In early morning of Aug 8th, 2010, the rain-triggered tremendous debris flows broke out simultaneously at the Sanyanyu ravine and Luojiayu ravine, which locate in the north part of Zhouqu County town. The debris flow ...In early morning of Aug 8th, 2010, the rain-triggered tremendous debris flows broke out simultaneously at the Sanyanyu ravine and Luojiayu ravine, which locate in the north part of Zhouqu County town. The debris flow is the most severe event of the same kind of disasters in the past sixty years in China, which caused great losses of people's lives and properties. Based on field investigation, remote sensing image interpretation and analysis of local climatological data, the local topographical conditions, active tectonic movement, massive debris source and torrential rains were the main formation causes which induced the catastrophic debris flows. Moreover, detailed geological surveys were carried out following the disaster, the other geological potential hazard sites were found out, and the geological and seismic hazard assessment has been put into practice. At last, scientific and appropriate countermeasures have been suggested to prevent and mitigate the extraordinarily serious debris flow.展开更多
Debris flows pose serious risks to communities in mountainous areas,often resulting in large losses of human life and property.The impeding presence of urban buildings often affects the runout behavior and deposition ...Debris flows pose serious risks to communities in mountainous areas,often resulting in large losses of human life and property.The impeding presence of urban buildings often affects the runout behavior and deposition of debris flows.But the impact of different building densities and sizes on debris flow dynamics has yet to be quantified to guide urban planning in debris flow risk zones.This study focused on a debris flow that occurred in Zhouqu County,Gansu Province,China on August 7th,2010,which was catastrophic and destroyed many buildings.The FLO-2D software was used to simulate this debris flow in two scenarios,i.e.the presence and the absence of buildings,to obtain debris-flow intensity parameters.The developed model was then used to further analyze the influence of large buildings and narrow channels within the urban environment.The simulation results show that considering the presence of buildings in the simulation is essential for accurate assessment of debris flow intensity and deposition distribution.The layout of buildings in the upstream urban area,such as large buildings or parallel buildings which form narrow channels,can affect the flow velocity and depth of debris flow heading towards downstream buildings.To mitigate damage to downstream buildings,the relative spacing(d/a)between upstream and downstream buildings should not exceed a value of two and should ideally be even lower.These findings provide valuable insights for improving the resistance of mountainous cities to urban debris flows.展开更多
Zhouqu County in Gansu Province, Northwest China, is typically highly prone to landslides. On July 12, 2018, a landslide blocked the Bailong River near Zhouqu County, posing a serious threat to the life and property o...Zhouqu County in Gansu Province, Northwest China, is typically highly prone to landslides. On July 12, 2018, a landslide blocked the Bailong River near Zhouqu County, posing a serious threat to the life and property of local residents and the safety of infrastructure. Small baseline subset interferometry synthetic aperture radar technology(SBAS-In SAR) was adopted to identify the potential active landslides in the surrounding area of Zhouqu County, using ascending and descending orbit Sentinel-1 satellite images taken from October 2017 to December 2018. The surface deformation areas detected by SBAS-In SAR were verified by optical remote sensing image interpretation and field investigation, and a total of 23 active landslides were identified finally. The deformation characteristics of four typical landslides are analysed in detail using deformation velocity and rainfall data. It is found that the deformation velocity of landslides in this area is mainly affected by rainfall and there is a lag effect. The results can provide a reference for the prevention and control of landslide risk in Zhouqu County.展开更多
基金supported by the National Natural Science Foundation of China[grant numbers 41421004 and 41210007]the International Innovation Team project of the Chinese Academy of Sciences entitled ‘High Resolution Numerical Simulation of Regional Environment’
基金Foundation item： Projects（40902094, 50978239） supported by the National Natural Science Foundation of China Project（20121ESLZ01） supported by the Institute of Earthquake Prediction, China Earthquake Administration
文摘In early morning of Aug 8th, 2010, the rain-triggered tremendous debris flows broke out simultaneously at the Sanyanyu ravine and Luojiayu ravine, which locate in the north part of Zhouqu County town. The debris flow is the most severe event of the same kind of disasters in the past sixty years in China, which caused great losses of people's lives and properties. Based on field investigation, remote sensing image interpretation and analysis of local climatological data, the local topographical conditions, active tectonic movement, massive debris source and torrential rains were the main formation causes which induced the catastrophic debris flows. Moreover, detailed geological surveys were carried out following the disaster, the other geological potential hazard sites were found out, and the geological and seismic hazard assessment has been put into practice. At last, scientific and appropriate countermeasures have been suggested to prevent and mitigate the extraordinarily serious debris flow.
基金This study was funded by the National Key Research and Development Program of China(Grant No.2019YFC1806001)the National Natural Science Foundation of China(Grant No.51988101,Grant No.52278376,Grant No.42007245)the Science and Technology Development Fund,Macao SAR(File nos.0083/2020/A2 and 001/2024/SKL).
文摘Debris flows pose serious risks to communities in mountainous areas,often resulting in large losses of human life and property.The impeding presence of urban buildings often affects the runout behavior and deposition of debris flows.But the impact of different building densities and sizes on debris flow dynamics has yet to be quantified to guide urban planning in debris flow risk zones.This study focused on a debris flow that occurred in Zhouqu County,Gansu Province,China on August 7th,2010,which was catastrophic and destroyed many buildings.The FLO-2D software was used to simulate this debris flow in two scenarios,i.e.the presence and the absence of buildings,to obtain debris-flow intensity parameters.The developed model was then used to further analyze the influence of large buildings and narrow channels within the urban environment.The simulation results show that considering the presence of buildings in the simulation is essential for accurate assessment of debris flow intensity and deposition distribution.The layout of buildings in the upstream urban area,such as large buildings or parallel buildings which form narrow channels,can affect the flow velocity and depth of debris flow heading towards downstream buildings.To mitigate damage to downstream buildings,the relative spacing(d/a)between upstream and downstream buildings should not exceed a value of two and should ideally be even lower.These findings provide valuable insights for improving the resistance of mountainous cities to urban debris flows.
基金The work was financially supported by the National Key Research and Development Program of China(No.2018YFC1505402)the National Natural Science Foundation of China(Nos.41941019,41521002)+1 种基金the Key R&D project of the Science and Technology Department of the Sichuan Province of China(No.2019YFG0460)the Science and Technology Innovation Fund of the Sichuan Earthquake Agency(No.201901)。
文摘Zhouqu County in Gansu Province, Northwest China, is typically highly prone to landslides. On July 12, 2018, a landslide blocked the Bailong River near Zhouqu County, posing a serious threat to the life and property of local residents and the safety of infrastructure. Small baseline subset interferometry synthetic aperture radar technology(SBAS-In SAR) was adopted to identify the potential active landslides in the surrounding area of Zhouqu County, using ascending and descending orbit Sentinel-1 satellite images taken from October 2017 to December 2018. The surface deformation areas detected by SBAS-In SAR were verified by optical remote sensing image interpretation and field investigation, and a total of 23 active landslides were identified finally. The deformation characteristics of four typical landslides are analysed in detail using deformation velocity and rainfall data. It is found that the deformation velocity of landslides in this area is mainly affected by rainfall and there is a lag effect. The results can provide a reference for the prevention and control of landslide risk in Zhouqu County.
