The M_(S)6.8 Luding earthquake in 2022 is located on the NNW-trending Moxi segment of the Xianshuihe fault with left-lateral strike-slip behavior.This area is where the Xianshuihe,Anninghe,Daliangshan and Longmenshan ...The M_(S)6.8 Luding earthquake in 2022 is located on the NNW-trending Moxi segment of the Xianshuihe fault with left-lateral strike-slip behavior.This area is where the Xianshuihe,Anninghe,Daliangshan and Longmenshan faults intersect.China Earthquake Administration has identified that intersection area,among the Moxi segment of the Xianshuihe fault,the Anninghe fault,the Daliangshan fault and the southern part of the Longmenshan fault,as a high-magnitude earthquake hazard area.According to existing data on the Luding earthquake,including the focal parameters,the spatial distribution of re-located aftershocks,dominated azimuth of the earthquake intensities and earthquake-induced ground fissures,we built a 3D earthquake fault model.We found that two discontinuous NNW-trending vertical strike-slip faults with left stepping were the seismogenic faults of the Luding earthquake.Its coseismic left-lateral dislocation triggered transtensional slips and aftershocks on the NW-trending secondary faults at its northernmost tensile area.Meanwhile,local crustal coseismic shortening on the side of Mt.Gongga triggered the aftershocks on the NE-and NW-trending secondary conjugated strike-slip faults,which were confirmed by GNSS observations and In SAR deformation field around the epicenter.This earthquake rupturing pattern also controlled the spatial distribution of the earthquake intensity IX area and earthquake chain hazards.The Coulomb stress calculation shows that the Luding earthquake increases the risk of high-magnitude earthquake occurrence on the southernmost part of the Xianshuihe fault and the Anninghe fault.Finally,we suggested doing good monitoring of the Anninghe fault and the southernmost part of the Xianshuihe fault and avoiding active faults with seismogenic capacity and areas prone to earthquake-chained hazards during the site selection and planning of reconstruction.展开更多
Numerous contaminated rock and soil slopes are widely distributed around the world.When these slopes become destabilized and slide,they not only cause loss of life and property damage but also severely contaminate the...Numerous contaminated rock and soil slopes are widely distributed around the world.When these slopes become destabilized and slide,they not only cause loss of life and property damage but also severely contaminate the surrounding soil and water environments.A novel hazard chain characterized by both geological hazards and environmental pollution can be defined,profoundly impacting the human-social-ecological system.Based on extensive historical events,this paper introduces the concept of the geological-environmental hazard chain,clarifies its components,and explores its evolutionary processes,zonal and stratification characteristics,and structure.It analyzes the types of hazard chains,hazard formation modes,and control factors,revealing their amplification and overlapping effects,and ultimately synthesizes the principles of coupling with concomitance.The research indicates that:(1)The geological-environmental hazard chain consists of eight major elements:Potential instability sources and potential pollution sources,primary geological hazards and proximal environmental pollution,secondary geological hazards and regional environmental pollution,as well as elements at risk and pollution receptors.This chain is the result of the coupling between geological and environmental hazard chains.(2)Horizontally,the evolution process can be summarized into four zones:slope failure-polluted source release(Ⅰ),flow cascades-migration and dispersion(Ⅱ),damming and sedimentation-retention and precipitation(Ⅲ),and flood propagation-watershed pollution(Ⅳ).Vertically,the evolution can be categorized into three layers:surface water-soil pollution,vadose zone pollution,and saturated zone pollution.Each zone and layer has distinct hazard and pollution characteristics,together forming a spatial network structure of the hazard chain.(3)The types of hazard chains can be divided into two main categories and four subcategories:Surface sedimentation-type(Ⅰ-Ⅱ-Ⅲ)and watershed pollution-type(Ⅰ-Ⅱ-Ⅳ,Ⅰ-Ⅲ-Ⅳ,Ⅰ-Ⅱ-Ⅲ-Ⅳ),each with corresponding hazard formation modes.Internal factors primarily control the type of hazard,while external factors govern the chain combination pattern.This combined action determines the specific hazard type and pattern of chain combination,both of which collectively affect the occurrence and evolution of the hazard chain.(4)The amplification and overlapping effects within the geological-environmental hazard chain are categorized into three types:Geological hazard chain effects,environmental hazard chain effects,and inter-chain effects.The hazard chain adheres to the principle of coupling with concomitance:The entire process of geological hazards and subsequent environmental pollution is dominated by amplification effects such as increased hazard and pollution intensity or expanded impact range.It is also influenced by overlapping effects,including repeated hazards and the overlap of pollution plumes.Geological and environmental hazard chains are sequentially connected over time and interlinked in space,driven by consistent forces.This principle can be expressed in a matrix format,allowing for the scientific quantification of amplification and overlapping effects through iterative calculations to address specific geological-environmental hazard chain issues.From the perspective of hazard chains,this study provides fundamental research ideas and theoretical basis for the issues of coupling and concomitance of geological hazards and secondary environmental pollution,and offers guidance for hazard prevention and pollution control measures concerning major safety and environmental risks in China.展开更多
Debris flows and landslides, extensively developing and frequently occurring along Parlung Zangbo, seriously damage the Highway from Sichuan to Tiebt(G318) at Bomi County. The disastrous debris flows of the Tianmo Wat...Debris flows and landslides, extensively developing and frequently occurring along Parlung Zangbo, seriously damage the Highway from Sichuan to Tiebt(G318) at Bomi County. The disastrous debris flows of the Tianmo Watershed on Sept. 4, 2007, July 25, 2010 and Sept. 4, 2010, blocked Parlung Zangbo River and produced dammed lakes, whose outburst flow made 50 m high terrace collapse at the opposite bank due to intense scouring on the foot of the terrace. As a result, the traffic was interrupted for 16 days in 2010 because that 900 m highway base was destructed and 430 m ruined. These debris flows were initiated by the glacial melting which was induced by continuous higher temperature and the following intensive rainfall, and expanded by moraines along channels and then blocked Parlung Zangbo. At the outlet of watershed,the density, velocity and peak discharge of debris flow was 2.06 t/m3, 12.7 m/s and 3334 m3/s, respectively. When the discharge at the outlet and the deposition volume into river exceeds 2125 m3/s and 126×103 m3, respectively, debris flow will completely blocked Parlung Zangbo. Moreover,if the shear stress of river flow on the foot of terrace and the inclination angel of terrace overruns 0. 377 N/m2 and 26°, respectively, the unconsolidated terrace will be eroded by outburst flow and collapse. It was strongly recommended for mitigation that identify and evade disastrous debris flows, reduce the junction angel of channels between river and watershed, build protecting wall for highway base and keep appropriate distance between highway and the edge of unconsolidated terrace.展开更多
The Wulipo landslide, triggered by heavy rainfall on July 10, 2013, transformed into debris flow,resulted in the destruction of 12 houses, 44 deaths, and 117 missing. Our systematic investigation has led to the follow...The Wulipo landslide, triggered by heavy rainfall on July 10, 2013, transformed into debris flow,resulted in the destruction of 12 houses, 44 deaths, and 117 missing. Our systematic investigation has led to the following results and to a new understanding about the formation and evolution process of this hazard. The fundamental factors of the formation of the landslide are a high-steep free surface at the front of the slide mass and the sandstone-mudstone mixed stratum structure of the slope. The inducing factor of the landslide is hydrostatic and hydrodynamic pressure change caused by heavy continuous rainfall. The geological mechanical model of the landslide can be summarized as "instability-translational slide-tension fracture-collapse" and the formation mechanism as "translational landslide induced by heavy rainfall". The total volume of the landslide is 124.6×104 m3, and 16.3% of the sliding mass was dropped down from the cliff and transformed into debris flow during the sliding process, which enlarged 46.7% of the original sliding deposit area. The final accumulation area is found to be 9.2×104 m2. The hazard is a typical example of a disaster chain involving landslide and its induced debris flow. The concealment and disaster chain effect is the main reason for the heavy damage. In future risk assessment, it is suggested to enhance the research onpotential landslide identification for weakly intercalated slopes. By considering the influence of the behaviors of landslide-induced debris flow, the disaster area could be determined more reasonably.展开更多
In October and November of 2018,the upper reach of the Yangtze River was blocked twice by landslide dams.A large landslide dam on a major river can impound a huge amount of water and trigger catastrophic flooding once...In October and November of 2018,the upper reach of the Yangtze River was blocked twice by landslide dams.A large landslide dam on a major river can impound a huge amount of water and trigger catastrophic flooding once it fails,imposing great risk to the downstream communities.Considering the chain of large dams and densely populated cities along the river,there is an urgent need to improve the system resilience of the Yangtze River to the landslide dam break hazard.This study presents a basin-scale emergency risk management framework based on an overtopping-erosion based dam failure model and a 1-D flood routing analysis model.Basin-wide inundation and detailed flood risk analyses are carried out considering engineering risk mitigation measures,which will facilitate the decision-making on future emergency risk mitigation plans.The proposed framework is applied to the landslide dam on the Yangtze River in November 2018.Results show that excavating a 15 m-depth diversion channel could effectively mitigate the flood risk of downstream areas.Further mitigation measures,including evacuation,removal of obstacles in the river,and preparation of certain intercept capacity in downstream reservoirs,are suggested based on the hazard chain risk analysis.The mitigation results in the case prove the effectiveness of the proposed framework.The incorporation of open-access global databases enables the application of the framework to any large river basin worldwide.展开更多
基金supported by the National Natural Science Foundation of China(41941016)the National Natural Science Foundation of China(U1839204)。
文摘The M_(S)6.8 Luding earthquake in 2022 is located on the NNW-trending Moxi segment of the Xianshuihe fault with left-lateral strike-slip behavior.This area is where the Xianshuihe,Anninghe,Daliangshan and Longmenshan faults intersect.China Earthquake Administration has identified that intersection area,among the Moxi segment of the Xianshuihe fault,the Anninghe fault,the Daliangshan fault and the southern part of the Longmenshan fault,as a high-magnitude earthquake hazard area.According to existing data on the Luding earthquake,including the focal parameters,the spatial distribution of re-located aftershocks,dominated azimuth of the earthquake intensities and earthquake-induced ground fissures,we built a 3D earthquake fault model.We found that two discontinuous NNW-trending vertical strike-slip faults with left stepping were the seismogenic faults of the Luding earthquake.Its coseismic left-lateral dislocation triggered transtensional slips and aftershocks on the NW-trending secondary faults at its northernmost tensile area.Meanwhile,local crustal coseismic shortening on the side of Mt.Gongga triggered the aftershocks on the NE-and NW-trending secondary conjugated strike-slip faults,which were confirmed by GNSS observations and In SAR deformation field around the epicenter.This earthquake rupturing pattern also controlled the spatial distribution of the earthquake intensity IX area and earthquake chain hazards.The Coulomb stress calculation shows that the Luding earthquake increases the risk of high-magnitude earthquake occurrence on the southernmost part of the Xianshuihe fault and the Anninghe fault.Finally,we suggested doing good monitoring of the Anninghe fault and the southernmost part of the Xianshuihe fault and avoiding active faults with seismogenic capacity and areas prone to earthquake-chained hazards during the site selection and planning of reconstruction.
基金supported by the National Natural Science Foundation of China(Grant Nos.51988101,52278376)。
文摘Numerous contaminated rock and soil slopes are widely distributed around the world.When these slopes become destabilized and slide,they not only cause loss of life and property damage but also severely contaminate the surrounding soil and water environments.A novel hazard chain characterized by both geological hazards and environmental pollution can be defined,profoundly impacting the human-social-ecological system.Based on extensive historical events,this paper introduces the concept of the geological-environmental hazard chain,clarifies its components,and explores its evolutionary processes,zonal and stratification characteristics,and structure.It analyzes the types of hazard chains,hazard formation modes,and control factors,revealing their amplification and overlapping effects,and ultimately synthesizes the principles of coupling with concomitance.The research indicates that:(1)The geological-environmental hazard chain consists of eight major elements:Potential instability sources and potential pollution sources,primary geological hazards and proximal environmental pollution,secondary geological hazards and regional environmental pollution,as well as elements at risk and pollution receptors.This chain is the result of the coupling between geological and environmental hazard chains.(2)Horizontally,the evolution process can be summarized into four zones:slope failure-polluted source release(Ⅰ),flow cascades-migration and dispersion(Ⅱ),damming and sedimentation-retention and precipitation(Ⅲ),and flood propagation-watershed pollution(Ⅳ).Vertically,the evolution can be categorized into three layers:surface water-soil pollution,vadose zone pollution,and saturated zone pollution.Each zone and layer has distinct hazard and pollution characteristics,together forming a spatial network structure of the hazard chain.(3)The types of hazard chains can be divided into two main categories and four subcategories:Surface sedimentation-type(Ⅰ-Ⅱ-Ⅲ)and watershed pollution-type(Ⅰ-Ⅱ-Ⅳ,Ⅰ-Ⅲ-Ⅳ,Ⅰ-Ⅱ-Ⅲ-Ⅳ),each with corresponding hazard formation modes.Internal factors primarily control the type of hazard,while external factors govern the chain combination pattern.This combined action determines the specific hazard type and pattern of chain combination,both of which collectively affect the occurrence and evolution of the hazard chain.(4)The amplification and overlapping effects within the geological-environmental hazard chain are categorized into three types:Geological hazard chain effects,environmental hazard chain effects,and inter-chain effects.The hazard chain adheres to the principle of coupling with concomitance:The entire process of geological hazards and subsequent environmental pollution is dominated by amplification effects such as increased hazard and pollution intensity or expanded impact range.It is also influenced by overlapping effects,including repeated hazards and the overlap of pollution plumes.Geological and environmental hazard chains are sequentially connected over time and interlinked in space,driven by consistent forces.This principle can be expressed in a matrix format,allowing for the scientific quantification of amplification and overlapping effects through iterative calculations to address specific geological-environmental hazard chain issues.From the perspective of hazard chains,this study provides fundamental research ideas and theoretical basis for the issues of coupling and concomitance of geological hazards and secondary environmental pollution,and offers guidance for hazard prevention and pollution control measures concerning major safety and environmental risks in China.
基金supported by the Key Program of National Natural Science Found of China(Grant No.41030742)the Grand Program of National Natural Science Found of China(Grant No.41190084)
文摘Debris flows and landslides, extensively developing and frequently occurring along Parlung Zangbo, seriously damage the Highway from Sichuan to Tiebt(G318) at Bomi County. The disastrous debris flows of the Tianmo Watershed on Sept. 4, 2007, July 25, 2010 and Sept. 4, 2010, blocked Parlung Zangbo River and produced dammed lakes, whose outburst flow made 50 m high terrace collapse at the opposite bank due to intense scouring on the foot of the terrace. As a result, the traffic was interrupted for 16 days in 2010 because that 900 m highway base was destructed and 430 m ruined. These debris flows were initiated by the glacial melting which was induced by continuous higher temperature and the following intensive rainfall, and expanded by moraines along channels and then blocked Parlung Zangbo. At the outlet of watershed,the density, velocity and peak discharge of debris flow was 2.06 t/m3, 12.7 m/s and 3334 m3/s, respectively. When the discharge at the outlet and the deposition volume into river exceeds 2125 m3/s and 126×103 m3, respectively, debris flow will completely blocked Parlung Zangbo. Moreover,if the shear stress of river flow on the foot of terrace and the inclination angel of terrace overruns 0. 377 N/m2 and 26°, respectively, the unconsolidated terrace will be eroded by outburst flow and collapse. It was strongly recommended for mitigation that identify and evade disastrous debris flows, reduce the junction angel of channels between river and watershed, build protecting wall for highway base and keep appropriate distance between highway and the edge of unconsolidated terrace.
基金funded by the key project of Sichuan province (Grand No. 2014SZ0163)the National Natural Science Foundation of China (Grant No. 41372301)the Key Deployment Project of Chinese Academy of Sciences (Grant No. KZZD-EW-05-01-02)
文摘The Wulipo landslide, triggered by heavy rainfall on July 10, 2013, transformed into debris flow,resulted in the destruction of 12 houses, 44 deaths, and 117 missing. Our systematic investigation has led to the following results and to a new understanding about the formation and evolution process of this hazard. The fundamental factors of the formation of the landslide are a high-steep free surface at the front of the slide mass and the sandstone-mudstone mixed stratum structure of the slope. The inducing factor of the landslide is hydrostatic and hydrodynamic pressure change caused by heavy continuous rainfall. The geological mechanical model of the landslide can be summarized as "instability-translational slide-tension fracture-collapse" and the formation mechanism as "translational landslide induced by heavy rainfall". The total volume of the landslide is 124.6×104 m3, and 16.3% of the sliding mass was dropped down from the cliff and transformed into debris flow during the sliding process, which enlarged 46.7% of the original sliding deposit area. The final accumulation area is found to be 9.2×104 m2. The hazard is a typical example of a disaster chain involving landslide and its induced debris flow. The concealment and disaster chain effect is the main reason for the heavy damage. In future risk assessment, it is suggested to enhance the research onpotential landslide identification for weakly intercalated slopes. By considering the influence of the behaviors of landslide-induced debris flow, the disaster area could be determined more reasonably.
基金financial support from the NSFC/RGC Joint Research Scheme(N_HKUST620/20 and 42061160480)the Project of Hetao Shenzhen-Hong Kong Science and Technology Innovation Cooperation Zone(HZQB-KCZYB-2020083).
文摘In October and November of 2018,the upper reach of the Yangtze River was blocked twice by landslide dams.A large landslide dam on a major river can impound a huge amount of water and trigger catastrophic flooding once it fails,imposing great risk to the downstream communities.Considering the chain of large dams and densely populated cities along the river,there is an urgent need to improve the system resilience of the Yangtze River to the landslide dam break hazard.This study presents a basin-scale emergency risk management framework based on an overtopping-erosion based dam failure model and a 1-D flood routing analysis model.Basin-wide inundation and detailed flood risk analyses are carried out considering engineering risk mitigation measures,which will facilitate the decision-making on future emergency risk mitigation plans.The proposed framework is applied to the landslide dam on the Yangtze River in November 2018.Results show that excavating a 15 m-depth diversion channel could effectively mitigate the flood risk of downstream areas.Further mitigation measures,including evacuation,removal of obstacles in the river,and preparation of certain intercept capacity in downstream reservoirs,are suggested based on the hazard chain risk analysis.The mitigation results in the case prove the effectiveness of the proposed framework.The incorporation of open-access global databases enables the application of the framework to any large river basin worldwide.
