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Natural Hazards
Journal Prestige (SJR): 0.767  Citation Impact (citeScore): 2 Number of Followers: 53  Hybrid journal (It can contain Open Access articles)ISSN (Print) 1573-0840 - ISSN (Online) 0921-030X Published by Springer-Verlag  [2469 journals]
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- Publisher Correction to; Simulation of the movement and dispersion of oil
slicks in the Arabian Gulf-
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PubDate: 2022-07-01
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- 3D simulation of ground motion for the 2015 Mw 7.8 Gorkha earthquake,
Nepal, based on the spectral element method-
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Abstract: Abstract The 2015 Mw7.8 Gorkha earthquake is the latest strong event with magnitude greater than Mw7.5 in the Himalayas. The occurrence of this event provides a good opportunity to better understand the characteristics of ground motion produced by a low dip thrust fault. In this study, we constructed a kinematic source model and established a numerical model that incorporates realistic surface topography, velocity structure and the Kathmandu basin for the Gorkha event. Based on the source and structure models, ground motions in the periods of 2–20 s were simulated by a spectral element method. Our results are as follow. (1) Ground motions show prominent directivity along strike. (2) The basin effect can amplify the amplitude of ground motion in Kathmandu especially on the horizontal component. (3) Horizontal ground motions in Kathmandu valley exhibit obvious amplification in the frequency range of 0.2–0.4 Hz, which is absent in vertical component. The results of this work are of importance for future studies on assessing seismic hazard in the Himalayas.
PubDate: 2022-07-01
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- Review on visualization technology in simulation training system for major
natural disasters-
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Abstract: Abstract Major natural disasters have occurred frequently in the last few years, resulting in increased loss of life and economic damage. Most emergency responders do not have first-hand experience with major natural disasters, and thus, there is an urgent need for pre-disaster training. Due to the scenes unreality of traditional emergency drills, the failure to appeal to the target audience and the novel coronavirus pandemic, people are forced to maintain safe social distancing. Therefore, it is difficult to carry out transregional or transnational emergency drills in many countries under the lockdown. There is an increasing demand for simulation training systems that use virtual reality, augmented reality, and mixed reality visualization technologies to simulate major natural disasters. The simulation training system related to natural disasters provides a new way for popular emergency avoidance science education and emergency rescue personnel to master work responsibilities and improve emergency response capabilities. However, to our knowledge, there is no overview of the simulation training system for major natural disasters. Hence, this paper uncovers the visualization techniques commonly used in simulation training systems, and compares, analyses and summarizes the architecture and functions of the existing simulation training systems for different emergency phases of common natural disasters. In addition, the limitations of the existing simulation training system in practical applications and future development directions are discussed to provide reference for relevant researchers to better understand the modern simulation training system.
PubDate: 2022-07-01
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- Selection of an appropriate bedrock for site amplification studies
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Abstract: Abstract The selection of half-space or reference sites significantly influences site amplification studies. However, there are no well-defined guidelines in the literature. Generally, a layer with a local shear wave velocity (VS) of more than 760 m/s is considered a bedrock/half-space/reference site. This study attempts to formulate a rationale for selecting bedrock stiffness to be used as a half-space/reference site. For this study, VS,30 (average shear wave velocity of top 30-m soil strata from shear wave velocity measurements) and the site’s fundamental frequency (obtained from horizontal-to-vertical spectral ratio of ambient vibration records) were used as proxies to study the influence of bedrock/half-space and development of a rationale for their selection. This study uses strong-motion data from India’s sixty-two strong-motion stations and a few from Japan (Kik-Net). The results suggest that considering a site with a shear wave velocity of 760 m/s may not be suitable as a half-space/bedrock for most geomorphological conditions. The results also recognize a pattern that can help in the development of a mathematical model for determining the bedrock for a site using VS,30 and its fundamental frequency as a proxy.
PubDate: 2022-07-01
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- Effect of herbaceous plant root density on slope stability in a shallow
landslide-prone area-
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Abstract: Abstract To evaluate the effects of herbaceous plants’ roots density on soil structure and slope stability in a shallow landslide-affected area, we determined the mechanical characteristics of roots of four herbs (Cynodon dactylon, Artemisia sacrorum, Digitaria sanguinalis, and Clematis florida) growing on slopes prone to landslides and analyzed their effects on soil physicochemical properties. Root tensile strength and shear strength of root–soil composites were determined at different root densities. The slope safety factor was simulated using the strength reduction method. Compared with bare land soil, rhizosphere soils were characterized by higher bulk density, porosity, nutrient content, aggregate content, and greater stability (p < 0.01). Among the four plant species studied, C. florida improved soil structure and soil nutrient contents most effectively. The roots of A. sacrorum displayed the highest tensile strength, reaching up to 248 Mpa. The root–soil complexes of A. sacrorum displayed the highest cohesion and cohesion growth rate compared to bare land. The roots of A.sacrrorum can therefore provide additional cohesion, while the cohesion increase rate of soil without roots varies from 83.30 to 195.94%. The cohesion and safety factor of root–soil complexes of C. dactylon decreased with increasing root density, while those of D. sanguinalis increased with increasing root density. Thus, herbs stabilize slopes by improving soil structure and the mechanical properties of their roots.
PubDate: 2022-07-01
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- Evaluation of collapse sensitivity of loess soils and its effect on the
distribution pattern of pseudokarst sinkholes at the regional scale (case
study: Golestan Province, northeastern Iran)-
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Abstract: Abstract The spread of loess soils in Golestan Province in northeastern Iran has caused numerous environmental issues. To evaluate the effect of loess collapse on the spatial distribution of pseudokarst sinkholes in this province, we have prepared undisturbed samples from 31 locations and characterized their physical and mechanical properties. Moreover, the collapse sensitivity in different parts of the study area has been determined by odometer tests and calculation of the collapse coefficient (Ic), the time required for 90% settlement (T90%), and initial collapse stress. Additionally, by conducting field surveying, using aerial photographs, satellite images, and drone flight, the coordinates of sinkholes were identified, and a map of their geographical distribution was prepared. The overlap of the sinkholes distribution map and the Ic changes map showed that although the amount of Ic of sandy loess soils (Zone III) is higher than that of silty loess soils (Zone II), the extent of destructive phenomena such as sinkholes is much greater in Zone II than in Zone III. The overlap of the map of sinkholes distribution with the map of changes in collapse sensitivity (Is) of loess soils showed that the density of sinkholes in Zone II (which has higher collapse sensitivity) is higher than Zone III. Also, the results show that with increasing initial collapse stress, the density of sinkholes increases. In Zone II, due to severe collapse sensitivity, the highest concentration of sinkholes is observed in a unit area, more than 0.18 per square kilometer. With a relatively severe to severe collapse sensitivity in Zone III, this concentration is 0.021 per square kilometer. Furthermore, in Zone I, the sinkholes (0.004 per square kilometer) have the least concentration.
PubDate: 2022-07-01
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- Effect of the tide on flood modeling and mapping in Kota Tinggi, Johor,
Malaysia-
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Abstract: Abstract This study aimed at mapping the Kota Tinggi flood event in 2006/2007 that had caused massive damages to properties and the environment. The flood was associated with unusually high intensity and continuous rainfall, and high tide. Therefore, a reliable technique of floodplain mapping is crucial for the improvement of flood control strategies and for preparing an evacuation plan. The main objective of this study is to incorporate the effect of tide on flood modeling analysis. The inundated areas were mapped for various annual recurrent intervals (ARI) using peak flow data from 1965 to 2010. The study used Light Detection and Ranging data for flood modeling using HEC-HMS, HEC-RAS, and HEC-GeoRAS. The Generalized Extreme Value model was found to be the best fit for the annual flood simulation. The HEC-HMS hydrologic model was calibrated and validated using observed hydrographs in September 2002 and January 2003, respectively. Due to riverbank overflow, the level-discharge rating curve during flood events is not valid which causes underestimation of the peak flow in the observed flow. Therefore, the simulated hydrographs which model the actual peak flow provide more reasonable results of 625.3 m3/s for the December 2006 flood and 743.9 m3/s for the January 2007 flood. The modeling took into account the tidal effect. When the tidal effect was not considered, the simulated flood depth was 43% lower than the observed flood. However, the inclusion of the tidal effect has reduced the simulation error with an average similarity with the observed flood at 91.4% based on site verification. The simulation results show that the river flow starts to over bank for ARIs exceeding 25 years.
PubDate: 2022-07-01
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- Spotting areas critical to storm waves and surge impacts on coasts with
data scarcity: a case study in Santa Catarina, Brazil-
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Abstract: Abstract The impacts of severe storms on the coastal zone, combined with rapid population growth in this area, have made coastal risk management an urgent need. However, integrated risk assessment can be a challenging task for many locations worldwide, as it normally requires the use of a large amount of data. The Coastal Risk Assessment Framework phase one (CRAF1) is a recently proposed analytical scheme based on empirical models and spatial analysis that combines different indicators to identify storm-induced hotspots. With a high degree of flexibility, the methodology was originally designed to be of broad use. Still, there is little information about the tool applicability in data scarcity conditions. In this study, we show that this approach can be applied, with some simplifications, on data-poor areas, allowing the identification of hotspots considering one or multiple hazards. Here, the coastal risk was assessed for erosion and coastal flooding events with return periods of 10 and 50 years on the Santa Catarina Central Coast. The study area is characterized by the occurrence of storm-induced impacts that historically cause disruption and damage to local communities. Although the components of risk have been assessed using various methods along this sector, to date, no integrated risk analysis has been presented in probabilistic terms. Predicted scenarios for the Santa Catarina Central Coast suggest that extreme episodes may cause several impacts, exposing urban settlements as well local road systems, especially in the municipalities of Tijucas and Florianópolis. The results show that the CRAF1 is an appropriate approach for a first-level risk analysis, even when implemented with poor data resolution, as it effectively points to some of the most vulnerable stretches detected in the study area.
PubDate: 2022-07-01
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- The challenge to use multi-temporal InSAR for landslide early warning
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Abstract: Abstract Satellite radar interferometry is a powerful tool for measuring displacements of the Earth’s surface. However, we recommend to extend the currently prevailing focus on ex-post analyses and monitoring towards ex-ante early warning applications. Underlying challenges and key requirements are discussed.
PubDate: 2022-07-01
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- Estimating the hazard of tree fall along railway lines: a new GIS tool
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Abstract: Abstract Trees along railway networks represent a high risk due to their potential to fall during extreme weather events. The identification of locations along railway tracks with highest tree fall hazard is an important part of a proactive natural hazard management. A new user-friendly GIS tool (as ArcGIS toolbox) was developed that provides the opportunity to detect individual trees along railway lines and to estimate the hazard of tree fall. By an automated analysis of open source digital remote sensing data and additional open source geodata, the tool allows for an up-to-date and area-wide monitoring of trees on railway lines and other infrastructural elements. Important parameters describing meteorological conditions, site conditions, topographic conditions and tree characteristics are implemented. The tool was successfully tested and applied to two federal states in Germany (Northrhine-Westphalia and Thuringia). Due to the automatization of most of the processes, it is possible to extend the application to larger areas with low effort, i.e., to the Germany-wide rail network or to other countries. It is also possible to perform the analysis for other modes of transport. In the context of natural hazard management, the tool can be applied in prevention and can usefully support already existing vegetation management concepts.
PubDate: 2022-07-01
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- Spatial data infrastructure (SDI) for inventory rockfalls with
fragmentation information-
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Abstract: The fragmentation phenomenon has a significant effect on rockfall risk assessment. This information is difficult to obtain, but it is key to improving rockfall modelling. For this reason, the RockModels team has gathered data on the fragmentation of several natural events since 2014 that nowadays wants to share them with professionals, academics and stakeholders. The best way for the dissemination of this information is the use of standard or data specifications in order to be interoperable. A fragmentation rockfall database has been created using all the gathered information, according to the INSPIRE Natural Hazard Area Data Specification currently in force. However, new tables have had to be added, since this specification does not consider fragmentation data. There are currently 6000 records of geometries of source areas, envelopes, deposits and mostly individual blocks. A web mapping application, with an automatic function for coordinate reference system transformation, has been created to facilitate access to the spatial database information. All that was developed on open-source software such as OpenLayers JavaScript library, database (PostGre-PostGIS) and the map generating Web Map Service (GeoServer). As more data are collected, the database can be easily updated and the new information will be published. Moreover, to improve data interpretation, a future task is to incorporate 3D models on the web application. The existence of this public database will facilitate research and advance in knowledge of this kind of natural hazards. Graphical abstract Rockfall volume distribution inventory data. Georeferenced rockfall database including fragmentation data according to Technical Data Specifications of INSPIRE for natural hazards zone. Database mapping of rockfall inventory data in a WMS open access. Geometric modelling and geovisualization to fragmentation process in rockfall investigations.
PubDate: 2022-07-01
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- Enhancing pedestrian evacuation routes during flood events
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Abstract: Abstract The increasing rate of anthropic activities in flood-prone areas and the effects of climate change are aggravating the dangers posed by floods to people. One of the main reasons for fatality during flood events is walking through floodwaters. Although authorities strongly advise against walking in flood waters, evacuations or the accessing of flooded areas by emergency services might be necessary. This research proposes a novel approach to increasing resilience by retrofitting existing infrastructures to enhance evacuation and access routes by reducing flood hazard rate based on flood and pedestrian characteristics. The methodology was applied to flash floods in two case studies in the UK, namely Boscastle and Borth, highlighting that retrofitting small regions of the existing roads and pathways to reduce flood hazard can enhance people’s safety during the evacuation, and hence provides a solution to improve the resilience of the existing environment.
PubDate: 2022-07-01
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- Contemporary integrated community planning: mixed-age, sustainability and
disaster-resilient approaches-
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Abstract: Abstract In recent years, conventional concepts of social reform planning for sustainable, safe and disaster-resilient communities have continuously driven the thought and practice of community planning and management; furthermore, environmental safety has become the common foundation of these visionary community models. Additionally, low birth rates and aging populations have become common social problems in numerous developed countries. This study integrated the design and planning of sustainable, disaster-resilient and intergenerational collective communities to develop factors and models of an intergenerational community. Moreover, this study constructed evaluation indicators for intergenerational communities under a safety basis, which were used as the foundation for planning and designing strategies. The system of intergenerational disaster-resilient collective community planning indicators covers 5 dimensions and 26 indicators, which focuses primarily on the establishment of community safety mechanisms and physical and mental health care for residents, including intergenerational community interactivity, provision of education and employment opportunities, provision of health and medical services, along with environmental and ecological conservation and maintenance management. By reconstructing the communication and economic model of communities as a whole, establishing community disaster management awareness and mechanisms on this basis is essential to facilitate their progress toward sustainable development. Through this framework of indicators, we aim to provide communities with a reference for future transformations in response to societal shifts.
PubDate: 2022-07-01
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- Prioritization of hazards for risk and resilience management through
elicitation of expert judgement-
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Abstract: Abstract Risk assessment in communities or regions typically relies on the determination of hazard scenarios and an evaluation of their impact on local systems and structures. One of the challenges of risk assessment for infrastructure operators is how to identify the most critical scenarios that are likely to represent unacceptable risks to such assets in a given time frame. This study develops a novel approach for prioritizing hazards for the risk assessment of infrastructure. Central to the proposed methodology is an expert elicitation technique termed paired comparison which is based on a formal mathematical technique for quantifying the range and variance in the judgements of a group of stakeholders. The methodology is applied here to identify and rank natural and operational hazard scenarios that could cause serious disruption or have disastrous effects to the infrastructure in the transnational Øresund region over a period of 5 years. The application highlighted substantial divergences of views among the stakeholders on identifying a single ‘most critical’ natural or operational hazard scenario. Despite these differences, it was possible to flag up certain cases as critical among the natural hazard scenarios, and others among the operational hazards.
PubDate: 2022-07-01
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- Stage-based flood inundation mapping
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Abstract: Abstract New methods allow the direct computation of flood inundation maps from lidar data, independently of discharge estimates, hydraulic analysis, or defined cross sections. One method projects the interpolated profile of measured flood levels onto surrounding topography, creating a smooth inundation surface that is entirely based on data and geometrical relationships. A second method computes inundation maps for any simple function that relates the water surface to the elevation of the channel bottom, exploiting their known, sub-parallel character. A final method theoretically combines the elevation of the channel bottom and the upstream catchment area for points along the thalweg, all defined by lidar data. Historical data from stream gauges can be incorporated to generate inundation maps for floods having different return periods. The conceptual simplicity and realism of these maps facilitate data-based planning.
PubDate: 2022-07-01
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- Trend analysis of lakes and sinkholes in the Konya Closed Basin, in Turkey
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Abstract: Abstract This study aims to investigate the trend of water-level changes in lakes (Lake Tuz and Lake Beyşehir) and sinkholes (Timraş and Kızören) in the Konya Closed Basin located in Turkey. Water-level changes in these lakes and sinkholes were investigated along with changes in meteorological parameters (precipitation, temperature, and evaporation) and groundwater trends that indicate the climate in the region. Several statistical tests can be used to determine the significance of hydrological trends over time. These tests are divided into two categories: parametric and nonparametric. In this study, the nonparametric Innovate Sen trend test, the Modified Mann–Kendall trend test, and the parametric Linear trend test were used. According to the trend analysis, the water levels of Kızören and Timraş sinkholes decreased over time, while the water levels of lakes Tuz and Beyşehir increased. These results are supported by the trends in the meteorological data and groundwater level data of the stations determined with the Thiessen polygons and sub-basin boundaries.
PubDate: 2022-07-01
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- The topographic threshold of gully erosion and contributing factors
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Abstract: Abstract The topographic threshold is based on the power relationship between area and slope and is widely applied in gully-erosion research; however, this relationship requires further testing. Accordingly, the Alamarvdasht Lamerd and Fadagh Larestan regions in Fars Province, Iran, were selected as case studies to explore the topographic threshold for gullies. Thirty active gullies were identified in each study area during field surveys, and data describing land use and land cover, drainage areas, slope, and the physical and chemical properties of the soils were assembled. Multivariate analysis was conducted using SPSS to determine the effects of these factors. Using the power relationship between the catchment area and slope for each gully, the analyses explored critical controls for gully development. The results showed that surface runoff was the most significant effective factor for gullies in the study areas. Sparse ground cover, fine-textured soils, and inappropriate land use contribute to gully development. The results suggest that the relationship between slope and drainage area in the Fadagh Larestan case study is S = 0.0192 A−0.159 for gully headcut areas and S = 0.0181 A−0.258 at gully outlets. The corresponding values of the exponent β at the gully headcuts and outlets at Fadagh were − 0.15, and −0.25, respectively. The corresponding relationships for gullies in the Alamarvdasht Lamerd area for the gully headcuts and outlets were S = 0.0143 A− 0.061 and S = 0.0073 A−0. 18, respectively, with β values of − 0.06 and − 0.18. This study provides a basis for determining the thresholds for initiating gully development. Analyses of the effective factors provide clues to improve the management of bare lands to prevent the initiation of gully erosion.
PubDate: 2022-07-01
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- Developing objective dry spell and drought triggers for drought monitoring
in the Niger Basin of West Africa-
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Abstract: Abstract To effectively manage drought in the Niger River Basin known for its high interannual rainfall variability and continuous adverse drought impacts and challenges, decision-makers need to distinguish dry spells from drought. Operational drought triggers also needed to activate water resource management measures and determine the level of intervention, which are presently lacking. With 36 years of precipitation reanalysis records from 60 locations, the study attempts to establish index- and percentiles-based thresholds for defining dry spell and drought through baseline assessment analysis of the historic 1980s regional drought-induced famine, using percentile rank approach. Results indicate 1980s drought-induced famine occurred within thresholds of 20th, 10th, 5th, and 2nd percentiles, while the drought precursors, the dry spells occur within 35th, 20th, 10th, and 5th percentiles. The corresponding objective index thresholds based on SPI-2 month ranges from − 0.22 to − 0.45, − 0.45 to − 0.93, − 0.93 to − 1.20, − 1.66 to − 1.83 defining dry spell, abnormal dry spell, critical/extreme dry spell, and drought conditions; and SPI-6 month thresholds of range − 0.38 to − 1.07, − 0.59 to − 1.58, − 0.64 to − 1.79 and − 0.67 to − 2.21 defining drought of moderate, severe, extreme, and exceptional intensities respectively depending on location. The thresholds vary from month to month, reflecting seasonality, and detect drought onset much earlier because of its lower values relative to the higher, subjective, and arbitrary fixed SPI thresholds of − 1.0 to − 1.49 for defining moderate drought conditions that could be misleading. The threshold validation results show a success rate of 50 to 70 percent. Results operationally useful for early drought detection.
PubDate: 2022-07-01
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- A methodology for mapping of quick clay in Sweden
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Abstract: Abstract Landslides may cause severe destruction that affects both the individuals and functions vital for society. Minor landslides in an area with quick clay may trigger secondary slides, influencing a much greater area compared to slides in areas with no quick clay. Today’s expanding societies demand new areas for exploitation. To effectively meet this demand, there is an increased need to identify areas where quick clay may occur. Direct or indirect methods for assessing the presence of quick clay have previously been presented as well as a strategy for site investigations in quick clay areas. In this article, a methodology for mapping quick clays for the Swedish conditions with methods commonly available in this area is presented. The methodology presented in the article is structured in steps with different levels of detail and visualized with two conceptual flowcharts. Depending on the stage of planning, different types of surveys are recommended. The methodology has been applied at four sites where integrated interpretation of airborne and ground geophysical measurements as well as geotechnical investigations have been carried out. The results from two of these sites are presented here. The study reveals that all the methods used have their advantages and limitations. However, a combined use of the information provides much more accurate interpretation that can be used for a more cost-effective future planning and decision-making.
PubDate: 2022-07-01
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- Comprehensive analysis using multiple-integrated techniques on the failure
mechanism and dynamic process of a long run-out landslide: Jichang
landslide case-
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Abstract: Abstract This study systematically investigates the failure mechanism and dynamic process of a long run-out landslide in Jichang town based on multiple-integrated geotechniques including field investigations, remote sensing analysis, electrical resistivity tomography (ERT) analysis, seismic signal analysis, and numerical simulations. Multi-period remote sensing images show that there was no deformation of the slope before failure that the landslide occurred suddenly, and that rainfall was the main triggering factor. The field investigations and the ERT analysis show that the bedrock of basalt below the Quaternary deposits is moderately strongly weathered and fractured and was full of water from the heavy rainfall that occurred before failure. In addition, field investigations and ERT results show that the geometry of the slip surface is stair-stepping, indicating that there was at least one locked segment on the potential failure path before failure. The authors conclude that the failure of the Jichang landslide was caused by fractured rock filled with rainwater that reduced the shear strength of the discontinuous planes and increased the pore water pressure and weight of the material; this caused the damage of the locked segments and triggered a sudden landslide. Seismic signal analysis shows that the entire run-out process lasted for 60 s and can be divided into three stages: the initial failure stage, the acceleration stage, and the deposition stage. The initial failure stage lasted for 20 s, the acceleration stage lasted for 15 s, and the deposition stage lasted for 25 s. The results of the landslide run-out simulation based on a 3D SPH model are consistent with the seismic signal analysis and show that the peak speed of the sliding mass reached up to 45 m/s. This study shows that the multiple-integrated geotechniques are very useful in run-out landslide investigation and can be used as a reference in similar future studies.
PubDate: 2022-07-01
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