initiation mechanisms of these surges were classified into three types by analyzing the video images: erosion by the surface flow,movement of deposits as a mass,and upward development of the fluid *** first type was associated with the progress of surface flow from the upper stream on unsaturated channel *** second type was likely caused by an increase in the pore water pressure associated with the rising in the groundwater level in channel deposits;a continuous water supply from the upper stream by the surface flow might have induced this *** third type was associated with changes in the downstream topography caused by *** flow velocity of most surges was less than 3 m s^(-1) and they usually stopped within 100 m from the initiation *** with abundant pore fluid had a higher flow velocity(about 3- 5 m s^(-1)) and could travel for alonger *** observations indicate that the surface flow plays an important role in the initiation of debris flows on channel deposits and talus slopes.