The role of source and site effects on structural failures due to Azores earthquakes

The existing building stock in Azores islands (Portugal) was severely damaged during 1980 and 1998 earthquakes. Structural failure was probably caused by a combination of factors that are not yet well understood. Earthquake source characteristics, site effects and structural vulnerability may be some of those factors. However, it is very difficult to assess the influence of each factor on structural failure, mainly because recorded accelerograms used in nonlinear structural analysis are influenced by both source characteristics and site conditions. The only way to overcome this problem is to control each factor individually which can be done by using simulated accelerograms. In our previous work, stochastic ground motion simulations results were compared with earthquake records. Results seem to indicate that simulated accelerograms can match recorded accelerograms if proper source characteristics and geological site conditions are selected. In this work, simulated accelerograms were used for seismic nonlinear structural analysis. Simulations were carried out considering several 1980 Azores earthquake possible sources and for different geological site conditions. Simulated accelerograms were then used to evaluate the structural nonlinear behaviour of a reinforced concrete structure and of two masonry structures. The results of this work highlight the importance of site conditions and earthquake source characteristics to the determination of the design seismic actions of Azores islands. This work was performed in the scope of “Strong ground motion for Azores – SiGMA” project, financed by the Portuguese Science and Technology Foundation (PTDC/CTE-GIX/121957/2010)

Seismic Vulnerability Analysis in 3D City Models (3DCM)

UID/SOC/04647/2013 SFRH/BPD/76893/2011Lisbon is a city with high seismic risk, having been hit in the past by strong earthquakes. That’s the reason why several seismic vulnerability studies have been made devoted to the buildings of the capital, aiming the creation of different scenarios that depend on the magnitude and source location of the earthquake. The results of these studies have been presented as maps resulting from crossing information contained in 2D layers and presented in a GIS environment. 3D City Models (3DCM) intend to associate a database of a city to a rigorous geospatial representation and close to the visible reality in an urban environment, combining geometry and semantics. As such, they may include tools that convey attribute analysis at different levels, allowing the generation of new knowledge on a phenomenon or its effects, not only at the statistical level but also in terms of visual impact on the object. In this project it is intended to extend into the third dimension a seismic vulnerability study of the buildings of Lisbon held in 2D and explore the gains of spatial analysis in 3D representations. The various parameters that contribute to assess seismic vulnerability of buildings may be analyzed individually or simultaneously. The application of this tool will be demonstrated in a pilot area of Lisbon.publishersversionpublishe

Intensity-Distance attenuation laws for the Portugal mainland using intensity data points

In this study, new intensity-distance attenuation law is presented, using directly the intensity observations, rather than the subjective, and sometimes controversial, isoseismal lines. This intensity-distance attenuation law is the only one defined for Portugal mainland, which is expressed as a function of magnitude. We computed this attenuation law using the slope and the intercept of the logarithmic regression of 25 events, with magnitudes between 4.4 and 6.2. Using the Bakun and Wentworth method (1997), this new attenuation law allows performing better results in the earthquake epicentral position and magnitude estimations of the 1909 Benavente event than the Atkinston and Boore attenuation law (1997). This law also gives good results in the study of site effects, presenting good matches between intensity residuals and geological structures where site effects are expected

Produção de medicamentos personalizados

Dissertação para obtenção do grau de Mestre no Instituto Superior de Ciências da Saúde Egas MonizA produção de medicamentos personalizados sendo muito antiga, foi quase abandonada pelo processo de industrialização massiva estando a ser retomada com o apoio das tecnologias de informação e das modernas técnicas de diagnóstico. Com efeito, o aperfeiçoamento dos meios de diagnóstico, os avanços da genética e o recurso a biomarcadores permitem monitorizar de forma célere os efeitos das terapias, possibilitando ajustá-las a indivíduos, subgrupos ou grupos de forma mais eficaz, o que supõe flexibilidade na produção de medicamentos específicos. Dada a necessidade de personalização dos medicamentos já disponibilizados pela indústria surgiram dispositivos, pouco rigorosos, para personalizar as doses. Na procura de precisão e de flexibilidade, explorou-se a impressão de fármacos. As técnicas de impressão a jato de tinta (continuous inkjet printing e drop on demand), são as mais usadas e permitem a formação e deposição, digitalmente controladas, de gotas com fármacos, geralmente veiculados num fluido, conseguindo-se quantidades exatas de um ou mais princípios ativos e perfis de libertação complexos. A impressão 3D, a partir do ano 2000, alargou o espectro de possibilidades. Através do depósito de camadas sobrepostas permite produzir formas farmacêuticas a três dimensões, maioritariamente dirigidas à via oral. A oncologia é a área onde os resultados são mais expressivos e convincentes e aquela em que a produção de medicamentos personalizados mais se desenvolveu. O futuro da produção de medicamentos personalizados anda a par da produção de dispositivos de diagnóstico e da nanoescala e enfrenta desafios, nomeadamente, económicos, legais e éticos. No entanto, reconhecidas as suas vantagens, na prevenção e tratamento de doentes, sem gasto de medicamentos inúteis e sem efeitos secundários indesejáveis, eles representam um benefício para a saúde e uma economia, pelo que, indústria e Estados encontrarão regras de colaboração, aceitáveis pelos Estados e que sirvam os objetivos da indústria e os interesses da comunidade

Monitorização Sísmica do Território do Parque Arqueológico do Vale do Côa (PAVC)

info:eu-repo/semantics/publishedVersio

The 1909 Benavente (Portugal) earthquake : search for the source

The Lower Tagus River Valley has been affected by severe earthquakes comprising distant events, as in 1755, and local earthquakes, as in 1344, 1531, and 1909. The 1909 earthquake was located NE of Lisbon, near Benavente, causing serious damage and many losses. Mw 6.0 has been assessed for this earthquake and a reverse faulting focal mechanism solution has been calculated. Poor epicenter location, possible directivity and site effects, low fault slip rates, and the thick Cenozoic sedimentary cover make difficult correlation with regional structures. The focal mechanism indicates an ENE reverse fault as source, though it does not match any outcropping active structure suggesting that the event could have been produced by a blind thrust beneath the Cenozoic sedimentary fill. Hidden sources, inferred from seismic reflection data, are a possible NE structure linking the Vila Franca de Xira and the Azambuja faults, or the southern extension of the later. Evidence of surface rupturing is inhibited by the thick Holocene alluvial cover and the high fluvial sedimentation rate, though a slightly depressed area was identified in the Tagus alluvial plain W of Benavente which was investigated as possible geomorphic evidence of co-seismic surface deformation. A high-resolution seismic reflection profile was acquired across a 0.5 m high scarp at this site, and two trenches were opened across the scarp for paleoseismic research. Some deformation of dubious tectonic origin was found, requiring further studies

Vs30 estimation using ambient vibrations and seismic refraction experiments - Application to the lower Tagus Valley (Portugal)

The town of Lisbon has been affected by several strong earthquakes in the past originated either offshore or inland. The main inland seismogenic zone is the Lower Tagus Valley (LTV) region oriented NNE-SSW and reaching the northern part of Lisbon at its southern end. It is composed by a system of faults mainly oriented according to the valley trend, but the identification of the particular seismogenic structures able to produce large earthquakes are still under debate. The strongest reported event was the January 31st, 1531 earthquake (Mw = 7.0) that produced large damage in the southern part of the valley, in particular in Lisbon. In recent years the seismic activity in the LTV is characterised by several small earthquakes. The last strong earthquake occurred on April 23rd, 1909 (Mw = 6.1) and destroyed several small towns located in the valley. Due to the concentration of economic and industrial facilities and population density, this region presents high seismic risk in the Portuguese context. Besides, this region can be also affected by large offshore earthquakes, as the 1755 earthquake which source is located southern of Portugal mainland, in the Atlantic Ocean, about 250 km far from Lisbon. In order to estimate soil ground motion associated to different seismic sources, a map of Vs30 is need. We present here a methodology to estimate Vs30 based on ambient vibrations surveys (single-station and arrays measurements), seismic refraction experiments and geologic and geotechnical information. This work was partially financed by the Portuguese project PTDC/CTE-GIX/102245/2008 NEFITAG - Strong ground motion and near field effects in the Lower Tagus Valley Region, and the Spanish funded Complementary Action CGL2010-11831-E Identificacion de efectos de sitio en los registros de intensidad sismica en Iberia