Geochemical modelling of the tonalitic and trondhjemitic granulites from the Itabuna-Salvador-Curaçá Block,Bahia, Brazil     

Ivana Conceição de Araújo Pinho  Johildo Salomão Figueiredo Barbosa  Angela Beatriz de Menezes Leal  Hervé Martin  Jean-Jacques Peucat 《Journal of South American Earth Sciences》2011,31(2-3):312-323

The studied tonalitic and trondhjemitic granulites are located in the SSE granulitic domain of the São Francisco craton, Bahia, Brazil, where they represent most of the southern part of the Archean and Paleoproterozoic Itabuna-Salvador-Curaçá Block (ISCB). Chemically, the tonalitic and trondhjemitic granulites belong to a low-K calc-alkaline suite; their REE patterns are steep with strong LREE/HREE fractionation and no significant Eu anomaly. Garnet-bearing mafic granulites that occur as enclaves in the tonalitic and trondhjemitic granulites were derived from basalts and/or gabbros of tholeiitic affinity. Geochemical modelling showed that the tonalitic and trondhjemitic granulites were produced by moderate fractional crystallization of an assemblage of hornblende and plagioclase, with subordinate amounts of magnetite, apatite, allanite and zircon. The garnet-bearing mafic granulites would be the source of the magmas that generated these rocks. Partial melting left a residue made up of plagioclase, garnet, orthopyroxene and hornblende.  相似文献   

The Global Earthquake Vulnerability Estimation System (GEVES): an approach for earthquake risk assessment for insurance applications   总被引：4，自引：0，他引：4  

Robin Spence  Emily So  Sarah Jenny  Hervé Castella  Michael Ewald  Edmund Booth 《Bulletin of Earthquake Engineering》2008,6(3):463-483

For the insurance and reinsurance industries, earthquake loss estimation is crucial not only to adequately price its product but also to manage the accumulation risk in the face of the ever-increasing exposure in highly seismic regions. Changes in the built environment and a continuously evolving earthquake science make it a necessity for the industry to constantly refine earthquake loss estimation models. In particular, it has been recognized for a long time that the vulnerability of buildings to ground shaking is a key parameter in any earthquake risk model. Current methods tend either to rely on the limited historical damage and loss data or on the numerical simulation of the response of individual buildings to the ground-shaking produced by earthquakes. Although both methods have their advantages and pitfalls, we are proposing here a simple solution, using transparent input data, that can be realistically used for the needs of the insurance and reinsurance industry, whether detailed information about the insured structures is available or not. The resulting product is known as GEVES (Global Earthquake Vulnerability Estimation System). It is primarily intended for evaluating the mean damage ratio (MDR) suffered by a portfolio of buildings classified by use, under the action of a given earthquake scenario (i.e. an earthquake of given size at a given distance from the portfolio of buildings). A key assumption was that macroseismic intensity rather than spectral displacement would be the basis of loss estimation. The paper describes the model with emphasis on its structure and the justification for the assumptions made. In addition to a new set of earthquake vulnerability functions, the paper also provides recommendations on some aspects of the earthquake hazard, in particular about how to define macroseismic intensity at the site of interest, for a given earthquake scenario. This paper also discusses validation of the GEVES model against calculated vulnerability approaches, and the treatment of uncertainty within the model.  相似文献   

Multi‐scale assessment of overflow‐driven lateral connectivity in floodplain and backwater channels using LiDAR imagery          下载免费PDF全文

Katarina Džubáková  Hervé Piégay  Jérémie Riquier  Milan Trizna 《水文研究》2015,29(10):2315-2330

Overflow‐driven lateral connectivity significantly influences the spatial distribution and diversity of floodplain habitats and biota. Proper understanding of lateral connectivity in floodplain and backwater channels is therefore critical for assessment of river quality and for targeting management or restoration actions. In this study, we present a methodological framework for spatial and temporal assessments of overflow‐driven lateral connectivity at two spatial scales: bypass reach and backwater channel. Firstly, we compute the relative elevations, as well as overflow discharge, duration, and frequency using a simple, raster‐based method that uses a LiDAR digital elevation model (DEM), rating curves, and streamflow time series. Subsequently, we analyse the accuracy of this approach with respect to the accuracy of a DEM and evaluate its further applications. Altogether, four 10‐km‐long bypass reaches and 11 backwater channels are analysed, located along the Rhône River corridor in France. The results proved the precision of the method to be affected by the LiDAR DEM accuracy, which was on average more precise in a typically homogeneous floodplain setting rather than for backwater channel plugs with pronounced topographic complexity and usually riparian forest canopy. Amongst the four studied reaches, Brégnier Cordon proved to have the greatest flooding dynamics, followed by Belley and Chautagne. The hydrological connectivity pattern of Pierre Bénite differed significantly. Three longitudinal patterns of hydrological connectivity of backwater channels displayed stepwise advancement of the water. The presented results can be used to assess ecological potential of floodplain habitats and their historic and prospective evolution through time. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

The Holocene volcanic history of Gran Canaria island: implications for volcanic hazards     

Alejandro Rodriguez‐Gonzalez  Jose L. Fernandez‐Turiel  Francisco J. Perez‐Torrado  Alex Hansen  Meritxell Aulinas  Juan C. Carracedo  Domingo Gimeno  Hervé Guillou  Raphaël Paris  Martine Paterne 《第四纪科学杂志》2009,24(7):697-709

Previous published data, combined with our results of 13 new radiocarbon ages and extensive geological fieldwork, indicate that during the past 11 ka 24 monogenetic basaltic eruptions occurred in the north sector of Gran Canaria. These eruptions can be grouped into three periods of eruptive activity: 1900–3200 ¹⁴C a BP; 5700–6000 ¹⁴C a BP; and an older period represented by only one eruption, El Draguillo, dated at 10 610 ± 190 ¹⁴C a BP. Archaeological studies have shown that the more recent eruptions affected prehistoric human settlements on the island. Field studies demonstrate that the eruptions typically built strombolian cones (30–250 m in height) and associated relatively long lava flows (100–10 350 m in length); a few eruptions also produced tephra fall deposits. The total erupted volume of these eruptions is about 0.388 km³ (46.1% as tephra fall, 41.8% as cinder cone deposits and 12.1% as lava flows). The relatively low eruption rate (～0.04 km³ ka^?1) during the past 11 ka is consistent with Gran Canaria's stage of evolution in the regional volcano‐tectonic setting of the Canary Archipelago. The results of our study were used to construct a volcanic hazards map that clearly delimits two sectors in the NE sector of Gran Canaria, where potential future eruptions would pose a substantial risk for densely populated areas. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   

Statistical modelling of Europe-wide landslide susceptibility using limited landslide inventory data   总被引：2，自引：0，他引：2  

M. Van Den Eeckhaut  J. Hervás  C. Jaedicke  J.-P. Malet  L. Montanarella  F. Nadim 《Landslides》2012,9(3):357-369

In many regions, the absence of a landslide inventory hampers the production of susceptibility or hazard maps. Therefore, a method combining a procedure for sampling of landslide-affected and landslide-free grid cells from a limited landslide inventory and logistic regression modelling was tested for susceptibility mapping of slide- and flow-type landslides on a European scale. Landslide inventories were available for Norway, Campania (Italy), and the Barcelonnette Basin (France), and from each inventory, a random subsample was extracted. In addition, a landslide dataset was produced from the analysis of Google Earth images in combination with the extraction of landslide locations reported in scientific publications. Attention was paid to have a representative distribution of landslides over Europe. In total, the landslide-affected sample contained 1,340 landslides. Then a procedure to select landslide-free grid cells was designed taking account of the incompleteness of the landslide inventory and the high proportion of flat areas in Europe. Using stepwise logistic regression, a model including slope gradient, standard deviation of slope gradient, lithology, soil, and land cover type was calibrated. The classified susceptibility map produced from the model was then validated by visual comparison with national landslide inventory or susceptibility maps available from literature. A quantitative validation was only possible for Norway, Spain, and two regions in Italy. The first results are promising and suggest that, with regard to preparedness for and response to landslide disasters, the method can be used for urgently required landslide susceptibility mapping in regions where currently only sparse landslide inventory data are available.  相似文献   

Flash flood mitigation as a positive consequence of anthropogenic forcing on the groundwater resource in a karst catchment   总被引：1，自引：1，他引：0  

Hervé Jourde  A. Lafare  N. Mazzilli  G. Belaud  L. Neppel  N. Dörfliger  F. Cernesson 《Environmental Earth Sciences》2014,71(2):573-583

The Mediterranean coastal region is prone to high-intensity rainfall events that are frequently associated with devastating flash floods. This paper discusses the role of a karst aquifer system in the flash floods of a Mediterranean river, the Lez river. Most of the Lez river watershed is located on karst terrains where interactions between surface water and groundwater take place. During extreme rainfall events, the presence of fractures and well-developed karst features in carbonate terrains enhances the infiltration processes and involves the concentration of the recharge into highly organized and permeable flow paths. The groundwater, therefore, quickly moves towards the natural outlets of the karst system. The influence of the Lez karst aquifer system on the associated river floods dynamics is analysed while considering the spatially distributed rainfall, as well as the time series of the groundwater level within the aquifer and of the Lez river discharge measured at various gauging stations. Special attention is given to the relative importance of the surface and underground processes involved in flash flood genesis. It is shown that the karst groundwater contributes to flash floods under certain conditions, while high-rate pumping within the karst aquifer, which generates significant drawdown, may mitigate flash floods under other conditions.  相似文献   

General database for ground water site information   总被引：3，自引：0，他引：3  

de Dreuzy JR  Bodin J  Le Grand H  Davy P  Boulanger D  Battais A  Bour O  Gouze P  Porel G 《Ground water》2006,44(5):743-748

In most cases, analysis and modeling of flow and transport dynamics in ground water systems require long-term, high-quality, and multisource data sets. This paper discusses the structure of a multisite database (the H+ database) developed within the scope of the ERO program (French Environmental Research Observatory, http://www.ore.fr). The database provides an interface between field experimentalists and modelers, which can be used on a daily basis. The database structure enables the storage of a large number of data and data types collected from a given site or multiple-site network. The database is well suited to the integration, backup, and retrieval of data for flow and transport modeling in heterogeneous aquifers. It relies on the definition of standards and uses a templated structure, such that any type of geolocalized data obtained from wells, hydrological stations, and meteorological stations can be handled. New types of platforms other than wells, hydrological stations, and meteorological stations, and new types of experiments and/or parameters could easily be added without modifying the database structure. Thus, we propose that the database structure could be used as a template for designing databases for complex sites. An example application is the H+ database, which gathers data collected from a network of hydrogeological sites associated with the French Environmental Research Observatory.  相似文献   

9. Life On Earth... And Elsewhere?     

Thierry Montmerle  Philippe Claeys  Muriel Gargaud  Purificatión López-García  Hervé Martin  Robert Pascal  Jacques Reisse  Franck Selsis 《Earth, Moon, and Planets》2006,98(1-4):299-312

This concluding chapter is divided into two main parts. The first part is a summary of the main facts and events which constitute the present body of knowledge of the chronology of life in the solar system, in the form of “highlights” in astronomy, geology, chemistry and biology. The second part raises the interrogation “Is life universal?”, and tries to provide answers based on these facts and events. These answers turn out to differ widely among the various disciplines, depending on how far they feel able to extrapolate their current knowledge.  相似文献   

Cold Dust and Very Cold Excess Emission in the Galaxy   总被引：2，自引：0，他引：2  

Hervé Bourdin  Françcois Boulanger  Jean-Philippe Bernard  Guilaine Lagache 《Astrophysics and Space Science》2002,281(1-2):243-246

We provide insight in the origin of the far-IR to mm emission from galaxies by presenting a decomposition of the Galaxy emission where we separate the contributions from dust in the atomic gas and dust associated with quiescent molecular gas as a function of Galacto-centric distance. This decomposition leaves a puzzling very cold emission excess with a brightness independent of Galactic longitude that might be pointing at interstellar matter in the outer Galaxy not traced by H I nor CO emission. This revised version was published online in September 2006 with corrections to the Cover Date.  相似文献   

Analysis of the tropical climate variability in a two-column framework     

Gilles Bellon  Guillaume Gastineau  Aur��lien Ribes  Herv�� Le Treut 《Climate Dynamics》2011,37(1-2):73-81

This work examines the relevance of a classical two-column modeling framework of the tropical climate in terms of observed natural variability. A method is developed to analyze the observed tropical climate in a simple framework that features a moist, ascending column and a dry, subsiding one. This method is used to analyze the natural variability of the tropical climate in the ERA40 reanalysis and in ISCCP satellite data. It appears that the seasonal cycle of the tropic-wide sea surface temperature (SST) is almost linearly linked to the seasonal cycle of the relative area of the moist regions, as predicted by the sensitivity of the two-column models. A more detailed analysis shows that this link is the product of a complex interaction and adjustments between the moist and dry regions. The seasonal cycle of low-cloud cover in the dry regions also appears to interact with the SST seasonal cycle: the low-cloud cover influences the tropic-wide SST via its direct radiative forcing on the local SST and it appears to be controlled by the SST difference between moist and dry regions. By contrast, the SST interannual variability appears to be driven by the El Ni?o Southern Oscillation (ENSO), with no significant impact from the changes in the relative area of the moist regions or in the low-cloud cover in the dry regions independently of the ENSO. ENSO-related changes in the area of moist regions and low-cloud cover constitute negative feedbacks on the ENSO-related SST variability.  相似文献