Debris flow often causes enormous loss to life and property,especially on alluvial fans.Engineering structures such as retention check dams are essential to reduce the damage.In hazard mitigation evaluation and planni...Debris flow often causes enormous loss to life and property,especially on alluvial fans.Engineering structures such as retention check dams are essential to reduce the damage.In hazard mitigation evaluation and planning it is of significance to determine the location,size and type of dam and the effects of damage mitigation.We present a numerical simulation method using Kanako simulator for hazard mitigation planning of debris flow disaster in Tanjutani Gully,Kyoto City,Japan.The simulations were carried out for three situations:1) the simulations of erosion,deposition,hydrograph changing and inundation when there were no mitigation measures;2) the simulations of check dams in four locations(470 m,810 m,1,210 m and 1,610 m from the upstream end) to identify the best location;3) the simulations of check dams of three types(closed,slit and grid) to analyze their effects on sediment trapping and discharge reduction.Based on the simulations,it was concluded that two closed check dams(located at 470 m and 1,610 m from the upstream end) in the channel and a drainage channel on the alluvial fan can reduce the risk on the alluvial fan to an acceptable level.展开更多
Since the disastrous aftermath of the 2004 Sumatra Tsunami(Indonesia)and the 2011 Tohoku Tsunami(Japan),China has made much effort to mitigate tsunami hazards.We briefly reviewed the progress of cataloguing,modeling,e...Since the disastrous aftermath of the 2004 Sumatra Tsunami(Indonesia)and the 2011 Tohoku Tsunami(Japan),China has made much effort to mitigate tsunami hazards.We briefly reviewed the progress of cataloguing,modeling,early warning and hazard analysis for tsunamis in China.Compiling a Chinese tsunami catalogue is a challenge at present due to a large number of inconsistent research results.In China,the numerical models widely used in engineering and related studies are developed by other countries,and the development of a domestic model is being funded by the Chinese government.The tsunami early warning system has been set up and used during the recent tsunami events,such as the Chile earthquake on February 27,2010.展开更多
In frame of the asteroid-comet hazard problem study, a qualitative analysis of some methods for the effect on a celestial near-Earth object (NEO)-an asteroid, a comet — is carried out. The goal of the effect is a cor...In frame of the asteroid-comet hazard problem study, a qualitative analysis of some methods for the effect on a celestial near-Earth object (NEO)-an asteroid, a comet — is carried out. The goal of the effect is a correction of this object’s orbit, its deflection from the Earth to prevent their collision. There are studied a mechanical impact-kinetic effect of the spacecraft (SC), a thermonuclear effect, an effect on a cometary nucleus for a controlled change of its dusty mantle and, therefore, its sublimation activity. Qualitative models of these effects are developed. Numerical analysis results are given for a group of NEOs such as some asteroids from the Apollo family (Apollo, Castalia, Nereus, Orpheus, Phaethon, Toutatis, etc.) and from the Aten family (Aten, Hathor, Khufu, etc.) as well as some short-periodic comets like the comet P/Biela. There are studied some characteristics of the effects on the NEOs such as the velocity impulse (or acceleration) applied to the celestial body, its deflection from the Earth. The study is supported by the Russian Foundation of Basic Studies (Grant N 01-01-00133).展开更多
The massive 8.0-magnitude Wenchuan Earthquake triggered huge landslides,avalanches,and debris flows that blocked rivers and created 34 important quake lakes,including the Tangjiashan Quake Lake on the Tongkou River.Mo...The massive 8.0-magnitude Wenchuan Earthquake triggered huge landslides,avalanches,and debris flows that blocked rivers and created 34 important quake lakes,including the Tangjiashan Quake Lake on the Tongkou River.More than half of these lakes were identified to be of moderate or high hazard levels,so activities needed to be undertaken for hazard mitigation of potential flooding.This paper presents the mitigation processes of quake lake hazards,which involve various techniques such as rapid hazard analysis,scenario-based mitigation planning,and real-time forecasting of outburst flooding for implementation actions.The shortage of hydrologic and geological data and the nature of emergency situations raise substantial challenges in the hazard mitigation of quake lakes.This paper suggests a potential approach in dealing with quake lake hazards,which integrates the automatic monitoring network,hydrologic models,and hydrodynamic models with a comprehensive indicator for hazard levels.The necessity of improving the integrated methodology is highlighted.展开更多
Tremendous losses were caused by ground fissure hazard both in USA and China. Six states of southwestern USA and seven provinces of central China were affected by the destructive ground fissures. The aseismic ground f...Tremendous losses were caused by ground fissure hazard both in USA and China. Six states of southwestern USA and seven provinces of central China were affected by the destructive ground fissures. The aseismic ground fissure hazards usually take place in land subsidence area. The comparison of the two countries' ground fissures were given including ground fissure formation, evolution, mechanics of destruction and countermeasures against them. The destructive ground fissures occurred about a half century earlier in USA than in China The mechanisms of various ground fissures were analyzed with interdisciplinary studies. It has been found that the preexisted faults are serving as the bases of forming modem ground fissure, and human activities, e.g. over pumping ground water, or oil, can accelerate the creeping of the fissures and make them destructive to many kinds of civil engineering. The countermeasures to mitigate ground fissure hazard were put forward, not only in science and technology but also in social administration. The successful practices in the two countries were introduced as examples.展开更多
The problem investigated in this research is about the potential risk of technological hazards, which poses a perilous threat to humankind and the environment. Rapid urbanization has been increasing the population den...The problem investigated in this research is about the potential risk of technological hazards, which poses a perilous threat to humankind and the environment. Rapid urbanization has been increasing the population density in an area, elevating the risk of exposure to technological disasters. Therefore, it is necessary to detect the areas with higher chemical risk to spread awareness about the potential risk zones and reduce actual damage and casualties resulting from the hazardous substance events. The basic design of the study utilizes geospatial analysis to map the TRI (Toxics Release Inventory) facilities in the communities of Texas to establish a relationship between potential </span><span style="font-family:Verdana;">hazardous material release zones and the human population at risk. The</span><span style="font-family:Verdana;"> study identified the vulnerable counties as well as investigated how those risk areas are related to race/ethnicity, income and education. The research would contribute to the policymakers acting on the hazard situation and keep them better prepared for</span><span style="color:red;"> </span><span style="font-family:Verdana;">chemical hazards. In addition, it would help the residents and emergency managers to better understand the circumstance to mitigate the consequences as well as increase their awareness to be ready for the uncertainties in the hotspots involved in high risk of the hazards.展开更多
There has been a large increase in the number of days per year with numerous EF1-EF5 tornadoes.Given the significant damage incurred by tornadoes upon communities,community resilience analyses for tornado-stricken com...There has been a large increase in the number of days per year with numerous EF1-EF5 tornadoes.Given the significant damage incurred by tornadoes upon communities,community resilience analyses for tornado-stricken communities have been gaining momentum.As the community resilience analysis aims to guide how to lay out effective hazard mitigation strategies to decrease damage and improve recovery,a comprehensive and accurate approach is necessary.Agent-based modeling,an analysis approach in which different types of agents are created with their properties and behavior clearly defined to simulate the processes of those agents in an external environ-ment,is the most comprehensive and accurate approach so far to conducting community resilience simulations and investigating the decision-making for mitigation and recovery under natural hazards.In this paper,agent-based models(ABMs)are created to simulate the recovery process of a virtual testbed based on the real-world community in Joplin City,MO.The tornado path associated with the real-world tornado event that occurred in May 2011 is adopted in the tornado hazard modeling for the Joplin testbed.In addition,agent-based models are created for another virtual community in the Midwest United States named Centerville using an assumed tornado scenario of the same EF-scale as that in Joplin.The effects of hazard mitigation strategies on the two communities are also explored.A comparison between the analysis results of these two testbeds can indicate the influence of the characteristics of a tornado-prone community on the resilience of the community as well as on the effects of hazard mitigation strategies.It is observed that a community’s level of development significantly impacts the tornado resilience.In addition,the effects of a specific type of hazard mitigation strategy on the recovery process are contingent upon testbed characteristics.展开更多
The regional forecast of landslide is one of the key points of hazard mitigation. It is also a hot and difficult point in research field. To solve this problem has become urgent task along with Chinese economy fast de...The regional forecast of landslide is one of the key points of hazard mitigation. It is also a hot and difficult point in research field. To solve this problem has become urgent task along with Chinese economy fast development. This paper analyzes the principle of regional landslide forecast and the factors for forecasting. The method of a combination of Information Value Model and Extension Model has been put forward to be as the forecast model. Using new result of Numerical Weather Foreeast Research and that combination model, we discuss the implementation feasibility of regional landslide forecast. Finally, with the help of Geographic Information System, an operation system for southwest of China landslide forecast has been developed. It can carry out regional landslide forecast daily and has been pilot run in NMC. Since this is the first time linking theoretical research with meteorological service, further works are needed to enhance it.展开更多
In recent studies, the effects of complex costal topography on tsunami run-up has sparked heated discussion. This study mainly aims at investigating the effects of complex costal topography on the tsunami inundation d...In recent studies, the effects of complex costal topography on tsunami run-up has sparked heated discussion. This study mainly aims at investigating the effects of complex costal topography on the tsunami inundation distance and the effectiveness of sand dunes in dissipating tsunami wave energy. The experiments were carried out in a wave flume to investigate the potential reduction effects of wave run-up by non erodible sand dune like features. The results show that increasing dunes spacing could not significantly affect inundation distance. However, if the height of sand dunes is of the same order of magnitude as the incoming tsunami wave and the gaps between the dunes are large enough, successful tsunami mitigation could also be possible.展开更多
Debris flow runoff process is one of key parameters for the design of emergency measures and control engineering. The Shenxi gully in Dujiangyan region,located in the meizoseismal areas of Wenchuan earthquake,was sele...Debris flow runoff process is one of key parameters for the design of emergency measures and control engineering. The Shenxi gully in Dujiangyan region,located in the meizoseismal areas of Wenchuan earthquake,was selected as the study area. Based on the research of hazard inducing environment,a soil conservation service( SCS) hydrological model was used to simulate the process of water flow,and then the debris flow runoff process was calculated using the empirical formula combining the results from the SCS hydrological model. Taking the debris flow event occurred on July 9th,2013 as an example,the peak discharges of water flow and debris flow were calculated as 162. 12 and 689. 22 m3/s,with error of 6. 03% compared to the measured values. The debris flow confluence process lasted 1. 8h, which was similar with the actual result. The proposed methodology can be applied to predict the debris flow runoff process in quake-hit areas of the Wenchuan earthquake and is of great importance for debris flow mitigation.展开更多
The International Union of Geological Sciences(IUGS)is evaluating whether there are additional geoscientific activities that would be beneficial in helping mitigate the impacts of tsunami.Public concerns about poor de...The International Union of Geological Sciences(IUGS)is evaluating whether there are additional geoscientific activities that would be beneficial in helping mitigate the impacts of tsunami.Public concerns about poor decisions and inaction,and advances in computing power and data mining call for new scientific approaches.Three fundamental requirements for mitigating impacts of natural hazards are defined.These are:(1)improvement of process-oriented understanding,(2)adequate monitoring and optimal use of data,and(3)generation of advice based on scientific,technical and socio-economic expertise.International leadership/coordination is also important.展开更多
Landslides are recurrent geological phenomena on Earth that cause heavy casualties and property losses annually.In this study,we use the V_(p)-k stacking and nonlinear waveform inversion methods of high-frequency rece...Landslides are recurrent geological phenomena on Earth that cause heavy casualties and property losses annually.In this study,we use the V_(p)-k stacking and nonlinear waveform inversion methods of high-frequency receiver functions extracted from local earthquakes,to sequentially invert Poisson’s ratios and S-wave velocities of the Quaternary Xishancun landslide,which is composed of three segments,i.e.,h1,h2,and h3 from bottom to top.Our results show that Poisson’s ratio values are generally higher than 0.33 and that the S-wave velocities vary from 0.1 to 0.9 km s^(-1).High Poisson’s ratios(>0.44)are mainly distributed in the juncture regions between different segments,as well as the western edge of h2.These zones show significant variation in landslide thickness and are potentially hazardous areas.Low velocities of 0.05–0.2 km s^(-1)with thicknesses of 10–30m are widely observed in the lower layer of the landslide.The high Poisson’s ratios and low-velocity layer may be related to water-rich materials in these areas.Our study suggests that the high-frequency receiver functions from local earthquakes can be used to delineate geotechnical structures,which is valuable for landslide stability analysis and hazard mitigation.展开更多
On 4 April 2013,a 1.5 million cubic meter landslide occurred in Sunjia Town,Wanzhou County,Three Gorges Reservoir,China.After initiation,the Sunjia landslide traveled about 30 m toward the northeast and destroyed most...On 4 April 2013,a 1.5 million cubic meter landslide occurred in Sunjia Town,Wanzhou County,Three Gorges Reservoir,China.After initiation,the Sunjia landslide traveled about 30 m toward the northeast and destroyed most of the infrastructure in its path.The landslide was triggered by heavy rainfall and previous slope excavations,but this slope also displayed a complicated failure process:the overlying earth slope first deformed and then induced sliding along underlying rock surfaces.Surface displacements that resulted from continuous creeping of the post-event slope were observed by an emergency monitoring system that revealed the disequilibrium state of the slope.To discuss the stability and future movements of the remaining unstable debris deposits,we developed a geotechnical model of the post-slide slope,calculated how it can slide again in an extreme rainfall scenario,and estimated the potential runout distance using the Tsunami Squares method.We then estimated the number of people and the value of the infrastructure threatened by this potential landslide.Lastly,we analyzed the vulnerability of elements at risk and quantitatively evaluated the hazard risk associated with the most dangerous scenario.This quantitative risk analysis provides a better understanding of,and technical routes for,hazard mitigation of rainfallinduced complex landslides.展开更多
Spatiotemporal analysis of fire activity is vital for determining why wildfires occur where they do,assessing wildfire risks,and developing locally relevant wildfire risk reduction strategies.Using various spatial sta...Spatiotemporal analysis of fire activity is vital for determining why wildfires occur where they do,assessing wildfire risks,and developing locally relevant wildfire risk reduction strategies.Using various spatial statistical methods,we determined hot spots of large wildfires(>100 acres)in Washington,the United States,and mapped spatiotemporal variations in large wildfire activity from 1970 to 2020.Our results found that all hot spots are located east of the crest of the Cascade Range.Our spatiotemporal analysis found that the geographic area wherein most of the state’s acres burned has shrunk considerably since 1970 and has become concentrated over the north-central portion of the state over time.This concentration of large wildfire activity in north-central Washington was previously unquantified and may provide important information for hazard mitigation efforts in that area.Our results highlight the advantages of using spatial statistical methods that could aid the development of natural hazard mitigation plans and risk reduction strategies by characterizing previous hazard occurrences spatially and spatiotemporally.展开更多
基金supported by the National Science and Technology Support Program(Grant No. 2012BAC06B02)the National Natural Science Foundation (Grant No. 40971014)
文摘Debris flow often causes enormous loss to life and property,especially on alluvial fans.Engineering structures such as retention check dams are essential to reduce the damage.In hazard mitigation evaluation and planning it is of significance to determine the location,size and type of dam and the effects of damage mitigation.We present a numerical simulation method using Kanako simulator for hazard mitigation planning of debris flow disaster in Tanjutani Gully,Kyoto City,Japan.The simulations were carried out for three situations:1) the simulations of erosion,deposition,hydrograph changing and inundation when there were no mitigation measures;2) the simulations of check dams in four locations(470 m,810 m,1,210 m and 1,610 m from the upstream end) to identify the best location;3) the simulations of check dams of three types(closed,slit and grid) to analyze their effects on sediment trapping and discharge reduction.Based on the simulations,it was concluded that two closed check dams(located at 470 m and 1,610 m from the upstream end) in the channel and a drainage channel on the alluvial fan can reduce the risk on the alluvial fan to an acceptable level.
基金supported by the National Natural Science Fund No.51278473the Environmental Protection Research Fund for Public Interest No.201209040the northeast Asia(China-Japan-Korea)cooperative research project of earthquake,tsunami and volcano No.ZRH2014-11.
文摘Since the disastrous aftermath of the 2004 Sumatra Tsunami(Indonesia)and the 2011 Tohoku Tsunami(Japan),China has made much effort to mitigate tsunami hazards.We briefly reviewed the progress of cataloguing,modeling,early warning and hazard analysis for tsunamis in China.Compiling a Chinese tsunami catalogue is a challenge at present due to a large number of inconsistent research results.In China,the numerical models widely used in engineering and related studies are developed by other countries,and the development of a domestic model is being funded by the Chinese government.The tsunami early warning system has been set up and used during the recent tsunami events,such as the Chile earthquake on February 27,2010.
文摘In frame of the asteroid-comet hazard problem study, a qualitative analysis of some methods for the effect on a celestial near-Earth object (NEO)-an asteroid, a comet — is carried out. The goal of the effect is a correction of this object’s orbit, its deflection from the Earth to prevent their collision. There are studied a mechanical impact-kinetic effect of the spacecraft (SC), a thermonuclear effect, an effect on a cometary nucleus for a controlled change of its dusty mantle and, therefore, its sublimation activity. Qualitative models of these effects are developed. Numerical analysis results are given for a group of NEOs such as some asteroids from the Apollo family (Apollo, Castalia, Nereus, Orpheus, Phaethon, Toutatis, etc.) and from the Aten family (Aten, Hathor, Khufu, etc.) as well as some short-periodic comets like the comet P/Biela. There are studied some characteristics of the effects on the NEOs such as the velocity impulse (or acceleration) applied to the celestial body, its deflection from the Earth. The study is supported by the Russian Foundation of Basic Studies (Grant N 01-01-00133).
基金supported by the State Key Laboratory of Hydroscience and Engineering(Grant No.2008-TC-1)China Ministry of Science and Technology through the 973 project(Grant No.2008CB425803).
文摘The massive 8.0-magnitude Wenchuan Earthquake triggered huge landslides,avalanches,and debris flows that blocked rivers and created 34 important quake lakes,including the Tangjiashan Quake Lake on the Tongkou River.More than half of these lakes were identified to be of moderate or high hazard levels,so activities needed to be undertaken for hazard mitigation of potential flooding.This paper presents the mitigation processes of quake lake hazards,which involve various techniques such as rapid hazard analysis,scenario-based mitigation planning,and real-time forecasting of outburst flooding for implementation actions.The shortage of hydrologic and geological data and the nature of emergency situations raise substantial challenges in the hazard mitigation of quake lakes.This paper suggests a potential approach in dealing with quake lake hazards,which integrates the automatic monitoring network,hydrologic models,and hydrodynamic models with a comprehensive indicator for hazard levels.The necessity of improving the integrated methodology is highlighted.
基金Austria International Academic Exchange Service Foundation.
文摘Tremendous losses were caused by ground fissure hazard both in USA and China. Six states of southwestern USA and seven provinces of central China were affected by the destructive ground fissures. The aseismic ground fissure hazards usually take place in land subsidence area. The comparison of the two countries' ground fissures were given including ground fissure formation, evolution, mechanics of destruction and countermeasures against them. The destructive ground fissures occurred about a half century earlier in USA than in China The mechanisms of various ground fissures were analyzed with interdisciplinary studies. It has been found that the preexisted faults are serving as the bases of forming modem ground fissure, and human activities, e.g. over pumping ground water, or oil, can accelerate the creeping of the fissures and make them destructive to many kinds of civil engineering. The countermeasures to mitigate ground fissure hazard were put forward, not only in science and technology but also in social administration. The successful practices in the two countries were introduced as examples.
文摘The problem investigated in this research is about the potential risk of technological hazards, which poses a perilous threat to humankind and the environment. Rapid urbanization has been increasing the population density in an area, elevating the risk of exposure to technological disasters. Therefore, it is necessary to detect the areas with higher chemical risk to spread awareness about the potential risk zones and reduce actual damage and casualties resulting from the hazardous substance events. The basic design of the study utilizes geospatial analysis to map the TRI (Toxics Release Inventory) facilities in the communities of Texas to establish a relationship between potential </span><span style="font-family:Verdana;">hazardous material release zones and the human population at risk. The</span><span style="font-family:Verdana;"> study identified the vulnerable counties as well as investigated how those risk areas are related to race/ethnicity, income and education. The research would contribute to the policymakers acting on the hazard situation and keep them better prepared for</span><span style="color:red;"> </span><span style="font-family:Verdana;">chemical hazards. In addition, it would help the residents and emergency managers to better understand the circumstance to mitigate the consequences as well as increase their awareness to be ready for the uncertainties in the hotspots involved in high risk of the hazards.
基金Financial support for this work was provided by the US Department of Commerce,the National Institute of Standards and Technology(NIST)under the Financial Assistance Award Number#70NANB20H008the US National Science Foundation(NSF)under Award Number 2052930.
文摘There has been a large increase in the number of days per year with numerous EF1-EF5 tornadoes.Given the significant damage incurred by tornadoes upon communities,community resilience analyses for tornado-stricken communities have been gaining momentum.As the community resilience analysis aims to guide how to lay out effective hazard mitigation strategies to decrease damage and improve recovery,a comprehensive and accurate approach is necessary.Agent-based modeling,an analysis approach in which different types of agents are created with their properties and behavior clearly defined to simulate the processes of those agents in an external environ-ment,is the most comprehensive and accurate approach so far to conducting community resilience simulations and investigating the decision-making for mitigation and recovery under natural hazards.In this paper,agent-based models(ABMs)are created to simulate the recovery process of a virtual testbed based on the real-world community in Joplin City,MO.The tornado path associated with the real-world tornado event that occurred in May 2011 is adopted in the tornado hazard modeling for the Joplin testbed.In addition,agent-based models are created for another virtual community in the Midwest United States named Centerville using an assumed tornado scenario of the same EF-scale as that in Joplin.The effects of hazard mitigation strategies on the two communities are also explored.A comparison between the analysis results of these two testbeds can indicate the influence of the characteristics of a tornado-prone community on the resilience of the community as well as on the effects of hazard mitigation strategies.It is observed that a community’s level of development significantly impacts the tornado resilience.In addition,the effects of a specific type of hazard mitigation strategy on the recovery process are contingent upon testbed characteristics.
文摘The regional forecast of landslide is one of the key points of hazard mitigation. It is also a hot and difficult point in research field. To solve this problem has become urgent task along with Chinese economy fast development. This paper analyzes the principle of regional landslide forecast and the factors for forecasting. The method of a combination of Information Value Model and Extension Model has been put forward to be as the forecast model. Using new result of Numerical Weather Foreeast Research and that combination model, we discuss the implementation feasibility of regional landslide forecast. Finally, with the help of Geographic Information System, an operation system for southwest of China landslide forecast has been developed. It can carry out regional landslide forecast daily and has been pilot run in NMC. Since this is the first time linking theoretical research with meteorological service, further works are needed to enhance it.
文摘In recent studies, the effects of complex costal topography on tsunami run-up has sparked heated discussion. This study mainly aims at investigating the effects of complex costal topography on the tsunami inundation distance and the effectiveness of sand dunes in dissipating tsunami wave energy. The experiments were carried out in a wave flume to investigate the potential reduction effects of wave run-up by non erodible sand dune like features. The results show that increasing dunes spacing could not significantly affect inundation distance. However, if the height of sand dunes is of the same order of magnitude as the incoming tsunami wave and the gaps between the dunes are large enough, successful tsunami mitigation could also be possible.
基金Water Resources Science and Technology Innovation Project of Guangdong Province,China(No.2016-15)National Natural Science Foundation of China(No.41372331)Science and Technology Planning Projects of Guangdong Province,China(Nos.2014A020219006,2014A020219006)
文摘Debris flow runoff process is one of key parameters for the design of emergency measures and control engineering. The Shenxi gully in Dujiangyan region,located in the meizoseismal areas of Wenchuan earthquake,was selected as the study area. Based on the research of hazard inducing environment,a soil conservation service( SCS) hydrological model was used to simulate the process of water flow,and then the debris flow runoff process was calculated using the empirical formula combining the results from the SCS hydrological model. Taking the debris flow event occurred on July 9th,2013 as an example,the peak discharges of water flow and debris flow were calculated as 162. 12 and 689. 22 m3/s,with error of 6. 03% compared to the measured values. The debris flow confluence process lasted 1. 8h, which was similar with the actual result. The proposed methodology can be applied to predict the debris flow runoff process in quake-hit areas of the Wenchuan earthquake and is of great importance for debris flow mitigation.
文摘The International Union of Geological Sciences(IUGS)is evaluating whether there are additional geoscientific activities that would be beneficial in helping mitigate the impacts of tsunami.Public concerns about poor decisions and inaction,and advances in computing power and data mining call for new scientific approaches.Three fundamental requirements for mitigating impacts of natural hazards are defined.These are:(1)improvement of process-oriented understanding,(2)adequate monitoring and optimal use of data,and(3)generation of advice based on scientific,technical and socio-economic expertise.International leadership/coordination is also important.
基金supported by the Strategic Priority Research Program(B)of Chinese Academy of Sciences(Grant No.XDB41000000)the National Natural Science Foundation of China(Grant Nos.41604056,41661164035)。
文摘Landslides are recurrent geological phenomena on Earth that cause heavy casualties and property losses annually.In this study,we use the V_(p)-k stacking and nonlinear waveform inversion methods of high-frequency receiver functions extracted from local earthquakes,to sequentially invert Poisson’s ratios and S-wave velocities of the Quaternary Xishancun landslide,which is composed of three segments,i.e.,h1,h2,and h3 from bottom to top.Our results show that Poisson’s ratio values are generally higher than 0.33 and that the S-wave velocities vary from 0.1 to 0.9 km s^(-1).High Poisson’s ratios(>0.44)are mainly distributed in the juncture regions between different segments,as well as the western edge of h2.These zones show significant variation in landslide thickness and are potentially hazardous areas.Low velocities of 0.05–0.2 km s^(-1)with thicknesses of 10–30m are widely observed in the lower layer of the landslide.The high Poisson’s ratios and low-velocity layer may be related to water-rich materials in these areas.Our study suggests that the high-frequency receiver functions from local earthquakes can be used to delineate geotechnical structures,which is valuable for landslide stability analysis and hazard mitigation.
基金supported by the National Natural Science Foundation of China(Grant Numbers 41907234 and 41907237)the Natural Science Foundation of Shaanxi Province(Grant Number 2017JQ4010 and 2018JQ4041)+1 种基金the Postdoctoral Research Foundation of China(Grant Number 2017M613033)the Fundamental Research Funds for the Central Universities,(Grant Numbers 300102210215,300102210210,300102219107 and 300102219104)。
文摘On 4 April 2013,a 1.5 million cubic meter landslide occurred in Sunjia Town,Wanzhou County,Three Gorges Reservoir,China.After initiation,the Sunjia landslide traveled about 30 m toward the northeast and destroyed most of the infrastructure in its path.The landslide was triggered by heavy rainfall and previous slope excavations,but this slope also displayed a complicated failure process:the overlying earth slope first deformed and then induced sliding along underlying rock surfaces.Surface displacements that resulted from continuous creeping of the post-event slope were observed by an emergency monitoring system that revealed the disequilibrium state of the slope.To discuss the stability and future movements of the remaining unstable debris deposits,we developed a geotechnical model of the post-slide slope,calculated how it can slide again in an extreme rainfall scenario,and estimated the potential runout distance using the Tsunami Squares method.We then estimated the number of people and the value of the infrastructure threatened by this potential landslide.Lastly,we analyzed the vulnerability of elements at risk and quantitatively evaluated the hazard risk associated with the most dangerous scenario.This quantitative risk analysis provides a better understanding of,and technical routes for,hazard mitigation of rainfallinduced complex landslides.
文摘Spatiotemporal analysis of fire activity is vital for determining why wildfires occur where they do,assessing wildfire risks,and developing locally relevant wildfire risk reduction strategies.Using various spatial statistical methods,we determined hot spots of large wildfires(>100 acres)in Washington,the United States,and mapped spatiotemporal variations in large wildfire activity from 1970 to 2020.Our results found that all hot spots are located east of the crest of the Cascade Range.Our spatiotemporal analysis found that the geographic area wherein most of the state’s acres burned has shrunk considerably since 1970 and has become concentrated over the north-central portion of the state over time.This concentration of large wildfire activity in north-central Washington was previously unquantified and may provide important information for hazard mitigation efforts in that area.Our results highlight the advantages of using spatial statistical methods that could aid the development of natural hazard mitigation plans and risk reduction strategies by characterizing previous hazard occurrences spatially and spatiotemporally.
