Institute Geologic Of Catalonia

Barcelona, Spain

Institute Geologic Of Catalonia

Barcelona, Spain
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Liesa M.,University of Barcelona | Carreras J.,Autonomous University of Barcelona | Castineiras P.,Complutense University of Madrid | Casas J.M.,University of Barcelona | And 2 more authors.
Geologica Acta | Year: 2011

New geochronological data from the Albera Massif confirm the presence of an Early - Mid Ordovician igneous event (472 - 465Ma) recorded in the pre-Variscan rocks of the Pyrenees. This event resulted in the emplacement of a large granitic body in the lower part of the pre-Upper Ordovician metasedimentary succession and in the intrusion of a series of metric sized dykes in the middle and upper parts of it. The two types of igneous rocks were gneissified during subsequent Variscan deformation. The geochronological data confirm the occurrence of the gneiss as having derived from an Ordovician intrusive sheet, as in other Pyrenean massifs. The dykes are considered to be the subvolcanic equivalent of the intrusive sheet. The data also provide insight into the age of the metasedimentary series of the massif and enable us to correlate the dated rocks with other gneissic and subvolcanic bodies of the Variscan massifs of the Pyrenees and Iberia.

Goded T.,Complutense University of Madrid | Goded T.,Institute of Geological & Nuclear Sciences | Buforn E.,Complutense University of Madrid | Macau A.,Institute Geologic Of Catalonia
Bulletin of Earthquake Engineering | Year: 2012

In this paper we present a site effects analysis carried out in Málaga city's historical centre (Southern Spain). Two different methodologies have been used: an experimental technique using ambient noise measurements and a 1D numerical method. Soil fundamental frequencies have been obtained from the first technique, and soil transfer functions have been calculated from the numerical methodology. In order to use these results in vulnerability studies, intensity increments for each type of soil have also been estimated. From this information, a seismic microzonation has been proposed for the city centre, classified in six types of soils. Soil fundamental frequencies vary between above 5.0 Hz at the hills of the city (where rock arises on the surface), and 1.0 Hz near Guadalmedina river. The results show regions with high intensity increments (I = +1.5) corresponding to areas which suffered heavy damage in the 1680 earthquake (I max = VIII-IX). Moreover, most of the monuments and historical buildings in the city are located in these high risk areas. Results underline the importance of this kind of studies for seismic risk mitigation, historical preservation and emergency planning in the main cities' historical centres. © Springer Science+Business Media B.V. 2012.

Goded T.,Complutense University of Madrid | Goded T.,Institute of Geological & Nuclear Sciences | Irizarry J.,Institute Geologic Of Catalonia | Buforn E.,Complutense University of Madrid
Bulletin of Earthquake Engineering | Year: 2012

A vulnerability analysis of some historical and monumental buildings in the city of Málaga is presented in this paper. More than twenty of these monuments were severely damaged or completely destroyed due to the large earthquake (I max = VIII-IX) occurred in the Málaga region in October 1680. The vulnerability index methodology has been used in this paper. This technique is based on statistical data from seismic damage caused to Italian monuments for the past 30 years. For each building, vulnerability curves have been obtained and damage grades have been estimated. A comparison has been carried out between the expected damage grades and the damage observed from past earthquakes, in order to check the feasibility of applying this methodology to Spanish monuments. This comparison has been possible due to the fact that detailed seismic damage information exists for monuments in the city of Málaga that still exist today, which is a very uncommon case in Spain. Results show a good consistency between expected and observed damage, especially for the churches type. Two seismic scenarios have been proposed for the city centre, one deterministic and one probabilistic, where 54 historical and modern buildings have been analyzed. Both scenarios show worrying results, especially for the types of churches, chapels and towers, where expected high probabilities of suffering very heavy damage or even collapse have been obtained. It is highly recommended to take the necessary measures, in the hope of trying to avoid the possible damage that can be expected from future earthquakes. © Springer Science+Business Media B.V. 2011.

Falgas E.,University of Barcelona | Ledo J.,University of Barcelona | Benjumea B.,Institute Geologic Of Catalonia | Queralt P.,University of Barcelona | And 3 more authors.
Surveys in Geophysics | Year: 2011

Groundwater management needs detailed aquifer characterization, especially in semiarid costal aquifer systems that are under hydrological pressure. Our study area is in the Tordera delta, northeastern coast of Spain, where a detrital fluvio-deltaic aquifer system has been developed above granitic basement. The main purpose of this study is to characterize the complex lithological structure and the seawater intrusion state by combining hydrological information, audiomagnetotelluric (AMT) and seismic reflection and refraction models. This allowed us to provide spatially continuous information about aquifer properties and processes. Thus, we have determined the thickness and continuity of the aquifer units, as well as the morphology and depth to the basement. The models revealed that the main seawater intrusion main path is found in the western deltaic area that coincides with an existing buried paleochannel. This new result explains the anomalously high chlorine concentrations observed in the deep semiconfined aquifer more than 1,500 m inland. © 2011 Springer Science+Business Media B.V.

Vila M.,Institute Geologic Of Catalonia | Fernandez M.,CSIC - Institute of Earth Sciences Jaume Almera | Jimenez-Munt I.,CSIC - Institute of Earth Sciences Jaume Almera
Tectonophysics | Year: 2010

Determining the temperature distribution within the lithosphere requires the knowledge of the radiogenic heat production (RHP) distribution within the crust and the lithospheric mantle. RHP of crustal rocks varies considerably at different scales as a result of the petrogenetic processes responsible for their formation and therefore RHP depends on the considered lithologies. In this work we address RHP variability of some common lithological groups from a compilation of a total of 2188 representative U, Th and K concentrations of different worldwide rock types derived from 102 published studies. To optimize the use of the generated RHP database we have classified and renamed the rock-type denominations of the original works following a petrologic classification scheme with a hierarchical structure. The RHP data of each lithological group is presented in cumulative distribution plots, and we report a table with the mean, the standard deviation, the minimum and maximum values, and the significant percentiles of these lithological groups. We discuss the reported RHP distribution for the different igneous, sedimentary and metamorphic lithological groups from a petrogenetic viewpoint and give some useful guidelines to assign RHP values to lithospheric thermal modeling. © 2010.

Lantada N.,University of Barcelona | Irizarry J.,Institute Geologic Of Catalonia | Barbat A.H.,University of Barcelona | Goula X.,Institute Geologic Of Catalonia | And 3 more authors.
Bulletin of Earthquake Engineering | Year: 2010

The vulnerability index method, in its version developed in the framework of the European project Risk-UE, has been adapted and applied in this article, to evaluate the seismic risk for the city of Barcelona (Spain) through a GIS based tool. According to this method, which defines five damage states, the action is expressed in terms of the macroseismic intensity and the seismic quality of the buildings by means of a vulnerability index. The probabilities of damage states are obtained considering a binomial or beta-equivalent probability distribution. The most relevant seismic risk evaluation results obtained, for current buildings and monuments of Barcelona, are given in the article as scenarios of expected losses. © 2009 Springer Science+Business Media B.V.

Madurell-Malapeira J.,Autonomous University of Barcelona | Minwer-Barakat R.,Autonomous University of Barcelona | Alba D.M.,Autonomous University of Barcelona | Garces M.,University of Barcelona | And 5 more authors.
Quaternary Science Reviews | Year: 2010

The late Early to early Middle Pleistocene section from Torrent de Vallparadís is a 20 m-thick, composite section with multiple stratigraphic horizons, which have yielded close to 30,000 remains of large and small vertebrates, as well as macrobotanical remains of non-carbonized wood and a complete pollen record. This series is well correlated on the basis of magnetostratigraphic and small mammal biostratigraphic data, ranging from 1.2 to 0.6 Ma. There are only a few other European localities recording this time interval from a faunal, floral and stratigraphical perspective, so that the Vallparadís series provides a unique opportunity to investigate the faunal and environmental changes that occurred in south-western Europe during the Early to Middle Pleistocene transition. This time interval recorded at Vallparadís coincides with major climatic changes at a global scale (the Middle Pleistocene Transition), which had important effects on the composition of mammalian assemblages. The remains recovered from the latest Early Pleistocene layers of the Vallparadís section show that most of the components of the Villafranchian carnivore guild survived until close to the Brunhes-Matuyama boundary (probably until the interglacial stage 21), which might have significantly influenced the foraging strategies of early Homo in Europe. On the other hand, the remains of the straight-tusked elephant, Elephas (Palaeoloxodon) antiquus, from the latest Early Pleistocene layers of Vallparadís represent the earliest European record of this species, indicating that the dispersal of African elements into Europe during the Middle Pleistocene Transition began earlier than previously thought, at close to 1 Ma. © 2010 Elsevier Ltd.

Vila M.,Institute Geologic Of Catalonia | Martinez-Llado X.,Center Tecnologic Of Manresa
Journal of Geochemical Exploration | Year: 2015

Geochemical reference levels are necessary preliminary steps for appropriate environmental legislation, especially in the assessment of management of soil pollution and protection measures. The problem of establishing reference levels in areas with variable basic geology and anthropogenic pressure is addressed by characterising the geochemistry of 82 representative samples of the geologic materials of the Congost River basin (NE Iberia). The samples have been grouped in a system of 12 operative geochemical units comprising the entire area of the basin. The 'total' and 'partial' concentrations of 54 chemical elements have been determined. The geochemical variability has been discussed by means of statistical methodologies, diagrams and GIS techniques.The analysed samples reveal that the composition of the Congost catchment is highly varied. The differences between the 'total' and 'partial' concentrations define complex patterns reflecting the mineralogy of samples. The results indicate that bedrock geology is the most important factor influencing the major and trace element distributions in the basin. Pb and Zn were observed to be enriched in units more exposed to pollution than their parent materials. In general, the defined operative geologic units are characterised by different major and trace element compositional ranges as a consequence of their lithological diversity. The fact that the samples have been linked to a system of regional geological units allows the geochemical comparison of materials from the Congost River basin with other reference materials from neighbouring areas, or worldwide. For such an approach, we have focused on the geochemistry of the Pleistocene detritic sediments. We close the study by proposing that a good way of expressing the geographic distribution of the geochemical variability of a region could be to apply geologic extrapolation of three representative statistics, an average value (the 50th percentile), a low value (the 25th percentile) and a high value (the 75th percentile). As an example, we present the Th maps, which permit the clear discussion of the Th distribution in the basin. © 2014 Elsevier B.V.

Irizarry J.,Institute Geologic Of Catalonia | Lantada N.,University of Barcelona | Pujades L.G.,University of Barcelona | Barbat A.H.,University of Barcelona | And 3 more authors.
Bulletin of Earthquake Engineering | Year: 2011

The Capacity Spectrum Based Method developed in the framework of the European project Risk-UE has been applied to evaluate the seismic risk for the city of Barcelona, Spain. Accordingly, four damage states are defined for the buildings, the action is expressed in terms of spectral values and the seismic quality of the buildings, that is, their vulnerability, is evaluated by means of capacity spectra. The probabilities of the damage states are obtained considering a lognormal probability distribution. The most relevant seismic risk evaluation results obtained for Barcelona, Spain, are given in the article as scenarios of expected losses. © 2010 Springer Science+Business Media B.V.

Gabas A.,Institute Geologic Of Catalonia | Macau A.,Institute Geologic Of Catalonia | Benjumea B.,Institute Geologic Of Catalonia | Bellmunt F.,University of Barcelona | And 2 more authors.
Surveys in Geophysics | Year: 2014

Urban geological mapping is a key to assist management of new developed areas, conversion of current urban areas or assessment of urban geological hazards. Geophysics can have a pivotal role to yield subsurface information in urban areas provided that geophysical methods are capable of dealing with challenges related to these scenarios (e.g., low signal-to-noise ratio or special logistical arrangements). With this principal aim, a specific methodology is developed to characterize lithological changes, to image fault zones and to delineate basin geometry in the urban areas. The process uses the combination of passive and active techniques as complementary data: controlled source audio-magnetotelluric method (CSAMT), magnetotelluric method (MT), microtremor H/V analysis and ambient noise array measurements to overcome the limitations of traditional geophysical methodology. This study is focused in Girona and Salt surrounding areas (NE of Spain) where some uncertainties in subsurface knowledge (maps of bedrock depth and the isopach maps of thickness of quaternary sediments) need to be resolved to carry out the 1:5000 urban geological mapping. These parameters can be estimated using this proposed methodology. (1) Acoustic impedance contrast between Neogene sediments and Paleogene or Paleozoic bedrock is detected with microtremor H/V analysis that provides the soil resonance frequency. The minimum value obtained is 0.4 Hz in Salt city, and the maximum value is the 9.5 Hz in Girona city. The result of this first method is a fast scanner of the geometry of basement. (2) Ambient noise array constrains the bedrock depth using the measurements of shear-wave velocity of soft soil. (3) Finally, the electrical resistivity models contribute with a good description of lithological changes and fault imaging. The conductive materials (1-100 Ωm) are associated with Neogene Basin composed by unconsolidated detrital sediments; medium resistive materials (100-400 Ωm) correspond to Paleogene, and resistive materials (600-1,000 Ωm) are related with complex basement, granite of Paleozoic. The Neogene basin-basement boundary is constrained between surface and 500 m depth, approximately. The new geophysical methodology presented is an optimized and fast tool to refine geological mapping by adding 2D information to traditional geological data and improving the knowledge of subsoil. © 2013 Springer Science+Business Media Dordrecht.

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