Digital elevation models(DEMs)are essential tools in environmental science,particularly for hazard assessments and landscape analyses.However,their application acrossmultiple environmental hazards simultaneously remai...Digital elevation models(DEMs)are essential tools in environmental science,particularly for hazard assessments and landscape analyses.However,their application acrossmultiple environmental hazards simultaneously remains in need for a multi-aspect critical assessment to promote their effectiveness in comprehensive risk management.This paper aims to review and critically assess the application of DEMs in mapping and managing specific environmental hazards,namely floods,landslides,and coastal erosion.In this regard,it seeks to promote their utility of hazard maps as key tools in disaster risk reduction and environmental planning by employing high-resolution DEMs integrated with advanced geographic information systems.The findings offer valuable insights into optimizing DEM technology for environmental management,contributing to safer and more resilient communities.The paper addresses an important gap in the geospatial analysis of natural hazards and serves as a foundational reference for future advancements in the field,emphasizing its importance to academic researchers and practical stakeholders in environmental and disaster management.展开更多
Tens of thousands of landslides were triggered by May 12, 2008 earthquake over a broad area. The main purpose of this article is to apply and verify earthquake-triggered landslide hazard analysis techniques by using w...Tens of thousands of landslides were triggered by May 12, 2008 earthquake over a broad area. The main purpose of this article is to apply and verify earthquake-triggered landslide hazard analysis techniques by using weight of evidence modeling in Qingshui （清水） River watershed, Deyang （德阳） City, Sichuan （四川） Province, China. Two thousand three hundred and twenty-one landslides were interpreted in the study area from aerial photographs and multi-source remote sensing imageries post-earthquake, verified by field surveys. The landslide inventory in the study area was established. A spatial database, including landslides and associated controlling parameters that may have influence on the occurrence of landslides, was constructed from topographic maps, geological maps, and enhanced thematic mapper （ETM＋） remote sensing imageries. The factors that influence landslide occurrence,such as slope angle, aspect, curvature, elevation, flow accumulation, distance from drainages, and distance from roads were calculated from the topographic maps. Lithology, distance from seismogenic fault, distance from all faults, and distance from stratigraphic boundaries were derived from the geological maps. Normalized difference vegetation index （NDV1） was extracted from ETM＋ images. Seismic intensity zoning was collected from Wenchuan （汶川） Ms8.0 Earthquake Intensity Distribution Map published by the China Earthquake Administration.Landslide hazard indices were calculated using the weight of evidence model, and landslide hazard maps were calculated from using different controlling parameters cases. The hazard map was compared with known landslide locations and verified. The success accuracy percentage of using all 13 controlling parameters was 71.82%. The resulting landslide hazard map showed five classes of landslide hazard, i.e., very high, high, moderate, low, and very low. The validation results showed satisfactory agreement between the hazard map and the existing landslides distribution data. The landslide hazard map can be used to identify and delineate unstable hazard-prone areas. It can also help planners to choose favorable locations for development schemes, such as infrastructural, buildings, road constructions, and environmental protection.展开更多
Flash flood hazard mapping is a supporting component of non-structural measures for flash flood prevention. Pilot case studies are necessary to develop more practicable methods for the technical support systems of fla...Flash flood hazard mapping is a supporting component of non-structural measures for flash flood prevention. Pilot case studies are necessary to develop more practicable methods for the technical support systems of flash flood hazard mapping. In this study, the headwater catchment of the Xiapu River Basin in central China was selected as a pilot study area for flash flood hazard mapping. A conceptual distributed hydrological model was developed for flood calculation based on the framework of the Xinanjiang model, which is widely used in humid and semi-humid regions in China. The developed model employs the geomorphological unit hydrograph method, which is extremely valuable when simulating the overland flow process in ungauged catchments, as compared with the original Xinanjiang model. The model was tested in the pilot study area, and the results agree with the measured data on the whole. After calibration and validation, the model is shown to be a useful tool for flash flood calculation. A practicable method for flash flood hazard mapping using the calculated peak discharge and digital elevation model data was presented, and three levels of flood hazards were classified. The resulting flash flood hazard maps indicate that the method successfully predicts the spatial distribution of flash flood hazards, and it can meet the current requirements in China.展开更多
It is well known that seismic hazard assessment should be implemented to design infrastructures in an earthquake-prone area such as Bengkulu.This paper presents local seismic hazard maps based on the response spectra ...It is well known that seismic hazard assessment should be implemented to design infrastructures in an earthquake-prone area such as Bengkulu.This paper presents local seismic hazard maps based on the response spectra of stiff and very dense soils in Bengkulu city,Indonesia.We collect the soil data and conduct the seismic wave propagation.The input motion for wave propagation analysis is generated from the spectral acceleration curves of stiff and dense soils.Various ground motion parameters such as peak ground acceleration,short-period and long-period spectral accelerations,and amplification factors are presented in microzonation maps.The results show that the peak ground acceleration in the study area ranges from 0.2 to 0.8 g,while the spectral acceleration varies between 0.5-1.5 g and 0.4-0.8 g for periods of 0.2 and 1 s,respectively.The amplification factor of the site is observed to vary from 0.5 to 1.6.Considering other spectral accelerations in Bengkulu,the spectral acceleration design shows a good performance.The results indicate the site characteristics of Bengkulu city,which can provide engineers with site class for structural building design.展开更多
This paper reports a method to make hazard maps of sediment disasters resulting from an earthquake and following heavy rainfall for the entire region of Gunma prefecture, Japan. Firstly, we identified the slopes in th...This paper reports a method to make hazard maps of sediment disasters resulting from an earthquake and following heavy rainfall for the entire region of Gunma prefecture, Japan. Firstly, we identified the slopes in the study area, which are susceptible to large-scale landslides and land failures during an earthquake with a magnitude of seven on the Richter scale. To analyze the sheer volume of the data, we employed a statistical method to evaluate the susceptibility, mainly considering geomorphologic conditions. Secondly, we extracted mudflow and slope failure susceptible areas and potential flooding zones resulting from a damming at a river triggered by the earthquake and heavy rainfall, and we identified the settlements which would be isolated by the road disruption caused by the sediment disasters. As the result, 359 settlements were classified as potential isolation areas. Combining the above-mentioned susceptibility maps, we obtained two types of sediment disaster hazard maps of the study area, depicting the potential hazards which would occur during the earthquake and the disasters which would be caused by heavy rainfall following the quake, respectively. These hazard maps and the disaster information would be useful for the regional disaster prevention planning and countermeasures in the future.展开更多
Flooding has been one of the recurring occurred natural disasters that induce detrimental impacts on humans, property and environment. Frequent floods is a severe issue and a complex natural phenomenon in Pakistan wit...Flooding has been one of the recurring occurred natural disasters that induce detrimental impacts on humans, property and environment. Frequent floods is a severe issue and a complex natural phenomenon in Pakistan with respect to population affected, environmental degradations, and socio-economic and property damages. The Super Flood, which hit Sindh in 2010, has turned out to be a wakeup call and has underlined the overwhelming challenge of natural calamities, as 2010 flood and the preceding flood in 2011 caused a huge loss to life, property and land use. These floods resulted in disruption of power, telecommunication, and water utilities in many districts of Pakistan, including 22 districts of Sindh. These floods call for risk assessment and hazard mapping of Lower Indus Basin flowing in the Sindh Province as such areas were also inundated in 2010 flood, which were not flooded in the past in this manner. This primary focus of this paper is the use of Multi-criteria Evaluation (MCE) methods in integration with the Geographical Information System (GIS) for the analysis of areas prone to flood. This research demonstrated how GIS tools can be used to produce map of flood vulnerable areas using MCE techniques. Slope, Aspect, Curvature, Soil, and Distance from Drainage, Land use, Precipitation, Flow Direction, and Flow Accumulation are taken as the causative factors for flooding in Lower Indus Basin. Analytical Hierarchy Process-AHP was used for the calculation of weights of all these factors. Finally, a flood hazard Map of Lower Indus Basin was generated which delineates the flood prone areas in the Sindh province along Indus River Basin that could be inundated by potential flooding in future. It is aimed that flood hazard mapping and risk assessment using open source geographic information system can serve as a handy tool for the development of land-use strategies so as to decrease the impact from flooding.展开更多
In recent years, global warming has gradually become obvious, thus created the climate change. Typhoon Morakot attacked Taiwan and brought heavy rainfall in August, 2009. In mountainous areas including Central and Sou...In recent years, global warming has gradually become obvious, thus created the climate change. Typhoon Morakot attacked Taiwan and brought heavy rainfall in August, 2009. In mountainous areas including Central and South Taiwan, the flood and debris flow disasters were induced by the typhoon. In this study, Changhua City is selected as the research region and the Delphi method is employed to interview experts and establish comprehensive evaluation criteria for assessing the evacuation plan on disaster areas. The concept is to combine the landslide potential analysis by geographic information systems with the flood or debris flow maps into the potential hazard map. Meanwhile, analytic hierarchy method (AHP) is comprehensively carried on the expert questionnaire survey for the potential hazard map of the compound disaster states. It should be useful for the local government and native people in the future.展开更多
The aim of this project was to prepare and study a hazard map of Nagadhunga-Naubise section of the Tribhuvan highway. This section lies in the Middle Mountain region of Nepal. For the preparation of the hazard map of ...The aim of this project was to prepare and study a hazard map of Nagadhunga-Naubise section of the Tribhuvan highway. This section lies in the Middle Mountain region of Nepal. For the preparation of the hazard map of the corridor three steps, initial study, field investigation, and data analysis and presentation were carried out. In the initial study, the collection of available data and review of the literature were done. The base map was then prepared from the topographical map. In the field investigation step, all information and maps prepared earlier in the initial study were verified by field check. In the final step, prepared and verified data were then analyzed for the hazard mapping. Topography (gradient, slope shape and slope aspect), geology, drainage and land-use were considered to be the major influencing factors in the slope stability. Pre-assigned hazard rating method was used for hazard mapping of the study area. The area was divided into equal facets. Then ratings of responsible factors to the hazard were assigned to each facet and overlaid based upon a predetermined rating scheme. Total estimated hazard was the sum of these ratings for each overlay. Hazard map was prepared by using three categories as low hazard, medium hazard and high hazard. The Geographic Information System (GIS) was the main tool for the data input, analysis, and preparing of the final hazard map. The hazard map showed the areas of different hazard potential classes of;“low” with 32% portion, “Medium” with 51%, and “high” with 17% portion.展开更多
The Kinta Valley is an area of karst in the north-western part of Peninsular Malaysia. Over 30 years of uncontrolled land use and development has led to significant changes in topography and geomorphology, such as the...The Kinta Valley is an area of karst in the north-western part of Peninsular Malaysia. Over 30 years of uncontrolled land use and development has led to significant changes in topography and geomorphology, such as the appearance of sinkholes. In this paper, geospatial techniques were utilized to the task of evaluating sinkholes susceptibility map using a spatial multi criteria evaluation approach (SMCE). Sinkhole location and a spatial database were applied to calculate eight inherent causative factors for limestone instability namely: lithology, structure (lineament), soil cover, slope, land use mining, urban area features, ponds and rivers. The preparation of the sinkhole geohazard map involved summing the weighted values for each hazard element, which permits the construction of geohazard model;the results of the analysis were validated using the previous actual sinkholes locations in the study area. The spatial distribution of sinkholes occurrence, urban development, faults distribution and ex-mining ponds are factors that are directly responsible for all sinkholes subsidence hazards. Further, the resulting geo-hazard map shows that 93% of recent sinkholes occur in areas where the model flags as “high” and “very high” potential hazard, located in the urbanized part of the valley, while less-developed areas to the west and southwest suffered less sinkhole development. The results can be used for hazard prevention and land-use planning.展开更多
This study addresses gaps in aftershock prediction research by proposing an interpretable hybrid machine learning model that leverages multi-source data.The model overcomes challenges related to the selection of influ...This study addresses gaps in aftershock prediction research by proposing an interpretable hybrid machine learning model that leverages multi-source data.The model overcomes challenges related to the selection of influencing factors,model types,prediction result visualization,and decision mechanism interpretability.It integrates mainshock factors,geological features,site characteristics,and terrain conditions using geospatial information system(GIS)technology.By employing the stacking algorithm to optimize and combine XGBoost and LightGBM models,the proposed model significantly improves the prediction performance.Visualization through aftershock hazard mapping offers a robust tool for aftershock warning.The Shapley additive explanations(SHAP)model is used to explain the decision-making process from both global and local perspectives.Results show that,compared to the optimized XGBoost-CMA_ES and LightGBM-CMA_ES hybrid models,the stacking model achieves area under the curve(AUC)increases of 7.71%and 5.72% on the test set,respectively,with a maximum prediction accuracy of 0.9344.The hazard zoning map identifies high-risk areas mainly around fault lines and near the epicenter.As hazard levels rise,the proportion and density of aftershocks in these areas increase.The SHAP model results highlight the distance to fault as the most critical factor.The study integrates local explanations with on-site investigations,effectively visualizing the contributions of different factors to aftershocks.This research provides new tools and methods for enhancing aftershock warning and response.展开更多
The rapid growth of impervious areas in urban basins worldwide has increased the number of impermeable surfaces in cities,leading to severe flooding and significant economic losses for civilians.This trend highlights ...The rapid growth of impervious areas in urban basins worldwide has increased the number of impermeable surfaces in cities,leading to severe flooding and significant economic losses for civilians.This trend highlights the urgent need for methodologies that assess flood hazards and specifically address the direct impact on pedestrians,which is often overlooked in traditional flood hazard analyses.This study aims to evaluate a methodology for assessing the risk to pedestrians from hydrodynamic forces during urban floods,with a specific focus on Cúcuta,Colombia.The methodology couples research outcomes from other studies on the impact of floodwaters on individuals of different ages and sizes with 1D/2D hydrological modeling.Advanced computational algorithms for image recognition were used to measure water levels at 5-s intervals on November 6,2020,using drones for digital elevation model data collection.In Cúcuta,where flood risk is high and drainage infrastructure is limited,the PCSWMM(Computer-based Urban Stormwater Management Model)was calibrated and validated to simulate extreme flood events.The model incorporated urban infrastructure details and geomorphological parameters of Cúcuta's urban basin.Four return periods(5,10,50,100),with extreme rainfall of 3 h,were used to estimate the variability of the risk map.The output of the model was analyzed,and an integrated and time-varying comparison of the results was done.Results show that the regions of high-water depth and high velocity could vary significantly along the duration of the different extreme events.Also,from 5 to 100 years return period,the percentage of area at risk increased from 9.6%to 16.6%.The pedestrian sensitivity appears much higher than the increase in velocities or water depth individually.This study identified medium to high-risk locations,which are dynamic in time.We can conclude dynamics are spatiotemporal,and the added information layer of pedestrians brings vulnerability information that is also dynamic.Areas of immediate concern in Cúcuta can enhance pedestrian safety during flash flood events.The spatiotemporal variation of patterns requires further studies to map trajectories and sequences that machine learning models could capture.展开更多
Through the field survey, previous researches and interpretation of aerial photos, a landslide information database of Xiaojiang Valley, Yunnan Province was set up based on the remote sensing (RS) and geographic infor...Through the field survey, previous researches and interpretation of aerial photos, a landslide information database of Xiaojiang Valley, Yunnan Province was set up based on the remote sensing (RS) and geographic information system (GIS) technologies. In the paper, a quantitative model for the landslide hazard assessment and zoning was presented, in which the potential energy could be obtained on basis of thorough analysis of the potential sliding volume, distance and direction of the landslide body. Taking landslide potential energy as the index of the hazard severity zonation, the study area was divided into severe, heavy, medium and light hazard zones.展开更多
Hazard maps are essential tools to aid decision makers in land-use planning,sustainable infrastructure development,and emergency preparedness.Despite the availability of historical data,there has been no attempt to pr...Hazard maps are essential tools to aid decision makers in land-use planning,sustainable infrastructure development,and emergency preparedness.Despite the availability of historical data,there has been no attempt to produce hazard maps for Kuwait.In cooperation with the World Bank,this study investigated the natural and anthropogenic hazards that affect Kuwait.The objective was to assess the hazards that face Kuwait and map the hazards of most concern.Hazard maps depicting the spatial distribution of hazard-prone areas are discussed in this article.Hazard assessment maps were generated using multiple datasets and techniques,including meteorological data,satellite imagery,and GIS.Hazard profiling identified a total of 25 hazards,of which five“priority”hazards were explored in detail:(1)surface water flooding;(2)dust storms and sand encroachment;(3)drought;(4)air pollution;and(5)oil spills.The results of this study can aid decision makers in targeting the hazards of most concern.The developed maps are valuable tools for emergency response and hazard mitigation.展开更多
This paper assesses the hazardousness, vulnerability and risk of debris flow and landslide in China and compiles maps with a scale of 1：6000000, based on Geographical Information System （GIS） technology, hazard reg...This paper assesses the hazardousness, vulnerability and risk of debris flow and landslide in China and compiles maps with a scale of 1：6000000, based on Geographical Information System （GIS） technology, hazard regionalization map, socioeconomic data from 2000. Integrated hazardousness of debris flow and landslide is equivalent to the sum of debris flow hazardousness and landslide hazardousness. Vulnerability is assessed by employing a simplified assessment model. Risk is calculated by the following formula： Risk = Hazardousness × Vulnerability. The analysis results of assessment of hazardousness, vulnerability and risk show that there are extremely high risk regions of 104 km2, high risk regions of 283008 km2, moderate risk regions of 3161815 km2, low risk regions of 3299604km2, and extremely low risk regions of 2681709 km2. Exploitation activities should be prohibited in extremely high risk and high risk regions and restricted in moderate risk regions. The present study on risk analysis of debris flow and landslide not only sheds new light on the future work in this direction but also provides a scientific basis for disaster prevention and mitigation policy making.展开更多
Different researchers select different factors and use different methods to assess the regional hazard degrees of debris now. consequenily, even for the same region, tb.. are often different hazard zonation maps, and ...Different researchers select different factors and use different methods to assess the regional hazard degrees of debris now. consequenily, even for the same region, tb.. are often different hazard zonation maps, and there must be some uncertainty in the zonations. Thus the ceriainty analysis of zonation maps becomes obviously important.For debris now hazard, those zonation maps with a certainty analysis could provide most valuable information for land users, hazard managers and policy makers. By comparison of three researchers’ findings in Yunnan Province, this paPer shows that seven to nine iafluential factors are chosen for the zonation maps. spatial density of debris flow ravines,regional average rock-weathering coefficient, yearly precipitation, days of≥50 mm daily rainfall, and proportion of sloping land with slope≥25℃to the total land are the most acceptable factors. Mathemahcal methods of maximum-minimumvalues, upperlower limit values and Fuzzy values are used to quantify the factors. Step-by-step methodoogy is commonly used for the zonation maps. Research results show that mchmum uncedrinty is 66. 6% and minimum uncertainty is 35.7% in debris now hazard maps of zhaotong Prefecture and Yunnan Province. Therefore there is still much work for us to improve the zonation methedology.展开更多
The fifth-generation seismic hazard map for China's mainland(CSHM5) was developed based on the delineated seismic source models and the ground motion models(GMMs) for the peak ground acceleration(PGA) for four dif...The fifth-generation seismic hazard map for China's mainland(CSHM5) was developed based on the delineated seismic source models and the ground motion models(GMMs) for the peak ground acceleration(PGA) for four different seismic regions. In the present study, we developed a new set of GMMs as functions of the rupture distance or the closest distance to the projection of the rupture plane. The development of the GMMs is based on the projection method and GMMs from the NGA-West2 project. We then estimated, mapped, and compared the seismic hazard in terms of PGA and pseudo-spectral acceleration by using the new set of GMMs and other relevant GMMs, and two seismic source models-one used in developing CSHM5, which includes the fault orientation characterization and the other based on a spatially smoothed source model. The comparison of the estimated seismic hazard indicates that CSHM5 may significantly underestimate the seismic hazard. Part of this is likely due to the inclusion of an additional 15 km focal depth in the original GMM that is adopted for CSHM5. The comparison of the obtained standardized uniform hazard spectra(UHS) to the standardized response spectrum implemented in the current structural design code shows that the value of the latter is greater than that of the former for the natural vibration period less than about 0.1 s or greater than 0.4 s and this is reversed for the natural vibration period around 0.2 s. It is recommended that the use of UHS for design code making should be seriously considered, or at least, the shape of the current implemented standardized design spectrum could be improved.展开更多
文摘Digital elevation models(DEMs)are essential tools in environmental science,particularly for hazard assessments and landscape analyses.However,their application acrossmultiple environmental hazards simultaneously remains in need for a multi-aspect critical assessment to promote their effectiveness in comprehensive risk management.This paper aims to review and critically assess the application of DEMs in mapping and managing specific environmental hazards,namely floods,landslides,and coastal erosion.In this regard,it seeks to promote their utility of hazard maps as key tools in disaster risk reduction and environmental planning by employing high-resolution DEMs integrated with advanced geographic information systems.The findings offer valuable insights into optimizing DEM technology for environmental management,contributing to safer and more resilient communities.The paper addresses an important gap in the geospatial analysis of natural hazards and serves as a foundational reference for future advancements in the field,emphasizing its importance to academic researchers and practical stakeholders in environmental and disaster management.
基金supported by the International Scientific Joint Project of China (No. 2009DFA21280)the National Natural Science Foundation of China (No. 40821160550)the Doctoral Candidate Innovation Research Support Program by Science & Technology Review (No. kjdb200902-5)
文摘Tens of thousands of landslides were triggered by May 12, 2008 earthquake over a broad area. The main purpose of this article is to apply and verify earthquake-triggered landslide hazard analysis techniques by using weight of evidence modeling in Qingshui （清水） River watershed, Deyang （德阳） City, Sichuan （四川） Province, China. Two thousand three hundred and twenty-one landslides were interpreted in the study area from aerial photographs and multi-source remote sensing imageries post-earthquake, verified by field surveys. The landslide inventory in the study area was established. A spatial database, including landslides and associated controlling parameters that may have influence on the occurrence of landslides, was constructed from topographic maps, geological maps, and enhanced thematic mapper （ETM＋） remote sensing imageries. The factors that influence landslide occurrence,such as slope angle, aspect, curvature, elevation, flow accumulation, distance from drainages, and distance from roads were calculated from the topographic maps. Lithology, distance from seismogenic fault, distance from all faults, and distance from stratigraphic boundaries were derived from the geological maps. Normalized difference vegetation index （NDV1） was extracted from ETM＋ images. Seismic intensity zoning was collected from Wenchuan （汶川） Ms8.0 Earthquake Intensity Distribution Map published by the China Earthquake Administration.Landslide hazard indices were calculated using the weight of evidence model, and landslide hazard maps were calculated from using different controlling parameters cases. The hazard map was compared with known landslide locations and verified. The success accuracy percentage of using all 13 controlling parameters was 71.82%. The resulting landslide hazard map showed five classes of landslide hazard, i.e., very high, high, moderate, low, and very low. The validation results showed satisfactory agreement between the hazard map and the existing landslides distribution data. The landslide hazard map can be used to identify and delineate unstable hazard-prone areas. It can also help planners to choose favorable locations for development schemes, such as infrastructural, buildings, road constructions, and environmental protection.
基金supported by the Key Project in the National Science and Technology Pillar Program during the Twelfth Five-Year Plan Period(Grant No.2012BAK10B04)the Specific Research Fund of the China Institute of Water Resources and Hydropower Research(Grant No.JZ0145B032014)
文摘Flash flood hazard mapping is a supporting component of non-structural measures for flash flood prevention. Pilot case studies are necessary to develop more practicable methods for the technical support systems of flash flood hazard mapping. In this study, the headwater catchment of the Xiapu River Basin in central China was selected as a pilot study area for flash flood hazard mapping. A conceptual distributed hydrological model was developed for flood calculation based on the framework of the Xinanjiang model, which is widely used in humid and semi-humid regions in China. The developed model employs the geomorphological unit hydrograph method, which is extremely valuable when simulating the overland flow process in ungauged catchments, as compared with the original Xinanjiang model. The model was tested in the pilot study area, and the results agree with the measured data on the whole. After calibration and validation, the model is shown to be a useful tool for flash flood calculation. A practicable method for flash flood hazard mapping using the calculated peak discharge and digital elevation model data was presented, and three levels of flood hazards were classified. The resulting flash flood hazard maps indicate that the method successfully predicts the spatial distribution of flash flood hazards, and it can meet the current requirements in China.
基金supported by the Mandatory Research Fund from the University of Bengkulu,with Grant No.3968/UN30.15/LT/2018
文摘It is well known that seismic hazard assessment should be implemented to design infrastructures in an earthquake-prone area such as Bengkulu.This paper presents local seismic hazard maps based on the response spectra of stiff and very dense soils in Bengkulu city,Indonesia.We collect the soil data and conduct the seismic wave propagation.The input motion for wave propagation analysis is generated from the spectral acceleration curves of stiff and dense soils.Various ground motion parameters such as peak ground acceleration,short-period and long-period spectral accelerations,and amplification factors are presented in microzonation maps.The results show that the peak ground acceleration in the study area ranges from 0.2 to 0.8 g,while the spectral acceleration varies between 0.5-1.5 g and 0.4-0.8 g for periods of 0.2 and 1 s,respectively.The amplification factor of the site is observed to vary from 0.5 to 1.6.Considering other spectral accelerations in Bengkulu,the spectral acceleration design shows a good performance.The results indicate the site characteristics of Bengkulu city,which can provide engineers with site class for structural building design.
文摘This paper reports a method to make hazard maps of sediment disasters resulting from an earthquake and following heavy rainfall for the entire region of Gunma prefecture, Japan. Firstly, we identified the slopes in the study area, which are susceptible to large-scale landslides and land failures during an earthquake with a magnitude of seven on the Richter scale. To analyze the sheer volume of the data, we employed a statistical method to evaluate the susceptibility, mainly considering geomorphologic conditions. Secondly, we extracted mudflow and slope failure susceptible areas and potential flooding zones resulting from a damming at a river triggered by the earthquake and heavy rainfall, and we identified the settlements which would be isolated by the road disruption caused by the sediment disasters. As the result, 359 settlements were classified as potential isolation areas. Combining the above-mentioned susceptibility maps, we obtained two types of sediment disaster hazard maps of the study area, depicting the potential hazards which would occur during the earthquake and the disasters which would be caused by heavy rainfall following the quake, respectively. These hazard maps and the disaster information would be useful for the regional disaster prevention planning and countermeasures in the future.
文摘Flooding has been one of the recurring occurred natural disasters that induce detrimental impacts on humans, property and environment. Frequent floods is a severe issue and a complex natural phenomenon in Pakistan with respect to population affected, environmental degradations, and socio-economic and property damages. The Super Flood, which hit Sindh in 2010, has turned out to be a wakeup call and has underlined the overwhelming challenge of natural calamities, as 2010 flood and the preceding flood in 2011 caused a huge loss to life, property and land use. These floods resulted in disruption of power, telecommunication, and water utilities in many districts of Pakistan, including 22 districts of Sindh. These floods call for risk assessment and hazard mapping of Lower Indus Basin flowing in the Sindh Province as such areas were also inundated in 2010 flood, which were not flooded in the past in this manner. This primary focus of this paper is the use of Multi-criteria Evaluation (MCE) methods in integration with the Geographical Information System (GIS) for the analysis of areas prone to flood. This research demonstrated how GIS tools can be used to produce map of flood vulnerable areas using MCE techniques. Slope, Aspect, Curvature, Soil, and Distance from Drainage, Land use, Precipitation, Flow Direction, and Flow Accumulation are taken as the causative factors for flooding in Lower Indus Basin. Analytical Hierarchy Process-AHP was used for the calculation of weights of all these factors. Finally, a flood hazard Map of Lower Indus Basin was generated which delineates the flood prone areas in the Sindh province along Indus River Basin that could be inundated by potential flooding in future. It is aimed that flood hazard mapping and risk assessment using open source geographic information system can serve as a handy tool for the development of land-use strategies so as to decrease the impact from flooding.
文摘In recent years, global warming has gradually become obvious, thus created the climate change. Typhoon Morakot attacked Taiwan and brought heavy rainfall in August, 2009. In mountainous areas including Central and South Taiwan, the flood and debris flow disasters were induced by the typhoon. In this study, Changhua City is selected as the research region and the Delphi method is employed to interview experts and establish comprehensive evaluation criteria for assessing the evacuation plan on disaster areas. The concept is to combine the landslide potential analysis by geographic information systems with the flood or debris flow maps into the potential hazard map. Meanwhile, analytic hierarchy method (AHP) is comprehensively carried on the expert questionnaire survey for the potential hazard map of the compound disaster states. It should be useful for the local government and native people in the future.
文摘The aim of this project was to prepare and study a hazard map of Nagadhunga-Naubise section of the Tribhuvan highway. This section lies in the Middle Mountain region of Nepal. For the preparation of the hazard map of the corridor three steps, initial study, field investigation, and data analysis and presentation were carried out. In the initial study, the collection of available data and review of the literature were done. The base map was then prepared from the topographical map. In the field investigation step, all information and maps prepared earlier in the initial study were verified by field check. In the final step, prepared and verified data were then analyzed for the hazard mapping. Topography (gradient, slope shape and slope aspect), geology, drainage and land-use were considered to be the major influencing factors in the slope stability. Pre-assigned hazard rating method was used for hazard mapping of the study area. The area was divided into equal facets. Then ratings of responsible factors to the hazard were assigned to each facet and overlaid based upon a predetermined rating scheme. Total estimated hazard was the sum of these ratings for each overlay. Hazard map was prepared by using three categories as low hazard, medium hazard and high hazard. The Geographic Information System (GIS) was the main tool for the data input, analysis, and preparing of the final hazard map. The hazard map showed the areas of different hazard potential classes of;“low” with 32% portion, “Medium” with 51%, and “high” with 17% portion.
文摘The Kinta Valley is an area of karst in the north-western part of Peninsular Malaysia. Over 30 years of uncontrolled land use and development has led to significant changes in topography and geomorphology, such as the appearance of sinkholes. In this paper, geospatial techniques were utilized to the task of evaluating sinkholes susceptibility map using a spatial multi criteria evaluation approach (SMCE). Sinkhole location and a spatial database were applied to calculate eight inherent causative factors for limestone instability namely: lithology, structure (lineament), soil cover, slope, land use mining, urban area features, ponds and rivers. The preparation of the sinkhole geohazard map involved summing the weighted values for each hazard element, which permits the construction of geohazard model;the results of the analysis were validated using the previous actual sinkholes locations in the study area. The spatial distribution of sinkholes occurrence, urban development, faults distribution and ex-mining ponds are factors that are directly responsible for all sinkholes subsidence hazards. Further, the resulting geo-hazard map shows that 93% of recent sinkholes occur in areas where the model flags as “high” and “very high” potential hazard, located in the urbanized part of the valley, while less-developed areas to the west and southwest suffered less sinkhole development. The results can be used for hazard prevention and land-use planning.
基金supported by the National Key Research and Development Program of China(Grant No.2023YFC3007203).
文摘This study addresses gaps in aftershock prediction research by proposing an interpretable hybrid machine learning model that leverages multi-source data.The model overcomes challenges related to the selection of influencing factors,model types,prediction result visualization,and decision mechanism interpretability.It integrates mainshock factors,geological features,site characteristics,and terrain conditions using geospatial information system(GIS)technology.By employing the stacking algorithm to optimize and combine XGBoost and LightGBM models,the proposed model significantly improves the prediction performance.Visualization through aftershock hazard mapping offers a robust tool for aftershock warning.The Shapley additive explanations(SHAP)model is used to explain the decision-making process from both global and local perspectives.Results show that,compared to the optimized XGBoost-CMA_ES and LightGBM-CMA_ES hybrid models,the stacking model achieves area under the curve(AUC)increases of 7.71%and 5.72% on the test set,respectively,with a maximum prediction accuracy of 0.9344.The hazard zoning map identifies high-risk areas mainly around fault lines and near the epicenter.As hazard levels rise,the proportion and density of aftershocks in these areas increase.The SHAP model results highlight the distance to fault as the most critical factor.The study integrates local explanations with on-site investigations,effectively visualizing the contributions of different factors to aftershocks.This research provides new tools and methods for enhancing aftershock warning and response.
基金University of PamplonaColombian School of Engineering Julio Garavito。
文摘The rapid growth of impervious areas in urban basins worldwide has increased the number of impermeable surfaces in cities,leading to severe flooding and significant economic losses for civilians.This trend highlights the urgent need for methodologies that assess flood hazards and specifically address the direct impact on pedestrians,which is often overlooked in traditional flood hazard analyses.This study aims to evaluate a methodology for assessing the risk to pedestrians from hydrodynamic forces during urban floods,with a specific focus on Cúcuta,Colombia.The methodology couples research outcomes from other studies on the impact of floodwaters on individuals of different ages and sizes with 1D/2D hydrological modeling.Advanced computational algorithms for image recognition were used to measure water levels at 5-s intervals on November 6,2020,using drones for digital elevation model data collection.In Cúcuta,where flood risk is high and drainage infrastructure is limited,the PCSWMM(Computer-based Urban Stormwater Management Model)was calibrated and validated to simulate extreme flood events.The model incorporated urban infrastructure details and geomorphological parameters of Cúcuta's urban basin.Four return periods(5,10,50,100),with extreme rainfall of 3 h,were used to estimate the variability of the risk map.The output of the model was analyzed,and an integrated and time-varying comparison of the results was done.Results show that the regions of high-water depth and high velocity could vary significantly along the duration of the different extreme events.Also,from 5 to 100 years return period,the percentage of area at risk increased from 9.6%to 16.6%.The pedestrian sensitivity appears much higher than the increase in velocities or water depth individually.This study identified medium to high-risk locations,which are dynamic in time.We can conclude dynamics are spatiotemporal,and the added information layer of pedestrians brings vulnerability information that is also dynamic.Areas of immediate concern in Cúcuta can enhance pedestrian safety during flash flood events.The spatiotemporal variation of patterns requires further studies to map trajectories and sequences that machine learning models could capture.
基金Supported by the Special Project of Chinese Academy of sciences for Mountain Hazards: Debris Flow and Landslide and Oriented Project of Knowledge Innovation of Chinese Academy of sciences(KZCX2-SW-319)
文摘Through the field survey, previous researches and interpretation of aerial photos, a landslide information database of Xiaojiang Valley, Yunnan Province was set up based on the remote sensing (RS) and geographic information system (GIS) technologies. In the paper, a quantitative model for the landslide hazard assessment and zoning was presented, in which the potential energy could be obtained on basis of thorough analysis of the potential sliding volume, distance and direction of the landslide body. Taking landslide potential energy as the index of the hazard severity zonation, the study area was divided into severe, heavy, medium and light hazard zones.
基金funded by the Kuwait Ministry of Finance for the Kuwait Institute for Scientific Research(KISR)under project no.P-KISR-06-02 entitled Multi-Hazard Macro-Assessment Study and Strengthening Environmental Crisis Management in Kuwait.
文摘Hazard maps are essential tools to aid decision makers in land-use planning,sustainable infrastructure development,and emergency preparedness.Despite the availability of historical data,there has been no attempt to produce hazard maps for Kuwait.In cooperation with the World Bank,this study investigated the natural and anthropogenic hazards that affect Kuwait.The objective was to assess the hazards that face Kuwait and map the hazards of most concern.Hazard maps depicting the spatial distribution of hazard-prone areas are discussed in this article.Hazard assessment maps were generated using multiple datasets and techniques,including meteorological data,satellite imagery,and GIS.Hazard profiling identified a total of 25 hazards,of which five“priority”hazards were explored in detail:(1)surface water flooding;(2)dust storms and sand encroachment;(3)drought;(4)air pollution;and(5)oil spills.The results of this study can aid decision makers in targeting the hazards of most concern.The developed maps are valuable tools for emergency response and hazard mitigation.
文摘This paper assesses the hazardousness, vulnerability and risk of debris flow and landslide in China and compiles maps with a scale of 1：6000000, based on Geographical Information System （GIS） technology, hazard regionalization map, socioeconomic data from 2000. Integrated hazardousness of debris flow and landslide is equivalent to the sum of debris flow hazardousness and landslide hazardousness. Vulnerability is assessed by employing a simplified assessment model. Risk is calculated by the following formula： Risk = Hazardousness × Vulnerability. The analysis results of assessment of hazardousness, vulnerability and risk show that there are extremely high risk regions of 104 km2, high risk regions of 283008 km2, moderate risk regions of 3161815 km2, low risk regions of 3299604km2, and extremely low risk regions of 2681709 km2. Exploitation activities should be prohibited in extremely high risk and high risk regions and restricted in moderate risk regions. The present study on risk analysis of debris flow and landslide not only sheds new light on the future work in this direction but also provides a scientific basis for disaster prevention and mitigation policy making.
文摘Different researchers select different factors and use different methods to assess the regional hazard degrees of debris now. consequenily, even for the same region, tb.. are often different hazard zonation maps, and there must be some uncertainty in the zonations. Thus the ceriainty analysis of zonation maps becomes obviously important.For debris now hazard, those zonation maps with a certainty analysis could provide most valuable information for land users, hazard managers and policy makers. By comparison of three researchers’ findings in Yunnan Province, this paPer shows that seven to nine iafluential factors are chosen for the zonation maps. spatial density of debris flow ravines,regional average rock-weathering coefficient, yearly precipitation, days of≥50 mm daily rainfall, and proportion of sloping land with slope≥25℃to the total land are the most acceptable factors. Mathemahcal methods of maximum-minimumvalues, upperlower limit values and Fuzzy values are used to quantify the factors. Step-by-step methodoogy is commonly used for the zonation maps. Research results show that mchmum uncedrinty is 66. 6% and minimum uncertainty is 35.7% in debris now hazard maps of zhaotong Prefecture and Yunnan Province. Therefore there is still much work for us to improve the zonation methedology.
基金supported by the Fundamental Research Funds for the Central Universities,CHD(Grant No.300102282103)Natural Science Basic Research Program of Shaanxi(Program No.2023-JC-QN-0512)(CF)+1 种基金the National Key R&D Program of China(Grant No.2023YFC3805202)(HPH)the Institute of Geophysics,China Earthquake Administration(WJX)is gratefully acknowledged.
文摘The fifth-generation seismic hazard map for China's mainland(CSHM5) was developed based on the delineated seismic source models and the ground motion models(GMMs) for the peak ground acceleration(PGA) for four different seismic regions. In the present study, we developed a new set of GMMs as functions of the rupture distance or the closest distance to the projection of the rupture plane. The development of the GMMs is based on the projection method and GMMs from the NGA-West2 project. We then estimated, mapped, and compared the seismic hazard in terms of PGA and pseudo-spectral acceleration by using the new set of GMMs and other relevant GMMs, and two seismic source models-one used in developing CSHM5, which includes the fault orientation characterization and the other based on a spatially smoothed source model. The comparison of the estimated seismic hazard indicates that CSHM5 may significantly underestimate the seismic hazard. Part of this is likely due to the inclusion of an additional 15 km focal depth in the original GMM that is adopted for CSHM5. The comparison of the obtained standardized uniform hazard spectra(UHS) to the standardized response spectrum implemented in the current structural design code shows that the value of the latter is greater than that of the former for the natural vibration period less than about 0.1 s or greater than 0.4 s and this is reversed for the natural vibration period around 0.2 s. It is recommended that the use of UHS for design code making should be seriously considered, or at least, the shape of the current implemented standardized design spectrum could be improved.
