Evaluation Of Geologic Hazards Research Articles

A Critical Analysis of Geological Hazard Risk Assessment Including Future Perspectives

Geological hazards are widely distributed, cause huge losses, and have always been the focus of attention for engineering and environmental geologists. Geological hazard evaluation is the basis of research and has important theoretical significance for preventing and controlling geological hazards. Therefore, geological hazard evaluation has become the focus of engineering and environmental geology. The question of how to build a universal index system model of geological hazard evaluation is an urgent problem that needs to be solved in geological hazard evaluation. Based on a large amount of previous research data, this paper takes landslide hazard as an example and systematically expounds the main problems that need to be solved in the current geological hazard evaluation from five aspects: basic concept, evaluation scope and accuracy, evaluation index system and evaluation criteria, evaluation method, and applicability of evaluation results. A landslide hazard assessment index system model is proposed, which applies to all regions, including all of the factors that may affect the formation of landslides. It is also hoped that this will be used as an example to establish various types of disaster evaluation and assessment systems. If the parameter has no value in the assessment process, it can be processed as 0. On this basis, further research is suggested from the perspectives of the geological hazard evaluation level, geological hazard evaluation theory, and method. To provide thoughts on and suggestions for geological hazard risk assessment method research, standard revision, investigation and evaluation, and risk management and control need to be considered.

Risk zonation of submarine geological hazards in the Chengdao area of the Yellow River subaqueous delta

Submarine geological disasters occur frequently in the Chengdao area of the Yellow River subaqueous delta, which seriously threaten the safe operation of marine engineering in the region. Therefore, it is of great significance to carry out risk zonation for this region. The current study presents a detailed assessment of risk zones related to submarine geological hazards in this region based on analytical hierarchy process (AHP). The system of assessment index for risk zonation was established with four aspects of hydrodynamic condition, engineering geological environment, disaster geological conditions and human engineering activities. Eight geological hazard evaluation factors were selected and the distribution characteristics of each evaluation factor were discussed in detail by combining qualitative analysis and quantitative calculation. The risk level of submarine geological hazards in the Chengdao area are divided into four types: low risk, relatively low risk, relatively high risk, and high risk. The results show that the areas with a high geological hazard risk in this region are mainly distributed in the areas with water depths of 9–12 m, where the hydrodynamic effect is strong, with many human engineering activities, and seriously suffered from geologic hazards. The study results can provide scientific basis for engineering construction and hazard prevention in the Chengdao area.

Evaluation of Geological Hazard Susceptibility Based on the Regional Division Information Value Method

The traditional susceptibility evaluation of geological hazards usually comprises a global susceptibility evaluation of the entire study area but ignores the differences between the local areas caused by spatial non-stationarity. In view of this, the geographically weighted regression model (GWR) was used to divide the study area at regional scale. Seven local areas were obtained with low spatial auto-correlation of each evaluation factor. Additionally, 11 evaluation factors, including the aspect, elevation, curvature, ground roughness, relief amplitude, slope, lithology, distance from the fault, height of the cut slope, multiyear average rainfall and the normalized difference vegetation index (NDVI) were selected to establish the evaluation index system of the geological hazard susceptibility. The Pearson coefficient was used to remove the evaluation factors with high correlation. The global and seven local areas were evaluated for susceptibility using the information value model and the global and regional division susceptibility evaluation results were obtained. The results show that the regional division information value model had better prediction performance (AUC = 0.893) and better accuracy. This model adequately considers the influence of the geological hazard impact factors in the different local areas on geological hazard susceptibility and weakens the influence of some factors that have higher influence in the global model but lower influence in local areas on the evaluation results. Therefore, the use of the regional division information value model for susceptibility evaluation is more consistent with the actual situation in the study area and is more suitable for guiding risk management and hazard prevention and mitigation.

Comparative Study of Geological Hazard Evaluation Systems Using Grid Units and Slope Units under Different Rainfall Conditions

The selection of evaluation units in geological hazard evaluation systems is crucial for the evaluation results. In an evaluation system, relevant geological evaluation factors are selected and the study area is divided into multiple regular or irregular independent units, such as grids, slopes, and basins. Each evaluation unit, which includes evaluation factor attributes and hazard point distribution data, is placed as an independent individual in a corresponding evaluation model for use in a calculation, and finally a risk index for the entire study area is obtained. In order to compare the influence of the selection of grid units or slope units—two units frequently used in geological hazard evaluation studies—on the accuracy of evaluation results, this paper takes Yuanyang County, Yunnan Province, China, as a case study area. The area was divided into 7851 slope units by the catchment basin method and 12,985,257 grid units by means of an optimal grid unit algorithm. Nine evaluation factors for geological hazards were selected, including elevation, slope, aspect, curvature, land-use type, distance from a fault, distance from a river, engineering geological rock group, and landform type. In order to ensure the objective comparison of evaluation results for geological hazard susceptibility with respect to grid units and slope units, the weighted information model combining the subjective weighting AHP (analytic hierarchy process) and the objective statistical ICM (information content model) were used to evaluate susceptibility with both units. Geological risk evaluation results for collapses and landslides under heavy rain (25–50 mm), rainstorm (50–100 mm), heavy rainstorm (150–250 mm), and extraordinary rainstorm (>250 mm) conditions were obtained. The results showed that the zoning results produced under the slope unit system were better than those produced under the grid unit system in terms of the distribution relationship between hazard points and hazard levels. In addition, ROC (receiver operating characteristic) curves were used to test the results of susceptibility and risk assessments. The AUC (area under the curve) values of the slope unit system were higher than those of the grid unit system. Finally, the evaluation results obtained with slope units were more reasonable and accurate. Compared with the results from an actual geological hazard susceptibility and risk survey, the evaluation results for collapse and landslide geological hazards under the slope unit system were highly consistent with the actual survey results.

Wetting Front Expansion Model for Non-Ponding Rainfall Infiltration in Soils with Uniform and Non-Uniform Initial Moisture Content

The rainfall infiltration model plays a key role in the fields of seepage theory and geological hazard evaluation. To reflect the change in the moisture content in soil during rainfall infiltration, the infiltration process was segmented into stages, and an improved unsaturated wetting front extension model was proposed by introducing unsaturated soil parameters on the basis of the traditional infiltration model. The variation rules of surface moisture content and wetting front depth were revealed under the condition of uniform or non-uniform moisture content distribution in soil. The results indicate that the surface moisture content and wetting front depth increase nonlinearly with time during the infiltration process, and the proposed model is in good agreement with the numerical simulation results, the maximum error is less than 5%, while the growth rate under two hypotheses shows obvious differences for different rainfall intensities. Moreover, due to the variation in the moisture content with time, the proposed model calculates a lower moisture content than that of the traditional model under the same conditions, but the expansion depth of the wetting front is higher and the range of influence on soil is greater.

Application of Certainty Factor and Bayesian statistics models for evaluation of landslides and environmental factors at Bao Thang district and Lao Cai city, Lao Cai province

The study area is heavily affected by landslides with increasing frequency and intensity, causing serious damages and affecting the sustainable socio-economic development of the region. The use of mathematical methods in landslide research is increasingly interested due to the quantitative nature of parameters and calculation results. This study aims to apply the Certainty Factor (CF) and Bayesian statistics models for geological hazard evaluation. Landslide distribution is identified from remote sensing images and field surveys. Landslide inventory maps (428 landslides) were compiled by reference to historical reports, Google Earth, and field mapping. All landslides were randomly separated into two data sets: 70% were used to establish the models (training data sets) and the rest for validation (validation data sets). Fifteen environmental factors from geology, topography and hydrological information of the studied area were extracted from the spatial database. Results show that the group of factors of slope angle, Terrain Ruggedness Index, fault/lineament density, stratigraphy, geoengineering characteristics, weathering types, and maximum daily rainfall play the most important role in the formation of landslides in the study area. Validation from Certainty Factor (CF) and Bayesian statistics models show 87% and 92% prediction accuracy between hazard maps and existing landslide locations. These models show reasonably accurate landslide predictions in the study area and can be served as the basis of landslide risk-management studies in the future.

Risk assessment of geological hazards in mountain town scale based on FLO-2D and GIS

Zhouqu County located in the Bailong River Basin of the Longnan Mountain, which is a high geological-hazard-prone area. This paper constructed the index system and evaluation model of geological hazard evaluation at the scale of town in mountainous area by taking Zhouqu County as an example, which carrying out work of geological hazard zoning, vulnerability assessment and risk assessment used by infinite slope model, Flo-2D and ArcGIS software on the basis of analysing geological conditions. The results show that :(1) Together with considering the slope stability and the threat of debris flow utilize the methods of infinite slope model and Flo-2D software and establishing prediction expression of the maximum sliding distance of landslide by using the detailed sample data of 46 locations in the river basin, which effectively improves the accuracy of hazard assessment.(2) The model of vulnerability evaluation eliminates the evaluation indexes with high repeatability, and selects the main property-type disaster bearing bodies for analysis, evaluation and economic accounting, which greatly improves the evaluation efficiency. (3) The risk assessment results can provide reliable technical support for the territorial spatial planning and disaster prevention and reduction of Zhouqu County as well as provide reference for the risk assessment of geological disasters in other towns in Longnan Mountain Area. (4) In addition to rainfall induced by urban geological disasters in mountainous areas of Bailong River Basin, the impact of earthquakes and human engineering activities cannot be ignored. To achieve the goal of high efficiency, rapid and accurate of the model of urban geological hazard risk assessment, it is necessary to conducts in-depth research on dynamic risk assessment technology and methods.

Research on Oblique Aerial Photography and its Application in Detection of Hidden Geological Hazards

The Wu Gorge section of the Three Gorges Reservoir is prone to landslides and collapses of rock masses, which poses considerable threats to the transportation safety along the watercourse of Yangtze River. The oblique aerial photography technique can accurately present the profile and texture information of the observed objects, which can provide data for early detection of geological hazards. In this study, the technique of oblique aerial photography was analyzed in depth, and the obtained oblique aerial photographs were combined with the position and orientation system (POS) data and the ground control points to build a three-dimensional model, and a geological disaster evaluation model was built based on such factors as geological conditions, landform, and hydrological conditions for geological hazard evaluation. Meanwhile, indoor interpretation and fieldwork surveys were performed to summarize the patterns of development and distribution of geological disasters, identify the major contributors to geological disasters in the study area, and master the characteristics of liability of the study area to geological disasters and hidden hazards.

Railway Alignment Optimization in Mountainous Regions Considering Spatial Geological Hazards: A Sustainable Safety Perspective

Sustainable railway construction and operation are threatened by densely occurring geological hazards in complex mountainous regions. Thus, during the alignment optimization process, it is vital to reduce the harmful impacts of geological hazards to a railway. However, current alignment-related studies solely consider such threats in existing geological hazard regions and, outside these regions, slight attention has been devoted to the assessment of potential hazardous impacts along the alignment. To this end, this paper proposes a novel railway alignment optimization model considering both existing and potential geological hazards based on quantitative geological hazard evaluation criteria from a sustainable safety perspective. More specifically, a geohazard zone classification method, within which an energy–slope model is integrated, is first developed. Three geohazard regions, namely the geohazard outbreak region, buffer region and fuzzy region, can then be obtained. Afterward, a spatial geological hazard assessment model is constructed considering the geological danger of three kinds of geohazards (debris flows, landslides and rockfalls) and railway construction vulnerability. This model is incorporated into a previous cost–hazard bi-objective alignment optimization model. Finally, the effectiveness of the proposed model is verified by applying it to a real-life case of the Sichuan–Tibet railway. The results show that this method can effectively optimize mountain railway alignments by concurrently reducing geological hazards and costs, which is beneficial to railway safety and sustainable construction and operation.

Mountain railway alignment optimization considering geological impacts: A cost‐hazard bi‐objective model

AbstractRailways are greatly threatened by geological hazards whose disastrous effects include severe economic losses as well as serious casualties. It is vital to properly account for such geological hazardous impacts during a railway alignment optimization process. However, geological factors are complex, especially in mountainous regions. Besides, economic factors are also crucial in railway alignment design. Therefore, railway alignment optimization can be termed as a cost‐hazard bi‐objective decision‐making process. So far, least‐cost railway alignment optimization has been studied quite thoroughly while the complicated geological hazard factors have received relatively little attention. In this study, a bi‐objective alignment optimization model considering cost and geological hazard is developed. A novel geological railway alignment optimization model is proposed, which includes spatial geological constraints and geological hazard evaluations, after geological railway alignment design criteria are presented and analyzed for three kinds of typical geological hazards: debris flows, landslides, and rockfalls. The geological hazard evaluation includes geological susceptibility and vulnerability assessments. Then, this model is integrated with a previous least‐cost alignment optimization model to construct a cost‐hazard bi‐objective model. The alignment searching processes are also improved to solve the proposed model by integrating geological‐constraints‐handling and bi‐objective alignment optimization approaches. Finally, the effectiveness of the proposed method is verified by applying it to a complicated real‐world case. The results show that the proposed method can produce less expensive and safer solutions than the best alignment designed by experienced human designers while satisfying all required design standards. Moreover, the method's applicability for solving actual problems is further demonstrated through the sensitivity analysis.

基于层次分析法的高速公路地质灾害危险性评估——以十宜高速兴山至长阳段为例

基于层次分析法的高速公路地质灾害危险性评估——以十宜高速兴山至长阳段为例

Geological Hazards During Construction and Operation of Shallow Subway Stations and Tunnels by the Example of the Kharkiv Metro (1968–2018)

Scientific, technical and practical problems have been considered in relation to geological hazards during construction and operation of metro objects such as shallow subway stations and tunnels. Analysis of five decades of the experience of construction and subsequent operation of the Kharkiv metro in rough engineering and geological conditions by construction of tunnels at shallow depths under the existing urban development allowed detecting and systematizing a set of the most essential adverse conditions, processes and phenomena. The main geological hazards are related to the expansion of quicksands, possibility of “flotation” of the underground structures, barrage effect, subsidence of the soil body by long-term dewatering, undermining of the built-in territories and difficulties by tunneling in technogenic fill-up grounds when crossing ravines and gullies. Most problems occur in the territories with a high groundwater level: geological risks in these areas increase, and serious incidents occur by sudden adverse changes of hydrodynamic conditions. Zones of high, medium and low geological hazards have been identified. Geological hazards have been defined at the section planned for extension of the metro line, for which calculations of the affluent value were made based on the barrage effect of tunnels on the groundwater flow. Taking into account the possibility of emergence of engineering and geological processes and prevention of their development provides safe and reliable construction and operation of shallow metro systems. The obtained results of evaluation of geological hazards can be used by designing and construction of underground objects in similar conditions.

Risk evaluation of geological hazards of mountainous tourist area: a case study of Mengshan, China

Risk evaluation is crucial for the construction projects in the areas with high risk of geological hazards. In this paper, based on the projects of Mengshan tourism area, geological hazard risk evaluation model is put forward based on the analysis of geological and environmental conditions as well as characteristics of construction works. Firstly, typical geological hazards of the area for evaluation are determined as collapse and landslide. And then, based on the comprehensive evaluation, 19 collapse zones and three landslide zones are determined in the area for evaluation. They are all stable at present in general, but some of them have high risk to collapse or landslide under rainstorm, weathering or other external forces in the future. At last, five regions are defined as dangerous, including three regions at level 1 and two regions at level 2. At the same time, some effective engineering measures are introduced to prevent the geological disasters according to the natural conditions and inducing factors of the hazards. Methods, procedure and the result put forward by the paper are useful and effective in risk evaluation of geological hazards, especially for the hilly and mountainous area similar as this case.

Geostatistical interpolators for the estimation of the geometry of anthropogenic deposits in Rome (Italy) and related physical–mechanical characterization with implications on geohazard assessment

The role played by the anthropogenic deposits with poor geotechnical characteristics to induce seismic amplification and its influence on hydrogeological conditions, due to its permeability characteristics, has been demonstrated by numerous studies conducted in urban environments. The historical center of Rome (Italy) is characterized by the presence of high thickness of anthropogenic deposits, a stratigraphic unit that accumulated during the centuries of urban development. The modeled reconstruction of this unit could provide a tool for the elaboration of preliminary maps used for urban planning by public institutions. In this work, the reconstruction of the basal surface of the anthropogenic deposits was carried out using lithostratigraphical and geotechnical data recorded in 1355 boreholes drilled within the historical center of Rome. Deterministic and geostatistical estimators have been then used to predict the values at non-sampled locations to construct different maps of the basal surface. Grid statistics allowed the comparison of the obtained maps to select the best spatial predictor. Mono and multivariate geostatistical intepolators [ordinary kriging, kriging with external drift (KED) and cokriging] have been selected and discussed, and KED was the best interpolator for the used dataset. The obtained surface was then used to calculate a thickness map by subtracting it to the Digital Terrain Model. Furthermore, results of some mechanical characteristics of the anthropogenic deposits are presented and discussed in the light of the reconstructed geometry. The knowledge of both geometry (i.e., basal surface and thickness) and mechanical characteristics of these deposits could provide useful information for the evaluation of geological hazards in urban areas.

Neotectonics and seismicity in southern Patagonia

Research for evaluation of geologic hazards involving earthquakes and volcanic eruptions in southern Argentina seems to have historically received little attention. Nevertheless, the relatively small work done indicates a Neogene tectonic architecture in the area with capability of generating potential hazardous earthquakes in a growing population region. Seismicity and some morphotectonic evidences of Quaternary activity of the Magallanes–Fagnano left‐lateral fault system in the transform boundary between South America and Scotia plates, are analysed in this paper. This fault system is considered to be an important seismogenic source, responsible for large earthquakes that have occurred in southern Argentina. Some examples from the South and Austral Andean Volcanic Zones are also examined in order to show recent volcanic activity which also generated crustal seismicity. Preliminary hazard estimation clearly shows the presence of both potentially active volcanic centres in southern Patagonia that may also trigger seismicity and the high probability for large crustal earthquake generation. Copyright © 2015 John Wiley & Sons, Ltd.

Engineering geological map of the Chiavari city area (Liguria, Italy)

An engineering geological map at a scale of 1:10,000 of the Chiavari city area (Northern Italy) – a major tourist and economic attraction of the Ligurian East Riviera – is presented in this paper. The municipality land shows an excellent geomorphological case-study of the well-known Ligurian coast: a floodplain, fairly wide and inhabited, formed by several floods of the two main rivers, a hill hinterland, reasonably inhabited, developed in marly limestones and sandy shales flysch and the coast – featuring cliffs and narrow pebbly beaches – deeply modified. This map was compiled by combining available geological data with a new engineering geomorphological field survey and including geotechnical data which were obtained from studies carried out for town planning and building purposes. On the basis of the critical review of the available lithostratigraphic data from drilling, as well as geotechnical and geophysical analyses carried out between 1981 and 2010 on the municipality land, an engineering geological map was compiled. Nine engineering geological units were established, based on their physical characterizations and geomechanical properties. This paper presents an example of geocartography that could be applied to urban land planning for housing and construction of technical works; it also represents the base for geological hazard evaluation.

Risk Evaluation of Regional Collapses Geological Hazard Based on D-S Evidence Theory-A case study of Haiyuan active fault belt in Ningxia Province

At the regional collapse of geological hazard evaluation process, in the selection of evaluation factors and determination of the weight, there are subjectivity, uncertainty, and many other issues. In this paper, the Haiyuan fault belt in Ningxia Province is the study area, respectively, with D-S evidence theory and fuzzy comprehensive evaluation methods to build a collapse of geological hazard assessment model, presented Concrete evidence theoretical algorithm. The application results show that the evidence theoretical evaluation model compared to fuzzy comprehensive evaluation model is more reliable and accurate. It solved the uncertainty evaluation issues.

AHP is Applied in the Evaluation of Geological Hazards in Urban Roads

City roads are playing vital roles in the economic development. And both highway roadbeds take place geological disasters frequently. This article evaluates geological disasters with the method of AHP. The indexes include lithology, geological structure, slope, high slope, slope structure types, groundwater, slope size, rainfall, river erosion, slope back excavation, earthquake, etc. Through the analysis of the formation mechanism and impact factors in landslide, the model of landslide hazard assessment is established. Then landslide risk factors are partitioned into different levels, and seven part of geological disasters area are calculated. At last determine the risk level of landslide areas comparing with the risk classification table.

Estimating slope failure potential in an earthquake prone area: a case study at Skolis Mountain, NW Peloponnesus, Greece

One of the most important issues in the evaluation of geological hazards is the delineation of landslide prone areas and the estimation of the slope failure potential. In this study, the GIS-based Newmark’s displacement method was applied for the first time in Greece, in order to compute the permanent displacement values and evaluate the slope failure potential in the area of the Skolis mountain in NW Peloponnesus, Greece. The resulting maps were validated using the distribution of secondary effects triggered by the 8 June 2008 earthquake. The study indicated that as the source areas of the rock falls were delineated by the Newmark displacement method, this may be a useful approach to predict earthquake-induced slope failures when the seismic potential of an area has been previously evaluated.

Geotechnical Studies in the Baltimore Canyon Trough Area

Summary This paper presents the results of a site investigation, the onshore laboratory testing program, and the interpretation of data from the standpoint of application and hazard. The study site was generally between the Atlantic Outer Continental Shelf (OCS) exploration leases in the Baltimore Canyon trough and potential markets on the U.S. east coast. Conclusions indicate that the shallow marine sediments from the Baltimore Canyon trough corridor area are typical of terrestrial soils from adjacent shore areas. Introduction Potential for future development on the Atlantic Potential for future development on the Atlantic OCS requires that the U.S. Bureau of Land Management anticipate where development may be proposed and conduct appropriate studies. These proposed and conduct appropriate studies. These studies include those by the USGS that are concerned with the evaluation of geological hazards. Current interest and activity in the Atlantic OCS centers on exploration drilling in the Baltimore Canyon trough area. In addition to the drilling locale itself, the routes for communication between the drilling sites and shoreline facilities should be studied. If commercial quantities of oil or gas are discovered in the Baltimore Canyon trough area, transport to shore most likely will be through pipelines supported in or on the sea bottom. This study is concerned with evaluating the engineering characteristics of the sediments and any potential hazards within a representative transection across the continental shelf in the Baltimore Canyon trough area. To collect specific information for the study, a cruise was conducted by the USGS using the R/V Annandale during Sept. 18-25, 1977. During the cruise, 20 vibracores were collected at 17 stations across the shelf in water depths of 35 to 70 m (Fig. 1). Immediately after the cruise, the cores were taken to the laboratories of Geotechnical Engineers Inc. of Winchester, MA. There, an extensive series of geotechnical engineering tests were carried out on the cores; these data are the basis of this report. Geotechnical engineering properties traditionally have been part of site-specific studies, such as for a particular platform location rather than as part of a particular platform location rather than as part of a regional survey. However, knowledge of geotechnical engineering properties can be applied in several different ways to regional investigations such as in the Baltimore Canyon trough area. The most obvious application is in the evaluation of geologic hazards. Many hazards are associated directly with an engineering characteristic of the marine sediments. For example, the potential for liquefaction or other undesirable response to dynamic loading is a characteristic of the natural sediments. Hazards associated with soft, compressible sediments or with low shearing resistance also can be evaluated on a regional basis. The key to applications such as these is to collect and test specimens that are representative of identifiable geologic formations or units. It then is necessary to interpret the test results in a way which allows rational extrapolation or interpolation throughout the geologic unit. Geotechnical engineering properties frequently are not fixed quantities (such properties frequently are not fixed quantities (such as specific gravity) but are variable with time or environmental location. The shearing resistance of a particular sediment, for example, is not a fixed particular sediment, for example, is not a fixed quantity. It will vary depending on environmental stress level (depth below sediment surface), stress history (previous erosion or deposition), and time. Use of geotechnical engineering test results in regional studies is most valuable if these factors are considered in the analysis.