Successful disaster management of the July 2020 Shaziba landslide triggered by heavy rainfall in Mazhe Village, Enshi City, Hubei Province, China

Abstract. The time series of normalized difference vegetation index (NDVI) and interferometric coherence extracted from optical and Synthetic Aperture Radar (SAR) images, respectively, have strong responses to sudden landslide failures in vegetated regions, which is expressed by a sudden increase or decrease in the values of NDVI and coherence. Compared with optical sensors, SAR sensors are not affected by cloud and daylight conditions and can detect the occurrence time of failure in near real-time. The purpose of this paper is to automatically determine the time of failure occurrence using time series coherence values. We propose, based on some existing anomaly detection algorithms, a deep neural network-based anomaly detection strategy that combines supervised and unsupervised learning without a priori knowledge about failure time. Our experiment using July 21, 2020 Shaziba landslide in China shows that in comparison to widely used unsupervised methodology, the use of our algorithm leads to a more accurate detection of the timing of the landslide failure.

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“…2). More information about this landslide can be found in the following references (Shen et al, 2021;Song et al, 2021;Xue et al, 2022).…”

Section: Time Series Anomaly Detection Strategy Combining Breakout De...mentioning

confidence: 99%

Application of Sar Time-Series and Deep Learning for Estimating Landslide Occurrence Time

Wang

Motagh

Plank

et al. 2022

Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci.

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“…Field investigations have suggested that rainfall infiltration and farmland irrigation have resulted in many slope failures and ground collapses. This can be attributed to loess water infiltration resulting in a loss of soil shear strength due to increasing soil moisture and groundwater level (Lian et al, 2020; Song et al, 2020; Wang et al, 2014). Wind‐blown loess generally deposits above the groundwater level in which it has a thick vadose zone (Hou et al, 2019; Rogers et al, 1994; Zhang, Li, & Li, 2014).…”

Section: Introductionmentioning

confidence: 99%

Verification on the mode of moisture transfer in the vadose zone of thick loess

Wang

et al. 2022

Hydrological Processes

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Precipitation is the only source of groundwater recharge in the Chinese loess region. However, rainfall has been the main driver of geological disasters and engineering challenges in China, such as landslides, slope collapse and sinking of foundations. The roles of preferential flow and piston flow in moisture transfer in the thick loess vadose zone remain controversial. This study used a 100‐m thick loess shaft to monitor soil moisture content and soil temperature over 5 years, whereas climate indices were monitored on the Earth surface. The soil water characteristic curves and hydraulic conductivity function of the loess and the palaeosol collected in the profile were measured in a laboratory. The soil profile moisture transfer process was simulated based on the climatic boundary conditions and measured hydraulic parameters. The monitored and simulated results suggest that loess moisture transfer is dominated by piston flow. The thick loess vadose zone above the groundwater level could be divided into two sub‐zones, namely the active and steady zones. The active zone has a thickness of ~7 m and shows a direct response to climate change, with soil moisture content regulated by rainfall infiltration, evaporation and transpiration and soil moisture moving as transient flow. Although preferential flow can move in the active zone along joints, fissures and holes when water accumulates in the lower ground during heavy rainfall, piston flow remains the main mode of water movement. The steady zone has a thickness of <7 m and is above the groundwater level. Soil moisture content and soil temperature in the steady zone show temporal stability and soil moisture moves as a steady flow. Piston flow is the only mode of water movement in the steady zone. Since percolation velocity in the steady zone is estimated to be 73.3 mm/year, 1330 years of rainfall infiltration through the 97.5 m thick vadose zone would be required to recharge groundwater.

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“…Xu et al [36] described the failure process, the emergency responses, and all efforts used to reduce the risk of the Yagu landslide on 20 March 2019. Song et al [37] then outlined the successful disaster management of the July 2020 Shaziba landslide induced by heavy rainfall. Junichi and Naoki [38] noted that both tangible and intangible measures for debris flows were effectively implemented by the Sabo department of MLIT.…”

Section: Introductionmentioning

confidence: 99%

Theoretical Description of the Hydrodynamic Process after Barrier Lake Formation and Emergency Responses Implementation

Wang

Tan

Shu

et al. 2021

Water

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Barrier lakes are secondary disasters with associated landslides and debris flow that can cause serious damage to the downstream populations and areas. Existing studies are lacking in comprehensive descriptions of the rescue process, where the main channel streamflow varies and topographic erosion develops, as well as engineering disposal performs. This paper aimed to theoretically investigate the formation and emergency responses to barrier lakes using on-the-spot investigation and calculus theory. The results showed that the formation of a barrier lake led to a sudden variation in the flow-change rate (normal to infinite). However, after implementing emergency measures, this rate returned to normal. The whole rescue process could be regarded as the accumulation of disposal effects. Volume changes in the main streams were expressed by a differential equation of the lake surface area and water level variations. In addition, a corresponding theoretical description of flow discharges was also given when engineering measures such as the excavation of diversion channels and engineering blasting were adopted. Specifically, the theoretical expressions of flow discharge were given respectively in the developing stage and breach stable stage after the excavation of diversion channels. The flow discharge through certain sections was also described theoretically when engineering blasting was chosen to widen and deepen the cross-section of the diversion channels. Overall, this paper mathematicizes and theorizes the existing emergency measures, which helps to better understand their implementation principles and application requirements.

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Successful disaster management of the July 2020 Shaziba landslide triggered by heavy rainfall in Mazhe Village, Enshi City, Hubei Province, China

Cited by 13 publications

References 6 publications

Application of Sar Time-Series and Deep Learning for Estimating Landslide Occurrence Time

Application of Sar Time-Series and Deep Learning for Estimating Landslide Occurrence Time

Verification on the mode of moisture transfer in the vadose zone of thick loess

Theoretical Description of the Hydrodynamic Process after Barrier Lake Formation and Emergency Responses Implementation

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