Assessment Of Physical Vulnerability Research Articles

Multi-vulnerability analysis for seismic risk management in historic city centres: an application to the historic city centre of La Serena, Chile

AbstractA comprehensive understanding of the elements at risk, through the identification of the main hazards, level of exposure and different dimensions of the vulnerability of the communities, is an essential step toward the definition and adoption of more effective risk reduction strategies. Historic urban centres have received special attention in the assessment of damage and physical vulnerability to earthquakes, but it is well known that vulnerability also depends on the social and demographic characteristics of communities. This paper discusses the application of a holistic approach aimed at assessing the seismic vulnerability of historic urban centres by considering their physical and social dimensions. Two index-based methodologies are presented, and the data are analyzed using the CENSUS block as the unit of study, which is scarcely present in the literature. The results of both indices are crossed through a matrix, which allows the classification of the blocks in five levels of priority and are mapped using a Geographic Information System tool. The Historic city centre of La Serena, one of the oldest in Chile, was selected as a case study. This historic city centre still preserves historic buildings of raw earth of diverse architectural typologies widely distributed throughout the country, which makes it relevant, not only by itself but as a model that can be replicated and extrapolated to other historic centres of similar constructive characteristics.

Assessment of Physical Vulnerability and Uncertainties for Debris Flow Hazard: A Review concerning Climate Change

Global climate change has increased severe torrential hazards, particularly debris flows in mountainous regions. After floods and earthquakes, debris flows are the most devastating natural hazard in the world. The effects of debris flow on human life and built environments necessitate reconsidering current infrastructure planning, engineering, and risk management practices. Hence, the vulnerability of elements at risk is critical for effective risk reduction systems. Therefore, this article reviews the existing physical vulnerability approach of infrastructure, particularly building toward debris flow hazards in the last 20 years. Furthermore, uncertainties associated with the vulnerability assessment and their quantification techniques have also been discussed in detail. It was found that matrices, curves, and indicators have been extensively used for vulnerability assessment approaches in the last two decades. However, if aleatory and epistemic uncertainties are not quantified or conserved in the vulnerability assessment process, it makes the system inefficient and unreliable. Moreover, data requirements, strengths, and weaknesses of approaches presented herein are highlighted with case studies. Finally, a thorough discussion on future needs in the field of risk assessment methodologies is highlighted by considering uncertainties into account.

Physical vulnerability to dynamic flooding: Vulnerability curves and vulnerability indices

Vulnerability analysis is crucial to assess natural hazard risk. Methods for vulnerability assessment include indices as well as vulnerability curves. Vulnerability curves make use of empirical data to show the relationship between the process intensity and the resulting degree of loss on each affected building whereas vulnerability indices are based on a number of indicators representing building characteristics and their surroundings. In the present paper, damage data from two relatively recent torrential events in the European Alps are used to compare results using a vulnerability curve (Beta model) and a physical vulnerability index (PVI). Following the application of both methods, their strengths and weaknesses are outlined. Vulnerability curves constitute a valuable quantitative method for the assessment of physical vulnerability but, in the present study, they tend to overestimate damages. On the other hand, vulnerability indices better support the understanding of local-scale damage patterns but they require detailed data and further research on weighting and indicator selection. The study leads to the conclusion that both methods complement each other providing better insights into the physical vulnerability of buildings exposed to torrential hazards. Furthermore, uncertainties associated with the two approaches are related to the required data. Therefore, a sensitivity analysis is carried out showing that process intensity is a key variable for the assessment of vulnerability, whereas, differences in the calculation of the degree of loss based on different building values are less important. Finally, the paper gives clear recommendations for improved event and damage documentation and provides an outlook on future needs in vulnerability assessment, including constant updating of both methods based on recent events.

Vulnerability and quality of life of older persons in the community in different situations of family care.

to correlate socio-contextual aspects, physical vulnerability and quality of life of older persons in the community in different situations of family care. epidemiological, a cross-sectional and analytical study, with elderly people in the community (n=769), with application of the instruments: Vulnerable Elders Survey-13 (VES-13), World Health Organization Quality of Life for Older Persons (WHOQOL-OLD) and the World Health Organization Quality of Life (WHOQOL-BREF); and socio-contextual data questionnaire. the population assessed presented an average of regular quality of life in both the WHOQOL-BREF and the WHOQOL-OLD. Older non-vulnerable persons (62.2%) and those with close family contact (82.6%) have a better quality of life than the vulnerable (p<0.0001). lower quality of life scores and more distant families are related to vulnerable elderly people; thus, the assessment of family proximity and physical vulnerability of older persons is shown to be an important factor in improving quality of life.

Assessment of physical vulnerability of buildings and socio-economic vulnerability of residents to rainfall induced cut slope failures: A case study in central highlands, Sri Lanka

In landslide-prone areas, the vulnerability of housing structures is assessed so that adaptation methods can be introduced to reduce risk. Socio-economic consideration is vital when considering cut slope failures. This paper is an attempt to assess both the physical vulnerability of housing structures and the socioeconomic conditions of residents, to provide a holistic understanding of cut slope failure disasters. Extensive fieldwork is vital to understanding the correlation between the physical vulnerability of housing structures and socio-economic conditions due to a lack of relevant data at a household level. Data was collected using a questionnaire survey and extensive field survey, conducted with randomly selected households (N = 322) in Ambagamuwa, Sri Lanka. Factors that influenced living near slope failures were identified. The semi-quantitative methodology used to assess the physical vulnerability of buildings exposed to cut slope failures combines the landslide intensity and the building resistance capacity, and was empirically evaluated by using several indicators related to building characteristics. Regression analysis was used to analyze the correlation between the physical vulnerability of buildings and socio-economic parameters, which was a novel approach. The results reveal the choice to live in areas of cut slope failure risk was dependent on a number of different priorities for communities and that 82% of houses had a moderate vulnerability. Household per capita income and education level of the household head had a significant influence on vulnerability to cut slope failures. The findings in this paper will assist decision-makers in disaster risk reduction to introduce appropriate protective measures to both buildings and cut slope failure hazards, with consideration of the socio-economic conditions of the community, to increase building resistance capacity and decrease the intensity of cut slope failures.

Discrete modelling of debris flows for evaluating impacts on structures

Lahars (volcanic debris flows) are natural phenomena that can generate severe damage and wreak havoc in densely populated urban areas. The evaluation of the forces and pressures generated by these mass flows on constructions (e.g., buildings, bridges and other infrastructure) is crucial for civil protection, assessment of physical vulnerability and risk management. The current tools developed to model the spread of flows at large scale in densely populated urban areas remain inaccurate in the evaluation of mechanical efforts. Here, we developed a discrete numerical model for evaluating debris-flow (DF) impact forces at the local scale of one structure (pillar or column) like a building, a bridge and other infrastructure. In this model, the large-sized solid particles that damage infrastructures and edifices are explicitly modelled using Distinct Element Method (DEM). We considered the fluid and fine-grained solid particles not only in the frame of the pressure exerted on structures, but also through their effects on the movement of particles, i.e. buoyancy and drag. The fluid velocity field and the fluid free surface obtained from Computational Fluid Dynamics (CFD) calculation based on Navier–Stokes equations are imported in the DEM simulation. This model is able to reproduce a range of magnitudes of DFs in terms of volumes, velocities and flow heights. Finally, the model provides insights on impact forces generated by particles on structures and on hydrostatic and/or dynamic pressure due to the combined effect of fluid and solid phases. The model provides results consistent with existing empirical models.

An Indicator-Based Approach for Micro-Scale Assessment of Physical Flood Vulnerability of Individual Buildings

The current trends of floods event in many countries are alarming. Hence, managing flood and the associated risk are crucial in order to reduce the loss and to be well prepared for the combined impact of urbanization and climate changes. The best approach to manage flood activities is a risk-based approach, where the vulnerability of elements at risk is reduced to a minimum. There is a significant number of studies that use an indicator-based approach for flood vulnerability assessment with focus on the macro-scale. However, this paper assesses physical flood vulnerability of buildings at micro-scale using an indicator-based method in Kota Bharu, Malaysia. The region is one of the most flood affected regions in Malaysia. Micro-scale vulnerability assessment considers damages for individual buildings at risk, rather than in aggraded manner. In this study, the methodology adopted involve the use of 1D-2D SOBEK flood modelling, the selection and weightage of indicators, development of spatial based building index and, production of building vulnerability maps. The findings demonstrate the physical pattern of flood vulnerability of buildings at a micro-scale. The approach can assist in flood management planning and risk mitigation at a local scale

An Assessment of Physical Vulnerability to Earthquake in an Urban Village of Delhi

An Assessment of Physical Vulnerability to Earthquake in an Urban Village of Delhi

Influence of the particle shape on the impact force of lahar on an obstacle

Lahars represent natural phenomena that can generate severe damage in densely populated urban areas. The evaluation of pressures generated by these mass flows on constructions (buildings, infrastructure…) is crucial for civil protection and assessment of physical vulnerability. The existing tools to model the spread of flows at large scale in densely populated urban areas remain inaccurate in the estimation of mechanical efforts. A discrete numerical model is developed for evaluating debris flow (DF) impact pressures at the local scale of one structure. The large-sized solid particles are modelled explicitly using Distinct Element Method (DEM) and the fine-grained solid particles are integrated in a fluid phase which generates two effects on the movement of particles, i.e. buoyancy and drag. Fluid velocity field and the fluid free surface are obtained from Computational Fluid Dynamics (CFD) code then imported in the DEM simulation in a one way coupling scheme. In this paper, the influence of particle shape on the impact forces generated on the obstacle is investigated: spherical particles and polygonal rigid blocks (r-blocks) are considered. The shape of the particle influences the contact surface and therefore the impact pressure. With an angular shape and several facets like r-blocks, the impact pressure on an obstacle is more important for a flow with the same characteristics.

Estimación del riesgo en edificaciones por deslizamientos causados por lluvias y sismos en la ciudad de Medellín, empleando herramientas de la Geomática

Este artículo presenta una estimación del riesgo en edificaciones por deslizamientos causados por lluvias y sismos en la ciudad de Medellín, empleando una plataforma de Sistemas de Información Geográfica (SIG). Para esto se implementó un modelo que considera las propiedades topográficas, geológicas, geotécnicas e hidrológicas de la zona en estudio. El modelo de cálculo usado para la valoración de la amenaza por deslizamiento, está fundamentado en el Método seudoestático de NewmarN para el cálculo de estabilidad de laderas y usa un enfoque probabilista el cual se basa en el método de primer orden y segundo momento —FOSM— para estimar la varia- ción de los parámetros geomecánicos del suelo. El abordaje para la valoración de la vulnerabilidad de las construcciones en el área de estudio se realizó mediante índi- ces de fragilidad estructural que consideran la definición de niveles de daño a través de árboles de decisión haciendo uso de la información catastral de la ciudad. El modelo calcula la probabilidad de que ocurra un deslizamiento dado que se presente un sismo que produzca una aceleración (Ah), considerando la incertidumbre de los parámetros geotécnicos y las condiciones de saturación del suelo, y multiplica tales valores con los índices de debilidad estructural para estimar los índices de daño de las construcciones, las cuales se asocian con el riesgo al considerar la variable eco- nómica correspondiente al costo de reposición de tales construcciones.

Physical vulnerability assessment of buildings exposed to landslides in India

Safe structures are the backbone of human coping capacity towards healthy living that can contribute significantly in reducing risk during hazards. However, due to various natural and anthropogenic activities, about 12.6% of land areas (excluding snow-covered area) in India are prone to landslide posing threat to life and property. Moreover, many structures in the hilly terrain of India are non-engineered which results in high vulnerability of buildings. Therefore, assessment of physical vulnerability is a fundamental step in reducing landslide risk. The study aims to present a methodology to assess vulnerability of the buildings using indicator-based approach at site-specific scale. Several studies to assess vulnerability of buildings due to landslides have been carried out by researchers from European countries. But these methodologies cannot be implemented successfully in India because of different geological and climatic condition. The different components of the discussed methodology for physical vulnerability of buildings exposed to landslides such as landslide intensity (a function of landslide velocity and volume) and resistance of buildings (a function of structural and non-structural features) are worked out and suggested by different researchers. However, putting them together, to present as a framework (specifically in Indian scenario) is the novelty of the present work. Further, consideration of the concept of ‘proximity of buildings to landslides’ in the process of site-specific vulnerability assessment is newly proposed. To address this issue, fifteen potential indicators contributing to vulnerability of buildings have been identified and a systematic form for documentation of data during field survey has also been prepared (keeping in view the construction bye-laws and techniques followed in India). The methodology discussed is further successfully implemented in ward number 10 of Gopeshwar Township (Chamoli District), Uttarakhand, India.

Spatial assessment of maize physical drought vulnerability in sub-Saharan Africa: Linking drought exposure with crop failure

Crop yields exhibit known responses to droughts. However, quantifying crop drought vulnerability is often not straightforward, because components of vulnerability are not defined in a standardized and spatially comparable quantity in most cases and it must be defined on a fine spatial resolution. This study aims to develop a physical crop drought vulnerability index through linking the drought exposure index (DEI) with the crop sensitivity index (CSI) in sub-Saharan Africa. Two different DEIs were compared. One was derived from the cumulative distribution functions fitted to precipitation and the other from the difference between precipitation and potential evapotranspiration. DEIs were calculated for one, three, six, nine, and twelve-month time scales. Similarly, CSI was calculated by fitting a cumulative distribution function to maize yield simulated using the Environmental Policy Integrated Climate model. Using a power function, curves were fitted to CSI and DEI relations resulting in different shapes explaining the severity of vulnerability. The results indicated that the highest correlation was found between CSI and DEI obtained from the difference between precipitation and potential evapotranspiration in one, three, and six-month time scales. Our findings show that southern African countries and some regions of the Sahelian strip are highly vulnerable to drought due to experiencing more water stress, whereas vulnerability in Central African countries pertains to temperature stresses. The proposed methodology provides complementary information on quantifying different degrees of vulnerabilities and the underlying reasons. The methodology can be applied to different regions and spatial scales.

Assessment of Urban Physical Seismic Vulnerability Using the Combination of AHP and TOPSIS Models: A Case Study of Residential Neighborhoods of Mymensingh City, Bangladesh

Mymensingh, one of the oldest municipalities of Bangladesh, is at great risk against earthquakes because three major faults viz. Dauki fault, Madhupur fault, and Sylhet-Assam fault are located around it, and possesses liquefaction susceptible soil type. The city has great significance from the economic and administrative point of view and recently declared as the 8th administrative division of Bangladesh which directly stimulates the unplanned future expansion. Considering the potentiality of haphazard development and high seismic risk, it is crucial to assess the seismic vulnerability for taking the judicious decision regarding risk reduction measures for the city. The study combines Technique for Order Preference by Similarity to Ideal Solution method (TOPSIS) and Analytical Hierarchical Process (AHP) models to assess the seismic vulnerability of residential neighborhoods of Mymensingh city as the probability of death and damage is remarkable in residential neighborhoods than other land use types. A combined quantitative methodology of AHP-TOPSIS is used in this study to quantify 13 important qualitative and quantitative factors of earthquake vulnerability, decided on expert opinions. The data of 13 vulnerability factors are collected from the Mymensingh Strategic Development Plan (MSDP, 2011-2031) database, done under Comprehensive Disaster Management Programme (CDMP)-II during 2012-2014. Geographic Information System is used in this study to analyze and mapping of seismic vulnerability. Results indicated that 37 residential neighborhoods are very highly vulnerable, 55 neighborhoods are highly vulnerable, 75 neighborhoods are moderately vulnerable and 74 neighborhoods are in the low vulnerable category.

A GIS-Based Fuzzy Decision Making Model for Seismic Vulnerability Assessment in Areas with Incomplete Data

Earthquakes are one of the natural disasters that threaten many lives every year. It is important to estimate seismic damages in advance to be able to reduce future losses. However, seismic vulnerability assessment is a complicated problem, especially in areas with incomplete data, due to incorporated uncertainties. Therefore, it is important to use adequate methods that take into account and handle the associated uncertainties. Although different seismic vulnerability assessment methods at the urban scale have been proposed, the purpose of this research is to introduce a new Geospatial Information System GIS-based model using a modified integration of Analytical Hierarchy Process (AHP), fuzzy sets theory, and Technique for Order Preference by Similarity to an Ideal Solution (TOPSIS) in a vector-based environment. The proposed method emphasizes handling one of the important uncertainties in areas with incomplete data, namely the ‘vagueness’ of the existing knowledge about influences of the criteria on seismic vulnerability, which is handled using fuzzy sets theory in this research. The applicability of the proposed method is tested in a municipality district of Tabriz, which is in a near vicinity to the fault system. It can be concluded that the proposed method contributes to a pragmatic and efficient assessment of physical seismic vulnerability under uncertainty, which provides useful information for assisting planners in mitigation and preparation stages in less-studied areas.

The drought risk of maize in the farming–pastoral ecotone in Northern China based on physical vulnerability assessment

Abstract. Climate change is affecting every aspect of human activities, especially the agriculture. In China, extreme drought events caused by climate change have posed a great threat to food safety. In this work we aimed to study the drought risk of maize in the farming–pastoral ecotone in Northern China based on physical vulnerability assessment. The physical vulnerability curve was constructed from the relationship between drought hazard intensity index and yield loss rate. The risk assessment of agricultural drought was conducted from the drought hazard intensity index and physical vulnerability curve. The probability distribution of drought hazard intensity index decreased from south-west to north-east and increased from south-east to north-west along the rainfall isoline. The physical vulnerability curve had a reduction effect in three parts of the farming–pastoral ecotone in Northern China, which helped to reduce drought hazard vulnerability on spring maize. The risk of yield loss ratio calculated based on physical vulnerability curve was lower compared with the drought hazard intensity index, which suggested that the capacity of spring maize to resist and adapt to drought is increasing. In conclusion, the farming–pastoral ecotone in Northern China is greatly sensitive to climate change and has a high probability of severe drought hazard. Risk assessment of physical vulnerability can help better understand the physical vulnerability to agricultural drought and can also promote measurements to adapt to climate change.

Vulnerability curves vs. vulnerability indicators: application of an indicator-based methodology for debris-flow hazards

Abstract. The assessment of the physical vulnerability of elements at risk as part of the risk analysis is an essential aspect for the development of strategies and structural measures for risk reduction. Understanding, analysing and, if possible, quantifying physical vulnerability is a prerequisite for designing strategies and adopting tools for its reduction. The most common methods for assessing physical vulnerability are vulnerability matrices, vulnerability curves and vulnerability indicators; however, in most of the cases, these methods are used in a conflicting way rather than in combination. The article focuses on two of these methods: vulnerability curves and vulnerability indicators. Vulnerability curves express physical vulnerability as a function of the intensity of the process and the degree of loss, considering, in individual cases only, some structural characteristics of the affected buildings. However, a considerable amount of studies argue that vulnerability assessment should focus on the identification of these variables that influence the vulnerability of an element at risk (vulnerability indicators). In this study, an indicator-based methodology (IBM) for mountain hazards including debris flow (Kappes et al., 2012) is applied to a case study for debris flows in South Tyrol, where in the past a vulnerability curve has been developed. The relatively "new" indicator-based method is being scrutinised and recommendations for its improvement are outlined. The comparison of the two methodological approaches and their results is challenging since both methodological approaches deal with vulnerability in a different way. However, it is still possible to highlight their weaknesses and strengths, show clearly that both methodologies are necessary for the assessment of physical vulnerability and provide a preliminary "holistic methodological framework" for physical vulnerability assessment showing how the two approaches may be used in combination in the future.

Assessment of physical vulnerability of buildings and analysis of landslide risk at the municipal scale: application to the Loures municipality, Portugal

Abstract. This study offers a semi-quantitative assessment of the physical vulnerability of buildings to landslides in a Portuguese municipality (Loures), as well as the quantitative landslide risk analysis computed as the product of the landslide hazard by the vulnerability and the economic value of the buildings. The hazard was assessed by combining the spatiotemporal probability and the frequency–magnitude relationship of the landslides. The physical vulnerability assessment was based on an inquiry of a pool of European landslide experts and a sub-pool of landslide experts who know the study area, and the answers' variability was assessed with standard deviation. The average vulnerability of the basic geographic entities was compared by changing the map unit and applying the vulnerability to all the buildings of a test site, the inventory of which was listed on the field. The economic value was calculated using an adaptation of the Portuguese Tax Services approach, and the risk was computed for different landslide magnitudes and different spatiotemporal probabilities. As a rule, the vulnerability values given by the sub-pool of experts who know the study area are higher than those given by the European experts, namely for the high-magnitude landslides. The obtained vulnerabilities vary from 0.2 to 1 as a function of the structural building types and the landslide magnitude, and are maximal for 10 and 20 m landslide depths. However, the highest risk was found for the landslides that are 3 m deep, because these landslides combine a relatively high frequency in the Loures municipality with a substantial potential damage.

A reliability assessment of physical vulnerability of reinforced concrete walls loaded by snow avalanches

Abstract. Snow avalanches are a threat to many kinds of elements (human beings, communication axes, structures, etc.) in mountain regions. For risk evaluation, the vulnerability assessment of civil engineering structures such as buildings and dwellings exposed to avalanches still needs to be improved. This paper presents an approach to determine the fragility curves associated with reinforced concrete (RC) structures loaded by typical avalanche pressures and provides quantitative results for different geometrical configurations. First, several mechanical limit states of the RC wall are defined using classical engineering approaches (Eurocode 2), and the pressure of structure collapse is calculated from the usual yield line theory. Next, the fragility curve is evaluated as a function of avalanche loading using a Monte Carlo approach, and sensitivity studies (Sobol indices) are conducted to estimate the respective weight of the RC wall model inputs. Finally, fragility curves and relevant indicators such a their mean and fragility range are proposed for the different structure boundary conditions analyzed. The influence of the input distributions on the fragility curves is investigated. This shows the wider fragility range and/or the slight shift in the median that has to be considered when a possible slight change in mean/standard deviation/inter-variable correlation and/or the non-Gaussian nature of the input distributions is accounted for.

Assessment of physical vulnerability and potential losses of buildings due to shallow slides

Physical vulnerability (PV) of buildings and associated potential losses (PLs) due to the occurrence of shallow slides are semi-quantitatively assessed at the regional scale in a municipality located in the North of Portugal. This work has four main purposes: (1) to identify and characterize the built environment exposed to shallow slides in the study area; (2) to assess the PV of each building type taking into account the building resistance (BR) and the landslide magnitude (LM); (3) to evaluate the economic value (EV) of each single exposed building using cadastral and market values; and (4) to estimate PLs on buildings due to landslide activity. The analysis is made for each single building of the study area, and this is an innovative contribution of this work. The semi-quantitative methodology to assess PV of buildings exposed to shallow translational slides combines the LM and the BR, which is empirically obtained weighting a set of parameters related to building characteristics. The quantification of the EV of buildings was carried out using an adaptation of the calculation formula used by the Portuguese Tax Services to determine the taxable value of buildings in Portugal. PLs result from the product between PV of the exposed buildings and their EV in euros. The overlapping of PLs of buildings with an available landslide susceptibility map, although does not provides any quantified risk analysis, provides valuable information to be used by spatial planning and civil protection stakeholders.

Assessment of physical vulnerability to agricultural drought in China

Food security has drawn great attention from both researchers and practitioners in recent years. Global warming and its resultant extreme drought events have become a great challenge to crop production and food price stability. This study aimed to establish a preliminary theoretical methodology and an operational approach for assessing the physical vulnerability of two wheat varieties (“Yongliang #4” and “Wenmai #6”) to agricultural drought using Environmental Policy Integrated Climate model (EPIC). Drought hazard index was set up based on output variables of the EPIC water stress (WS), including the magnitude and duration of WS during the crop-growing period. The physical vulnerability curves of two wheat varieties to drought were calculated by the simulated drought hazard indexes and loss ratios. And the curve’s effect on drought disaster risk was defined as A, B and C sections, respectively. Our analysis results showed that (a) physical vulnerability curves varied between two wheat varieties, which were determined by genetic parameters of crops; (b) compared with spring wheat “Yongliang 4#” winter wheat “Wenmai 6#” was less vulnerable to drought under the same drought hazard intensity scenario; (c) the wheat physical vulnerability curve to drought hazard displayed a S shape, suggesting a drought intensity–dependent magnifying or reducing effect of the physical vulnerability on drought disasters; (d) the reducing effect was mainly in the low-value area of vulnerability curve, whereas the magnifying effect was in the middle-value area, and the farming-pastoral zone and the Qinling Mountain–Huaihe River zone formed important spatial division belts.