Potential Geological Disasters Research Articles

Detection and Monitoring of Potential Geological Disaster Using SBAS-InSAR Technology

Detection and Monitoring of Potential Geological Disaster Using SBAS-InSAR Technology

Pore pressure built-up in hydrate-bearing sediments during phase transition: A poromechanical approach

Due to the density contrast between the hydrate and methane gas, the pore pressure is accumulated in the sediment during the decomposition process of methane hydrate. This accumulation of pore pressure decreases the magnitude of effective stress, further triggering potential geological disasters such as landslide. This paper establishes a theoretical framework to investigate the evolution of fluid pressure in the hydrate-bearing sediments during the decomposition process. This model consists of two parts: an unsaturated thermo-poromechanical constitutive law as well as a phase equilibrium equation. Compared with the existing studies, the present work incorporates the effect of pore volume change into the pressure built-up model. In addition, the capillary effect is considered, which plays a nontrivial role in fine-grained sediments. Based on this model, the evolution of fluid pressure is investigated in undrained conditions. It is shown that four mechanisms mainly contribute to the pressure built-up: the density contrast between decomposing hydrate and producing fluid, the variation of pore volume, the compaction of hydrate due to variation of capillary pressure, and the thermal deformation of pore constituents induced by temperature change. Among these mechanisms, the density contrast dominates the pore pressure accumulation. Under the combined effect of these contributions, the evolution of fluid pressure exhibits a strong nonlinearity during the decomposition process and can reach up to dozens of mega Pascal. Nevertheless, this high-level pressure built-up results in a significant tensile strain, yielding potential fracturing of the sediment.

Spatial distribution and influencing factors of mountainous geological disasters in southwest China: A fine-scale multi-type assessment

Abstract: Geological disasters have long been a constant threat to socioeconomic development and human life and property. Many studies focus on the occurred geological disasters and ignore the potential risk events. Fine-scale multi-type analysis of Potential Geological Disasters Spots (PGDSs) is a necessary but insufficiently explored research field in China’s mountainous areas. Taking Meigu County (Sichuan Province, Southwest China), a typical disaster-prone region, as the study area. Average nearest neighbor (ANN), standard deviational ellipse (SDE), kernel density estimation (KDE), and ordinary least squares (OLS) regression are used to assess the spatial distribution of potential geological disasters spots and their influencing factors. The findings show that: potential geological disasters spots have a significant spatial heterogeneity and exhibited a prominent clustering characteristic. They were distributed in an elevation range of 1,500–2000 m, which receives an average monthly rainfall of more than 240 mm, as well as in highly foliated (0.6 < Normalized Difference Vegetation Index (NDVI) < 0.8), west-facing (247.5–292.5°), and slopes of 10–20°. In addition, slope, aspect, population density, and rainfall were found as the main influencing factors. The results provide practical rural development measures with support for potential geological disasters spots avoidance and preparedness.

Deformation Detection and Attribution Analysis of Urban Areas near Dianchi Lake in Kunming Using the Time-Series InSAR Technique

The main city of Kunming is located on the north bank of Dianchi Lake. The complex geological environment, large-scale construction, and expansion of the city in recent years have caused uneven land surface subsidence and threatened public safety. In this study, Sentinel-1 ascending and descending orbit datasets were collected for the period of February 2018 to May 2021. The characteristics of surface displacement in the Kunming downtown area were monitored using the time-series interferometric synthetic aperture radar (InSAR) technique, and attribution analysis was performed. It was found that areas with more severe surface settlement were concentrated in the International Exhibition Center area and the large, newly built communities near Dianchi Lake and the Xiaobanqiao Region. The multifactor attribution analysis results demonstrated that the subsidence areas are concentrated in urban villages and engineered, construction-intensive areas in the lakeside sedimentary layer area, with the maximum displacement rate reaching −23.12 mm/a in the line-of-sight direction of the Sentinel-1 ascending dataset. The reliability of the InSAR results was cross-validated with ascending and descending results. This study provides a scientific reference for urban development planning and potential geological disaster detection in Kunming.

Microscale evidence for and formation mechanisms of shear-strength anisotropy of a loess-paleosol sequence since the late Early Pleistocene: The case study of the Xiushidu profile, Southern Chinese loess Plateau

The shear-strength anisotropy of loess-paleosol sequences (LPS) provides vital information for engineering and construction activities and mitigation against geological disasters. The shear-strength anisotropy of undisturbed and disturbed samples from a profile from Xiushidu village, Jingyang County, in the Chinese Loess Plateau, and the formation mechanisms of such anisotropy were studied through direct shear tests and the microstructural analysis of their characteristics. Our results suggest that the shear strength of loess layers L1, L2, L3, L4, and L5 along the vertical direction was greater than that along the horizontal direction, under different values of axial compression. Under the same vertical pressure, the shear strength along the vertical direction was also generally greater for the layers above the seventh paleosol layer (S6), while the opposite result appears in the layers below S6. For the disturbed samples, their anisotropic characteristics are the same as for the undisturbed samples. The microstructure characteristics, including skeleton particles, contact relations, pore forms, cementation degree, and pore area ratio (PAR), explicated the reasons for the anisotropy of shear strength. Moreover, the influence of PAR, porosity (n), and dry density (ρd) on the shear strength in the vertical direction are greater than that in the horizontal direction, and the influence of water content is opposite to that of PAR, n, and ρd. Gravity, van der Waals forces, and hydrogeochemical reactions play important roles in the shear-strength anisotropy of the LPS. Therefore, research on the anisotropy of shear strength contributes to increasing our understanding of such layers, in preventing and mitigating against potential geological disasters and in implementing more appropriate engineering construction techniques.

Monitoring, Prediction, and Evaluation of Mountain Geological Hazards Based on InSAR Technology

When traditional geological hazard survey methods are used for deformation monitoring in mountainous areas, it often shows the disadvantages of low applicability of monitoring methods and limited accuracy of detection results. In recent years, synthetic aperture radar interferometry (InSAR) technology has incomparable advantages in surface deformation monitoring, such as all-weather detection, wide detection range, high detection accuracy, and low detection cost. At the same time, InSAR technology can also provide data and technical support for the subsequent task of potential geological disaster point identification and geological disaster risk zoning in the study area. Alos-2 radar is selected; in this paper the satellite image is the research data, and the InSAR technology is used to complete the surface deformation detection. Then, based on the previous surface deformation monitoring results, the potential geological disaster points in the study area are extracted, and the distribution law and incubation conditions of the disaster points are analyzed and described. According to the field conditions of a certain area, the surface distribution, development causes, and inducing mechanism of the potential geological disaster points are explored; the results show that the development of geological disasters in the study area is affected by many factors such as landform, geological environment, climate, hydrology, and human activities. Based on this, 11 factors such as formation lithology, slope, and river are used as evaluation factors for mountain geological disaster monitoring, prediction, and evaluation analysis. Finally, the improved analytic hierarchy process information model is used to complete the monitoring, prediction, evaluation, and analysis of regional geological hazards in the study area. In this paper, the improved AHP-information method is used to classify the risk of mountain geological disasters in the study area. Finally, the evaluation results are verified, which proves that the improved AHP-information method is reliable, and its mountain geological disaster monitoring and prediction evaluation effect is better than the traditional AHP-information method.

Geological Mapping of the Longkeyang and Surrounding Regions, Bodeh District, Pemalang Regency, Central Java

Geological mapping is one of the important things as part of a field study to obtain geological knowledge. This is due to the need for a geologist who is required to be able to understand the geological conditions of an area, one of which is by conducting mapping activities in the field. In conducting this research activity, it is divided into two stages, namely the field stage and the laboratory stage. The purpose of this research is to determine the characteristics and geological conditions, identify resource potentials and potential geological disasters in the research area. Based on the analysis, it was found that the geomorphological units of the study area were divided into 4 (four), namely the Mount Ketos Homocline Hills Unit, the Polaga River Anticline Valley Unit, the Sarangkadu Cycline Hills Unit, and the Mount Lanji Intrusion Hills Unit. The geology of the study area consists of three rock units in order from oldest to youngest, namely the claystone-sandstone unit and the sandstone-claystone unit and the diorite intrusion unit. The geological structure of the pinnacle area is in the form of folds and faults, namely, Polaga River Anticlines, Sarangkadu Synclines, Polaga River Right Shear Fault, Polaga River Left Shear Fault. The geological history of the study area begins with the deposition of claystone-sandstone units during the Middle Miocene in the Upper Bathyal environment. Furthermore, after the claystone-sandstone units were deposited, during the Middle Miocene – Late Miocene in the Deep Neuritic environment, sandstone-claystone units were deposited with a turbidity deposition mechanism. As well as the geological resource potential of the research area in the form of utilization of river deposits in the form of chunks of igneous rock, river sand deposits and indications of the presence of gold. Meanwhile, the potential for geological disasters in the form of landslides.

Lessons from the casualties caused by the Changning Ms 6.0 earthquake in China

This paper summarizes the Ms 6.0 earthquake disaster that occurred in Changning, Sichuan Province, China, on 17 June 2019. Additionally, a description of the disaster emergency response on both governmental and non-governmental levels is provided. As determined by on-site investigation and analysis, the direct causes of the earthquake casualties are summarized. Among them, 66% of the casualties can be attributed to the lack of anti-seismic measures, 25% to improperly avoiding danger during the earthquake, 6% to earthquake-induced geological disasters, and 3% to pre-existing diseases exacerbated by the earthquake. Responding to the causes of these four casualty types, we summarize 4 lessons: 1) build housing in accordance with earthquake-resistant requirements, 2) propagandize common sense about avoiding danger during earthquakes to public, 3) investigate and evaluate potential geological disasters in the stricken area and try to prevent and mitigate them, and 4) establish cooperation with health organizations, focusing on people who are older or have serious illnesses and give them help.

MANAJEMEN RISIKO BENCANA GEOLOGI

Geological disasters can occur all over the world, including in this beloved Indonesian earth. There are many potential geological disasters in Indonesia, including landslides, flash floods, earthquakes, tsunamis, and volcanic disasters. The occurrence of geological disasters that occur especially in Indonesia can cause significant losses (risks). Various types of victims can be identified from each disaster incident. The amount of damage caused as a result of geological disasters, namely the worst is the loss of human life, then loss of property, as well as damage to the earth and the environment. The earth and the environment should be a unit that provides mutual benefits and does not give or cause harm.There are several Geological disasters that were previously unpredictable and occurred suddenly, for example the tsunami disaster in Aceh that occurred in 2006, and landslides that occurred in several regions in Indonesia. However, there are some natural disasters that can be predicted from the start, for example, the possibility of flash floods in an area due to environmental damage due to land conversion. Minimizing the victims of geological disasters can be done through analysis through risk management. Analysis through methods, strategies and policies will provide benefits for the government, society and other parties with the aim of being able to anticipate the risk of geological disasters in order to reduce losses. Environmental damage due to geological disaster needs to be rearranged according to functions that are more beneficial to human welfare

Preliminary Identification of Geological Hazards from Songpinggou to Feihong in Mao County along the Minjiang River Using SBAS-InSAR Technique Integrated Multiple Spatial Analysis Methods

Landslides and collapses are common geological hazards in mountainous areas, posing significant threats to the lives and property of residents. Therefore, early identification of disasters is of great significance for disaster prevention. In this study, we used Small Baseline Subset Interferometric Synthetic Aperture Radar (SBAS-InSAR) technology to process C-band Sentinel-1A images to monitor the surface deformation from Songpinggou to Feihong in Maoxian County, Sichuan Province. Visibility analysis was used to remove the influence of geometric distortion on the SAR images and retain deformation information in the visible area. Hot spot and kernel density analyses were performed on the deformation data, and 18 deformation clusters were obtained. Velocity and slope data were integrated, and 26 disaster areas were interpreted from the 18 deformation clusters, including 20 potential landslides and 6 potential collapses. A detailed field investigation indicated that potential landslides No. 6 and No. 8 had developed cracks and were severely damaged, with a high probability of occurrence. Potential collapse No. 22 had developed fissures, exposing a dangerous rock mass and posing significant threats to the lives and property of residents. This study shows that the proposed method that combines visibility analysis, InSAR deformation rates, and spatial analysis can quickly and accurately identify potential geological disasters and provide guidance for local disaster prevention and mitigation.

Sliding mechanical properties of fault gouge studied from ring shear test-based microscopic morphology characterization

Fault activity is a factor causing geological disasters and controlling their spatial distribution. The information on fault activity can be recorded by the microstructure of the fault gouge sliding surface, which provides an approach to study the macroscopic mechanical behavior of faults. In this study, the ring shear test was used to simulate the shear sliding behavior of a fault gouge under different stress states and water contents, and the microstructure of the shear sliding surface was quantitatively analyzed using scanning electron microscopy (SEM). The results revealed an evident relationship between the microstructure and macroscopic mechanical properties of the fault gouge. The microstructure, represented by sliding scratches, was primarily created by the movement of coarse particles, such as sand and quartz. An index of the sliding scratch ratio was proposed to characterize the microstructure. The sliding scratch ratio is negatively correlated with water content and normal stress, and a multivariate model of sliding scratch ratio was established with water content, normal stress and coarse particle contents. Allying the model to natural scratches of the fault gouge reveals that the observed sliding scratches were formed during slope sliding, which proves the influence of fault on the occurrence of the studied landslide. Influenced by the “Gully Land Consolidation” projects in the Loess Plateau of China, the groundwater level may increase and then weaken the shear strength of fault gouge, reducing the stability of slopes crossed by fault zone. Therefore, more attention should be paid to potential geological disasters induced by faults in gully filled areas

Mechanical and Microstructural Properties of Alkali Wastes as Filling Materials for Abandoned Salt Caverns

Alkali solid waste from soda industries has previously been stacked on surface and contaminated soil and groundwater. In China, an engineering method of filling alkali wastes into abandoned salt caverns is adopted. This method can solve the problem of waste disposal and the potential geological disasters associated with salt caverns. In such filling projects, the engineering properties of alkali wastes are important for the safety and stability of salt caverns. In this study, the microstructural and mechanical properties of alkali wastes were investigated. X-ray diffraction (XRD) and scanning electron microscope (SEM) were used to analyze the microstructure and mineralogy of such wastes. Direct shear tests were conducted to evaluate the mechanical performance and to obtain the strength parameters of alkali wastes. The basic physical characteristics, microstructure, mineral compositions, and mechanical properties of alkali wastes vary significantly at different burial depths. Moreover, the strength properties of alkali wastes are close to those of the two other common filling materials, sandstone–mudstone mixtures and tailings. The research results can be used as a reference for similar filling projects and can also be beneficial for the cyclic utilization of alkali wastes. An engineering method that utilizes alkali solid wastes to fill abandoned salt caverns is introduced, and the engineering properties of alkali wastes are studied.

Study of energy-efficient architecture address utilizing topography and geomorphology based on Google Earth and its remote sensing data

In this paper, we describe the formatting guidelines for ACM SIG Proceedings. With the development of social economy, smart cities, especially green energy-saving buildings, are foremost trend in the future. The location of green buildings has a very important impact on the design and plan of future smart cities. The influence of the natural environment, especially that of the topography and landform on the location of architectural design is very significant. Google Earth (GE) platform can provide sufficient remote sensing data, which greatly interpret and promote surface information. However, just few people have done related research. This article takes Beijing as an example and uses Google Earth platform and the remote sensing data to obtain the 3D digital elevation model (DEM) data; and then Google earth’s geomorphology data are used to analyze the landform features. Finally, by analyzing their characteristics and distribution features, five energy-saving building locations were selected in Beijing. It can be concluded that GE, is an effective and potential platform for providing remote sensing data, and analyzing the DEM and landform. The rational analysis of the building addresses in this paper could help the buildings to avoid potential geological disasters and make full use of natural resources. Moreover, this research on energyefficient building addresses make a suggestion for future smart city planning.

A novel environmental restoration method for an abandoned limestone quarry with a deep open pitand steep palisades: acasestudy.

In general, exploitation of rock materials, such as limestone or granite exploitation, can cause serious damage to the environment near a mine area. With economic development and the ever-increasing demand for ore resources, mining activities have induced very serious environmental issues in China. Therefore, environmental restoration work around mines in China is urgently required. This study explores the Chuankou open-pit limestone quarry in Tongchuan City, Shaanxi Province, Northwest China, as the engineering case. The environmental issues caused by over 40 years of limestone exploitation, including land degradation, land occupation, dust pollution and potential geological disasters, were investigated. Combining the characteristics of this quarry with a summary of previous studies on environmental restoration work, this paper proposes a novel and systematic method that was comprehensively carried out through engineering and revegetation measures. The engineering measure, that is, the construction of an artificial slope by using local abandoned construction materials, solved the environmental problems in this quarry and provided site conditions favourable for revegetation. The revegetation measure restored the local ecosystem. This method provides both a new idea for the sustainable development of a mining area and a useful reference for analogous engineering cases.

Time-History Analysis of Collapse Impacts on Pipeline Buried in Different Depths

This research explores a numerical simulation analysis method for rock-collapse impacts on pipelines. Dynamic Time-History Analysis of the Transient Full-Newton’s Method is conducted to gain the deformation, axial force, shear and moment of a 0.8 m diameter pipe under rock collapse when buried in six depths interval between 0.5 ~ 3 m. The results show a significant reduction in pipeline damages when the buried depth is 2.0 m, deeper than that, a gentle decrease appears in the response curves. This result indicates that in potential geological disaster areas, the buried depth of an oil / gas pipeline should be no less than 2.0 m. This research provides a practical guideline to pipeline construction in potential disaster areas.

Quantitative foundation stability evaluation of urban karst area: Case study of Tangshan, China

Karst is a potential geological disaster threatening urban construction. However, the existing methods for evaluating the stability of karst foundations are qualitative. This makes it difficult to propose reasonable and practical suggestions for optimal treatment measures in engineering projects. This paper presents a set of quantitative comprehensive evaluation methods to analyze the karst foundations in a residential area of Tangshan, China. Analyses of the karst formation mechanism and development law are undertaken in combination with a numerical simulation to evaluate the stability of the karst foundations of urban high-rise buildings using the results of a field research to determine the model and the parameters for the numerical calculation. The depth of influence of the foundation of an 8-storey building is less than 30m. Thus, treatment of the building foundation is not required if there is no karst in the range of 30m under the surface. However, foundation treatment in the karst zone up to 7m is required for a 26-storey building with a depth of influence of about 60m in order to meet the requirements of foundation stability.The employment of a combined approach method is proposed, therefore, as it provides a systematic and practical method for the challenge of optimizing the foundation treatment method for urban high-rise structures in karst areas.

基于高密度数值方法的水体油气储层断面的勘探

水体断层破碎带严重影响着水体下资源开采安全，因此对水体断面的地质调查是资源勘探技术中最基础的过程。通过水底断面的地质调查，能够更好地对油气储层开采中可能遇到的地质灾害进行评估，预测可能危及钻井安全的地质因素。高密度电阻率法具有智能化、分辨率高以及一次布设、效率高等特点，与传统电阻率法相比勘探能力显著提高。本文将高密度数值分析的方法应用于油气储层地质中水体断层调查，通过查明水体断面勘探线上河床及两岸基岩起伏形态及风化层度，分析了电法工作在油气储层地质中的干扰类型和干扰来源，重点对高密度方法所采得数据采用数值计算处理。研究结果表明，高密度数值分析方法能够有效摸清水体断面的工程地质概况，对于水体下资源开采中可能遇到的地质灾害开展了深入分析，具有重要的应用价值。 Water fault fractured zone is significant to the resources mining safety under water, and the geo-logical survey of water section is the basic process of resources exploration technology. It can evaluate the potential geological disaster in the hydrocarbon reservoirs mining and forecast the geological factors that endanger the drilling safety by the means of geological survey of water sec-tion. Meanwhile, compared with the traditional resistivity method, high density resistivity method with the characteristics of intellectualization, high resolution, one-time layout and high efficiency, significantly increases the exploration capability. This paper applied the high density numerical analysis method in the geological survey of hydrocarbon reservoirs water section, by ascertaining the fluctuating form of bedrock and the degree of weathered layer, analyzed the interfere type and source of resistivity method in the hydrocarbon reservoirs, and focused on the numerical analysis in the data processing. The results showed that the high density numerical analysis method can effectively ascertain the geological situation of hydrocarbon reservoirs water section. Then, the potential geological disaster in the resources exploration process was analyzed and the applicability of this method was proved.

A New Approach of Geological Disasters Forecasting using Meteorological Factors based on Genetic Algorithm Optimized BP Neural Network

The monitoring and forecasting of the mining slope deformation are of great significance to prevent potential geological disasters in mining regions and the geological factors have been widely used for the purpose of mining slope deformation monitoring. However, literature review shows that very little work has been done in prediction of mining slope deformation using meteorological factors. To address this issue, a new method is proposed using the meteorological factors to forecast the mining slope deformation. Herein, the meteorological factors include the temperature, atmospheric pressure, cumulative rainfall, relative humidity and refractive index of the mining slope. A genetic algorithm optimized BP neural network (GA-BPNN) was employed to fuse the meteorological factors to establish the prediction model for the mining slope deformation. The experiments have been implemented to evaluate the new approach and a comparison between the GA-BPNN, BPNN and radical basis function neural network (RBF) prediction models has been carried out. The analysis results show that the proposed method can provide precise prediction of the mining slope deformation and its performance is superior to its rivals. DOI: http://dx.doi.org/10.5755/j01.eee.20.4.4238

Study on the support–anchor combined technique to control perilous rock at the source of avalanche by fracture mechanics

As a kind of existing and potential geological disaster at the source of avalanche on cliffs or steep slopes, perilous rock has developed in the western area of China widely, and it has posed a serious threat to highways, railways, pipelines, cities, and mining for a long time. More than ten years of engineering experience have shown the necessity and importance to pay our attention to the avalanche sources in active collapse mitigation. The support–anchor combined technique is devoted to the active hazard mitigation measures of perilous rock. This paper introduces fracture mechanics to investigate the design procedure of the support–anchor combined technique. To obtain reasonable design parameters of the technique, both stability assessment criterion and three safety classes of protection engineering for perilous rock is proposed, further, stable analysis methods for various types of perilous rock are established by using fracture mechanics. Abiding by the idea that to improve stability coefficient to a higher level, the support force of structure and the anchorage force of anchorbolt from the support–anchor combined technique are introduced into stability analysis methods established above, which can estimate the section dimension of support subunit and the amount of anchorbolt of the technique. Engineering applications of the technique in thousands of protection engineering have identified the remarkable effectiveness

A WebGIS-Based Information System for Monitoring and Warning of Geological Disasters for Lanzhou City, China

Monitoring and warning of geological disasters accurately and in a timely fashion would dramatically mitigate casualties and economic losses. This paper takes Lanzhou city as an example and designs a Web-based system, namely the information system for geological disaster monitoring and warning (ISGDMW). Presented are its framework, key developing technologies, database, and working flow. The information system adopts a Browser/Server (B/S) structure and has three-tier architecture, combining in-situ monitoring instruments, the wireless sensor network, WebGIS techniques and the grey system theory. The framework of the ISGDMW can be divided into three categories: (1) in-situ monitoring system, it aims to monitor geological disaster sites and get state information of geological disaster sites; (2) database, manage in-situ monitoring data, antecedent field investigating data and basic data; (3) analyzing and warning system, analyze in-situ monitoring data, understand the deformation trend of the potential geological disaster, and release disaster warning information to the public. The ISGDMW allow the processes of geological disaster monitoring, in-situ monitoring data analysis, geological disaster warning to be implemented in an efficient and quick way, and can provide scientific suggestions to commanders for quick response to the possibility of geological disaster.