Characteristic and Causes of Group-occurring Debris Flow in
详细信息
- 责任者：Su Pengcheng (Key Laboratory of Mountain Hazards and Surface Process ; Chinese Academy of Sciences ; Chengdu 610041 ; China) ; Wei Fangqian
- 刊名：Journal of Mountain Science
- 出版年：2010
- 卷期：28(5)
- 关键词：泥石流 ; 四川
- 页码：p.593-606
- 图表：illus., 3 tables, 11 refs.
- 分类号：1800
- issnNo：ISSN1008-2786
- isbnNo：CN51-1516/P
摘要
Rainfall-induced debris flows in recent years have brought about tremendous damages to Dechang County,the southwest of Sichuan.This paper explores the coupling of rainfall and the surface conditions that impacts the formation of debris flow.Interpretation of TM images(30 m)reveals the concentration of debris flow in rivers of Anning,Cida,Yalong,and Laonian.It is shown that debris flow is closely related to the slope of valley and the NDVI,among the factors including elevation,slope,strata and rock.And combination of slope and rock can be used to identify debris flow valley at accuracy up to 92%.For the study area of Dechang with high vegetation cover rate,the valley prone to debris flow satisfies the following conditions:(1)the average slope is bigger than 20;(2)NDVI is between 0.1 and 0.3.Combining the surface conditions and the local rainstorm processes reveals that debris flow depends on the center and route of rainfall.This is well confirmed by the event group on August 24,2004.It is also shown that the occurrence had a one hour lag after the rainfall peak,which is crucial for the forecasting.Finally,a new mitigation idea is proposed for group-occurring debris flow of Dechang county.