Estimación del riesgo sísmico en puerto príncipe (Haití)

Tras el devastador terremoto del 12 de enero de 2010 en Puerto Príncipe, Haití, las autoridades locales, numerosas ONGs y organismos nacionales e internacionales están trabajando en el desarrollo de estrategias para minimizar el elevado riesgo sísmico existente en el país. Para ello es necesario, en primer lugar, estimar dicho riesgo asociado a eventuales terremotos futuros que puedan producirse, evaluando el grado de pérdidas que podrían generar, para dimensionar la catástrofe y actuar en consecuencia, tanto en lo referente a medidas preventivas como a adopción de planes de emergencia. En ese sentido, este Trabajo Fin de Master aporta un análisis detallado del riesgo sísmico asociado a un futuro terremoto que podría producirse con probabilidad razonable, causando importantes daños en Puerto Príncipe. Se propone para ello una metodología de cálculo del riesgo adaptada a los condicionantes de la zona, con modelos calibrados empleando datos del sismo de 2010. Se ha desarrollado en el marco del proyecto de cooperación Sismo-Haití, financiado por la Universidad Politécnica de Madrid, que comenzó diez meses después del terremoto de 2010 como respuesta a una petición de ayuda del gobierno haitiano. El cálculo del riesgo requiere la consideración de dos inputs: la amenaza sísmica o movimiento esperado por el escenario definido (sismo de cierta magnitud y localización) y los elementos expuestos a esta amenaza (una clasificación del parque inmobiliario en diferentes tipologías constructivas, así como su vulnerabilidad). La vulnerabilidad de estas tipologías se describe por medio de funciones de daño: espectros de capacidad, que representan su comportamiento ante las fuerzas horizontales motivadas por los sismos, y curvas de fragilidad, que representan la probabilidad de que las estructuras sufran daños al alcanzar el máximo desplazamiento horizontal entre plantas debido a la mencionada fuerza horizontal. La metodología que se propone especifica determinadas pautas y criterios para estimar el movimiento, asignar la vulnerabilidad y evaluar el daño, cubriendo los tres estados del proceso. Por una parte, se consideran diferentes modelos de movimiento fuerte incluyendo el efecto local, y se identifican los que mejor ajustan a las observaciones de 2010. Por otra se clasifica el parque inmobiliario en diferentes tipologías constructivas, en base a la información extraída en una campaña de campo y utilizando además una base de datos aportada por el Ministerio de Obras Públicas de Haití. Ésta contiene información relevante de todos los edificios de la ciudad, resultando un total de 6 tipologías. Finalmente, para la estimación del daño se aplica el método capacidad-demanda implementado en el programa SELENA (Molina et al., 2010). En primer lugar, utilizado los datos de daño del terremoto de 2010, se ha calibrado el modelo propuesto de cálculo de riesgo sísmico: cuatro modelos de movimiento fuerte, tres modelos de tipo de suelo y un conjunto de funciones de daño. Finalmente, con el modelo calibrado, se ha simulado un escenario sísmico determinista correspondiente a un posible terremoto con epicentro próximo a Puerto Príncipe. Los resultados muestran que los daños estructurales serán considerables y podrán llevar a pérdidas económicas y humanas que causen un gran impacto en el país, lo que pone de manifiesto la alta vulnerabilidad estructural existente. Este resultado será facilitado a las autoridades locales, constituyendo una base sólida para toma de decisiones y adopción de políticas de prevención y mitigación del riesgo. Se recomienda dirigir esfuerzos hacia la reducción de la vulnerabilidad estructural - mediante refuerzo de edificios vulnerables y adopción de una normativa sismorresistente- y hacia el desarrollo de planes de emergencia. Abstract After the devastating 12 January 2010 earthquake that hit the city of Port-au-Prince, Haiti, strategies to minimize the high seismic risk are being developed by local authorities, NGOs, and national and international institutions. Two important tasks to reach this objective are, on the one hand, the evaluation of the seismic risk associated to possible future earthquakes in order to know the dimensions of the catastrophe; on the other hand, the design of preventive measures and emergency plans to minimize the consequences of such events. In this sense, this Master Thesis provides a detailed estimation of the damage that a possible future earthquake will cause in Port-au-Prince. A methodology to calculate the seismic risk is proposed, adapted to the study area conditions. This methodology has been calibrated using data from the 2010 earthquake. It has been conducted in the frame of the Sismo-Haiti cooperative project, supported by the Technical University of Madrid, which started ten months after the 2010 earthquake as an answer to an aid call of the Haitian government. The seismic risk calculation requires two inputs: the seismic hazard (expected ground motion due to a scenario earthquake given by magnitude and location) and the elements exposed to the hazard (classification of the building stock into building typologies, as well as their vulnerability). This vulnerability is described through the damage functions: capacity curves, which represent the structure performance against the horizontal forces caused by the seisms; and fragility curves, which represent the probability of damage as the structure reaches the maximum spectral displacement due to the horizontal force. The proposed methodology specifies certain guidelines and criteria to estimate the ground motion, assign the vulnerability, and evaluate the damage, covering the whole process. Firstly, different ground motion prediction equations including the local effect are considered, and the ones that have the best correlation with the observations of the 2010 earthquake, are identified. Secondly, the classification of building typologies is made by using the information collected during a field campaign, as well as a data base provided by the Ministry of Public Works of Haiti. This data base contains relevant information about all the buildings in the city, leading to a total of 6 different typologies. Finally, the damage is estimated using the capacity-spectrum method as implemented in the software SELENA (Molina et al., 2010). Data about the damage caused by the 2010 earthquake have been used to calibrate the proposed calculation model: different choices of ground motion relationships, soil models, and damage functions. Then, with the calibrated model, a deterministic scenario corresponding to an epicenter close to Port-au-Prince has been simulated. The results show high structural damage, and therefore, they point out the high structural vulnerability in the city. Besides, the economic and human losses associated to the damage would cause a great impact in the country. This result will be provided to the Haitian Government, constituting a scientific base for decision making and for the adoption of measures to prevent and mitigate the seismic risk. It is highly recommended to drive efforts towards the quality control of the new buildings -through reinforcement and construction according to a seismic code- and the development of emergency planning.

El Terremoto de Lorca (2011) en el contexto de la peligrosidad y el riesgo sísmico en Murcia.

Este trabajo presenta un análisis de diferentes aspectos relacionados con el sismo principal del 11 de Mayo de 2011, con epicentro en las proximidades de Lorca, que abarcan desde el movimiento fuerte registrado hasta el daño observado en diferentes tipologías constructivas, contrastando todo ello con los resultados de estudios previos de peligrosidad y riesgo sísmico en la provincia de Murcia. La cuestión esencial que se plantea en el análisis es si tanto el movimiento como el daño entraban dentro de lo esperado o pueden considerarse anómalos en el marco del riesgo sísmico del sureste de España. A este respecto se hacen una serie de reflexiones y se extraen lecciones aprendidas del terremoto, que llevan a proponer recomendaciones de cara a la revisión de la Norma Sismorresistente Española, así como a definir medidas para la reducción del riesgo sísmico en la región. Abstract: An analysis of the different aspects related to the May 11th, 2011 Lorca earthquake is presented,covering recorded ground motions, damage observed in different building typologies, and contrasting these observations with previous results on seismic hazard and seismic risk obtained in the province of Murcia. The essential question addressed in the analysis is whether observed ground motions and physical damage can be considered as expected or as anomalous in the frame of seismic risk in southeastern Spain. In this respect, a number of reflections are carried out and several learned lessons from the earthquake are extracted, which leads to the proposal of different recommendations for the future revision of the Spanish earthquake-resistant provisions, as well as for defining risk reduction measurements in the region.

Contribución metodológica para incorporar fallas activas en la modelización de la fuente dirigida a estimaciones de peligrosidad sísmica. Aplicación al sur de España

En el presente trabajo se desarrolla una metodología para caracterizar fallas activas como fuentes sísmicas independientes en combinación con zonas sismogenéticas tipo área de cara a la estimación probabilista poissoniana de la peligrosidad sísmica. Esta metodología está basada en el reparto de la tasa de momento sísmico registrada en una región entre las fuentes potencialmente activas subyacentes (fallas activas modelizadas de forma independiente y una zonificación sismogenética), haciendo especial hincapié en regiones de sismicidad moderada y fallas de lento movimiento. Se desarrolla una aplicación de la metodología en el sureste de España, incorporando al cálculo 106 fuentes sísmicas independientes: 95 de tipo falla (catalogadas como fallas activas en la base de datos QAFI) y 11 zonas sismogenéticas de tipo área. Del mismo modo, se estima la peligrosidad sísmica con el método clásico zonificado y se comparan los resultados, analizando la influencia de la inclusión de las fallas de forma independiente en la estimación de la peligrosidad. Por último, se desarrolla una aplicación de la metodología propuesta en la estimación de la peligrosidad sísmica considerando un modelo temporal no poissoniano. La aplicación se centra en la falla de Carboneras, mostrando la repercusión que puede tener este cambio de modelo temporal en la estimación final de la peligrosidad. ABSTRACT A new methodology of seismic source characterization to be included in poissonian, probabilistic seismic hazard assessments, is developed in this work. Active faults are considered as independent seismogenic sources in combination with seismogenic area sources. This methodology is based in the distribution of the seismic moment rate recorded in a region between the potentially active underlying seismic sources that it contains (active faults modeled independently and an area-source seismic model), with special emphasis on regions with moderate seismicity and faults with slow deformation rates. An application of the methodology is carried out in the southeastern part of Spain, incorporating 106 independent seismic sources in the computations: 95 of fault type (catalogued as active faults in the Quaternary Active Fault Database, QAFI) and 11 of area-source type. At the same time, the seismic hazard is estimated following the classical area-source method. The results obtained using both methodologies (the classical one and the one proposed in this work9 are compared, analyzing the influence of the inclusion of faults as independent sources in hazard estimates. Finally, an application of the proposed methodology considering a non-poissonian time model is shown. This application is carried out in the Carboneras fault and shows the repercussion that this change of time model has in the final hazard estimates.

Foreword special issue Lorca’s earthquake

(This is an excerpt from the content) On May 11 2011 at 1705 hours, a small 4.5 Mw. magnitude earthquake struck the town of Lorca in south-eastern Spain. Other than alarmed citizens, only minor damage to buildings occurred due to this quake. Unfortunately at 1847 hours, a second shock registering a magnitude of 5.1 Mw. and very shallow (just around 2 km under the city) produced the largest seismic catastrophe registered in Spain in the last 120 years. This second shock is commonly referred to as “Lorca’s earthquake” and the following papers describe the context, circumstances and consequences of the event. Spain is a country of moderate seismic hazard in a global context. Before the Lorca earthquake, the most destructive earthquake in modern times was the so-called “Andalusian earthquake” (25th December 1884) that resulted in 750 fatalities and more than 1,500 injuries, reaching X in Mercalli’s intensity scale. Despite the lack of catastrophic events in the last 120 years, Spain has always had a scientific interest in seismic ...

Using damage from 2010 Haiti earthquake for vulnerability estimation of typical structures in Port-au-Prince (Haiti).

After the 2010 Haiti earthquake, that hits the city of Port-au-Prince, capital city of Haiti, a multidisciplinary working group of specialists (seismologist, geologists, engineers and architects) from different Spanish Universities and also from Haiti, joined effort under the SISMO-HAITI project (financed by the Universidad Politecnica de Madrid), with an objective: Evaluation of seismic hazard and risk in Haiti and its application to the seismic design, urban planning, emergency and resource management. In this paper, as a first step for a structural damage estimation of future earthquakes in the country, a calibration of damage functions has been carried out by means of a two-stage procedure. After compiling a database with observed damage in the city after the earthquake, the exposure model (building stock) has been classified and through an iteratively two-step calibration process, a specific set of damage functions for the country has been proposed. Additionally, Next Generation Attenuation Models (NGA) and Vs30 models have been analysed to choose the most appropriate for the seismic risk estimation in the city. Finally in a next paper, these functions will be used to estimate a seismic risk scenario for a future earthquake.

Modelización de las fallas activas para la estimación de la Peligrosidad Sísmica. Aplicación Metodológica en Haití

The development of this Master's Thesis is aimed at modeling active for estimating seismic hazard in Haití failures. It has been used zoned probabilistic method, both classical and hybrid, considering the incorporation of active faults as independent units in the calculation of seismic hazard. In this case, the rate of seismic moment is divided between the failures and the area seismogenetic same region. Failures included in this study are the Septentrional, Matheux and Enriquillo fault. We compared the results obtained by both methods to determine the importance of considering the faults in the calculation. In the first instance, updating the seismic catalog, homogenization, completeness analysis and purification was necessary to obtain a catalog ready to proceed to the estimation of the hazard. With the seismogenic zoning defined in previous studies and the updated seismic catalog, they are obtained relations Gutenberg-Richter recurrence of seismicity, superficial and deep in each area. Selected attenuation models were those used in (Benito et al., 2011), as the tectonic area of study is very similar to that of Central America. Its implementation has been through the development of a logical in which each branch is multiplied by an index based on the relevance of each combination of models. Results are presented as seismic hazard maps for return periods of 475, 975 and 2475 years, and spectral acceleration (SA) in structural periods: 0.1 - 0.2 - 0.5 - 1.0 and 2.0 seconds, and the difference accelerations between maps obtained by the classical method and the hybrid method. Maps realize the importance of including faults as separate items in the calculation of the hazard. The morphology of the zoned maps presented higher values in the area where the superficial and deep zone overlap. In the results it can determine that the minimum values in the zoned approach they outweigh the hybrid method, especially in areas where there are no faults. Higher values correspond to those obtained in fault zones by the hybrid method understanding that the contribution of the faults in this method is very important with high values. The maximum value of PGA obtained is close to Septentrional in 963gal, near to 460 gal in Matheux, and the Enriquillo fault line value reaches 760gal PGA in the Eastern segment and Western 730gal in the segment. This compares with that obtained in the zoned approach in this area where the value of PGA obtained was 240gal. These values are compared with those obtained by Frankel et al., (2011) with those have much similarity in values and morphology, in contrast to those presented by Benito et al., (2012) and the Standard Seismic Dominican Republic

Desarrollos metodológicos y aplicaciones hacia el cálculo de la peligrosidad sísmica en el ecuador continental y estudio de riesgo sísmico en la ciudad de Quito

En el presente trabajo de tesis se desarrolla, en primer lugar, un estudio de peligrosidad sísmica en Ecuador continental, siguiendo una metodología probabilista zonificada. El estudio se plantea a escala regional y presenta como principales aportaciones: 1) la elaboración de un Estado del Arte sobre Tectónica y Geología de Ecuador, concluyendo con la identificación de las principales fuentes sísmicas; 2) La confección de un Catálogo Sísmico de proyecto, recopilando información de distintas agencias, que ha sido homogeneizado a magnitud momento, Mw, depurado de réplicas y premonitores y corregido por la falta de completitud para la estimación de tasas en diferentes rangos de magnitud; 3) la propuesta de un nueva zonificación sísmica, definiendo las zonas sismogenéticas en tres regímenes tectónicos: cortical, subducción interfase y subducción in-slab; 4) la caracterización sísmica de cada zona estimando los parámetros de recurrencia y Magnitud Máxima (Mmax), considerando para este último parámetro una distribución de valores posibles en función de la sismicidad y tectónica, tras un exhaustivo análisis de los datos existentes; 5) la generación de mapas de peligrosidad sísmica de Ecuador continental en términos de aceleración pico (PGA) y espectral SA (T= 1s) , en ambos casos para periodos de retorno (PR) de 475, 975 y 2475 años; 6) La estimación de espectros de peligrosidad uniforme (UHS) y sismos de control mediante desagregación de la peligrosidad, para PR de 475 y 2475 años en 4 capitales de provincia: Quito, Esmeraldas, Guayaquil y Loja. Una segunda parte del trabajo se destina al cálculo del riesgo sísmico en el Barrio Mariscal Sucre de Quito, lo que supone incidir ya a una escala municipal. Como principales contribuciones de este trabajo se destacan: 1) definición del escenario sísmico que más contribuye a la peligrosidad en Quito, que actuará como input de cálculo del riesgo; 2) caracterización de la acción sísmica asociada a ese escenario, incluyendo resultados de microzonación y efecto local en la zona de estudio; 3) Elaboración de una Base de Datos partiendo de información catastral e identificación de las tipologías dominantes; 4) Asignación de clases de vulnerabilidad y obtención de porcentajes de daño esperado en cada clase ante la acción sísmica definida previamente, con la consiguiente representación de mapas de vulnerabilidad y daño; 5) mapas de indicadores globales del riesgo sísmico; 6) Base de datos georreferenciada con toda la información generada en el estudio. Cabe destacar que el trabajo, aunque no formula nuevos métodos, si plantea una metodología integral de cálculo del riesgo sísmico, incorporando avances en cada fase abordada, desde la estimación de la peligrosidad o la definición de escenarios sísmicos con carácter hibrido (probabilista-determinista), hasta la asignación de vulnerabilidades y estimación de escenarios de daño. Esta tesis trata de presentar contribuciones hacia el mejor conocimiento de la peligrosidad sísmica en Ecuador y el riesgo sísmico en Quito, siendo uno de los primeros estudios de tesis que se desarrolla sobre estos temas en el país. El trabajo puede servir de ejemplo y punto de partida para estudios futuros; además de ser replicable en otras ciudades y municipios de Ecuador. -------------------- ABSTRACT: ------------------ This thesis first develops a study of seismic hazard in mainland Ecuador, following a zoned, probabilistic methodology. The study considers a regional scale and presents as main contributions: 1) The development of a State of Art on the Tectonics and Geology of Ecuador, concluding with the identification of the main seismic sources; 2) The creation of a Seismic Catalog project, collecting information from different agencies, which has been homogenized to Moment magnitude, Mw, purged from aftershocks and premonitories and corrected for the lack of completeness to estimate rates in different maggnitude ranges; 3) The proposal of a new seismic zoning, defining the seismogenic zones in three tectonic regimes: cortical, subduction interface and subduction in-slab; 4) The seismic characterization of each zone, estimating the parameters of recurrence and Maximum Magnitude (Mmax), considering the latter as a distribution of possible values, depending on the seismicity and tectonics, and after a thorough analysis of the existing data; 5) Seismic hazard maps of continental Ecuador in terms of peak ground acceleration (PGA) and spectral SA(T=1), and return periods (PR) of 475, 975 and 2475 years; 6) Uniform hazard spectra (UHS) and control earthquakes obtained by hazard disaggregation, for PR 475 and 2475 years in four provincial capitals: Quito, Esmeraldas, Guayaquil and Loja. The second section focuses on the calculation of seismic risk in the Quito Mariscal Sucre parish, which is already supposed to be influencing at a municipal level. The main contributions here are the: 1) Definition of the seismic scenario that contributes most to the hazard in Quito, which acts as an input in the risk calculation; 2) Characterization of the seismic action associated with that scenario, including results of micro-zoning and local effect in the study area; 3) Development of a database, based on cadastral data and identification of key typologies; 4) Allocation of vulnerability classes and obtaining percentages of damage expected in each class faced with the seismic action previously defined, with the consequent representation of maps of vulnerability and damage; 5) Global maps of seismic risk indicators; 6) Geo-referenced database with all the information generated in the study. It should be noted that although new methods are not prescribed, this study does set a comprehensive methodology for the calculation of seismic risk, incorporating advances in each phase approached, from the hazard estimation, or definition of seismic scenarios applying a hybrid (deterministic-probabilistic) method, to the allocation of vulnerabilities and estimation of damage scenarios. This thesis aims to present contributions leading to a better understanding of seismic hazard in Ecuador and seismic risk in Quito, and is one of the first studies in the country to develop such themes. This study can serve as an example and starting point for future studies, which could replicate this methodology in other cities and municipalities.

Using the damage from 2010 Haiti earthquake for calibrating vulnerability models of typical structures in Port-au-Prince (Haiti)

After the 2010 Haiti earthquake, that hits the city of Port-au-Prince, capital city of Haiti, a multidisciplinary working group of specialists (seismologist, geologists, engineers and architects) from different Spanish Universities and also from Haiti, joined effort under the SISMO-HAITI project (financed by the Universidad Politecnica de Madrid), with an objective: Evaluation of seismic hazard and risk in Haiti and its application to the seismic design, urban planning, emergency and resource management. In this paper, as a first step for a structural damage estimation of future earthquakes in the country, a calibration of damage functions has been carried out by means of a two-stage procedure. After compiling a database with observed damage in the city after the earthquake, the exposure model (building stock) has been classified and through an iteratively two-step calibration process, a specific set of damage functions for the country has been proposed. Additionally, Next Generation Attenuation Models (NGA) and Vs30 models have been analysed to choose the most appropriate for the seismic risk estimation in the city. Finally in a next paper, these functions will be used to estimate a seismic risk scenario for a future earthquake.

3D geometry of growth strata in a fault-propagation fold: insights into space–time evolution of the Crevillente Fault (Abanilla-Alicante sector), Betic Cordillera, Spain

This work presents a 3D geometric model of growth strata cropping out in a fault-propagation fold associated with the Crevillente Fault (Abanilla-Alicante sector) from the Bajo Segura Basin (eastern Betic Cordillera, southern Spain). The analysis of this 3D model enables us to unravel the along-strike and along-section variations of the growth strata, providing constraints to assess the fold development, and hence, the fault kinematic evolution in space and time. We postulate that the observed along-strike dip variations are related to lateral variation in fault displacement. Along-section variations of the progressive unconformity opening angles indicate greater fault slip in the upper Tortonian–Messinian time span; from the Messinian on, quantitative analysis of the unconformity indicate a constant or lower tectonic activity of the Crevillente Fault (Abanilla-Alicante sector); the minor abundance of striated pebbles in the Pliocene-Quaternary units could be interpreted as a decrease in the stress magnitude and consequently in the tectonic activity of the fault. At a regional scale, comparison of the growth successions cropping out in the northern and southern limits of the Bajo Segura Basin points to a southward migration of deformation in the basin. This means that the Bajo Segura Fault became active after the Crevillente Fault (Abanilla-Alicante sector), for which activity on the latter was probably decreasing according to our data. Consequently, we propose that the seismic hazard at the northern limit of the Bajo Segura Basin should be lower than at the southern limit.

Evaluation of Potential Post-Glacial Faults Using Bare-Earth LiDAR Topographic Data Near Ridley Island, British Columbia

I present results of my evaluation to identify topographic lineaments that are potentially related to post-glacial faulting using bare-earth LiDAR topographic data near Ridley Island, British Columbia. The purpose of this evaluation has been to review bare-earth LiDAR data for evidence of post-glacial faulting in the area surrounding Ridley Island and provide a map of the potential faults to review and possibly field check. My work consisted of an extensive literature review to understand the tectonic, geologic, glacial and sea level history of the area and analysis of bare-earth LiDAR data for Ridley Island and the surrounding region. Ridley Island and the surrounding north coast of British Columbia have a long and complex tectonic and geologic history. The north coast of British Columbia consists of a series of accreted terranes and some post-accretionary deposits. The accreted terranes were attached to the North American continent during subduction of the Pacific Plate between approximately 200 Ma and 10 Ma. The terrane and post-accretionary deposits are metamorphosed sedimentary, volcanic and intrusive rocks. The rocks have experienced significant deformation and been intruded by plutonic bodies. Approximately 10 Ma subduction of the Pacific Plate beneath the North America Plate ceased along the central and north coast of British Columbia and the Queen Charlotte Fault Zone was formed. The Queen Charlotte Fault Zone is a transform-type fault that separates the Pacific Plate from the North America Plate. Within the past 1 million years, the area has experienced multiple glacial/interglacial cycles. The most recent glacial cycle occurred approximately 23,000 to 13,500 years ago. Few Quaternary deposits have been mapped in the area. The vast majority of seismicity around the northwest coast of British Columbia occurs along the Queen Charlotte Fault Zone. Numerous faults have been mapped in the area, but there is currently no evidence to suggest these faults are active (i.e. have evidence for post-glacial surface displacement or deformation). No earthquakes have been recorded within 50 km of Ridley Island. Several small earthquakes (less than magnitude 6) have been recorded within 100 km of the island. These earthquakes have not been correlated to active faults. GPS data suggests there is ongoing strain in the vicinity of Ridley Island. The strain has the potential to be released along faults, but the calculated strain may be a result of erroneous data or accommodated aseismically. Currently, the greatest known seismic hazard to Ridley Island is the Queen Charlotte Fault Zone. LiDAR data for Ridley Island, Digby Island, Lelu Island and portions of Kaien Island, Smith Island and the British Columbia mainland were reviewed and analyzed for evidence of postglacial faulting. The data showed a strong fabric across the landscape with a northwest-southeast trend that appears to mirror the observed foliation in the area. A total of 80 potential post-glacial faults were identified. Three lineaments are categorized as high, forty-one lineaments are categorized as medium and thirty-six lineaments are categorized as low. The identified features should be examined in the field to further assess potential activity. My analysis did not include areas outside of the LiDAR coverage; however faulting may be present there. LiDAR data analysis is only useful for detecting faults with surficial expressions. Faulting without obvious surficial expressions may be present in the study area.

Vasa Creek Channel Conditions and Slope Stability, Bellevue, Washington

The focus of this report is is the channel conditions at Vasa Creek, Bellevue, Washington, with regard to kokanee habitat and slope stability. This required a geomorphic and geologic assessment of the stream and riparian corridor along Vasa Creek. I focused my efforts in a 720m study-reach just south of I-90 in which City of Bellevue had no information. My assessment is divided into 3 categories: channel morphology, geology, and landslide hazards. I described the channel morphology by determining the gradient of the channel, longitudinal and cross-channel geometries, grain size distribution, embeddedness observations, type of channel reaches present, and the locations of significant in-channel woody-debris, landslides, scarps, landslide debris, and erosional features. This was done by conducting a longitudinal survey, 7 cross-channel surveys, pebble counts, and visual observations with the aid of a GPS device for mapping. I completed my geological assessment using both field observations and borehole data provided by GeoMapNW. Borehole data provided logs of the subsurface material at specific locations. In the field, I interpreted local geology using material in the channel as well as exposures in the adjacent slope. I completed the landslide hazard assessment using GIS methods supplemented by field observations. GIS methods included the use of aerial LiDAR to discern slope values and locations of features. Features of interest include the locations of scarps, landslides, landslide debris, and erosional features which were observed in the field. I classified 4 slope classes using ArcMap10 along with the locations of previously mapped landslides, scarps, and landslide debris. I describe the risk of slope failure according to the Washington Administration Code definition of critical areas (WAC 365-190-120 6a-i). My results are presented in the form of a map suite containing a channel morphology map, geology map, and landslide hazard map. The channel is a free-formed alluvial plane-bed reach with infrequent step-pools with riffles associated with landslide debris that chokes the channel. Overall I found that there is not the potential for kokanee habitat due flashy behavior (sudden high flow events), landslide inundation, and a lack of favorable conditions within the channel. The updated geologic map displays advance outwash deposits and alluvium present within the study-reach, as opposed to exposures of the Blakeley Formation along with other corrections from borehole data interpretations. The landslide hazard map shows that there are areas at high risk for slope failure along the channel that should be looked into further.

Modellazione strutturale di edifici storici in muratura e misti: valutazioni comparate e criteri operativi

L’obiettivo della presente tesi è evidenziare l’importanza dell’approccio critico alla valutazione della vulnerabilità sismica di edifici in muratura e misti Il contributo della tesi sottolinea i diversi risultati ottenuti nella modellazione di tre edifici esistenti ed uno ipotetico usando due diversi programmi basati sul modello del telaio equivalente. La modellazione delle diverse ipotesi di vincolamento ed estensione delle zone rigide ha richiesto la formulazione di quattro modelli di calcolo in Aedes PCM ed un modello in 3muri. I dati ottenuti sono stati confrontati, inoltre, con l’analisi semplificata speditiva per la valutazione della vulnerabilità a scala territoriale prevista nelle “Linee Guida per la valutazione e riduzione del rischio sismico del Patrimonio Culturale”. Si può notare che i valori ottenuti sono piuttosto diversi e che la variabilità aumenta nel caso di edifici non regolari, inoltre le evidenze legate ai danni realmente rilevati sugli edifici mostrano un profondo iato tra la previsione di danno ottenuta tramite calcolatore e le lesioni rilevate; questo costituisce un campanello d’allarme nei confronti di un approccio acritico nei confronti del mero dato numerico ed un richiamo all’importanza del processo conoscitivo. I casi di studio analizzati sono stati scelti in funzione delle caratteristiche seguenti: il primo è una struttura semplice e simmetrica nelle due direzioni che ha avuto la funzione di permettere di testare in modo controllato le ipotesi di base. Gli altri sono edifici reali: il Padiglione Morselli è un edificio in muratura a pianta a forma di C, regolare in pianta ed in elevazione solamente per quanto concerne la direzione y: questo ha permesso di raffrontare il diverso comportamento dei modelli di calcolo nelle sue direzioni; il liceo Marconi è un edificio misto in cui elementi in conglomerato cementizio armato affiancano le pareti portanti in muratura, che presenta un piano di copertura piuttosto irregolare; il Corpo 4 dell’Ospedale di Castelfranco Emilia è un edificio in muratura, a pianta regolare che presenta le medesime irregolarità nel piano sommitale del precedente. I dati ottenuti hanno dimostrato un buon accordo per la quantificazione dell’indice di sicurezza per i modelli regolari e semplici con uno scarto di circa il 30% mentre il delta si incrementa per le strutture irregolari, in particolare quando le pareti portanti in muratura vengono sostituite da elementi puntuali nei piani di copertura arrivando a valori massimi del 60%. I confronti sono stati estesi per le tre strutture anche alla modellazione proposta dalle Linee Guida per la valutazione dell’indice di sicurezza sismica a scala territoriale LV1 mostrando differenze nell’ordine del 30% per il Padiglione Morselli e del 50% per il Liceo Marconi; il metodo semplificato risulta correttamente cautelativo. È, quindi, possibile affermare che tanto più gli edifici si mostrano regolari in riferimento a masse e rigidezze, tanto più la modellazione a telaio equivalente restituisce valori in accordo tra i programmi e di più immediata comprensione. Questa evidenza può essere estesa ad altri casi reali divenendo un vero e proprio criterio operativo che consiglia la suddivisione degli edifici esistenti in muratura, solitamente molto complessi poiché frutto di successive stratificazioni, in parti più semplici, ricorrendo alle informazioni acquisite attraverso il percorso della conoscenza che diviene in questo modo uno strumento utile e vitale. La complessità dell’edificato storico deve necessariamente essere approcciata in una maniera più semplice identificando sub unità regolari per percorso dei carichi, epoca e tecnologia costruttiva e comportamento strutturale dimostrato nel corso del tempo che siano più semplici da studiare. Una chiara comprensione del comportamento delle strutture permette di agire mediante interventi puntuali e meno invasivi, rispettosi dell’esistente riconducendo, ancora una volta, l’intervento di consolidamento ai principi propri del restauro che includono i principi di minimo intervento, di riconoscibilità dello stesso, di rispetto dei materiali esistenti e l’uso di nuovi compatibili con i precedenti. Il percorso della conoscenza diviene in questo modo la chiave per liberare la complessità degli edifici storici esistenti trasformando un mero tecnicismo in una concreta operazione culturale . Il presente percorso di dottorato è stato svolto in collaborazione tra l’Università di Parma, DICATeA e lo Studio di Ingegneria Melegari mediante un percorso di Apprendistato in Alta Formazione e Ricerca.

Dimensions of perception and recognition of danger

Despite abundant literature on human behaviour in the face of danger, much remains to be discovered. Some descriptive models of behaviour in the face of danger are reviewed in order to identify areas where documentation is lacking. It is argued that little is known about recognition and assessment of danger and yet, these are important aspects of cognitive processes. Speculative arguments about hazard assessment are reviewed and tested against the results of previous studies. Once hypotheses are formulated, the reason for retaining the reportory grid as the main research instrument are outlined, and the choice of data analysis techniques is described. Whilst all samples used repertory grids, the rating scales were different between samples; therefore, an analysis is performed of the way in which rating scales were used in the various samples and of some reasons why the scales were used differently. Then, individual grids are looked into and compared between respondents within each sample; consensus grids are also discussed. the major results from all samples are then contrasted and compared. It was hypothesized that hazard assessment would encompass three main dimensions, i.e. 'controllability', 'severity of consequences' and 'likelihood of occurrence', which would emerge in that order. the results suggest that these dimensions are but facets of two broader dimensions labelled 'scope of human intervention' and 'dangerousness'. It seems that these two dimensions encompass a number of more specific dimensions some of which can be further fragmented. Thus, hazard assessment appears to be a more complex process about which much remains to be discovered. Some of the ways in which further discovery might proceed are discussed.

Field data, numerical simulations and probability analyses to assess lava flow hazards at Mount Etna

Improving lava flow hazard assessment is one of the most important and challenging fields of volcanology, and has an immediate and practical impact on society. Here, we present a methodology for the quantitative assessment of lava flow hazards based on a combination of field data, numerical simulations and probability analyses. With the extensive data available on historic eruptions of Mt. Etna, going back over 2000 years, it has been possible to construct two hazard maps, one for flank and the other for summit eruptions, allowing a quantitative analysis of the most likely future courses of lava flows. The effective use of hazard maps of Etna may help in minimizing the damage from volcanic eruptions through correct land use in densely urbanized area with a population of almost one million people. Although this study was conducted on Mt. Etna, the approach used is designed to be applicable to other volcanic areas.

Upper-Pleistocene terrace deposits in Mediterranean climate: geomorphological and source-rock control on mineral and geochemical signatures (Betic Cordillera, SE Spain)

Mineral and chemical composition of alluvial Upper-Pleistocene deposits from the Alto Guadalquivir Basin (SE Spain) were studied as a tool to identify sedimentary and geomorphological processes controlling its formation. Sediments located upstream, in the north-eastern sector of the basin, are rich in dolomite, illite, MgO and KB2BO. Downstream, sediments at the sequence base are enriched in calcite, smectite and CaO, whereas the upper sediments have similar features to those from upstream. Elevated rare-earth elements (REE) values can be related to low carbonate content in the sediments and the increase of silicate material produced and concentrated during soil formation processes in the neighbouring source areas. Two mineralogical and geochemical signatures related to different sediment source areas were identified. Basal levels were deposited during a predominantly erosive initial stage, and are mainly composed of calcite and smectite materials enriched in REE coming from Neogene marls and limestones. Then the deposition of the upper levels of the alluvial sequences, made of dolomite and illitic materials depleted in REE coming from the surrounding Sierra de Cazorla area took place during a less erosive later stage of the fluvial system. Such modification was responsible of the change in the mineralogical and geochemical composition of the alluvial sediments.