Técnicas innovadoras para la evaluación del riesgo sísmico y su gestión en centros urbanos: Acciones ex ante y ex post

The objectives of this thesis are: the ex ante seismic risk evaluation for urban centers, the disaster risk management evaluation and the ex post risk evaluation of the damaged buildings after an earthquake. A complete review of the basic concepts and of the most important recent works performed in these fields. These aspects are basic for the development of the new ex ante and ex post seismic risk evaluation approaches which are proposed in this thesis and for the s evaluation of the effectiveness of the disaster risk management.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. In Chapter 3 of this thesis, 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, which favour the second order effects when a hazard event strikes an urban centre. The proposed general urban risk evaluation method is multi-hazard and holistic, that is, an integrated and comprehensive approach whose objective is to guide decision-making. This method has been applied to the cities of Bogota, Colombia, and Barcelona, Spain, and it is being applied to Metro Manila, Philippines.Chapter 4 develops a methodology for the disaster risk management evaluation. A disaster risk management index, DRMi, is conceptually supported and formulated, which measures the performance and the effectiveness of the risk management in a territory that can be a country, a subnational region or a city. The proposed DRMi is developed by quantifying four public policies: the risk identification, the risk reduction, the disaster management and the governance and financial protection. With this methodology eleven countries of Latin America and the Caribbean; Colombia at subnational level and Bogota at urban level were evaluated.In chapter 5 a methodology for the ex-post evaluation of the seismic damage is developed, using computational intelligence techniques. It has the objective of assisting non-expert professionals of building construction in evaluating the damage and safety of buildings after strong earthquakes, facilitating decision-making on their habitability and reparability during the emergency response phase. This neuro-fuzzy system has been adopted for its official use by the cities of Bogota and Manizales, in Colombia.The conclusions of this thesis are shown in Chapter 6, where also future lines of investigation are presented. The main conclusions are:- The proposed model for the holistic evaluation of the seismic risk facilitates the integral risk management and the decision making on risk reduction. The analysis of the results allows to establish priorities for the mitigation and actions of prevention and planning aiming to modify the conditions that influence on the risk of the zone.- The proposed disaster risk management index, DRMi, is consistent, methodical and has been developed to measure the risk management performance. This index allows to make the evaluation in a systematic and quantitative way and allows to define operation objectives and to improve the efficiency of the risk management. - A novel system of support to the habitability and damage evaluation of buildings, based on fuzzy logic and artificial neural networks was proposed. This kind of tool is useful due to the type of information that is handled, which is subjective and incomplete. Linguistic qualifications can appropriately be represented by fuzzy sets. An artificial neuronal network was used to calibrate the system starting from the experts judgment.Finally, several annexes are included which include details on methodological and calculation aspects related to the of proposed risk evaluation methods.Postprint (published version

Evaluation of social context integrated into the study of seismic risk for urban areas

Usually the seismic risk evaluation involves only the estimation of the expected physical damage, casualties or economic losses. This article corresponds to a holistic approach for seismic risk assessment which involves the evaluation of the social fragility and the lack of resilience. The complementary evaluation of social context aspects such as the distribution of the population, the absence of economic and social development, deficiencies in institutional management, and lack of capacity for response and recovery; is useful in order to have seismic risk evaluation suitable to support a decision making processes for risk reduction. The proposed methodology allows a standardized assessment of the social fragility and lack of resilience, by means of an aggravating coefficient of which summarizes the characteristics of the social context using fuzzy sets and Analytic Hierarchy Process (AHP). The selection of 20 social indicators is based on the indicators used by urban observatories of United Nations and other social researchers. These indicators are classified according to social item they describe, in six categories. Applying the determination level analysis, thirteen prevailing social indicators are selected. The proposed methodology has been applied in the cities of Merida (Venezuela) and Barcelona (Spain).Peer ReviewedPostprint (published version

Disaster risk reduction: a decision-making support tool based on the morphological analysis

Risk management due to natural hazards is a multidimensional and complex problem since it requires the knowledge and experience of several disciplines. The effectiveness of risk management can be analyzed, inviting to the action through weakness identification of the urban area. This article proposes a methodology based on the morphological analysis to support the decision-making on disaster risk management, taking as a starting point the results of a holistic evaluation of the seismic risk. The results of the holistic evaluation of risk are achieved aggravating the physical risk using the contextual conditions, such as the socio-economic fragility and the lack of resilience. In consequence, the risk mitigation can be performed through the reduction of the potential damage and consequences involved; and the improvement of social conditions. The proposed methodology allows prioritizing the risk reduction strategies according to i) performance level of component indicators involved into the Disaster Risk Management index, DRMi; ii) physical risk factors dependent from the potential damages, and iii) aggravating factors involved in the aggravating coefficient. Moreover, it involves 35 strategies to reduce the physical risk and the aggravating social conditions of the urban area. The proposed methodology has been applied to the city of Mérida (Venezuela), located within an area of high seismic activity. The performance level of the indicators involved in the DRMi was evaluated by a survey to local experts. As a result, eleven strategies have been identified to reduce the potential damage and to improve the social conditions of this city.Peer ReviewedPostprint (author's final draft

Numerical method for the holistic evaluation of the seismic risk based on the fuzzy sets theory

La teoría de conjuntos difusos ofrece un puente entre el procesamiento simbólico y el numérico que permite el uso de conceptos cualitativos útiles en el proceso de toma de decisiones relacionadas con la gestión del riesgo sísmico y, en general, con la gestión del riesgo de desastres. Su utilización en la evaluación del riesgo sísmico es necesaria en el caso en que los datos para aplicar un método de evaluación convencional del riesgo no estén disponibles o sean insuficientes. Una posible solución, considerada en este artículo, consiste en sustituir la información que falta por la opinión de expertos y en procesar las variables cualitativas y las calificaciones lingüísticas que se obtengan de dichas opiniones en lugar de valores numéricos. El procesamiento se realiza utilizando la teoría de conjuntos difusos. Para lograr una gestión eficaz, el riesgo se debe definir como las posibles consecuencias físicas, económicas, sociales y ambientales que pueden ocurrir en un período de tiempo determinado debido a fenómenos peligrosos. Desde esta perspectiva holística, y utilizando la teoría de conjuntos difusos, el método numérico propuesto calcula un nivel de riesgo físico y un nivel de agravamiento relacionado con las condiciones de fragilidad social y falta de resiliencia, para determinar un nivel de riesgo total. En el artículo se incluyen 2 ejemplos de aplicación del método propuesto y los resultados obtenidos se comparan con los correspondientes a un método convencional de evaluación holística.The fuzzy set theory offers a bridge between the symbolic and numerical processing, allowing managing qualitative concepts useful in the decision-making process related to the seismic risk management and, in general, to the disaster risk management. Its use in the seismic risk evaluation is necessary in the cases where the data required to apply a conventional method of assessing risk are not available or are insufficient. One possible solution, considered in this article, is to replace the missing information by expert opinions and to process the resulting qualitative variables and linguistic qualifications instead of numerical values. This process is based on the fuzzy set theory. In order to achieve an effective management, the risk must be defined as the potential physical, economic, social and environmental consequences which occur due to hazards in a given period of time. From this holistic perspective and using the fuzzy set theory, the proposed numerical method calculates a level of the physical risk and level of the aggravating conditions related to social fragility and to the lack of resilience, to determine a total risk level. In the article are included two examples of application of the proposed method and the obtained results are compared with those corresponding to a conventional method of holistic evaluation.Peer Reviewe

A method for the evaluation of the risk management performance

Peer ReviewedPostprint (published version

Disaster risk since a macroeconomic perspective: a metric for fiscal vulnerability evaluation

The various planning agencies dealing with the economy, the environment, housing, infrastructure, agriculture, or health, to mention but a few relevant areas, must be made aware of the risks that each sector faces. In addition, the concerns of different levels of government should be addressed in a meaningful way. If risk is not presented and explained in a way that attracts stakeholders’ attention and concern, it will not be possible to make progress in reducing the impact of disasters. This means that appropriate evaluation tools are necessary to make it easy to understand the problem and guide the decision-making process, using the language of the policy makers and stakeholders. In this framework the Disaster Deficit Index (DDI) was developed, thinking in the need to have an appropriate figure to measure risk from macroeconomic and financial perspective and to evaluate the contingent liabilities that a potential extreme disaster may represent for the fiscal sustainability of a country. This extended abstract presents the model of the DDI and the results for fourteen countries of the Americas to express risk in the language of the finance decision makers and to guide the governmental investment for risk reduction, retention and transfer.Peer ReviewedPostprint (published version

Methodologies and tools of risk management: Hurricane Risk index (HRi)

Mexico is recognized worldwide for the extension of its coastlines and its tourist exploitation. Quintana Roo is one of the Mexican states, which has a shoreline of approximately 800 km, known as the Mexican Caribbean. The hurricanes that form in the Atlantic Ocean are the main natural hazard to which this region is exposed. In this article, hurricane risk is evaluated for coastal cities through the definition of a system of indicators. Based on this indicators system, the Hurricane Risk Index (HRi) is calculated. This system allows the construction of vulnerability indices for different dimensions: physical, environmental, social, economic, cultural and institutional. The obtained results can contribute to the definition of public prevention policies and actions to reduce the levels of vulnerability and increase the resilience of these communities. This indicators model is applied to two coastal cities of the Mexican Caribbean; Mahahual, obtaining an HRi of 82.13%, and Chetumal obtaining an HRi of 69.31%, corresponding to the impact of Hurricane Dean in 2007. The proposed indicators system can be replicated for different hazards.Peer ReviewedPostprint (author's final draft

Sistema de indicadores para la evaluación de riesgos

Para corregir las causas del riesgo mediante acciones de intervención de la vulnerabilidad y mediante el fortalecimiento de la capacidad de gestión del riesgo en todas sus modalidades y ámbitos, es necesario identificar y reconocer el riesgo existente y las posibilidades de generación de nuevos riesgos desde la perspectiva de los desastres naturales. Esto implica dimensionar o medir el riesgo y monitorearlo con el fin de determinar la efectividad y eficiencia de las medidas de intervención; sean estas tanto correctivas como prospectivas. La evaluación y seguimiento del riesgo es un paso ineludible para su reconocimiento por parte de los diversos actores sociales y los órganos de decisión responsables de la gestión. Es decir, es necesario hacer manifiesto el riesgo, socializarlo e identificar sus causas. En consecuencia, dicha evaluación y seguimiento debe realizarse utilizando herramientas apropiadas e idóneas que faciliten la comprensión del problema y orienten la toma de decisiones. El propósito del sistema de indicadores aquÃí descrito es dimensionar la vulnerabilidad y el riesgo, usando indicadores relativos, para facilitar a los tomadores de decisiones de cada país , región o ciudad tener acceso a información relevante que les permita identificar y proponer acciones efectivas de gestión del riesgo, considerando aspectos económicos, sociales, institucionales y técnicos. Este sistema de indicadores permite representar el riesgo y la gestión del riesgo a escala nacional, subnacional, y urbano, facilitándo la identificación de los aspectos esenciales que lo caracterizan desde una perspectiva económica y social, así como también comparar estos aspectos o el riesgo mismo de los diferentes países o unidades territoriales estudiadas.Postprint (published version

Comparing observed damages and losses with modelled ones using a probabilistic approach: the Lorca 2011 case

A loss and damage assessment was performed for the buildings of Lorca, Spain, considering an earthquake hazard scenario with similar characteristics to those of a real event which occurred on May 11th, 2011, in terms of epicentre, depth and magnitude while also considering the local soil response. This low-to moderate earthquake caused severe damage and disruption in the region and especially on the city. A building by building resolution database was developed and used for damage and loss assessment. The portfolio of buildings was characterized by means of indexes capturing information from a structural point of view such as age, main construction materials, number of stories, and building class as well as others related to age and vulnerability classes. A replacement cost approach was selected for the analysis in order to calculate the direct losses incurred by the event. Seismic hazard and vulnerability were modelled in a probabilistic way, considering their inherent uncertainties which were also taken into account in the damage and loss calculation process. Losses have been expressed in terms of the mean damage ratio of each dwelling and since the analysis has been performed on a geographical information system platform, the distribution of the damage and its categories was mapped for the entire urban centre. The simulated damages and losses were compared with the observed ones reported by the local authorities and institutions that inspected the city after the event.Peer ReviewedPostprint (author's final draft

Evaluation of the habitability of buildings affected by an earthquake using the fuzzy sets theory and the artificial neural networks

La teoría de conjuntos difusos y las redes neuronales son herramientas de inteligencia computacional que cada vez tienen un uso más extendido en la ingeniería sísmica. En este artículo se desarrolla un método y una herramienta computacional que hace uso de estas técnicas para apoyar la evaluación del daño y de la seguridad de los edificios después de sismos fuertes. Se utiliza una red neuronal artificial de tres capas y un algoritmo de aprendizaje tipo Kohonen, así como conjuntos difusos para manipular información subjetiva como las calificaciones de los niveles de daño presentes en los edificios evaluados. También se aplica una base de reglas difusas para contribuir al proceso de toma de decisiones. Se ha desarrollado un programa de ordenador que utiliza estas técnicas, cuyos datos de entrada del programa corresponden a la información subjetiva e incompleta del estado del edificio obtenida por profesionales posiblemente inexpertos en el campo de la evaluación del comportamiento sísmico de los edificios. El método propuesto ha sido implementado en una herramienta de especial utilidad durante la fase de respuesta a emergencias, que facilita las decisiones sobre habitabilidad y reparabilidad de los edificios. Para ilustrar su aplicación, se incluyen ejemplos de aplicación del programa para dos clases diferentes de edificios.The fuzzy sets theory and the artificial neural networks are computational intelligence tools which are nowadays widely used in earthquake engineering. This paper develops a method and a computer program which use these computational intelligence tools in order to support the damage and safety evaluation of buildings after strong earthquakes. The model uses an artificial neural network with three layers and a Kohonen learning algorithm; it also uses fuzzy sets in order to manage subjective information such as linguistic qualification of the damage levels in buildings and a fuzzy rule base to support the decision making process. All these techniques are incorporated in the developed computer program. The input data is the subjective and incomplete information about the building state obtained by possibly non experienced evaluators in the field of the seismic performance of buildings. The proposed method is implemented in a tool especially useful in the emergency response phase, when it supports the decision making regarding the building habitability and reparability. In order to show its effectiveness, two examples are included for two different types of buildings.Peer Reviewe