Variability in rainfall threshold for debris flow after Wenchuan earthquake in Gaochuan River watershed, Southwest China
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- 作者：Tian-Tao Li ; Run-Qiu Huang ; Xiang-Jun Pei
- 刊名：Natural Hazards
- 出版年：2016
- 出版时间：July 2016
- 年：2016
- 卷：82
- 期：3
- 页码：1967-1980
- 全文大小：6,606 KB
- 刊物类别：Earth and Environmental Science
- 刊物主题：Earth sciences
Hydrogeology
Geophysics and Geodesy
Geotechnical Engineering
Civil Engineering
Environmental Management - 出版者：Springer Netherlands
- ISSN：1573-0840
- 卷排序：82
文摘
Wenchuan earthquake occurred 7 years ago, and more than 100 landslides and rock avalanches were triggered by the earthquake in Gaochuan river watershed, in Southwest China, including the Daguangbao landslide, which is the largest one triggered by Wenchuan earthquake, having a volume around 1.15 billion m3. The massive landslide deposits provided uncountable material source for debris flow in the study area, resulting in 25 debris flow events occurred in the past 6 years (2009–2014). The purpose of this paper is to analyze the variability in the rainfall threshold for debris flow after the earthquake in the study area. Results suggest that the critical rainfall threshold is closely related to the rainfall intensity (I) and the antecedent accumulated precipitation (P). There was a sudden drop of the rainfall threshold when the earthquake happened. During the 6 years, the rainfall threshold value kept increasing gradually in a linear trend. However, it is now still much lower than the original rainfall threshold prior to the earthquake. The threshold is expected to reach the original level around 2022 based on the analysis of existing data. Our study indicates that the increase of rainfall threshold is related to the decrease of sediments. And there are still lots of loose deposits in the gullies. Thus, the debris flow can still happen in a high possibility in the next few years.KeywordsDebris flowWenchuan earthquakeRainfall thresholdLoose depositLandslide