Article
Engineering, Environmental
Jiang Xiong, Chuan Tang, Ming Chen, Xianzheng Zhang, Qingyun Shi, Lingfeng Gong
Summary: The article analyzes a catastrophic debris flow event triggered by heavy rainfall in Wenchuan County, China on August 20, 2019, and further discusses the long-term trend of debris flow in the county. The analysis shows that while debris flow activity is decreasing in Wenchuan County, it will still take more than 5 to 10 years to recover to pre-earthquake levels.
BULLETIN OF ENGINEERING GEOLOGY AND THE ENVIRONMENT
(2021)
Article
Engineering, Geological
Xiaojun Guo, Yong Li, Xingchang Chen, Ju Zhang, Yuqing Sun
Summary: The study focused on the formation conditions of debris flow/flood in two watersheds in the Wenchuan Earthquake area, China, and found that the runoff and rainfall conditions required for such events increased over time. This increase was attributed to the recovery of vegetation and the reduction of source materials, leading to a higher forecasting efficiency compared to actual monitored flow behaviors and previously proposed rainfall thresholds.
Article
Engineering, Environmental
Ming Chang, Xiangyang Dou, Tristram C. Hales, Bin Yu
Summary: Research in the Wenchuan earthquake region of Southwest China has found that post-earthquake debris flows can be classified into short-term, medium persistent, and long-term intermittent rainfall patterns, each with different characteristics in terms of rainfall intensity, duration, and cumulative rainfall. These patterns have implications for infiltration, saturation, and triggering mechanisms of debris flows. By establishing rainfall-threshold patterns, it is possible to predict the critical initiation conditions of debris flows in different watersheds based on intensity-duration curves.
BULLETIN OF ENGINEERING GEOLOGY AND THE ENVIRONMENT
(2021)
Article
Engineering, Geological
Xianzheng Zhang, Chenxiao Tang, Ning Li, Jiang Xiong, Ming Chen, Mingwei Li, Chuan Tang
Summary: It is recognized that post-seismic mass movements usually occur in the first few years after an earthquake. However, a major debris flow occurred in Wenchuan County in 2019, 11 years after the 2008 Wenchuan earthquake, indicating a different temporal evolution pattern. The investigation results show that active landslides mainly occurred in high-elevation areas without vegetation cover, and the debris flows were mainly initiated by run-off erosion of debris in steep channels. Additionally, more debris flows occurred in the northern part of the study area, where the relative annual rainfall and coseismic landslide density were low.
Article
Engineering, Geological
Wen Zhang, Junqi Chen, Junhua Ma, Chen Cao, Han Yin, Jia Wang, Bo Han
Summary: This study investigates the evolution of sediment and the impact of check dams on it in the Chutou gully during the 2019 and 2020 debris flow. The results show that the sediment evolution remains active in recent years, emphasizing the need for debris flow protection in seismic areas. Check dams play an essential role in protecting against debris flows and significantly influence sediment evolution. It is important to focus on the storage capacity and stability of check dams to prevent subsequent debris flow.
Article
Engineering, Geological
Zhuoyan Jiang, Xuanmei Fan, Srikrishnan Siva Subramanian, Fan Yang, Ran Tang, Qiang Xu, Runqiu Huang
Summary: This study analyzed the evolution of probabilistic rainfall thresholds for post-seismic debris flows using a Bayesian technique, based on triggering and non-triggering rainfall data after the Wenchuan earthquake. The results indicated that antecedent precipitation plays a crucial role in low-intensity long-duration rainfall-induced debris flows, while short-duration high-intensity events are less affected. The study also found that the I-T-D model performed best in investigating uncertainties of rainfall threshold models, providing valuable insights for improving early warning systems for post-seismic debris flows.
ENGINEERING GEOLOGY
(2021)
Article
Geosciences, Multidisciplinary
Xudong Hu, Feng Yang, Kaiheng Hu, Miao Ding, Shuang Liu, Li Wei
Summary: In a seismic basin, the connectivity between earthquake-induced landslides and debris-flow channels plays a crucial role in determining the sediment volume transported into debris flows and the magnitude of the debris flows. This study developed a normalized index of sediment connectivity to analyze the evolution of landslide sediment transport capacity. By simulating two debris-flow events, the results showed a good agreement between the simulated and observed debris-flow magnitudes, indicating the suitability of the normalized landslide connectivity index for estimating the movable volume. Additionally, a negative correlation was found between the sediment connectivity index and landslide characteristics, suggesting a decay of spatial connectivity over time and a corresponding reduction in debris-flow magnitude.
Article
Engineering, Geological
S. Zhang, J. Y. Peng, M. P. Zhang, Y. B. Chen, Y. Y. Han, C. X. Su, D. Y. Zhuang
Summary: The occurrence of debris flows after the Wenchuan earthquake resulted in significant damage to infrastructure and the loss of many lives. This study analyzed the evolution of debris flows over a 10-year period after the earthquake to gain a better understanding of its long-term impact. Through remote sensing images and field investigations, the movement of loose deposits in debris flow gullies along Provincial Road 303 was tracked. The study found a gradual transportation of loose deposits into channels and a decreasing trend in mass transport rate from 2010 to 2018. The occurrence frequency, magnitude, and mobility of debris flows were also found to decrease.
ENGINEERING GEOLOGY
(2023)
Article
Engineering, Geological
Fan Yang, Xuanmei Fan, Zhenlei Wei, Srikrishnan Siva Subramanian, Theo W. J. Van Asch, Qiang Xu
Summary: Strong earthquakes can trigger extensive landslides, generating loose deposits that can become debris flows through subsequent rainfall. The parameters controlling post-earthquake debris flow activity and magnitude were poorly understood. This study analyzed debris flows in a representative catchment in the Wenchuan earthquake-hit region from 2008 to 2020, investigating changes in parameters such as material depletion, grain size, and vegetation recovery. The results provide important implications for risk assessment and prediction of future debris flows in earthquake-prone regions.
ENGINEERING GEOLOGY
(2023)
Article
Engineering, Geological
Fan Yang, Xuanmei Fan, Srikrishnan Siva Subramanian, Xiangyang Dou, Junlin Xiong, Bing Xia, Zongyang Yu, Qiang Xu
Summary: Enhanced debris flow activity has been observed in Sichuan Province, Southwest China after the 2008 Wenchuan earthquake, with intense activity still present more than a decade later. A heavy rainstorm in August 2019 triggered catastrophic debris flows in the epicentral area. Analysis revealed that the 2019 debris flows were mainly initiated by concentrated runoff erosion, differing from previous events.
Article
Geography, Physical
Yu Yang, Chenxiao Tang, Chuan Tang, Ming Chen, Yinghua Cai, Xianghang Bu, Chang Liu
Summary: In recent decades, extreme earthquakes have occurred worldwide, with the Wenchuan earthquake in 2008 resulting in numerous landslides and post-earthquake debris flows. Monitoring data indicates that debris flows have posed long-term threats for over ten years after the earthquake. It is crucial to determine the spatial and temporal changes of debris flows and the evolving influence of condition factors in the earthquake-affected area. A comprehensive database of 1628 debris flow events occurring between 2000 and 2020 was established, and the debris flow intensity (DFI) was characterized using a grid calculation method. The results suggest that lithology, rainfall, and slope degree were the primary controlling factors before the earthquake, but coseismic landslides became the main promoting factor after the earthquake. The requirements for rainfall, slope degree, and terrain relief amplitude increased over time, and the post-earthquake debris flow activity was categorized into three phases: active, unstable, and recession, with a return to pre-earthquake levels anticipated by 2045.
Article
Geosciences, Multidisciplinary
Ning Li, Chuan Tang, Tao Yang
Summary: This paper analyzes the development and characteristics of landslides in Miansi town, which is located in the strong earthquake area, in the 10 years after the earthquake. The study finds that the total area of landslides increased significantly in the initial years but slowed down after a heavy rainfall event in 2013. The study also investigates the factors influencing the probability of landslides.
Article
Engineering, Civil
Guo Xiaojun, Cui Peng, Chen Xingchang, Li Yong, Zhang Ju, Sun Yuqing
Summary: Rainfall in mountainous watershed exhibits high spatial variability due to elevation effects, leading to uncertainties in forecasting hydrological hazards like water floods and debris flows. This study investigates the spatial variation of rainfall in a small watershed with 10 rain gauges, establishing a rainfall-elevation relationship based on 52 rainstorm events. Results show lower interpolation errors in areas with high rainfall amounts, while estimating rainfall in high-elevation regions proves more challenging. The study highlights the importance of gauge placement and spacing in accurate rainfall estimation for hazard forecasting.
JOURNAL OF HYDROLOGY
(2021)
Article
Engineering, Geological
Ming Chen, Chuan Tang, Xianzheng Zhang, Jiang Xiong, Ming Chang, Qingyun Shi, Feilong Wang, Mingwei Li
Summary: This study proposes a quantitative method to assess the physical fragility of buildings to debris flows in the Wenchuan earthquake-affected areas by analyzing debris flow activity and building damage features. Physical fragility curves for different building structures are proposed based on the probability of exceeding different damage states corresponding to different intensities of debris flows. Using the proposed physical fragility functions, the structural resistance of buildings to debris flows in the affected region can be assessed, providing a scientific basis for risk management and mitigation strategies.
ENGINEERING GEOLOGY
(2021)
Article
Engineering, Geological
Jiang Xiong, Chuan Tang, Hai Tang, Ming Chen, Xianzheng Zhang, Qinyun Shi, Ming Chang, Lingfeng Gong, Ning Li, Mingwei Li
Summary: This study investigates the long-term changes in hillslope erosion and landslide-channel coupling by quantifying the coupling degree using a landslide-channel coupling index (LCCI) and estimating the hillslope erosion driven by landslides. The results show that the overall landslide activity and coupling degree decayed following the Wenchuan earthquake, and the hillslope erosion driven by landslides also followed a power law decay. Although the coupling degree and sediment supply to channels have decreased, strong rainfall events can still result in significant sediment delivery.
ENGINEERING GEOLOGY
(2022)
