Different slope geohazards have different causal mechanisms.This study aims to propose a method to investigate the decision-making mechanisms for the susceptibility of different slope geohazards.The study includes a g...Different slope geohazards have different causal mechanisms.This study aims to propose a method to investigate the decision-making mechanisms for the susceptibility of different slope geohazards.The study includes a geospatial dataset consisting of 1203 historical slope geohazard units,including slope creeps,shallow slides,rockfalls and debris flows,and 584 non-geohazard units,and 22 initial condition factors.Following a 7:3 ratio,the data were randomly divided into a test set and a training set,and an ensemble SMOTE-RF-SHAP model was constructed.The performance and generalization ability of the model were evaluated by confusion matrix and the receiver operating characteristic(ROC)for the four types of geohazards.The decision-making mechanism of different geohazards was then identified and investigated using the Shapley additive explanations(SHAP)model.The results show that the hybrid optimization improves the overall accuracy of the model from 0.486 to 0.831,with significant improvements in the prediction accuracy for all four types of slope geohazards,as well as reductions in misclassification and omission rates.Furthermore,this study reveals that the main influencing factors and spatiotemporal distribution of different slope geohazards exhibit high similarity,while the impacts of individual factors and different factor values on different slope geohazards demonstrate significant differences.For example,prolonged continuous rainfall can erode rock masses and lead to slope creep,increased rainfall may trigger shallow mountain landslides,and sudden surface runoff can even cause debris flows.These findings have important practical implications for slope geohazards risk management.展开更多
On February 8,2025,a remote area in the Caribbean Sea was rocked by a large M_(W)7.6(USGS,2025) earthquake,centered 209 km SSW of Georgetown,the capital of the Cayman Islands,and the largest city(population~41 000) of...On February 8,2025,a remote area in the Caribbean Sea was rocked by a large M_(W)7.6(USGS,2025) earthquake,centered 209 km SSW of Georgetown,the capital of the Cayman Islands,and the largest city(population~41 000) of the British Overseas Territories(Figure 1).The earthquake was significant due to its large magnitude,potential regional impact,and the possibility of generating a tsunami.展开更多
The lower Yarlung Tsangpo River basin of the Qinghai-Tibet Plateau frequently experiences geo-hazardous occurrences such as landslides,ice/rock avalanches and debris flows,causing loss of human lives and damage to inf...The lower Yarlung Tsangpo River basin of the Qinghai-Tibet Plateau frequently experiences geo-hazardous occurrences such as landslides,ice/rock avalanches and debris flows,causing loss of human lives and damage to infrastructure.However,a comprehensive inventory map of geohazards is lacking for this region,due to the extreme challenges of the geomorphological and environmental conditions(i.e.,steep terrain,dense vegetation cover,and the presence of ice and snow).To this end,we propose a novel approach for mapping active geohazards in complex mountainous regions through InSAR phase gradient measurements based on a deep learning algorithm,which is then applied to the lower Yarlung Tsangpo River basin for the first time,in order to prepare an inventory map of active geohazards using ascending and descending Sentinel-1 SAR images acquired between March 2017 and July 2023.First,the InSAR phase gradient stacking method was introduced to estimate ground deformation,which offers significant advantages in minimizing the influence of InSAR decorrelation and effectively suppressing topographic residuals and atmospheric delays.InSAR phase gradient rates effectively retrieve patterns of localized ground deformation associated with geohazard activity.Then,a DeepLabv3 deep learning model was established and trained with phase gradient rate maps of manually labeled geohazards,in order to achieve the automatic identification of active geohazards.Our results show that there are 277 active geohazards within the lower Yarlung Tsangpo River basin,encompassing an area of~25600 km^(2).The DeepLabv3 model achieved good precision,recall rate and F1 scores at 92,86 and 90%,respectively.The distribution of detected geohazards is closely correlated with the topographic factors,faults and river system.Compared to the results derived from Small Baseline Subset InSAR(SBAS-InSAR)and optical images,the proposed approach can obtain high density pixels of InSAR measurement in low-coherence scenarios,thus enabling high-accuracy mapping of active geohazards in complex mountainous areas.展开更多
With offshore resource exploration moving to the deep water, marine geohazards have been attracting attention from the academic and industry. Research achievements of marine geohazards were reviewed in this paper. We ...With offshore resource exploration moving to the deep water, marine geohazards have been attracting attention from the academic and industry. Research achievements of marine geohazards were reviewed in this paper. We analyzed and discussed typical issues among marine geohazards, including coastal erosion, submarine slope failure, turbidity current and special hazards induced by gas hydrate dissociation, in terms of their definition, distribution, characteristics and case studies. Major international projects on marine geohazards headed by the United States, Europe, Japan and other international organizations are introduced as well. Three marine geohazard survey methods, including geophysical survey, geotechnical exploration and in-situ observation, were summarized with a brief description of each approach, respectively. Especially, the history of marine geohazard researches in China is briefly reviewed, showing the disparity between China and developed countries in the study of marine geohazards narrows gradually. The potential research tendency in future was suggested.展开更多
Various geological processes and features that might inflict hazards identified in the South China Sea by using new technologies and methods.These features include submarine landslides,pockmark fields,shallow free gas...Various geological processes and features that might inflict hazards identified in the South China Sea by using new technologies and methods.These features include submarine landslides,pockmark fields,shallow free gas,gas hydrates,mud diapirs and earthquake tsunami,which are widely distributed in the continental slope and reefal islands of the South China Sea.Although the study and assessment of geohazards in the South China Sea came into operation only recently,advances in various aspects are evolving at full speed to comply with National Marine Strategy and‘the Belt and Road’Policy.The characteristics of geohazards in deep-water seafloor of the South China Sea are summarized based on new scientific advances.This progress is aimed to aid ongoing deep-water drilling activities and decrease geological risks in ocean development.展开更多
The Lushan Earthquake induced a large number of geohazards. They are widely distributed and caused serious damages. The basic characteristics, formation mechanisms and typical cases of geohazards induced by Lushan Ear...The Lushan Earthquake induced a large number of geohazards. They are widely distributed and caused serious damages. The basic characteristics, formation mechanisms and typical cases of geohazards induced by Lushan Earthquake are described, and compares to the relationships of Lushan and Wenchuan earthquakes between geohazards and earthquake magnitude, geomorphology, slope angle, elevation and seismic intensity in the most affected areas in the article.（1） The numbers and volumes of landslides and rockslides differ significantly between the two earthquakes due to their differing magnitudes. The Lushan Earthquake is associated with fewer and smaller-magnitude geohazards, within the immediate area, which mainly consist of small-and medium-sized shallow landslides and rockslides, and occur on steep slopes and mountain valleys. The largest landslide induced by Lushan Earthquake is the Gangoutou Landslide debris flow with a residual volume of about 2.48×106 m3. The most dangerous debris flow is at Lengmugou gulley in Baoxing County, which has similar geomorphological features and disaster modes as a previous disaster in Zhouqu County, Gansu Province.（2） Geohazards induced by the Lushan Earthquake show four mechanisms： cracking-rockslides-collision- scraping and then debris flows, cracking-rockslides, vibration-rainfall-rockslides-landslide and then debris flow, vibration-throwing or scrolling.（3） There are significant similarities and differences between the geohazards induced by these two earthquakes. The types of geohazards are the same but the volume, quantity and other factors differ： geohazards are concentrated on slope angles of 10°-40° in the Lushan Earthquake area, especially within 10°-20°, and at absolute elevation of 500-2000 m above sea level（a.s.l.）. Geohazards within the Wenchuan Earthquake area are concentrated on steeper slope angles of 30°-40° at higher absolute elevations of 1500-2000 m.s.l..展开更多
Many natural landscapes that lie in high mountain regions are highly susceptible to geological hazards, and their values and integrity are strongly threatened by the hazards. A preliminary framework was proposed to un...Many natural landscapes that lie in high mountain regions are highly susceptible to geological hazards, and their values and integrity are strongly threatened by the hazards. A preliminary framework was proposed to undertake a quantitative assessment of the impact of earthquake-induced geological hazards on the natural landscapes. Four factors reflecting the aesthetic value, ecological value, integrity of landscapes were selected to assess their vulnerability. The impact of earthquake-induced geological hazards on the landscapes is quantitatively expressed as the product of their vulnerability and resilience. The assessment framework was applied to Jiuzhaigou Valley which was severely struck by the Ms 7.0 earthquake on August 8, 2017. Field survey, satellite image interpretation, high-resolution DEM and unmanned aerial vehicle(UAV) reconnaissance were used to retrieve the values of the assessment factors. Twenty seven World Heritage Sites in the valley strongly influenced by the earthquakeinduced geohazards were evaluated. The impact values of two sites of them(Sparking Lake and Nuorilang Waterfall) are up to 8.24 and 4.65, respectively, and their natural landscapes were greatly damaged. The assessment results show a good agreement with the actual damages of the heritage sites.展开更多
Determining the main controlling factors of earthquake-triggered geohazards is a prerequisite for studying earthquake geohazards and post-disaster emergency response.By studying these factors,the geomorphic and geolog...Determining the main controlling factors of earthquake-triggered geohazards is a prerequisite for studying earthquake geohazards and post-disaster emergency response.By studying these factors,the geomorphic and geological factors controlling the nature,condition,and distribution of earthquake-induced geohazards can be analyzed.Such insights facilitate earthquake disaster prediction and emergency response planning.The authors combined field investigations and spatial data analysis to examine geohazards induced by seismic events,examining ten earthquakes including the Wenchuan,Yushu,Lushan events,to elucidate the main control factors of seismic geohazard.The authors observed that seismic geohazard occurrence is usually affected by many factors,among which active nature of the seismogenic fault,seismic peak ground acceleration(PGA),topographic slope and geomorphic height differences,and distance from the fault zone and river system are the most important.Compared with strike-slip earthquakes,thrust earthquakes induce more high-altitude and high-speed remote landslides,which can cause great harm.Slopes of 0°–40°are prone to secondary seismic geohazards,which are mainly concentrated 0–6 km from the river system.Secondary geohazards are not only related to seismogenic fault but also influenced by the associated faults in the earthquake area.The maximum seismic PGA and secondary seismic geohazard number are positively correlated,and the horizontal and vertical ground motions play leading and promoting roles in secondary geohazard formation,respectively.Through the research,the spatial distribution of seismic geohazards is predicted,providing a basis for the formulation of emergency response plans following disasters.展开更多
Geohazards along highways are the main natural hazards that could affect the safety and operation of highway systems.Understanding the risks faced by highways in areas affected by geohazards is an urgent problem to be...Geohazards along highways are the main natural hazards that could affect the safety and operation of highway systems.Understanding the risks faced by highways in areas affected by geohazards is an urgent problem to be solved.This study used historical geohazard events from Sichuan Province and highway network data to propose a geohazard risk index that reflects the risk geohazards along highways.Furthermore,this work applied the entropy method and expert scoring to calculate the weight of the index.The spatial distributions of landslides,debris flows,collapses,and unstable slopes along the highways were analysed based on ArcGIS spatial statistics,and the highway geohazard intensity index were obtained.The relationships between slope,rainfall,vegetation coverage,rock type,land use,and incision depth with geohazards were analysed,and the highway geohazard susceptibility index was calculated by the weighted information method.Based on the intensity and susceptibility index,we obtained a geohazard risk index which can better evaluate the risk of highways,and made a highway geohazard risk map to aid the prevention and mitigation of geohazards along highways and assist with highway network planning.展开更多
China has been affected by some of the world’s most serious geological disasters and experiences high economic damage every year.Geohazards occur not only in remote areas but also in highly populated cities.In the fr...China has been affected by some of the world’s most serious geological disasters and experiences high economic damage every year.Geohazards occur not only in remote areas but also in highly populated cities.In the framework of the Dragon-432365 Project,this paper presents the main results and the major conclusions derived from an extensive exploitation of Sentinel-1,ALOS-2(Advanced Land Observing Satellite 2),GF-3(Gao Fen Satellite 3),and latest launched SAR(Synthetic Aperture Radar),together with methods that allow the evaluation of their importance for various geohazards.Therefore,in the scope of this project,the great benefits of recent remote sensing data(wide spatial and temporal coverage)that allow a detailed reconstruction of past displacement events and to monitor currently occurring phenomena are exploited to study different areas and geohazards problems,including:surface deformation of mountain slopes;identification and monitoring of ground movements and subsidence;landslides;ground fissure;and building inclination studies.Suspicious movements detected in the different study areas were cross validated with different SAR sensors and truth data.展开更多
Geohazards,such as earthquakes,landslides, tsunamis,volcanic eruptions,floods,melting permafrost, and metastable soils impact people’s lives worldwide.Population growth is forcing people to live in areas that have cl...Geohazards,such as earthquakes,landslides, tsunamis,volcanic eruptions,floods,melting permafrost, and metastable soils impact people’s lives worldwide.Population growth is forcing people to live in areas that have classically supported low population densities including steep slopes,low-lying coasts,and along floodplains and currently climate change is exacerbating risk in these regions.展开更多
We want to talk about the geohazards in Pamir mountains,in Tajikistan,using different materials and researches about it.Also we are trying to look deeply into this problem,and want to research how about
Across a gradient belt of the Western Sichuan Plateau,geohazards have seriously limited economic and social development.According to incomplete statistics,15,673 geohazards have been recorded in the study area.In orde...Across a gradient belt of the Western Sichuan Plateau,geohazards have seriously limited economic and social development.According to incomplete statistics,15,673 geohazards have been recorded in the study area.In order to mitigate the threat of geohazards to human engineering activities in the region,an overall understanding of the distribution pattern of geohazards and susceptibility assessment are necessary.In this paper,a gradient belt of the Western Sichuan Plateau and its zoning criteria were defined.Subsequently,on the basis of relief amplitude,distance to faults,rainfall,and human activities,three indicators of endogenic process were introduced:Bouguer gravity anomaly gradient,vertical deformation gradient,and horizontal deformation gradient.Thereafter,the distribution patterns of geohazards were investigated through mathematical statistics and ArcGIS software.By randomly selecting 10,449 hazards,a geohazard susceptibility map was generated using the Information Value(IV)model.Finally,the IV model was validated against 5224 hazards using the Area Under Curve(AUC)method.The results show that 47.6%of the geohazards were distributed in the zone of steep slope.Geohazards showed strong responses to distance to faults,human activities,and annual rainfall.The distribution of geohazards in the gradient belt of the Western Sichuan Plateau is more sensitive to vertical internal dynamics factors(such as vertical deformation gradient and Bouguer gravity anomaly gradient)without any apparent sensitivity to horizontal internal dynamics factors.The areas of high and very-high risk account for up to 32.22%,mainly distributed in the Longmenshan and Anning River faults.According to the AUC plot,the success rate of the IV model for generating the susceptibility map is 76%.This susceptibility map and geohazard distribution pattern can provide a reference for geological disaster monitoring,preparation of post-disaster emergency measures,and town planning.展开更多
Geohazards induced by the Lushan Ms 7.0 earthquake on April 20, 2013 mainly have four types： collapse, landslide, slope debris flow, and sand-soil liquefaction. These geohazards mainly occurred near the epicenter, on...Geohazards induced by the Lushan Ms 7.0 earthquake on April 20, 2013 mainly have four types： collapse, landslide, slope debris flow, and sand-soil liquefaction. These geohazards mainly occurred near the epicenter, on steep slopes or below cliffs in high mountain and deep valley areas, and at or near fault ends. They have no obvious relationships to active faults, but their relationships to the weathering degree and structures of rock and rock mass are obvious. Compared with the Wenchuan Ms 8.0 earthquake on May 12, 2008, the Lnshan earthquake is relatively little in the impact force and the throwing amount. All of these should be related to the magnitude of this earthquake, not very large but not very little. This character of the Lushan earthquake would make some processes uncompleted so as to bring about some concealed geohazards. Finally, in order to deal with challenges presented by such conceal geohazards, some brief recommendations are put forward.展开更多
The rapid identification based on InSAR technology was proved to be effective in our emergency investigation of surface ruptures and geohazards induced by the Yushu earthquake.The earthquake-generating fault of the Yu...The rapid identification based on InSAR technology was proved to be effective in our emergency investigation of surface ruptures and geohazards induced by the Yushu earthquake.The earthquake-generating fault of the Yushu earthquake is the Yushu section of the Garze-Yushu faults zone.It strikes NWW-NW,23 km long near the Yushu County seat,dominated by left-lateral strike slip,and appearing as a surface rupture zone.The macroscopic epicenter is positioned at Guo-yang-yan-song-duo of Gyegu Town(33°03'11"N,96°51'26"E),where the co-seismic horizontal offset measured is 1.75 m.Geohazards induced by the Yushu earthquake are mainly rockfalls,landslides,debris flows,and unstable slopes.They are controlled by the earthquake-generating fault and are mostly distributed along it.There are several geohazard chains having been established,such as earthquake,canal damage,soil liquefying,landslide-debris flow,earthquake,soil liquefying,roadbed deformation,etc.In order to prevent seismic hazards,generally,where there is a visible surface rupture induced by the Yushu earthquake,reconstruction should be at least beyond 20 m,on each side,from it.Sufficient attention should also be given to potential geohazards or geohazard chains induced by the earthquake.展开更多
This paper discusses the rational exploitation of main resources and prevention of geohazards in karst regions. There exist relationship chains between natural disasters in the earth, which include the chain between g...This paper discusses the rational exploitation of main resources and prevention of geohazards in karst regions. There exist relationship chains between natural disasters in the earth, which include the chain between geological hazards and climatic hazards, the chain between geological hazards and biogenic hazards as well as the one between geological hazards. Irrational exploitation of all resources will inevitably cause hazards. Therefore it is very important to discuss the problem related to prevention of geohazards by rational exploitation of resources.展开更多
Evacuation strategies play a crucial role in mitigating human casualties from geohazards.While evacuation simulations have been widely used to investigate crowd behavior in response to disasters such as fires and eart...Evacuation strategies play a crucial role in mitigating human casualties from geohazards.While evacuation simulations have been widely used to investigate crowd behavior in response to disasters such as fires and earthquakes,their application to investigating crowd behavior in response to geohazards in mountainous areas has been limited.In this study,a framework was developed for simulating and optimizing evacuation strategies in response to geohazards in mountainous areas that considers the behavioral characteristics of residents.First,a simulation scenario is constructed by analyzing satellite imagery of the region of interest to identify and classify various geographic features.Characteristic parameters are then embedded into a hybrid algorithm that combines the ant colony system algorithm with a social force model to simulate realistic evacuation scenarios that reflect crowd behavior during emergencies.Based on the results of numerical simulations,the existing configuration of shelter locations are optimized to address the chaos and congestion resulting from crowd behavior.As a case study,the proposed framework was applied to constructing geohazard scenarios for a community in the Longmen Mountains area of China and conducting numerical simulations to optimize the evacuation strategy.The results show that the optimized strategies helped facilitate the safe evacuation of residents.The proposed framework represents a multidisciplinary approach to developing evacuation strategies in response to geohazards in mountainous areas while considering crowd behavior.This research has practical implications for guiding public evacuations in mountain communities under the backdrop of geohazards and provides innovative solutions for crowd evacuations in similar scenarios.展开更多
A joint meeting of the 2nd G-EVER(Asia-Pacific Region Global Earthquake and Volcanic Eruption Risk Management)International Symposium and the 1st IUGS(International Union of Geological Sciences)&SCJ(Science Counci...A joint meeting of the 2nd G-EVER(Asia-Pacific Region Global Earthquake and Volcanic Eruption Risk Management)International Symposium and the 1st IUGS(International Union of Geological Sciences)&SCJ(Science Council of Japan)International Workshop on Natural Hazards was held on October 19-20,2013,in Sendai,Japan.The workshop also included a field trip on October 21(please refer to the article by E.Tsukuda in this issue for details).The aim of the joint meeting and workshop was to examine the most recent observations and data from seismically active subduction zone environments and to discuss the most effective methods in order to reduce the risks from natural disasters such as earthquakes,tsunamis,landslides,and volcanic eruptions,particularly in and around active subduction zones.展开更多
As the Wenchuan Earthquake was of high magnitude and shallow seismic focus, it caused great dam- age and serious geohazards. By the field investigation and the interpretation of remote-sensing infor- mation after the ...As the Wenchuan Earthquake was of high magnitude and shallow seismic focus, it caused great dam- age and serious geohazards. By the field investigation and the interpretation of remote-sensing infor- mation after the earthquake and by using means of GIS technology, the distribution of geohazards triggered by the earthquake are analyzed and the conclusions are as follows: (1) The earthquake geo- hazards showed the feature of zonal distribution along the earthquake fault zone and linear distribution along the rivers; (2) the distribution of earthquake geohazards had a marked hanging wall effect, for the development density of geohazards in the hanging wall of earthquake fault zone was obviously higher than that in the foot wall and the width of strong development zone in the hanging wall was about 10 km; (3) the topographical slope was a main factor which controlled the development of earthquake geo- hazards and a vast majority of hazards were distributed on the slopes of 20° to 50°; (4) the earthquake geohazards had a corresponding relationship with the elevation and micro-landform, for most hazards happened in the river valleys and canyon sections below the elevation of 1500 to 2000 m, particularly in the upper segment of canyon sections (namely, the turning point from the dale to the canyon). Thin ridge, isolated or full-face space mountains were most sensitive to the seismic wave, and had a striking amplifying effect. In these areas, collapses and landslides were most likely to develop; (5) the study also showed that different lithologies determined the types of geohazards, and usually, landslides oc- curred in soft rocks, while collapses occurred in hard rocks.展开更多
Ecological security provides the basis of maintaining both a sustainable regional ecosystem and economic development.However,few studies have focused on how the features such as topography and geomorphology,lithologic...Ecological security provides the basis of maintaining both a sustainable regional ecosystem and economic development.However,few studies have focused on how the features such as topography and geomorphology,lithologic stratigraphic assemblages,and geohazard distribution affect the construction of ecological security patterns and the layout of optimization measures.In order to comprehensively reveal the key areas and key objects of ecological restoration in karst basins,this study takes the Beipan River Basin(BRB)as an example,constructs an ecological security pattern(ESP)based on the methods of morphological spatial pattern analysis(MSPA),landscape connectivity analysis and circuit theory,and lays out the optimization measures in combination with the spatial distribution characteristics of topographic and geomorphological differences and lithological stratigraphic combinations.The results show that 151 ecological sources,343 ecological corridors,121 pinch points and 178 barriers constitute the ESP of the BRB.Lithology is closely related to the spatial distribution characteristics of ecological source sites.Level 1 and 2 ecological sources(The ecological sources were categorized into level 1,level 2,and level 3 source from high to low importance.)are concentrated in the Emeishan basalt region of the upstream and the clastic and impure carbonate rock region of the downstream part of the BRB;level 3ecological sources are concentrated in the carbonate rock region of the midstream.Taking into account the outstanding ecological problems in the basin,and based on the characteristics of lithology and geohazard distribution,we propose the optimization scheme of“three axes,three zones and multiple points”for the ESP and the layout of specific measures of the BRB.The results can provide scientific references for maintaining ecological security maintenance in karst ecologically fragile areas.展开更多
基金the National Key Research and Development Program of China(Grant No.2023YFC3007203).
文摘Different slope geohazards have different causal mechanisms.This study aims to propose a method to investigate the decision-making mechanisms for the susceptibility of different slope geohazards.The study includes a geospatial dataset consisting of 1203 historical slope geohazard units,including slope creeps,shallow slides,rockfalls and debris flows,and 584 non-geohazard units,and 22 initial condition factors.Following a 7:3 ratio,the data were randomly divided into a test set and a training set,and an ensemble SMOTE-RF-SHAP model was constructed.The performance and generalization ability of the model were evaluated by confusion matrix and the receiver operating characteristic(ROC)for the four types of geohazards.The decision-making mechanism of different geohazards was then identified and investigated using the Shapley additive explanations(SHAP)model.The results show that the hybrid optimization improves the overall accuracy of the model from 0.486 to 0.831,with significant improvements in the prediction accuracy for all four types of slope geohazards,as well as reductions in misclassification and omission rates.Furthermore,this study reveals that the main influencing factors and spatiotemporal distribution of different slope geohazards exhibit high similarity,while the impacts of individual factors and different factor values on different slope geohazards demonstrate significant differences.For example,prolonged continuous rainfall can erode rock masses and lead to slope creep,increased rainfall may trigger shallow mountain landslides,and sudden surface runoff can even cause debris flows.These findings have important practical implications for slope geohazards risk management.
文摘On February 8,2025,a remote area in the Caribbean Sea was rocked by a large M_(W)7.6(USGS,2025) earthquake,centered 209 km SSW of Georgetown,the capital of the Cayman Islands,and the largest city(population~41 000) of the British Overseas Territories(Figure 1).The earthquake was significant due to its large magnitude,potential regional impact,and the possibility of generating a tsunami.
基金financially supported by the Joint Funds of the National Natural Science Foundation of China(Grant No.U2244226)the National Key R&D Program of China(No.2022YFC3004302)+7 种基金Chinese Geological Survey Project(No.DD20230538)the Science Foundation of Gansu Province(No.23JRRA830)the Science and Technology Major Project of Gansu Province(No.23ZDFA007)the Foundation for Innovation Groups of Basic Research in Gansu Province(24JRRA169)Power China Project(No.CD2C20230228)the Lanzhou Youth Science and Technology Talent Innovation Project(No.2024-QN-170)supported by the ESA-MOST China DRAGON-5(Grant No.59339)DRAGON-6 project(Grant No.95355).
文摘The lower Yarlung Tsangpo River basin of the Qinghai-Tibet Plateau frequently experiences geo-hazardous occurrences such as landslides,ice/rock avalanches and debris flows,causing loss of human lives and damage to infrastructure.However,a comprehensive inventory map of geohazards is lacking for this region,due to the extreme challenges of the geomorphological and environmental conditions(i.e.,steep terrain,dense vegetation cover,and the presence of ice and snow).To this end,we propose a novel approach for mapping active geohazards in complex mountainous regions through InSAR phase gradient measurements based on a deep learning algorithm,which is then applied to the lower Yarlung Tsangpo River basin for the first time,in order to prepare an inventory map of active geohazards using ascending and descending Sentinel-1 SAR images acquired between March 2017 and July 2023.First,the InSAR phase gradient stacking method was introduced to estimate ground deformation,which offers significant advantages in minimizing the influence of InSAR decorrelation and effectively suppressing topographic residuals and atmospheric delays.InSAR phase gradient rates effectively retrieve patterns of localized ground deformation associated with geohazard activity.Then,a DeepLabv3 deep learning model was established and trained with phase gradient rate maps of manually labeled geohazards,in order to achieve the automatic identification of active geohazards.Our results show that there are 277 active geohazards within the lower Yarlung Tsangpo River basin,encompassing an area of~25600 km^(2).The DeepLabv3 model achieved good precision,recall rate and F1 scores at 92,86 and 90%,respectively.The distribution of detected geohazards is closely correlated with the topographic factors,faults and river system.Compared to the results derived from Small Baseline Subset InSAR(SBAS-InSAR)and optical images,the proposed approach can obtain high density pixels of InSAR measurement in low-coherence scenarios,thus enabling high-accuracy mapping of active geohazards in complex mountainous areas.
基金granted by the National Natural Science Foundation of China(Grant No.41427803)
文摘With offshore resource exploration moving to the deep water, marine geohazards have been attracting attention from the academic and industry. Research achievements of marine geohazards were reviewed in this paper. We analyzed and discussed typical issues among marine geohazards, including coastal erosion, submarine slope failure, turbidity current and special hazards induced by gas hydrate dissociation, in terms of their definition, distribution, characteristics and case studies. Major international projects on marine geohazards headed by the United States, Europe, Japan and other international organizations are introduced as well. Three marine geohazard survey methods, including geophysical survey, geotechnical exploration and in-situ observation, were summarized with a brief description of each approach, respectively. Especially, the history of marine geohazard researches in China is briefly reviewed, showing the disparity between China and developed countries in the study of marine geohazards narrows gradually. The potential research tendency in future was suggested.
基金funded by the MOST 973 program (No. 2015CB251201)the Guangzhou Marine Geology Survey project (Nos. GZH201400210 and GZH201601040) the National Natural Science Foundation of China (Nos. 91228208 and 41666012)
文摘Various geological processes and features that might inflict hazards identified in the South China Sea by using new technologies and methods.These features include submarine landslides,pockmark fields,shallow free gas,gas hydrates,mud diapirs and earthquake tsunami,which are widely distributed in the continental slope and reefal islands of the South China Sea.Although the study and assessment of geohazards in the South China Sea came into operation only recently,advances in various aspects are evolving at full speed to comply with National Marine Strategy and‘the Belt and Road’Policy.The characteristics of geohazards in deep-water seafloor of the South China Sea are summarized based on new scientific advances.This progress is aimed to aid ongoing deep-water drilling activities and decrease geological risks in ocean development.
文摘The Lushan Earthquake induced a large number of geohazards. They are widely distributed and caused serious damages. The basic characteristics, formation mechanisms and typical cases of geohazards induced by Lushan Earthquake are described, and compares to the relationships of Lushan and Wenchuan earthquakes between geohazards and earthquake magnitude, geomorphology, slope angle, elevation and seismic intensity in the most affected areas in the article.（1） The numbers and volumes of landslides and rockslides differ significantly between the two earthquakes due to their differing magnitudes. The Lushan Earthquake is associated with fewer and smaller-magnitude geohazards, within the immediate area, which mainly consist of small-and medium-sized shallow landslides and rockslides, and occur on steep slopes and mountain valleys. The largest landslide induced by Lushan Earthquake is the Gangoutou Landslide debris flow with a residual volume of about 2.48×106 m3. The most dangerous debris flow is at Lengmugou gulley in Baoxing County, which has similar geomorphological features and disaster modes as a previous disaster in Zhouqu County, Gansu Province.（2） Geohazards induced by the Lushan Earthquake show four mechanisms： cracking-rockslides-collision- scraping and then debris flows, cracking-rockslides, vibration-rainfall-rockslides-landslide and then debris flow, vibration-throwing or scrolling.（3） There are significant similarities and differences between the geohazards induced by these two earthquakes. The types of geohazards are the same but the volume, quantity and other factors differ： geohazards are concentrated on slope angles of 10°-40° in the Lushan Earthquake area, especially within 10°-20°, and at absolute elevation of 500-2000 m above sea level（a.s.l.）. Geohazards within the Wenchuan Earthquake area are concentrated on steeper slope angles of 30°-40° at higher absolute elevations of 1500-2000 m.s.l..
基金supported by "8.8" Jiuzhaigou earthquake stricken area ecological disaster prevention and control of key scientific and technological support project of Land and Resources Department of Sichuan Province(Research on Prevention and Control Technology of Ecological Debris Flow Disasters)(Grant No.KJ-2018-24)the National Natural Science Foundation of China(Grant No.41790434 and 41601011)
文摘Many natural landscapes that lie in high mountain regions are highly susceptible to geological hazards, and their values and integrity are strongly threatened by the hazards. A preliminary framework was proposed to undertake a quantitative assessment of the impact of earthquake-induced geological hazards on the natural landscapes. Four factors reflecting the aesthetic value, ecological value, integrity of landscapes were selected to assess their vulnerability. The impact of earthquake-induced geological hazards on the landscapes is quantitatively expressed as the product of their vulnerability and resilience. The assessment framework was applied to Jiuzhaigou Valley which was severely struck by the Ms 7.0 earthquake on August 8, 2017. Field survey, satellite image interpretation, high-resolution DEM and unmanned aerial vehicle(UAV) reconnaissance were used to retrieve the values of the assessment factors. Twenty seven World Heritage Sites in the valley strongly influenced by the earthquakeinduced geohazards were evaluated. The impact values of two sites of them(Sparking Lake and Nuorilang Waterfall) are up to 8.24 and 4.65, respectively, and their natural landscapes were greatly damaged. The assessment results show a good agreement with the actual damages of the heritage sites.
基金supported by the National Natural Science Foundation of China(41977258)the National Key Research and Development Program of China(2017YFC1501005 and 2018YFC1504704)。
文摘Determining the main controlling factors of earthquake-triggered geohazards is a prerequisite for studying earthquake geohazards and post-disaster emergency response.By studying these factors,the geomorphic and geological factors controlling the nature,condition,and distribution of earthquake-induced geohazards can be analyzed.Such insights facilitate earthquake disaster prediction and emergency response planning.The authors combined field investigations and spatial data analysis to examine geohazards induced by seismic events,examining ten earthquakes including the Wenchuan,Yushu,Lushan events,to elucidate the main control factors of seismic geohazard.The authors observed that seismic geohazard occurrence is usually affected by many factors,among which active nature of the seismogenic fault,seismic peak ground acceleration(PGA),topographic slope and geomorphic height differences,and distance from the fault zone and river system are the most important.Compared with strike-slip earthquakes,thrust earthquakes induce more high-altitude and high-speed remote landslides,which can cause great harm.Slopes of 0°–40°are prone to secondary seismic geohazards,which are mainly concentrated 0–6 km from the river system.Secondary geohazards are not only related to seismogenic fault but also influenced by the associated faults in the earthquake area.The maximum seismic PGA and secondary seismic geohazard number are positively correlated,and the horizontal and vertical ground motions play leading and promoting roles in secondary geohazard formation,respectively.Through the research,the spatial distribution of seismic geohazards is predicted,providing a basis for the formulation of emergency response plans following disasters.
基金funded by Chang’an University(Xi’an,China)through the National Key Research&Development Program of China(2020YFC1512003)。
文摘Geohazards along highways are the main natural hazards that could affect the safety and operation of highway systems.Understanding the risks faced by highways in areas affected by geohazards is an urgent problem to be solved.This study used historical geohazard events from Sichuan Province and highway network data to propose a geohazard risk index that reflects the risk geohazards along highways.Furthermore,this work applied the entropy method and expert scoring to calculate the weight of the index.The spatial distributions of landslides,debris flows,collapses,and unstable slopes along the highways were analysed based on ArcGIS spatial statistics,and the highway geohazard intensity index were obtained.The relationships between slope,rainfall,vegetation coverage,rock type,land use,and incision depth with geohazards were analysed,and the highway geohazard susceptibility index was calculated by the weighted information method.Based on the intensity and susceptibility index,we obtained a geohazard risk index which can better evaluate the risk of highways,and made a highway geohazard risk map to aid the prevention and mitigation of geohazards along highways and assist with highway network planning.
基金National Natural Science Foundation of China(Nos.41590852,42071453)。
文摘China has been affected by some of the world’s most serious geological disasters and experiences high economic damage every year.Geohazards occur not only in remote areas but also in highly populated cities.In the framework of the Dragon-432365 Project,this paper presents the main results and the major conclusions derived from an extensive exploitation of Sentinel-1,ALOS-2(Advanced Land Observing Satellite 2),GF-3(Gao Fen Satellite 3),and latest launched SAR(Synthetic Aperture Radar),together with methods that allow the evaluation of their importance for various geohazards.Therefore,in the scope of this project,the great benefits of recent remote sensing data(wide spatial and temporal coverage)that allow a detailed reconstruction of past displacement events and to monitor currently occurring phenomena are exploited to study different areas and geohazards problems,including:surface deformation of mountain slopes;identification and monitoring of ground movements and subsidence;landslides;ground fissure;and building inclination studies.Suspicious movements detected in the different study areas were cross validated with different SAR sensors and truth data.
文摘Geohazards,such as earthquakes,landslides, tsunamis,volcanic eruptions,floods,melting permafrost, and metastable soils impact people’s lives worldwide.Population growth is forcing people to live in areas that have classically supported low population densities including steep slopes,low-lying coasts,and along floodplains and currently climate change is exacerbating risk in these regions.
文摘We want to talk about the geohazards in Pamir mountains,in Tajikistan,using different materials and researches about it.Also we are trying to look deeply into this problem,and want to research how about
文摘Across a gradient belt of the Western Sichuan Plateau,geohazards have seriously limited economic and social development.According to incomplete statistics,15,673 geohazards have been recorded in the study area.In order to mitigate the threat of geohazards to human engineering activities in the region,an overall understanding of the distribution pattern of geohazards and susceptibility assessment are necessary.In this paper,a gradient belt of the Western Sichuan Plateau and its zoning criteria were defined.Subsequently,on the basis of relief amplitude,distance to faults,rainfall,and human activities,three indicators of endogenic process were introduced:Bouguer gravity anomaly gradient,vertical deformation gradient,and horizontal deformation gradient.Thereafter,the distribution patterns of geohazards were investigated through mathematical statistics and ArcGIS software.By randomly selecting 10,449 hazards,a geohazard susceptibility map was generated using the Information Value(IV)model.Finally,the IV model was validated against 5224 hazards using the Area Under Curve(AUC)method.The results show that 47.6%of the geohazards were distributed in the zone of steep slope.Geohazards showed strong responses to distance to faults,human activities,and annual rainfall.The distribution of geohazards in the gradient belt of the Western Sichuan Plateau is more sensitive to vertical internal dynamics factors(such as vertical deformation gradient and Bouguer gravity anomaly gradient)without any apparent sensitivity to horizontal internal dynamics factors.The areas of high and very-high risk account for up to 32.22%,mainly distributed in the Longmenshan and Anning River faults.According to the AUC plot,the success rate of the IV model for generating the susceptibility map is 76%.This susceptibility map and geohazard distribution pattern can provide a reference for geological disaster monitoring,preparation of post-disaster emergency measures,and town planning.
基金financially supported by the Project of China Special Project of Basic Work of Science and Technology (2011FY110100-2)Project of the 12th Five-year National Sci-Tech Support Plan of China (grant No. 2011BAK12B09)+1 种基金the National Science Foundation of China (grant No. 41072269)China Geological Survey (grant No. 1212010914025)
文摘Geohazards induced by the Lushan Ms 7.0 earthquake on April 20, 2013 mainly have four types： collapse, landslide, slope debris flow, and sand-soil liquefaction. These geohazards mainly occurred near the epicenter, on steep slopes or below cliffs in high mountain and deep valley areas, and at or near fault ends. They have no obvious relationships to active faults, but their relationships to the weathering degree and structures of rock and rock mass are obvious. Compared with the Wenchuan Ms 8.0 earthquake on May 12, 2008, the Lnshan earthquake is relatively little in the impact force and the throwing amount. All of these should be related to the magnitude of this earthquake, not very large but not very little. This character of the Lushan earthquake would make some processes uncompleted so as to bring about some concealed geohazards. Finally, in order to deal with challenges presented by such conceal geohazards, some brief recommendations are put forward.
基金supported by the National Natural Science Foundation of China(grant No.40902059)the Land Resource Survey Project of China Geological Survey (grant No.1212010914025,No.1212011014035)the Fundamental Research Fund of Institute of Geomechanics, CAGS(grant No.DZLXJK200906)
文摘The rapid identification based on InSAR technology was proved to be effective in our emergency investigation of surface ruptures and geohazards induced by the Yushu earthquake.The earthquake-generating fault of the Yushu earthquake is the Yushu section of the Garze-Yushu faults zone.It strikes NWW-NW,23 km long near the Yushu County seat,dominated by left-lateral strike slip,and appearing as a surface rupture zone.The macroscopic epicenter is positioned at Guo-yang-yan-song-duo of Gyegu Town(33°03'11"N,96°51'26"E),where the co-seismic horizontal offset measured is 1.75 m.Geohazards induced by the Yushu earthquake are mainly rockfalls,landslides,debris flows,and unstable slopes.They are controlled by the earthquake-generating fault and are mostly distributed along it.There are several geohazard chains having been established,such as earthquake,canal damage,soil liquefying,landslide-debris flow,earthquake,soil liquefying,roadbed deformation,etc.In order to prevent seismic hazards,generally,where there is a visible surface rupture induced by the Yushu earthquake,reconstruction should be at least beyond 20 m,on each side,from it.Sufficient attention should also be given to potential geohazards or geohazard chains induced by the earthquake.
文摘This paper discusses the rational exploitation of main resources and prevention of geohazards in karst regions. There exist relationship chains between natural disasters in the earth, which include the chain between geological hazards and climatic hazards, the chain between geological hazards and biogenic hazards as well as the one between geological hazards. Irrational exploitation of all resources will inevitably cause hazards. Therefore it is very important to discuss the problem related to prevention of geohazards by rational exploitation of resources.
基金supported by the National Natural Science Foundation of China(Grant No.42471225)the Sichuan Science and Technology Program(Grant No.2022JDJQ0015)。
文摘Evacuation strategies play a crucial role in mitigating human casualties from geohazards.While evacuation simulations have been widely used to investigate crowd behavior in response to disasters such as fires and earthquakes,their application to investigating crowd behavior in response to geohazards in mountainous areas has been limited.In this study,a framework was developed for simulating and optimizing evacuation strategies in response to geohazards in mountainous areas that considers the behavioral characteristics of residents.First,a simulation scenario is constructed by analyzing satellite imagery of the region of interest to identify and classify various geographic features.Characteristic parameters are then embedded into a hybrid algorithm that combines the ant colony system algorithm with a social force model to simulate realistic evacuation scenarios that reflect crowd behavior during emergencies.Based on the results of numerical simulations,the existing configuration of shelter locations are optimized to address the chaos and congestion resulting from crowd behavior.As a case study,the proposed framework was applied to constructing geohazard scenarios for a community in the Longmen Mountains area of China and conducting numerical simulations to optimize the evacuation strategy.The results show that the optimized strategies helped facilitate the safe evacuation of residents.The proposed framework represents a multidisciplinary approach to developing evacuation strategies in response to geohazards in mountainous areas while considering crowd behavior.This research has practical implications for guiding public evacuations in mountain communities under the backdrop of geohazards and provides innovative solutions for crowd evacuations in similar scenarios.
文摘A joint meeting of the 2nd G-EVER(Asia-Pacific Region Global Earthquake and Volcanic Eruption Risk Management)International Symposium and the 1st IUGS(International Union of Geological Sciences)&SCJ(Science Council of Japan)International Workshop on Natural Hazards was held on October 19-20,2013,in Sendai,Japan.The workshop also included a field trip on October 21(please refer to the article by E.Tsukuda in this issue for details).The aim of the joint meeting and workshop was to examine the most recent observations and data from seismically active subduction zone environments and to discuss the most effective methods in order to reduce the risks from natural disasters such as earthquakes,tsunamis,landslides,and volcanic eruptions,particularly in and around active subduction zones.
基金Supported by the Key Basic Research Program of the Ministry of Science and Tech-nology of China (Grant No. 2008CB425800)
文摘As the Wenchuan Earthquake was of high magnitude and shallow seismic focus, it caused great dam- age and serious geohazards. By the field investigation and the interpretation of remote-sensing infor- mation after the earthquake and by using means of GIS technology, the distribution of geohazards triggered by the earthquake are analyzed and the conclusions are as follows: (1) The earthquake geo- hazards showed the feature of zonal distribution along the earthquake fault zone and linear distribution along the rivers; (2) the distribution of earthquake geohazards had a marked hanging wall effect, for the development density of geohazards in the hanging wall of earthquake fault zone was obviously higher than that in the foot wall and the width of strong development zone in the hanging wall was about 10 km; (3) the topographical slope was a main factor which controlled the development of earthquake geo- hazards and a vast majority of hazards were distributed on the slopes of 20° to 50°; (4) the earthquake geohazards had a corresponding relationship with the elevation and micro-landform, for most hazards happened in the river valleys and canyon sections below the elevation of 1500 to 2000 m, particularly in the upper segment of canyon sections (namely, the turning point from the dale to the canyon). Thin ridge, isolated or full-face space mountains were most sensitive to the seismic wave, and had a striking amplifying effect. In these areas, collapses and landslides were most likely to develop; (5) the study also showed that different lithologies determined the types of geohazards, and usually, landslides oc- curred in soft rocks, while collapses occurred in hard rocks.
基金jointly supported by the Key Project of the Natural Science Foundation of Guizhou Province(No.Qiankehe Jichu-ZK[2023]Zhongdian027)the Project of the Science and Technology Innovation Base Construction of Guizhou Province(No.Qiankehe Zhongyindi[2023]005)Philosophy and Social Science Planning Subjects in Guizhou Province in 2022(No.22GZYB53)。
文摘Ecological security provides the basis of maintaining both a sustainable regional ecosystem and economic development.However,few studies have focused on how the features such as topography and geomorphology,lithologic stratigraphic assemblages,and geohazard distribution affect the construction of ecological security patterns and the layout of optimization measures.In order to comprehensively reveal the key areas and key objects of ecological restoration in karst basins,this study takes the Beipan River Basin(BRB)as an example,constructs an ecological security pattern(ESP)based on the methods of morphological spatial pattern analysis(MSPA),landscape connectivity analysis and circuit theory,and lays out the optimization measures in combination with the spatial distribution characteristics of topographic and geomorphological differences and lithological stratigraphic combinations.The results show that 151 ecological sources,343 ecological corridors,121 pinch points and 178 barriers constitute the ESP of the BRB.Lithology is closely related to the spatial distribution characteristics of ecological source sites.Level 1 and 2 ecological sources(The ecological sources were categorized into level 1,level 2,and level 3 source from high to low importance.)are concentrated in the Emeishan basalt region of the upstream and the clastic and impure carbonate rock region of the downstream part of the BRB;level 3ecological sources are concentrated in the carbonate rock region of the midstream.Taking into account the outstanding ecological problems in the basin,and based on the characteristics of lithology and geohazard distribution,we propose the optimization scheme of“three axes,three zones and multiple points”for the ESP and the layout of specific measures of the BRB.The results can provide scientific references for maintaining ecological security maintenance in karst ecologically fragile areas.
