Moldels for reproducing the damage scenario of the Lorca earthquake

A damage scenario modelling is developed and compared with the damage distribution observed after the 2011 Lorca earthquake. The strong ground motion models considered include five modern ground motion prediction equations (GMPEs) amply used worldwide. Capacity and fragility curves from the Risk-UE project are utilized to model building vulnerability and expected damage. Damage estimates resulting from different combinations of GMPE and capacity/fragility curves are compared with the actual damage scenario, establishing the combination that best explains the observed damage distribution. In addition, some recommendations are proposed, including correction factors in fragility curves in order to reproduce in a better way the observed damage in masonry and reinforce concrete buildings. The lessons learned would contribute to improve the simulation of expected damages due to future earthquakes in Lorca or other regions in Spain with similar characteristics regarding attenuation and vulnerability

Study of seismic vulnerability and the damage seen in the town of Lorca after the earthquake of 2011.

Análisis de los factores de vulnerabilidad que mas influencia han tenido en el daño del terremoto de Lorca

How new fault data and models affect seismic hazard results? Examples from southeast Spain

In this work, we study the impact of different approaches to incorporate faults in a seismic hazard assessment analysis. Firstly, we consider two different methods to distribute the seismicity of the study area into faults and area-sources, based on magnitude partitioning and on moment rate distribution. We use two recurrence models to characterize fault activity: the characteristic earthquake model and the modified Gutenberg-Richter exponential frequency-magnitude distribution. An application of the work is developed in the region of Murcia (southeastern Spain), due to the availability of fault data and because is one of the areas in Spain with higher seismic hazard. The parameters used to model fault sources are derived from paleoseismological and field studies obtained from the literature and online repositories. Additionally, for some significant faults only, geodetically-derived slip rates are used to compute recurrence periods. The results of all the seismic hazard computations carried out using different models and data are represented in maps of expected peak ground accelerations for a return period of 475 years. Maps of coefficients of variation are presented to constraint the variability of the end-results to different input models and values. Additionally, the different hazard maps obtained in this study are compared with the seismic hazard maps obtained in previous work for the entire Spanish territory and more specifically for the region of Murcia. This work is developed in the context of the MERISUR project (ref. CGL2013-40492-R), with funding from the Spanish Ministry of Economy and Competitiveness

Methodology for an effective risk assessment of urban areas: progress and first results of the merisur project

The progress and results the MERISUR, Methodology for an Effective RISk assessment of URban areas, are presented. This project aims at developing an effective methodology for urban seismic risk assessment that provides solutions to some deficiencies detected after recent damaging events worldwide, including risk mitigation actions based on benefit/cost ratios. In a fisrt stage, the hazard and vulnerability models are developed and improved. A procedure to determine the hazard-controlling seismogenic fault, contsistent with different probability levels, is established. Methods to include active faults as individual sources and to consider near filed effects that significantly amplify ground motions are proposed. A more complete description of seismic vulnerability encompassing structural, non-structural components is accomplished. Vulnerability modifiers to incorporate effects or urban parameters on vulnerability classes are also quantified. A distinction is also made between damage to structural and non-structural building elements. For this purpose, a pushover analysis is specifically carried out to model building response and damage trends on non-structural elements. This gives the primary damage. In addition, the area covered by the resulting debris is also estimated both in inner spaces (within the building) and in the outer space (public roads and streets). In this way, a volume of debris will be associated to each area unit of the city, and the potential damage to persons and elements exposed, such as urban furniture and vehicles, will be assessed. This constitutes the secondary damage. A static level of occupation (building, urban furniture, etc.) and a dynamic level of occupation (persons, vehicles) will be assigned to each area unit of the city, hereby defining the exposure in time and space. Earthquake losses related to primary damage of building components and to secondary damage (such as urban furniture and vehicles) will be also assessed. Cost/benefit ratios between ex ante risk mitigation measurements will be developed in order to decide whether risk transfer or risk retention is preferable for different risk scenarios. This analysis will confer effectiveness to the results of a seismic risk study. Overall, the estimate of earthquake losses and cost/benefit ratios are topics with little presence in the scientific literature concerning damaging earthquakes in Spain. Thus, the results of this study will provide effective solutions to the challenge to society tackled in this proposal

Modelizaciones y análisis de sensibilidad en la evaluación integral del riesgo sísmico a escala urbana : aplicación a la ciudad de Lorca

En esta tesis se presenta una propuesta metodológica para la evaluación integral del riesgo sísmico en un entorno urbano, con alto grado de resolución, identificando los métodos actuales y modelos óptimos para la caracterización de las cuatro fases principales en el cálculo del riesgo: peligrosidad, efecto local, vulnerabilidad y cuantificación del daño. Como contribución inédita se incorpora en la metodología un árbol lógico para considerar distintas distribuciones de vulnerabilidad que se simulan estocásticamente por un método de Montecarlo y diferentes métodos de cálculo del daño, con el fin de cuantificar las incertidumbres inherentes a estos dos aspectos. La metodología propuesta es aplicada al núcleo urbano de la ciudad de Lorca, para la cual se realiza realiza un cálculo de peligrosidad con enfoque probabilista-determinista, mediante dos métodos de cálculo: clásico zonificado (MCZ) e hibrido (MH) considerando como fuentes sísmicas zonas y fallas, del que se identifican dos escenarios sísmicos: 1) un sismo de Mw 5.2 a corta distancia para periodo de retorno PR 475 años y 2) Un sismo de Mw 6.3 a 15 km para PR de 975 años. El primer escenario coincide con las características del sismo de Lorca, 2011, por lo que se simula el escenario de daños tomando la localización y el plano de ruptura de la falla de Alhama de Murcia que generó el terremoto, y considerando diferentes modelos de movimiento fuerte (GMPEs). Se analiza la sensibilidad de los diferentes modelos y métodos en los resultados de peligrosidad y se identifican los que reproducen mejor las aceleraciones registradas en el sismo de 2011. Se realiza además un análisis de sensibilidad considerando distintas distribuciones de vulnerabilidad y efectuando simulaciones de Montecarlo con muestras de 100, 1000, 2000 y 3000 edificios, para valorar el efecto que tiene la asignación de vulnerabilidad en los resultados de daño. Este método se aplica al caso concreto de Lorca, calculando el daño para la distribución de vulnerabilidad de una muestra detallada obtenida en campaña de campo y para la vulnerabilidad asignada a todo el parque inmobiliario de la ciudad de Lorca, comparando los resultados teóricos con los daños observados tras el terremoto. Los modelos y resultados de la calibración con el escenario del sismo de Lorca 2011, se utilizan para simular el segundo escenario, correspondiente a un sismo extremo de Mw 6.5, con 5 % de probabilidad de excedencia en 50 años. Estos resultados pueden ser de utilidad para la definición de planes de emergencia en la ciudad de Lorca. Finalmente se extraen una serie de conclusiones referentes a las diferentes fases del cálculo, a los modelos que reproducen mejor el movimiento y los daños, al impacto de usar diferentes modelos y métodos en los resultados finales y a la incertidumbre inherente a cada aspecto del problema. Se ha desarrollado un software específico para aplicar la metodología propuesta que puede considerarse otra contribución de esta tesis. ----------ABSTRACT---------- This thesis presents a methodological proposal for the comprehensive assessment of the seismic risk in an urban environment, with a high degree of resolution, identifying the current methods and optimal models for the characterization of the four main phases in the risk calculation: hazard, local effect, vulnerability and damage quantification. As an unpublished contribution, a logic tree is incorporated into the methodology for the consideration of different vulnerability distributions that are stochastically simulated by the Montecarlo method and different analysis procedures for damage estimation, in order to quantify the uncertainties inherent in these two aspects. The proposed methodology is applied to the urban center of Lorca, Spain. A seismic hazard assessment is carried out with a probabilistic-deterministic approach, by means of two methods: classic area source method (MCZ) and an hybrid method (MH) considering zones and faults, from which two seismic scenarios are identified: 1) an Mw 5.2 earthquake at a short distance for a return period of RP 475 years and 2) an Mw 6.3 earthquake at 15 km for RP of 975 years. The first scenario coincides with the characteristics of the earthquake of Lorca, 2011, so there ir a simulation for the damage scenario taking into account the location and the plane of rupture of the fault Alhama de Murcia that generated the earthquake, and considering different ground motion prediction equations (GMPEs). The sensitivity of the different models and methods in the hazards assessment results is analyzed, identifying the ones that reproduce the best the accelerations recorded in the 2011 earthquake. A sensitivity analysis was also performed with different vulnerability distributions and Montecarlo simulations with samples of 100, 1000, 2000 and 3000 buildings, in orden to assess the effect of vulnerability distributions on the damage results. This method is applied to the specific case of Lorca, with the quantification of damage for the vulnerability assessment of a detailed building stock sample obtained in a field campaign and for the vulnerability assigned to the entire building stock of Lorca comparing the theoretical results with the observed damage after the earthquake. The models and results of the calibration with the scenario of the 2011 Lorca earthquake are used to simulate the second scenario, corresponding to an extreme earthquake Mw 6.5, with a 5% probability of exceedance in 50 years. These results can be useful for the definition of emergency plans in Lorca. Finally, a series of conclusions are drawn concerning the different phases of the calculation, the models that better reproduce movement and damage, the impact of using different models and methods in the final results and the uncertainty inherent in each aspect of the problem. A specific software has been developed for the application od the proposed methodology. It can be considered as another contribution of this thesis

Análisis de modelos y datos nuevos sobre fallas en la peligrosidad sísmica

El objeto de este trabajo es estudiar el impacto del uso de diferentes modelos de fuente sísmica y de datos relativamente nuevos sobre los resultados de peligrosidad sísmica. Se consideran do métodos para separar la sismicidad asignada a fallas y zonas de sismicidad uniformemente distribuida. El primero se basa en la repartición de la sismicidad de acuerdo con el valor de magnitud. Los terremotos grandes ocurren en fuentes tipo fallas y responden a un modelo de recurrencia del terremoto característico. La sismicidad restante se asocia a la zona, modelizada mediante un modelo de Gutenberg-Richter modificado. El segundo método reparte el potencial sísmico entre zonas y fallas según la distribución de tasa de momento sísmico de las diferentes fuentes dentro del intervalo de magnitudes en el que el catálogo es completo. En este caso, todas las fuentes son representadas por un modelo de recurrencia de Gutenberg-Richter modificado. Se realiza una aplicación en Murcia, por ser una de las más activas de España y en la que hay disponibilidad de datos de deformación de fallas obtenidos a partir de estudios paleosismológicos y de medidas GPS. Los resultados apuntan a una variabilidad significativa (un factor x2) en los valores de aceleración máxima del terreno esperada dependiendo de la tasa de deformación de fallas y el modelo de fuente considerado. Los mapas de coeficiente de variación muestran que la variabilidad debida a ambos factores repercute de forma similar en los resultados finales. Este trabajo es parte del proyecto MERISUR (ref. CGL2013-40492-R), Ministerio de Economía y Competitividad

Análisis de modelos y datos nuevos sobre fallas en la peligrosidad sísmica

El objeto de este trabajo es estudiar el impacto del uso de diferentes modelos de fuente sísmica y de datos relativamente nuevos sobre los resultados de peligrosidad sísmica. Se consideran do métodos para separar la sismicidad asignada a fallas y zonas de sismicidad uniformemente distribuida. El primero se basa en la repartición de la sismicidad de acuerdo con el valor de magnitud. Los terremotos grandes ocurren en fuentes tipo fallas y responden a un modelo de recurrencia del terremoto característico. La sismicidad restante se asocia a la zona, modelizada mediante un modelo de Gutenberg-Richter modificado. El segundo método reparte el potencial sísmico entre zonas y fallas según la distribución de tasa de momento sísmico de las diferentes fuentes dentro del intervalo de magnitudes en el que el catálogo es completo. En este caso, todas las fuentes son representadas por un modelo de recurrencia de Gutenberg-Richter modificado. Se realiza una aplicación en Murcia, por ser una de las más activas de España y en la que hay disponibilidad de datos de deformación de fallas obtenidos a partir de estudios paleosismológicos y de medidas GPS. Los resultados apuntan a una variabilidad significativa (un factor x2) en los valores de aceleración máxima del terreno esperada dependiendo de la tasa de deformación de fallas y el modelo de fuente considerado. Los mapas de coeficiente de variación muestran que la variabilidad debida a ambos factores repercute de forma similar en los resultados finales. Este trabajo es parte del proyecto MERISUR (ref. CGL2013-40492-R), Ministerio de Economía y Competitividad

How new fault data and models affect seismic hazard results? Examples from southeast Spain

In this work, we study the impact of different approaches to incorporate faults in a seismic hazard assessment analysis. Firstly, we consider two different methods to distribute the seismicity of the study area into faults and area-sources, based on magnitude partitioning and on moment rate distribution. We use two recurrence models to characterize fault activity: the characteristic earthquake model and the modified Gutenberg-Richter exponential frequency-magnitude distribution. An application of the work is developed in the region of Murcia (southeastern Spain), due to the availability of fault data and because is one of the areas in Spain with higher seismic hazard. The parameters used to model fault sources are derived from paleoseismological and field studies obtained from the literature and online repositories. Additionally, for some significant faults only, geodetically-derived slip rates are used to compute recurrence periods. The results of all the seismic hazard computations carried out using different models and data are represented in maps of expected peak ground accelerations for a return period of 475 years. Maps of coefficients of variation are presented to constraint the variability of the end-results to different input models and values. Additionally, the different hazard maps obtained in this study are compared with the seismic hazard maps obtained in previous work for the entire Spanish territory and more specifically for the region of Murcia. This work is developed in the context of the MERISUR project (ref. CGL2013-40492-R), with funding from the Spanish Ministry of Economy and Competitiveness

Methodology for an effective risk assessment of urban areas: progress and first results of the merisur project

The progress and results the MERISUR, Methodology for an Effective RISk assessment of URban areas, are presented. This project aims at developing an effective methodology for urban seismic risk assessment that provides solutions to some deficiencies detected after recent damaging events worldwide, including risk mitigation actions based on benefit/cost ratios. In a fisrt stage, the hazard and vulnerability models are developed and improved. A procedure to determine the hazard-controlling seismogenic fault, contsistent with different probability levels, is established. Methods to include active faults as individual sources and to consider near filed effects that significantly amplify ground motions are proposed. A more complete description of seismic vulnerability encompassing structural, non-structural components is accomplished. Vulnerability modifiers to incorporate effects or urban parameters on vulnerability classes are also quantified. A distinction is also made between damage to structural and non-structural building elements. For this purpose, a pushover analysis is specifically carried out to model building response and damage trends on non-structural elements. This gives the primary damage. In addition, the area covered by the resulting debris is also estimated both in inner spaces (within the building) and in the outer space (public roads and streets). In this way, a volume of debris will be associated to each area unit of the city, and the potential damage to persons and elements exposed, such as urban furniture and vehicles, will be assessed. This constitutes the secondary damage. A static level of occupation (building, urban furniture, etc.) and a dynamic level of occupation (persons, vehicles) will be assigned to each area unit of the city, hereby defining the exposure in time and space. Earthquake losses related to primary damage of building components and to secondary damage (such as urban furniture and vehicles) will be also assessed. Cost/benefit ratios between ex ante risk mitigation measurements will be developed in order to decide whether risk transfer or risk retention is preferable for different risk scenarios. This analysis will confer effectiveness to the results of a seismic risk study. Overall, the estimate of earthquake losses and cost/benefit ratios are topics with little presence in the scientific literature concerning damaging earthquakes in Spain. Thus, the results of this study will provide effective solutions to the challenge to society tackled in this proposal

Sismo-Haití: Proyecto de cooperación para el cálculo de la peligrosidad y el riesgo sísmico en Haití

El terremoto ocurrido el 12 de enero de 2010 en Haití devastó la ciudad de Puerto Príncipe, interrumpiendo la actividad social y económica. El proyecto Sismo-Haití surgió como respuesta a la solicitud de ayuda del país ante esta catástrofe y está siendo llevado a cabo por el grupo de investigación en Ingeniería Sísmica de la Universidad Politécnica de Madrid, especialistas en geología y sismología de las universidades Complutense de Madrid, Almería y Alicante, el Consejo Superior de Iinvestigaciones Científicas y técnicos locales. En el marco del citado proyecto se realizará un estudio de la amenaza sísmica, con la consiguiente obtención de mapas de aceleraciones que sirvan de base para una primera normativa sismorresistente en el país. Asimismo, se llevará a cabo un estudio de riesgo sísmico en alguna población piloto, incluyendo estudios de microzonación y vulnerabilidad sísmica, así como la estimación de daños y pérdidas humanas ante posibles sismos futuros, cuyos resultados irán dirigidos al diseño de planes de emergencia. En este trabajo se presentan los primeros avances del proyecto. Uno de los objetivos más importantes del proyecto Sismo-Haití es la formación de técnicos en el país a través de la transmisión de conocimientos y experiencia que el grupo de trabajo tiene en materia de peligrosidad y riesgo sísmico, así como en todo lo relacionado con la gestión de la emergencia.The January, 2010 Haiti earthquake devastated the city of Pot au Prince, interrupting the social and economical activity. The Sismo-Haiti cooperative project emerged as a response to the Haitian country assistance request and it is being carried out by the Earthquake Engineering Researching Group (Technical University of Madrid), specialists in Geology and Seismology from the Complutense University of Madrid, the Universities of Almería and Alicante, the High Council for Scientific Research and local technicians. Within the frame of the mentioned project, a seismic hazard assessment will be conducted and the hazard maps to be obtained will be used as a basis for the first Haitian seismic code. As well, a seismic risk estimation in a pilot city will be carried out, including micro-zoning and seismic vulnerability studies and the evaluation of damage and human losses due to possible future earthquakes; the results will be used to design post-event emergency plans. In this paper, the first results of this project are presented. An important goal of the Sismo-Haiti project is to contribute to the transfer of knowledge and expertise on seismic hazard and risk as well as other topics related to emergency management.Depto. de Geodinámica, Estratigrafía y PaleontologíaDepto. de Física de la Tierra y AstrofísicaFac. de Ciencias GeológicasTRUEpu