GIS-Based Mapping of Seismic Parameters for the Pyrenees

In the present paper, three of the main seismic parameters, maximum magnitude -Mmax, b-value, and annual rate -AR, have been studied for the Pyrenees range in southwest Europe by a Geographic Information System (GIS). The main aim of this work is to calculate, represent continuously, and analyze some of the most crucial seismic indicators for this belt. To this end, an updated and homogenized Poissonian earthquake catalog has been generated, where the National Geographic Institute of Spain earthquake catalog has been considered as a starting point. Herein, the details about the catalog compilation, the magnitude homogenization, the declustering of the catalog, and the analysis of the completeness, are exposed. When the catalog has been produced, a GIS tool has been used to drive the parameters’ calculations and representations properly. Different grids (0.5 × 0.5° and 1 × 1°) have been created to depict a continuous map of these parameters. The b-value and AR have been obtained that take into account different pairs of magnitude–year of completeness. Mmax has been discretely obtained (by cells). The analysis of the results shows that the Central Pyrenees (mainly from Arudy to Bagnères de Bigorre) present the most pronounced seismicity in the range

A Novel Method for Seismogenic Zoning Based on Triclustering: Application to the Iberian Peninsula

A previous definition of seismogenic zones is required to do a probabilistic seismic hazard analysis for areas of spread and low seismic activity. Traditional zoning methods are based on the available seismic catalog and the geological structures. It is admitted that thermal and resistant parameters of the crust provide better criteria for zoning. Nonetheless, the working out of the rheological profiles causes a great uncertainty. This has generated inconsistencies, as different zones have been proposed for the same area. A new method for seismogenic zoning by means of triclustering is proposed in this research. The main advantage is that it is solely based on seismic data. Almost no human decision is made, and therefore, the method is nearly non-biased. To assess its performance, the method has been applied to the Iberian Peninsula, which is characterized by the occurrence of small to moderate magnitude earthquakes. The catalog of the National Geographic Institute of Spain has been used. The output map is checked for validity with the geology. Moreover, a geographic information system has been used for two purposes. First, the obtained zones have been depicted within it. Second, the data have been used to calculate the seismic parameters (b-value, annual rate). Finally, the results have been compared to Kohonen’s self-organizing maps.Ministerio de Economía y Competitividad TIN2014-55894-C2-RJunta de Andalucía P12-TIC-1728Universidad Pablo de Olavide APPB81309

Statistical analysis of different seismogenic zonings of the Iberian Peninsula and adjacent areas through a Geographic Information System

The knowledge of the seismic hazard in the Iberian Peninsula (IP) and its neighboring area is important to address the mitigation of damage that earthquakes could cause in it. The occurrence of earthquakes in the area is quite frequent because it is in the contact zone between the Eurasian Plate and the African Plate. The general objective of this document is the calculation, representation and analysis of a set of seismic parameters (b-value, maximum magnitude and annual rate of earthquakes per unit area) of the Iberian Peninsula and its adjacent area, considering geographic information systems (GIS) as a basic working tool. These systems allow the integration of data from different information sources, as well as rigorous and quality analysis and graphical representations. To achieve this goal, having a quality seismic catalog is essential. Therefore, one has been compiled for the area as complete, rigorous and extensive in the time possible, and further, revised, homogeneous in size (magnitude) and with independent events. This has served as the basis for the works exposed here. For the generation of this catalog, the database of earthquakes of the National Geographic Institute of Spain has been consider as a starting point, that has been revised (especially the magnitude) and completed with other databases and specific studies. In addition, the catalog of work has included earthquakes for which only macroseismic (and reliable) information is available as well as those recorded during the instrumental period according to the scientific advances of each moment. Then, the size of all the events has been transformed to moment magnitude (Mw) in order to compare it, taking into account only the events with Mw greater or equal to 3.0. Subsequently, a process of elimination of non-main shocks (foreshocks, aftershocks and swarms) has been carried out. Finally, a completeness date has been considered for each magnitude. In this thesis, the b-value, the annual rate of earthquakes per unit area and the maximum magnitude have been calculated, represented and analyzed. In addition, it has been done through two approaches. The first deals with zoning related to Spanish seismic regulations and are based on both geological characteristics and seismicity of the area; and others that are based on objective and mathematically robust criteria and considers only seismicity. In the second approach, a set of multiresolution grids have been established, in which zonings are defined according to a purely geographic criterion. The size of the cells (zones) has been 0.5º x 0.5º for the calculation of the maximum magnitude recorded and 1º x 1º and 2º x 2º for the b-value and the annual rate normalized with the area. In both types of zoning, after the calculations and the representation of the seismic parameters, an analysis of them has been carried out. From this analysis it can be deduced that in some areas there has not been a quantity of events that allows to derive seismic parameters with solidity from a statistical point of view. It can also be concluded that earthquakes with maximum recorded magnitude have a marine epicenter and are located in the SW of the IP. Moreover, the b-value takes a value of 1.0 or somewhat lower in the contact zone between the Eurasian and African plates (a value that decreases further to the east), while in the mainland, 1.2 can be considered an approximate value, with somewhat higher values in some areas. Finally, regarding the annual rate, it should be noted that the highest values (close to 1E-3 events / km2) appear in the Granada basin and in the Pyrenees Region and to a lesser extent, to the SW of Cabo de San Vicente, in Galicia and a large part of the southeast of the IP where values greater than 1E-4 are exceeded.El conocimiento de la peligrosidad sísmica en la península ibérica y su entorno es importante para abordar la mitigación de los daños que los terremotos podrían causar en la misma. La ocurrencia de terremotos en el área es bastante frecuente porque se encuentra en la zona de contacto entre la placa euroasiática y la africana. El objetivo general de esta tesis doctoral es el cálculo, representación y análisis de un conjunto de parámetros que intervienen en la definición de la peligrosidad sísmica de la península ibérica y su área adyacente, considerando como herramienta básica de trabajo los sistemas de información geográfica. Estos permiten la integración de datos de distintas fuentes de información, así como el análisis y representaciones gráficas rigurosas y de calidad. Para la consecución de este objetivo, el disponer de un catálogo sísmico de calidad es fundamental. Por tanto, se ha compilado uno para la zona lo más completo, riguroso y extenso en el tiempo posible y además, revisado, homogéneo en tamaño (magnitud) y con eventos independientes. Este ha servido como base para los trabajos que aquí se exponen. Para la generación del mismo, se ha partido de la base de datos de terremotos del Instituto Geográfico Nacional de España, que se ha visto revisada (sobre todo la magnitud) y completada con otras bases de datos y estudios específicos. Además, en el catálogo del trabajo se han incluido, desde terremotos de los que únicamente se dispone de información macrosísmica (y fiable) como los registrados durante la época instrumental según los avances científicos de cada momento. Luego, se ha transformado el tamaño de todos los eventos a magnitud momento (Mw) para poder compararlo, tomando solo los eventos con Mw mayor o igual a 3,0. Posteriormente, se ha llevado a cabo un proceso de eliminación de terremotos no principales (premonitores, réplicas y enjambres). Finalmente, se ha considerado una fecha de completitud para cada magnitud. En esta tesis se han calculado, representado y analizado el parámetro b-value, la tasa anual de terremotos por unidad de área y la magnitud máxima. Además, se ha hecho a través de dos aproximaciones. La primera versa sobre zonificaciones relacionadas con la normativa sismorresistente española y basadas tanto en las características geológicas como en la sismicidad de la zona; y por otras que parten de criterios objetivos y robustos matemáticamente y están basadas solo en la sismicidad. En la segunda aproximación, se han establecido un conjunto de mallas multirresolución, en las que las zonificaciones son definidas según un criterio puramente geográfico. El tamaño de las celdas (zonas) ha sido de 0,5º x 0,5º para el cálculo de la magnitud máxima registrada y de 1º x 1º y 2º x 2º para el del b-value y la tasa anual normalizada con el área. En ambos tipos de zonificaciones, tras los cálculos y la representación de los parámetros sísmicos, se ha llevado a cabo un análisis de los mismos. De este se deduce que en algunas zonas no ha ocurrido una cantidad de eventos que permita extraer parámetros sísmicos con solidez desde un punto de vista estadístico. También se puede concluir que los terremotos con magnitud máxima registrada tienen epicentro marino y se encuentran al suroeste de la península ibérica. Por otro lado, el b-value toma un valor de 1,0 o algo menor en la zona de contacto entre las placas euroasiática y africana (valor que disminuye más al este), mientras que en tierra firme como valor aproximado se puede considerar 1,2, con valores algo mayores en algunas zonas. Finalmente, respecto a la tasa anual de terremotos, cabe comentar que los valores más altos (cercanos a 1E-3 eventos / km2) aparecen en la cuenca de Granada y en la región de los Pirineos y, en menor medida al SO del Cabo de San Vicente, en Galicia y gran parte del sureste peninsular donde se superan valores mayores a 1E-4.Premio Extraordinario de Doctorado U

Comparative analysis between the Spanish and Portuguese seismic codes. Application to a border RC primary school

The Iberian Peninsula is close to the Eurasia-Africa plate boundary resulting in a considerable seismic hazard. In fact, the southwestern Iberian Peninsula is affected by far away earthquakes of long-return period with large-very large magnitude. A project named PERSISTAH (Projetos de Escolas Resilientes aos SISmos no Território do Algarve e de Huelva, in Portuguese) aims to cooperatively assess the seismic vulnerability of primary schools located in the Algarve (Portugal) and Huelva (Spain). Primary schools have been selected due to the considerable amount of similar buildings and their seismic vulnerability. In Portugal, the Decreto Lei 235/83 (RSAEEP) is mandatory while in Spain, the mandatory code is the Seismic Building Code (NCSE-02). In both countries, the Eurocode-8 (EC-8) is recommended. Despite the fact that both regions would be equally affected by an earthquake, both seismic codes are significantly different. This research compares the seismic action of Ayamonte (Huelva) and Vila Real de Santo António (Portugal). Both towns are very close and located at both sides of the border. Moreover, they share the same geology. This analysis has been applied considering a RC primary school building located in Huelva. To do so, the performance-based method has been used. The seismic action and the damage levels are compared and analysed. The results have shown considerable differences in the seismic actions designation, in the performance point values and in the damage levels. The values considered in the Portuguese code are significantly more unfavourable. An agreement between codes should be made for border regions.This work has been supported by the INTERREG-POCTEP Spain-Portugal programme and the European Regional Development Fund through the 0313_PERSISTAH_5_P project and the VI-PPI of the University of Seville by the granting of a scholarship. The grant provided by the Instituto Universitario de Arquitectura y Ciencias de la Construcción is acknowledged.info:eu-repo/semantics/publishedVersio

Detection of ionospheric signatures from GPS-derived total electron content maps

The processing of measurement data from satellite constellations such as Global Navigation Satellite Systems (GNSS), including the well-known Global Positioning System (GPS), have been successfully applied to virtually all areas of geophysical sciences. In this work, a method is described where Geographical Information Systems (GIS) are employed to build hourly ionospheric Total Electron Content (TEC) maps for 2011 over the southern Iberian Peninsula. The maps used GPS-derived geometryfree linear combinations attained from station data from the Algarve, Alentejo (Portugal), Andalusia, Murcia and Valencia (Spain) regions. Following the construction of the ionospheric maps, it was possible to relate these results to natural phenomena. The observed phenomena included diurnal and seasonal variations: daytime TEC maxima, nighttime TEC peaks, summer TEC value decreases, and spring and fall TEC maxima. After validation of these periodic phenomena, detection of non-periodic changes, such as solar flares and tectonic interactions with the ionosphere were attempted. The results showed a TEC increase following a selected solar flare event and a potential TEC build-up prior to the 2011 Lorca earthquake. Further studies could open up the possibility of building early warning systems. The presented methods, based on available software packages, are also of value in monitoring the effect of the ionosphere on radio signals, satellite and mobile communication, power grids, and for accurate GNSS navigation

GIS-based study of the evolution of the IGN's strong motion network of mainland Spain and the balearics

In some countries with seismicity, an adequate detection network is essential to assess seismic hazards. The Instituto Geográfico Nacional (National Geographic Institute/IGN) of Spain manages a strong motion network distributed throughout the whole country and an earthquake detection network composed of velocity stations. This paper aims at studying the development of the strong motion network of the Spanish National Seismic Network (focusing on mainland Spain and the Balearics) in the last three decades. A Geographic Information System (GIS) has been implemented to integrate the attributes from the IGN's database concerning the earthquake catalogue, seismograph and accelerometer networks, which enabled to analyse the data and map the distribution of detection equipments in the region. The irregularly distributed Spanish strong motion network was greatly expanded from 1990 to 2010. In the past decade, it developed at a slower rate, but more modern technology was implemented

As-Built 3D Heritage City Modelling to Support Numerical Structural Analysis: Application to the Assessment of an Archaeological Remain

Terrestrial laser scanning is a widely used technology to digitise archaeological, architectural and cultural heritage. This allows for modelling the assets’ real condition in comparison with traditional data acquisition methods. This paper, based on the case study of the basilica in the Baelo Claudia archaeological ensemble (Tarifa, Spain), justifies the need of accurate heritage modelling against excessively simplified approaches in order to support structural safety analysis. To do this, after validating the 3Dmeshing process frompoint cloud data, the semi-automatic digital reconstitution of the basilica columns is performed. Next, a geometric analysis is conducted to calculate the structural alterations of the columns. In order to determine the structural performance, focusing both on the accuracy and suitability of the geometric models, static and modal analyses are carried out by means of the finite element method (FEM) on three different models for the most unfavourable column in terms of structural damage: (1) as-built (2) simplified and (3) ideal model without deformations. Finally, the outcomes show that the as-built modelling enhances the conservation status analysis of the 3D heritage city (in terms of realistic compliance factor values), although further automation still needs to be implemented in the modelling process

Identification and characterization of fluid escape structures (pockmarks) in the Estremadura Spur, based on single-channel seismic reflection record

Tese de mestrado em Geologia, apresentada à Universidade de Lisboa, através da Faculdade de Ciências, 2015O Esporão da Estremadura é um promontório localizado na Margem Oeste Ibérica, entre o Cabo Carvoeiro e o Cabo da Roca. Apresenta uma forma trapezoidal com uma área de cerca de 3583 km2, e prolonga-se desde a margem até às montanhas submarinas de Tore. O Esporão da Estremadura separa a Planície Abissal Ibérica, a norte, da Planície Abissal do Tejo, a sul. No ano de 2011, durante uma campanha oceanográfica do projecto PACEMAKER identificou-se, através dos dados sísmicos de reflexão, um conjunto de pequenas depressões no fundo do mar (pelo menos 70), reconhecidas como pockmarks. Este campo de pockmarks localiza-se entre os 240 e 350 m, na região NW da plataforma externa do Esporão da Estremadura, conhecida como Monoclinal da Lourinhã. Estas estruturas apresentam diâmetros que variam entre alguns metros a mais de 400 m e até cerca de 4 m de profundidade. Os pockmarks são estruturas formadas pela libertação rápida e abrupta de fluidos, que migram através da coluna sedimentar, no fundo do mar. Foram descritos pela primeira vez por King & McLean (1970) na plataforma continental ao largo da Nova Escócia, Canadá. Apresentam topografia negativa e uma morfologia muito caraterística, sob a forma de depressão cónica circular ou elíptica, com flancos íngremes e fundo relativamente plano. Os pockmarks ocorrem em sedimentos finos e permeáveis, individualmente ou em grandes clusters, em variados ambientes geológicos como as plataformas continentais, os taludes continentais e nos fundos dos oceanos profundos. Encontram-se frequentemente associados a depósitos sedimentares com hidratos de gás nas margens continentais. A sua distribuição não ocorre de forma aleatória, estando frequentemente relacionados a estruturas da sub-superficie marinha, como falhas e zonas de maior permeabilidade, que servem de condutas para a migração de fluídos para a superfície. O estudo dos pockmarks é importante uma vez que estão muitas vezes relacionados com sistemas ativos de migração de hidrocarbonetos e portanto são estruturas de interesse para a indústria petrolífera. São também importantes devido ao perigo associado ao escape de gás do fundo do mar em zonas de exploração ou de transporte de petróleo e/ou gás. A Margem Oeste Ibérica começou a desenvolver-se durante a abertura do Oceano Atlântico Norte. Este processo iniciou-se no Triásico Superior até ao momento de rutura continental entre as margens da Ibéria e da Terra Nova, no Cretácico Inferior. Existem na margem, no offshore e também no onshore, diversas bacias sedimentares relacionadas com a abertura do Atlântico, como a Bacia Lusitânica. No Cenozoico a margem sofre uma fase de inversão tectónica generalizada, relacionada com as fases Pirenaica e Bética da Orogenia Alpina, o que levou ao soerguimento de algumas regiões da margem continental, como por exemplo o Esporão da Estremadura. O auge da deformação ocorreu no Miocénico, possivelmente durante o Tortoniano, com compressão máxima NW-SE. Os pockmarks identificados no Esporão da Estremadura são a primeira evidência de processos de escape de fluidos identificados na Margem Oeste Ibérica e o presente trabalho é o primeiro estudo realizado sobre estas estruturas. As ocorrências escape de fluidas conhecidas, mais próximas da margem e portanto do Esporão da Estremadura, são a Ria de Vigo, o Estuário de Aveiro e o Golfo de Cádiz. A principal motivação deste trabalho é o estudo das estruturas (pockmarks) e dos processos de escape de fluídos que ocorrem no fundo do mar do Esporão da Estremadura. Os principais objetivos podem resumidos nos seguintes tópicos: (1) Mapeamento batimétrico da área de estudo e, portanto do campo de pockmarks; (2) Descrição da morfologia e características do fundo do mar na área com pockmarks e na plataforma envolvente; (3) Caraterização estratigráfica e estrutural dos sedimentos Cenozoicos do Esporão da Estremadura e (4) Compreender a origem estratigráfica dos fluidos que dão origem aos pockmarks e o que controla a sua migração e escape no fundo do mar. Para a realização deste estudo foram utilizados dados batimétricos, de refletividade do fundo do mar (backscatter), sísmica SPARKER 2D monocanal de alta resolução e observações diretas do fundo do mar, através de vídeos adquiridos em mergulhos com um submarino ROV (Remotely Operated Vehicle). Estes dados foram essencialmente obtidos durante a missão oceanográfica do projeto PACEMAKER (sísmica de alta resolução e batimetria), em colaboração com o projeto TOPOMED (TOPOEUROPE/0001/2007). Durante a campanha EMEPC/PEPC/LUSO/2015 (no âmbito do projeto PES – PTDC/GEO-FIQ/5162/2014) foram adquiridos novos dados de batimetria no Esporão da Estremadura, que complementaram os dados anteriores. Foram também realizados dois mergulhos com o ROV Luso em duas das depressões (pockmarks) identificadas no fundo marinho. A partir dos dados batimétricos foram criados mapas batimétricos e de refletividade do fundo do mar, onde foram observadas depressões topográficas com formas circulares a alongadas e com backscatter elevado, interpretadas como pockmarks. De modo a melhorar a qualidade dos dados sísmicos estes foram processados, através do software SPW (Parallel Geoscience Corporation). Foram realizados vários passos de processamento para as 14 linhas sísmicas PACEMAKER, como por exemplo, a aplicação de um filtro butterworth, correção do swell e das máres e migração Stolt. Os resultados do processamento foram considerados positivos, uma vez que a maioria do ruído que mascarava o sinal sísmico foi eliminado, sendo possível observar a sub-superficie do Esporão da Estremadura até cerca de 500 ms TWT. Após o processamento sísmico foi realizada a interpretação dos perfis sísmicos no software SeisWorks da Landmark Graphic Corporation, sendo desenvolvido um modelo sísmostratigráfico. Foram identificadas seis unidades sísmicas (U1 a U6) separadas por horizontes (M a H4) que marcam importantes descontinuidades ou variações na fácies sísmica. A unidade sísmica mais antiga, U1, foi sujeita a uma intensa deformação dúctil, ao contrário das restantes unidades, pelo que a descontinuidade que separa U1 e U2 foi associada ao auge da deformação alpina, no Miocénico (Tortoniano). Assim, esta unidade sísmica U1 será anterior ao Tortoniano, provavelmente de idades do Miocénico inferior e médio. As restantes unidades sísmicas, U2 a U6, formam uma sequência sísmica de idades compreendidas entre o Pliocénico e o Holocénico. No registo sísmico foram também identificadas várias evidências para a existência da migração e acumulação de fluidos. Além dos pockmarks, que já tinham sido identificados anteriormente, foram observados paleo-pockmarks (enterrados a varias profundidades), condutas de migração dos fluidos, zonas de transparência, turbidez e de blanking acústico. Deste modo, foi interpretado que os fluidos estão a migrar verticalmente e a acumular-se nas unidades sísmicas Plio-Quaternárias. Os mergulhos com o ROV mostraram que, apesar da resposta de backscatter de alta refletividade associada aos pockmarks e das evidências para a existência de fluidos observadas na sísmica, no fundo do mar não se encontram evidências para a actividade atual do sistema de escape de fluidos. As depressões visitadas com o submarino mostraram que as estruturas estão cobertas por sedimentos arenosos e não foi observada fauna nem registado o borbulhar característico de seeps ativas. Pode então ser concluído que na atualidade os fluidos não alcançam o fundo do mar, estando a acumular-se em zonas mais permeáveis dos sedimentos. Foram propostos dois modelos evolutivos, coexistentes no Esporão da Estremadura, para o sistema de migração de fluidos: (1) Atividade cíclica das seeps e (2) selagem do sistema pela precipitação de carbonatos autigénicos (MDAC). O primeiro baseia-se na observação de pockmarks “empilhados” (stacked pockmarks) no registo sísmico, o que sugere que a migração e escape dos fluidos é periódica, possivelmente condicionada pelas variações eustáticas do nível do mar. O segundo modelo consiste na descativação de condutas de migração de fluidos, pela precipitação de MDAC, o que causa o enterramento do pockmark alimentados por essas condutas. Posteriormente, ocorre a criação de novos caminhos de migração para os fluidos, que se acumulam em zonas permeáveis dos sedimentos até existir pressão suficiente para escaparem pelo fundo do mar.Located on the West Iberian margin, between Cabo Carvoeiro and Cabo da Roca, the Estremadura Spur is a trapezoidal promontory elongated in an east-west direction, extending until the Tore seamount. In 2011, during the scientific cruise 64PE332 (PACEMAKER project; Kim & the shipboard scientific party, 2011) a seismic reflection SPARKER survey discovered a field with more than 70 pockmarks in the NW region of the Estremadura Spur outer shelf (in the Lourinhã Monocline). Pockmarks are the seabed culminations of fluid migration through the sedimentary column and their characteristic seabed morphologies correspond to cone-shaped circular or elliptical depressions. Pockmarks have proven to be important seabed features that provide information about fluid flow on continental margins, being used by the oil and gas industry as an exploration tool and as an indicator of hydrocarbon sources for prospecting. These pockmarks and the associated fluid escape process are the main objectives of this work that aims to contribute to the characterization of the structures and to the understanding to their structural and stratigraphic control. In pursuing such objectives the following methodological approaches were used: 1) Seismic processing and interpretation of the high resolution 2D single-channel SPARKER seismic dataset acquired during the PACEMAKER cruise. In addition, it was done the interpretation of 2D multi-channel seismic lines from TGSNOPEC, which provides information about the deep structure of this area; and 2) Bathymetric and Backscatter interpretation. During the EMEPC/PEPC/LUSO/2015 multi-beam bathymetry that complemented the PACEMAKER bathymetric coverage was acquired and were realized two dives using EMEPC Remotely Operated Vehicle (ROV) Luso. These dives allowed the direct observation of the seafloor and the recollection of push-core samples. The analysis of the PACEMAKER high-resolution seismic allowed the identification of six seismic units, disturbed by the migration and accumulation of fluids. There was concluded that the Estremadura Spur outer shelf has been affected by several episodes of fluid migration and fluid escape during the Pliocene-Quaternary that are expressed by a vast number of seabed and buried pockmarks. At present the pockmarks are mainly inactive, as the seabed pockmarks are recovered by recent sediments. The NW region of the Estremadura Spur outer shelf has been affected by several episodes of fluid migration and fluid escape that are expressed by a vast number of seabed and buried pockmarks. It was concluded that the migration of fluids to the seabed occurred over the Pliocene-Quaternary, as indicated by the buried pockmarks at different depths. At present the pockmarks are mainly inactive, as the seabed pockmarks are recovered by recent sediments. The stacking of various pockmarks suggests a cyclical fluid flow activity that can passably be the result of the eustatic sea level variations and the subsequent changes of the hydrostatic pressure. An alternative hypothesis can be considered assuming the episodes of intense fluid flow as being associated with the local seismicity. Precipitation of methane-derived authigenic carbonates (MDAC) inside the migration conduits that originate pockmarks can force the deactivation of the fluid migration pathways and, consequently, the deactivation of the related pockmarks and creation of new migration pathways

Overview of recent seismic risk analyses in Spain

Different institutions have produced or updated regional seismic risk studies in particular regions of Spain. Despite the final purpose of all these studies is the same (to serve as basis for the development and implementation of local emergency and response plans), approaches to estimate risk to structures and individuals differ significantly from one study to another because these institutions worked independently. The technical characteristics of the different risk studies are analyzed and discussed in this presentation

Incorporating Descriptive Metadata into Seismic Source Zone Models for Seismic Hazard Assessment: A case study of the Azores-West Iberian region

In probabilistic seismic-hazard analysis (PSHA), seismic source zone (SSZ) models are widely used to account for the contribution to the hazard from earth- quakes not directly correlated with geological structures. Notwithstanding the impact of SSZ models in PSHA, the theoretical framework underlying SSZ models and the criteria used to delineate the SSZs are seldom explicitly stated and suitably docu- mented. In this paper, we propose a methodological framework to develop and docu- ment SSZ models, which includes (1) an assessment of the appropriate scale and degree of stationarity, (2) an assessment of seismicity catalog completeness-related issues, and (3) an evaluation and credibility ranking of physical criteria used to delin- eate the boundaries of the SSZs. We also emphasize the need for SSZ models to be supported by a comprehensive set of metadata documenting both the unique character- istics of each SSZ and the criteria used to delineate its boundaries. This procedure ensures that the uncertainties in the model can be properly addressed in the PSHA and that the model can be easily updated whenever new data are available. The pro- posed methodology is illustrated using the SSZ model developed for the Azores–West Iberian region in the context of the Seismic Hazard Harmonization in Europe project (project SHARE) and some of the most relevant SSZs are discussed in detail