Abstract

Abstract

The system of indicators described in this monograph has been the main objective of the operation ATN / JF-7907-RG of the IDB, coordinated by the Instituto de  Environmental Studies, IDEA, of the Universidad Nacional de Colombia, sede Manizales, within the regional program on "Information and Risk Indicators and Risk Management" for the Americas, promoted by the IDB, ECLAC and the IDEA between March 2003 and May 2005. The purpose of the indicator system described herein is to assess vulnerability and risk, using relative indicators, to facilitate the decision makers of each country, region or city to have access to relevant information that allows them to identify and propose effective risk management actions, considering economic, social, institutional and technical aspects. This system of indicators makes possible the description of risk and risk management at the national, subnational and urban levels, facilitating the identification of the essential aspects that characterize it from an economic and social perspective, as well as comparing these aspects or the risks themselves among different countries or territorial units. The proposed indicators have been designed for measuring and monitoring purposes over time and for the identification of conditions of insecurity and their causes, using criteria related to the degrees of threat to which the territorial units are exposed and their socio-economic circumstances that influence their vulnerability. The system of indicators described here is framed within a holistic evaluation approach, which, due to its flexibility and possible compatibility with other specific evaluation approaches, will be increasingly used and accepted as one of the best options for the representation of risk and of its management, due to its complex and imprecise nature. Its strength lies in the possibility of disaggregating the results and identifying the factors towards which risk management actions should be oriented, in order to assess their effectiveness. Its main objective is to stimulate decision-making and not the precise evaluation of the risk that is commonly supported in the concept of physical truth.

Abstract

From a holistic perspective, disaster risk requires a multidisciplinary evaluation that takes into account not only the expected physical damage, the number and type of casualties or economic losses, but also the conditions related to social fragility and lack of resilience conditions, which favor the second order effects when a hazard event strikes an urban center. In this chapter, the urban risk is evaluated using composite indicators or indices. Expected building damage and losses in the infrastructure, obtained from loss scenarios are basic information for the evaluation of the physical risk index in each unit of analysis. The holistic evaluation of disaster risk is achieved affecting the physical risk with an impact factor, obtained from contextual conditions, such as the socioeconomic fragility and the lack of resilience, that aggravate the physical risk. Available data about these conditions at urban level are necessary to apply the method. The model is explained and the benefits of this approach are illustrated, inviting to the risk management of urban centers.

Abstract

Within the framework described in Chapter 1, this chapter shows the evaluation of the seismic risk of the city of Barcelona, Spain, by applying a probabilistic analysis. On this basis a holistic evaluation of risk is performed taking into account social fragilityand lack of resilience aspects. Finally, the evaluation of the disaster risk management performance is conducted.

Abstract

Risk is defined as the potential economic, social and environmental consequences of hazardous events that may occur in a specified area unit and period. The evaluation of physical vulnerability and risk of buildings is the main purpose of this chapter. Nevertheless, it is shown the necessity of considering not only the expected physical damage but also the social fragility and the lack of resilience of the exposed community, that is, a holistic evaluation of risk aiming at guiding decision making.  Both the vulnerability index and capacity spectrum methods for the evaluation of the physical risk are discussed herein. Both provide good results for the considered case study the urban area of Barcelona, Spain. Both methods show how a city, located in a low to moderate hazard region, which has paid no attention to the seismic performance of their buildings, has buildings with a high seismic vulnerability and a considerable seismic risk.

Abstract

The seismic risk evaluation usually works with a fragmented concept of risk, which depends on the scientific discipline in charge of the assessment. To achieve an effective performance of the risk management, it is necessary to define risk as the potential economic, social and environmental consequences due to a hazardous phenomenon in a period of time. This article presents a methodology which evaluates the seismic risk from a holistic perspective, which means, it takes into account the expected physical damage and also the conditions related to social fragility and lack of resilience, which favour the second order effects when a hazard event strikes an urban centre. This seeks to obtain results which are useful in the decision making process for risk reduction. The proposed method for urban seismic risk evaluation uses the fuzzy sets theory in order to handle qualitative concepts and variables involved in the assessment, the physical risk level and aggravation level, related to the social fragility and the lack of resilience, are evaluated and finally a total risk level is determinate.

Abstract

Risk has been defined, for management purposes, as the potential economic, social and environmental consequences of hazardous events that may occur in a specified period of time. However, in the past, the concept of risk has been defined in a fragmentary way in many cases, according to each scientific discipline involved in its appraisal. From the perspective of this article, risk requires a multidisciplinary evaluation that takes into account not only the expected physical damage, the number and type of casualties or economic losses, but also the conditions related to social fragility and lack of resilience conditions, which favour the second order effects (indirect effects) when a hazard event strikes an urban centre. The proposed general method of urban risk evaluation is multi hazard and holistic, that is, an integrated and comprehensive approach to guide decision-making. The evaluation of the potential physical damage (hard approach) as the result of the convolution of hazard and physical vulnerability of buildings and infrastructure is the first step of this method. Subsequently, a set of social context conditions that aggravate the physical effects are also considered (soft approach). In the method here proposed, the holistic risk evaluation is based on urban risk indicators. According to this procedure, a physical risk index is obtained, for each unit of analysis, from existing loss scenarios, whereas the total risk index is obtained by factoring the former index by an impact factor or aggravating coefficient, based on variables associated with the socioeconomic conditions of each unit of analysis. Finally, the proposed method is applied in its single hazard form to the holistic seismic risk evaluation for the cities of Bogota (Colombia) and Barcelona (Spain).

Abstract

Disaster risk is not only associated with the occurrence of intense hazard events but also with the vulnerability conditions that favour or facilitate disasters when such events occur. Vulnerability is closely linked to social processes and governance weaknesses in disaster-prone areas and is usually related to a set of factors of fragility, susceptibility, and lack of resilience of the exposed human settlements. The holistic risk assessment aims to reflect risk from a comprehensive perspective by using, in one hand, the physical risk or potential physical damage directly linked to the occurrence of hazard events and, on the other hand by capturing how underlying risk drivers or amplifiers –social, economic, environmental factors, non-hazard dependent elements, may worsen the current existing physical risk conditions in terms of lack of capacity to anticipate or resist, or to respond and recover from adverse impacts. This article presents the results of the holistic evaluation obtained at subnational level in Colombia in the framework of the Risk Atlas of Colombia of the National Unit for Disaster Risk Management, UNGRD. The evaluation was performed using the probabilistic physical risk results obtained in the multi-hazard risk assessment and 16 socio-economic indicators available for 1,123 municipalities of Colombia. These results are useful to identify risk drivers that are associated not only to the physical vulnerability of the buildings and infrastructure but also to social issues that should be examined and tackled in a comprehensive way.