Natural Hazard Assessment Research Articles

A comparative assessment of GIS-based data mining models and a novel ensemble model in groundwater well potential mapping

In recent years, application of ensemble models has been increased tremendously in various types of natural hazard assessment such as landslides and floods. However, application of this kind of robust models in groundwater potential mapping is relatively new. This study applied four data mining algorithms including AdaBoost, Bagging, generalized additive model (GAM), and Naive Bayes (NB) models to map groundwater potential. Then, a novel frequency ratio data mining ensemble model (FREM) was introduced and evaluated. For this purpose, eleven groundwater conditioning factors (GCFs), including altitude, slope aspect, slope angle, plan curvature, stream power index (SPI), river density, distance from rivers, topographic wetness index (TWI), land use, normalized difference vegetation index (NDVI), and lithology were mapped. About 281 well locations with high potential were selected. Wells were randomly partitioned into two classes for training the models (70% or 197) and validating them (30% or 84). AdaBoost, Bagging, GAM, and NB algorithms were employed to get groundwater potential maps (GPMs). The GPMs were categorized into potential classes using natural break method of classification scheme. In the next stage, frequency ratio (FR) value was calculated for the output of the four aforementioned models and were summed, and finally a GPM was produced using FREM. For validating the models, area under receiver operating characteristics (ROC) curve was calculated. The ROC curve for prediction dataset was 94.8, 93.5, 92.6, 92.0, and 84.4% for FREM, Bagging, AdaBoost, GAM, and NB models, respectively. The results indicated that FREM had the best performance among all the models. The better performance of the FREM model could be related to reduction of over fitting and possible errors. Other models such as AdaBoost, Bagging, GAM, and NB also produced acceptable performance in groundwater modelling. The GPMs produced in the current study may facilitate groundwater exploitation by determining high and very high groundwater potential zones.

Improving the assessment of the natural fire hazard in nature reserves.

Improving the assessment of the natural fire hazard in nature reserves.

Functional Loss Risks of highways in Permafrost Areas Due to Climate Change

The article gives the analysis of functioning of highways, which are exposed to the destruction risks caused by climate change in the territories of the Arctic zone and the location of permafrost, original methods for preserving transport infrastructure facilities survival are proposed. Methods for quantitative risk assessment of natural hazards for transport infrastructure, adaptation measures in road construction to possible climate change are discussed. The technology of self-adjusting soils stabilization using vapor-liquid seasonal cooling devices immersed inside screw piles is proposed for improving the reliability of pile-elevated road structures.

Modelling the susceptibility of pine stands to bark stripping by Chacma baboons (Papio ursinus) in the Mpumalanga Province of South Africa

Context Commercial pine (Pinus spp.) plantations in southern Africa have been subjected to bark stripping by Chacma baboons (Papio ursinus) for many decades, resulting in severe financial losses to producers. The drivers of this behaviour are not fully understood and have been partially attributed to resource distribution and availability. Aims The study sought to develop a spatially explicit ecological-risk model for bark stripping by baboons to understand the environmental factors associated with the presence of damage in the pine plantations of the Mpumalanga province of South Africa. Methods The model was developed in Random Forests, a machine learning algorithm. Baboon damage information was collected through systematic surveys of forest plantations conducted annually. Environmental predictors included aspects of climate, topography and compartment-specific attributes. The model was applied to the pine plantations of the study area for risk evaluation. Key results The Random Forests classifier was successful in predicting damage occurrence (F1 score=0.84, area under curve (AUC)=0.96). Variable predictors that contributed most to the model classification accuracy were related to pine-stand characteristics, with the age of trees being the most important predictor, followed by species, site index and altitude. Variables pertaining to the environment surrounding a pine stand did not contribute substantially to the model performance. Key conclusions (1) The study suggests that bark stripping is influenced by compartment attributes; (2) predicted risk of bark stripping is higher in stands above the age of 5 years planted on high-productivity forestry sites, where site index (SI) is above 25; (3) presence of damage is not related to the proximity to natural areas; (4) further studies are required to investigate ecological and behavioural patterns associated with bark stripping. Implications The model provides a tool for understanding the potential extent of the risk of bark stripping by baboons within this region and it can be applied to other forestry areas in South Africa for risk evaluation. It contributes towards the assessment of natural hazards potentially affecting pine plantations and supports the development of risk-management strategies by forest managers. The model highlights opportunities for cultural interventions that may be tested for damage control.

Natural and human hazard assessment of the archaeological sites of Paphos area (Cyprus) with the use of remote sensing and GIS.

The study focuses on the creation of an innovative methodology for the development of a risk assessment model for the archaeological sites of western Cyprus (Paphos district). On site observation is the most common way for monitoring cultural heritage sites and monuments in Cyprus. However, this procedure which includes data collection, periodical observations, and multivariate risk assessment analysis, is practically difficult to be accomplished with the traditional practices and methods since it is time consuming and cost insufficient. Thus, the use of modern technologies such as Remote Sensing and GIS is anticipated to provide a tool of directives for the protection and preservation of cultural heritage sites from anthropogenic and environmental threats. These technologies provide to scientists integrated monitoring capabilities and have the unique advantage to store and manipulate a large amount of spatial and attribute data simultaneously. This study aims to integrate both satellite remote sensing techniques and GIS in a multidisciplinary approach, for monitoring natural and anthropogenic hazards with the use of archived and up-to-dated multi-temporal remotely sensed images in the study area, namely in areas nearby cultural heritage sites and monuments in Paphos area (Cyprus).According to the results, extensive construction and building development has taken placein the broader area. It was also proved that vast number of sites is established on areas prone to erosion and landslide phenomena.

Interaction prediction between groundwater and quarry extension using discrete choice models and artificial neural networks

Groundwater and rock are intensively exploited in the world. When a quarry is deepened the water table of the exploited geological formation might be reached. A dewatering system is therefore installed so that the quarry activities can continue, possibly impacting the nearby water catchments. In order to recommend an adequate feasibility study before deepening a quarry, we propose two interaction indices between extractive activity and groundwater resources based on hazard and vulnerability parameters used in the assessment of natural hazards. The levels of each index (low, medium, high, very high) correspond to the potential impact of the quarry on the regional hydrogeology. The first index is based on a discrete choice modelling methodology while the second is relying on an artificial neural network. It is shown that these two complementary approaches (the former being probabilistic while the latter fully deterministic) are able to predict accurately the level of interaction. Their use is finally illustrated by their application on the Boverie quarry and the Tridaine gallery located in Belgium. The indices determine the current interaction level as well as the one resulting from future quarry extensions. The results highlight the very high interaction level of the quarry with the gallery.

A decision model for intergenerational life-cycle risk assessment of civil infrastructure exposed to hurricanes under climate change

Public awareness of civil infrastructure performance has increased considerably in recent years as a result of repeated natural disasters. Risks from natural hazards may increase dramatically in the future, given current patterns of urbanization and population growth in hazard-prone areas. Risk assessments for infrastructure with expected service periods of a century or more are highly uncertain, and there is compelling evidence that climatology will evolve over such intervals. Thus, current natural hazard and risk assessment models, which are based on a presumption of stationarity in hazard occurrence and intensity, may not be adequate to assess the potential risks from hazards occurring in the distant future. This paper addresses two significant intergenerational elements – the potential impact of non-stationarity in hazard due to climate change and intergenerational discounting practices – that are essential to provide an improved decision support framework that accommodates the needs and values of future generations. The framework so developed is tested through two benchmark problems involving buildings exposed to hurricanes.

Taking Advantage of the ESA G-POD Service to Study Ground Deformation Processes in High Mountain Areas: A Valle d’Aosta Case Study, Northern Italy

This paper presents a methodology taking advantage of the GPOD-SBAS service to study the surface deformation information over high mountain regions. Indeed, the application of the advanced DInSAR over the arduous regions represents a demanding task. We implemented an iterative selection procedure of the most suitable SAR images, aimed to preserve the largest number of SAR scenes, and the fine-tuning of several advanced configuration parameters. This method is aimed at minimizing the temporal decorrelation effects, principally due to snow cover, and maximizing the number of coherent targets and their spatial distribution. The methodology is applied to the Valle d’Aosta (VDA) region, Northern Italy, an alpine area characterized by high altitudes, complex morphology, and susceptibility to different mass wasting phenomena. The approach using GPOD-SBAS allows for the obtainment of mean deformation velocity maps and displacement time series relative to the time period from 1992 to 2000, relative to ESR-1/2, and from 2002 to 2010 for ASAR-Envisat. Our results demonstrate how the DInSAR application can obtain reliable information of ground displacement over time in these regions, and may represent a suitable instrument for natural hazards assessment.

Assessment of Natural Radioactivity and radiation hazards in beach sand samples from Kanyakumari District, TamilNadu

<div><p><em>Natural radionuclides of terrestrial origin have very long half – lives or driven from very long – lived parent radionuclides, which have been created in stellar processes before the earth formation. The study of natural radioactivity in marine and coastal environments is of significant importance for better understanding of oceanographic and sedimentological processes. The sampling sites are selected to cover randomly to cover the southern part. The soil samples have been collected in beach sides. In situ gamma measurements were conducted using a high-purity germanium (HPGe) detector (coaxial cylinder of 50.1 mm in diameter and 44 mm in length) with a relative efficiency of 50% and an energy resolution (FWHM) of 1.8 keV at the 1.33 MeV reference transition of <sup>60</sup>Co. The measurements shows that the values of the absorbed dose rates in air in the investigated area are lower than the recommended limit by the United Nations Scientific Committee on the Effect of Atomic Radiation.</em></p></div>

Perspectives on global dynamic exposure modelling for geo-risk assessment

The need for a global approach to natural hazard and risk assessment is becoming increasingly apparent to the disaster risk reduction community. Different natural (e.g. earthquakes, tsunamis, tornadoes) and anthropogenic (e.g. industrial accidents) hazards threaten millions of people every day all over the world. Yet, while hazards can be so different from each other, the exposed assets are mostly the same: populations, buildings, infrastructure and the environment. Exposure should be regarded as a dynamic process, as best exemplified by rapid urbanization, depopulation of rural areas and all of the changes associated with the actual evolution of the settlements themselves. The challenge is thus to find innovative, efficient methods to collect, organize, store and communicate exposure data on a global scale, while also accounting for its inherent spatio-temporal dynamics. The aim of this paper is to assess the challenge of implementing an exposure model at a global scale, suitable for different geo-hazards within a dynamic and scalable framework. In this context, emerging technologies, from remote sensing to crowd-sourcing, are assessed for their usability in exposure modelling and a road map is laid out towards a global exposure model that will continuously evolve over time by the continuous input and updating of data, including the consideration of uncertainties. Such an exposure model would lay the basis for global vulnerability and risk assessments by providing reliable, standardized information on the exposed assets across a range of different hazards.

Critical Uncertainties and Gaps in the Environmental- and Social-Impact Assessment of the Proposed Interoceanic Canal through Nicaragua.

The proposed interoceanic canal will connect the Caribbean Sea with the Pacific Ocean, traversing Lake Nicaragua, the major freshwater reservoir in Central America. If completed, the canal would be the largest infrastructure-related excavation project on Earth. In November 2015, the Nicaraguan government approved an environmental and social impact assessment (ESIA) for the canal. A group of international experts participated in a workshop organized by the Academy of Sciences of Nicaragua to review this ESIA. The group concluded that the ESIA does not meet international standards; essential information is lacking regarding the potential impacts on the lake, freshwater and marine environments, and biodiversity. The ESIA presents an inadequate assessment of natural hazards and socioeconomic disruptions. The panel recommends that work on the canal project be suspended until an appropriate ESIA is completed. The project should be resumed only if it is demonstrated to be economically feasible, environmentally acceptable, and socially beneficial.

Origin and chronology of the Augias deposit in the Ionian Sea (Central Mediterranean Sea), based on new regional sedimentological data

In the Ionian Sea (Central Mediterranean Sea), several thick acoustically transparent layers are present including the Augias deposit. The Augias deposit is the most recent, thick layer covering the entire floor of the Ionian Abyssal Plain with an average thickness of 10–12m and a maximum thickness of up to 24m in the Sirte Abyssal Plain. This deposit has also been observed in several adjacent smaller basins in waters deeper than 3000m. Its estimated volume is>65km3. There are multiple plausible hypotheses regarding its age and triggering event, which include the 1600 BC Santorini volcanic caldera collapse, the 365 AD Crete M 8.5 earthquake and other smaller earthquakes such as the 374 AD Calabria M 6.3 earthquake and the 361 AD Sicily M 6.6 earthquake. Understanding the cause of this mass-transport deposit is crucial for improving the natural hazard assessment of a vast area between southern Italy and western Greece. In this study, we propose a new interpretation of the Augias deposit in terms of sedimentary processes and origin, based on sediment cores collected in the NW Ionian Sea during the CIRCEE cruise onboard R/V Le Suroit in October 2013.The sedimentological analysis of seven piston cores reveals three sedimentary facies corresponding to the Augias deposit: 1) “homogenite”, 2) “megaturbidite” and 3) “thick sandy turbidite”. These sedimentary facies are distributed within specific morpho-tectonic regions as defined by newly acquired bathymetric data, indicating a strong control by transport and depositional processes. Sixteen radiocarbon dates obtained above and below the Augias deposit indicate a possible time window of about 500years. This means that we cannot definitively prove a link to the 365 AD Crete earthquake, but we regard it as the most likely trigger. Other depositional models may be plausible, but here we propose a sequence of events as follows: (1) earthquake shock and possible triggering of submarine mass flow in the eastern part of the Ionian Sea (western Hellenic subduction zone); (2) tsunami waves amplified by the confined morphology of the Sicily and Calabria continental shelves inducing an intense re-suspension of fine-grained sediment and massive destabilization at the heads of submarine canyons triggering turbidity currents; (3) gravity driven downslope transport of suspended sediment toward the deep basin and decantation; and (4) a final stage of decantation from seiche waves forming the majority of the homogenite facies in the Ionian Abyssal Plain.

Resolving regional frequency analysis of precipitation at large and complex scales using a bottom-up approach: The Latin America and the Caribbean Drought Atlas

Summary Hydrologic frequency analysis is a statistical technique for the assessment of natural hazards, particularly the so-called water hazards caused exclusively by extreme hydrologic events. In particular, L-moments based regional frequency analysis (RFA-LM) has being adopted as the standard method for hydrologic frequency analysis in many parts of the world and for many other applications relating to hydrological extremes. However, despite the widespread use of RFA-LM, its application at large network and high and complex spatial scale conditions (LNHCSSC) has been poorly studied. The lack of studies about RFA-LM under such conditions and its use preferentially at subnational scales and areas with low number of rain gauge stations, or based on grid data, may be explained by the fact that the most difficult, less robust, and most subjective stage of RFA-LM is the delineation of homogeneous regions. This work proposes an integral procedure for the application of RFA-LM under LNHCSSC. The proposed method is applied to the study of drought event frequency in three case studies from Latin America, and incorporates innovating aspects compared to the state-of-the-art RFA-LM. These aspects are specifically (a) the decoupling of the cause of homogeneity from the regionalization stage; (b) the proposal of regionalization efficiency metrics; (c) the development of a regionalization algorithm; and (d) the development of a frequency estimation and mapping method for ungauged sites.

Unsteady granular flows down an inclined plane.

The continuum description of granular flows is still a challenge despite their importance in many geophysical and industrial applications. We extend previous works, which have explored steady flow properties, by focusing on unsteady flows accelerating or decelerating down an inclined plane in the simple shear configuration. We solve the flow kinematics analytically, including predictions of evolving velocity and stress profiles and the duration of the transient stage. The solution shows why and how granular materials reach steady flow on slopes steeper than the angle of repose and how they decelerate on shallower slopes. The model might facilitate development of natural hazard assessment and may be modified in the future to explore unsteady granular flows in different configurations.

Extreme events in the sedimentary record of maar Lake Pavin: Implications for natural hazards assessment in the French Massif Central

A set of sedimentary cores, high resolution swath bathymetry and subbottom profiler data provides new insights on sedimentary processes in meromictic maar Lake Pavin, France. Three sedimentary environments (i.e., littoral, plateau and basin) have been identified in the lake from sediment composition using bulk organic geochemistry and the analysis of hydroacoustic images. Various forms of rapidly deposited layers (RDLs) have been identified and radiocarbon dated. An up to date stratigraphy of sedimentary events matching coeval RDLs across the lake is presented and illustrates a wide range of natural hazards linked to Lake Pavin during the last 2000 years. In AD 600, a sudden lake outburst triggered a slump deposit along with a 9 m lake-level drop that drove shifts in sedimentary organic matter composition. Outside the lake, outburst flood deposits have been described downstream and provide sedimentary evidence for this event. The lake-level drop also favored the generation of gravity reworking processes, as shown by (1) a regional earthquake-triggered large slope failure on the plateau connected to a mass-wasting deposit in the basin dated to AD 1300, and (2) a succession of turbidites in AD 1825 and AD 1860 contemporaneous to two historic earthquakes, suggesting that this lake is sensitive to earthquakes with a minimum epicentral intensity of V. Finally, past observations of lake water color changes in AD 1783 and AD 1936, similar to reports in other meromictic lakes, match iron-rich deposits identified in maar lake sediments and suggest that Lake Pavin could have undergone limnic eruptions.

Integrated assessment of socio-economic risks of hazardous hydrological phenomena in Slavyansk municipal district

In 2012, the damage costs of floods in Russia amounted to about €300m, and these floods have caused nearly 200 fatalities (Kotlyakov et al. in Reg Res Rus 3(1):32–39, 2013). Risk assessment is one of the most pressing scientific topics in Russia, but most of the works are devoted to natural hazards assessment. The purpose of this work is to estimate the influence of hazardous hydrological phenomena on society. The field research was conducted in the Slavyansk municipal district in the Krasnodar region (the south-western part of Russia), which is a highly populated coastal territory with a high frequency of hazardous hydrological events. Modified methods of the Ministry of the Russian Federation for Affairs for Civil Defence, Emergencies and Elimination of Consequences of Natural Disasters (EMERCOM) were used for potential economic damage calculation. The paper did not only focus on direct, tangible risks, but also included social risk (i.e. risk to life and health). Social vulnerability has been calculated directly as a percentage of vulnerable people, estimated in opinion polls, while in many recent papers the social vulnerability index was calculated as a combination of several statistical indicators. The resulting percentage of vulnerable people was converted to numbers of potential victims. Finally, the social risk was expressed by financial indicators in terms of the cost of the value of statistical life lost (Mrozek and Taylor in J Policy Anal Manag 21(2):253–270, 2002; Viscusi and Aldy in J Risk Uncertain 27(1):5–76, 2003). Social risk can be underestimated in comparison with economic risk because of a low “value of life” in Russia (no life insurance, neglecting of basic safety rules, etc.) (Guriev in Myths of economics, Alpina Business Books, Moscow, 2009).

Effect of increasing mining rate on longwall coal mining – Western donbass case study

Abstract This paper presents the problems associated with the rapid change of the rock stress-strain state in terms of increasing the rate of coal mining. Parameters of the roof collapse are determined depending on the rate of a longwall advancing under conditions of poor rocks. Statistical data are processed to obtain a general trend concerning the mining rate impact on the roof collapse. The statistical strength theory is applied to explain the increase in mined-out space and the size of hanging roof behind a coal face. Numerical simulation is carried out to determine a critical size of mined-out space that provokes a roof collapse. The area of yielded rocks is outlined using the criterion developed taking into account the rate of longwall advancing. A general regularity is obtained to determine the roof collapse parameters. The developed technics gives a possibility to predict the moment of general roof collapse at the initial stage of longwalling to prevent the negative effect of the rapid stress redistribution provoking joints propagation and intensive gas release. The estimation of the rock stress-strain state considering the rate of mining operations can be useful for tasks related to a new technology implementation. The statistical strength theory and failure criterion applied together provides adequate planning of mining activities and the assessment of natural hazards.

Measurement of natural radioactivity and radiation hazards assessment in rock samples of Ramanagara and Tumkur districts, Karnataka, India

The present study deals with the activity concentration of natural primordial radionuclides, namely 226Ra, 232Th, and 40K in different rock samples of Ramanagara and Tumkur districts, and has been studied by using gamma ray spectrometry. The average activity concentration of 226Ra, 232Th, and 40K in the collected rock samples was found to be 41.08 ± 2.12, 86.26 ± 2.94, and 869.29 ± 3.78 Bq.kg−1, respectively. The average radium equivalent activity (Raeq) was found as 225.29 Bq.kg−1 and these values are well within the recommended limit prescribed for dwellings as 370 Bq.kg−1. The external (H ex) and internal hazard index (H in) values are also less than unity. The mean value of absorbed dose rate in rock samples was found as 107.33 nGy.h−1, respectively, and is slightly higher than the worldwide average value. The average indoor and outdoor annual effective dose values for rock samples are 0.526 mSv.y−1 and 0.131 mSv.y−1, respectively. These values are lower than the average world recommended value of 1 mSv.y−1.

Natural radioactivity and radiation hazard assessment of phosphate mining, Quseir-Safaga area, Central Eastern Desert, Egypt

Quseir-Safaga area, Central Eastern Desert, Egypt, includes Duwi Formation, which contains uranium-bearing phosphate beds. The present work used the integrated carborne γ-ray spectrometric data, X-ray analysis and HPGe γ-ray spectrometer data to investigate the radioactive zones at this area. Carborne γ-ray spectrometric survey revealed an increase of equivalent uranium, up to 182ppm. Maps were drawn to show the results of the three radioelements K, eU, eTh and the eU/eTh ratio. The eU and (eU/eTh) maps reveal that there are twelve important anomalies, associated mainly with phosphate mines. The Hamrawein mines at the northwestern part in the study area seem to represent the highest U-anomalies.Twelve phosphate samples were collected from the determined twelve anomalies. They were analyzed with HPGe detector gamma-ray spectrometer. It was found that the results of radioelement concentrations by carborne survey agree well with that obtained by HPGe. Both of them show that phosphate mines effectively contribute to eU anomalies, occurring in the study area. Meanwhile, 40K, 238U and 232Th concentrations in phosphate samples range from 91 to 169, 864 to 3104 and 28.4 to 106Bq/kg respectively. The highest concentration of 238U (3104Bq/kg) occurs in the north of the studied area, close to Hamrawein city. The average concentration of 238U in the analyzed samples is 1766Bq/kg, which is 53 times higher than the worldwide average value reaching 33Bq/kg. The highest 232Th concentration value reaching 106Bq/kg is 2.4 times higher than the worldwide value attaining 45Bq/kg. The absorbed dose rate for the phosphate samples shows the highest value reaching 1468nGy/h. This is more than 25 times the worldwide average value 58nGy/h. The annual effective absorbed dose is also high and reached 1.8mSv/y, which is about twice higher than the permitted value for public exposure of 1.0mSv/y. The maximum external hazardous index value of 9.2 is more than nine times the unity permitted in ICRP, 2000.

Natural Hazard Assessment and Monitoring in the Black Hills and Adjacent Areas, South Dakota and Wyoming, USA, Using Remote Sensing and GIS-Methods

This research considers the support provided by remote sensing and GIS methods for the delineation of potential sites susceptible to natural hazards such as earthquakes, flash floods and karst phenomena in the Black Hills area in South Dakota and Wyoming, USA. By an integration of satellite data (Landsat, Sentinel), evaluations of digital elevation model data (DEM) and DEM derived morphometric maps, meteorological, geophysical and geological data in a GIS database an overview of potentially affected sites could be achieved. The analysis of digital enhanced satellite imageries, digital topographic data and open source geodata contributed to the acquisition of the specific tectonic, geomorphologic / topographic settings influencing local site Original Research Article