Rainfall thresholds for debris flow initiation in the Wenchuan earthquake-stricken area, southwestern China

Landslides ◽  
2013 ◽  
Vol 11 (5) ◽  
pp. 877-887 ◽  
Author(s):  
Wei Zhou ◽  
Chuan Tang
2016 ◽  
Vol 16 (2) ◽  
pp. 483-496 ◽  
Author(s):  
D. L. Liu ◽  
S. J. Zhang ◽  
H. J. Yang ◽  
L. Q. Zhao ◽  
Y. H. Jiang ◽  
...  

Abstract. The activities of debris flow (DF) in the Wenchuan earthquake-affected area significantly increased after the earthquake on 12 May 2008. The safety of the lives and property of local people is threatened by DFs. A physics-based early warning system (EWS) for DF forecasting was developed and applied in this earthquake area. This paper introduces an application of the system in the Wenchuan earthquake-affected area and analyzes the prediction results via a comparison to the DF events triggered by the strong rainfall events reported by the local government. The prediction accuracy and efficiency was first compared with a contribution-factor-based system currently used by the weather bureau of Sichuan province. The storm on 17 August 2012 was used as a case study for this comparison. The comparison shows that the false negative rate and false positive rate of the new system is, respectively, 19 and 21 % lower than the system based on the contribution factors. Consequently, the prediction accuracy is obviously higher than the system based on the contribution factors with a higher operational efficiency. On the invitation of the weather bureau of Sichuan province, the authors upgraded their prediction system of DF by using this new system before the monsoon of Wenchuan earthquake-affected area in 2013. Two prediction cases on 9 July 2013 and 10 July 2014 were chosen to further demonstrate that the new EWS has high stability, efficiency, and prediction accuracy.


2019 ◽  
Vol 23 (3 Part A) ◽  
pp. 1563-1570
Author(s):  
Zhi-Long Zhang ◽  
Jing Xie ◽  
De-Ke Yu ◽  
Zhi-Jie Wen

This paper addresses a debris flow disaster in Yingxiu town after the Wenchuan earthquake. Through site investigation and data review, the geography and geological environment of the basin and the development, formation conditions and activity characteristics of the debris flow in the basin are analyzed. Calculate and analyze the characteristics of the debris flow, such as gravity, flow velocity and impact force. According to the management idea of combination of blocking and discharging, this paper proposes to arrange three blocking dams in the main ditch, construct drainage gullies in the downstream accumulation section, and prevent and control the aqueduct in the intersection of the main ditch and the G213 national road, which will be similar to the earthquake in the future. It is provided as a reference for research and prevention of the debris flow.


2012 ◽  
Vol 145 (1) ◽  
pp. 241-245 ◽  
Author(s):  
Wen Zheng ◽  
Yu Xu ◽  
Lihuan Liao ◽  
Xuyu Yang ◽  
Xiaodong Gu ◽  
...  

2021 ◽  
Author(s):  
Li Ning ◽  
Tang Chuan ◽  
Zhang Xianzheng ◽  
Chang Ming ◽  
Shu Zhile ◽  
...  

Abstract On August 20, 2019, at 2 a.m., a disastrous debris flow occurred in Chediguan gully in Yinxing town, China. The debris flow destroyed the drainage groove and the bridge at the exit of the gully. In addition, the debris flow temporarily blocked the Minjiang River during the flood peak, flooding the Taipingyi hydropower station 200 m upstream and leaving two plant workers missing. To further understand the activity of the debris flow after the Wenchuan earthquake, the characteristics of this debris flow event were studied. Eleven years after the Wenchuan earthquake, a disastrous debris flow still occurred in the Chediguan catchment, causing more severe losses than those of earlier debris flows. In this paper, the formation mechanism and dynamic characteristics of this debris flow event are analysed based on a drone survey, high-definition remote sensing interpretations and other means. The catastrophic debris flow event indicates that debris flows in the Wenchuan earthquake area are still active. A large amount of dredging work in the main gully could effectively reduce the debris flow risk in the gully. In addition, it is also important to repair or rebuild damaged mitigation measures and to establish a real-time monitoring and early warning system for the high-risk gully.


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