Urban Seismic Risk Evaluation: A Holistic Approach

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).

Reflections on a Science and Technology Agenda for 21st Century Disaster Risk Reduction

“…Efforts to quantify risk have typically considered a limited number of dimensions like the physical dimension (for example, buildings and mortality) and economic aspects of vulnerability, but social vulnerability is poorly understood and difficult to measure. Measuring vulnerability and exposure requires an integrated understanding of components and how these factors combine to contribute to the resilience 27 of communities (Carreño et al 2007;Burton and Silva 2014). These approaches include methods that use predominantly statistical data gathered from published sources, and approaches that involve surveying local populations.…”

Seismic risk analysis of urban non-engineered buildings: application to an informal settlement in Mérida, Venezuela

“…Numerous recent studies are oriented to the development, application and validation of techniques to evaluate the seismic strength of buildings; this knowledge allows predicting the expected damage in populated areas thus enabling better decision making on seismic risk prevention and protection. There are several methods for vulnerability evaluation and numerous applications to urban areas have been reported (ATC-13, 1985;Yépez, 1996;Barbat et al, 1996Barbat et al, , 1998Barbat et al, , 2006aBarbat et al, , 2006bBarbat et al, , 2008Barbat et al, and 2009Lagomarsino and Giovinazzi, 2006;Dolce et al, 2006;Carreño et al, 2007;Park et al, 2009. These methods can be broadly classified in two groups: procedures based on vulnerability indices and procedures based on capacity spectra (ATC-40, 1996).…”

Probabilistic prediction of wildfire economic losses to housing in Cyprus using Bayesian network analysis

“…the probability of a house being destroyed by a specific fire. This framework dates back to 1980 (Office of the United Nations Disaster Relief Co-ordinator (UNDRO) 1980) and is commonly used in earthquake (Carreño et al 2007), flood (Kron 2002) or landslide (Guzzetti et al 2005) risk assessments; it has also been adopted by the International Panel on Climate Change (IPCC) (Cardona et al 2012).…”