Isotope measurements and ground water flow modeling using MODFLOW for understanding environmental changes caused by a well field in semiarid Brazil     

Luiz Alberto Ribeiro Mendonça  Horst Frischkorn  Marlúcia Freitas Santiago  Josué Mendes Filho 《Environmental Geology》2005,47(8):1045-1053

Measurements of the environmental isotopes carbon-14 and oxygen-18 and of the electrical conductivity in ground water, together with MODFLOW-88 (DOS) simulations of pumping tests, were used to achieve a detailed understanding of the functioning of an aquifer in the area of a well field. The methodology was applied in the sedimentary basin of the Cariri region, in the south of Ceará State in Brazil. Localized hydraulic connections between adjacent aquifer units could be detected, and mixing ratios for the contributions from the units involved were determined. Cone of depression simulations for a three-year drought period revealed well interference and a drastic lowering of the piezometric level, thereby explaining the hydrogeologic changes and transformations in vegetation that were observed in the area of the well field. The combined use of the modeling tools and the geochemical field observations is shown to provide more detailed insight into the conceptual model of the groundwater flow system.  相似文献   

Observations of physical effects from tsunamis of December 30, 2002 at Stromboli volcano, southern Italy   总被引：1，自引：0，他引：1  

Stefano Tinti  Alessandra Maramai  Alberto Armigliato  Laura Graziani  Anna Manucci  Gianluca Pagnoni  Filippo Zaniboni 《Bulletin of Volcanology》2006,68(5):450-461

On December 30, 2002, following an intense period of activity of Stromboli volcano (south Tyrrhenian Sea, Italy), complex mass failures occurred on the northwest slope of the mountain which also involved the underwater portion of the volcanic edifice for a total volume of about 2–3×10⁷ m³. Two main landslides occurred within a time separation of 7 min, and both set tsunami waves in motion that hit the coasts of Stromboli causing injuries to three people and severe damage to buildings and structures. The tsunamis also caused damage on the island of Panarea, some 20 km to the SSE from the source. They were observed all over the Aeolian archipelago, at the island of Ustica to the west, along the northern Sicily coasts to the south as well as along the Tyrrhenian coasts of Calabria to the east and in Campania to the north. This paper presents field observations that were made in the days and weeks immediately following the events. The results of the quantitative investigations undertaken in the most affected places, namely along the coasts of Stromboli and on the island of Panarea, are reported in order to highlight the dynamics of the attacking waves and their impact on the physical environment, on the coastal structures and on the coastal residential zone. In Stromboli, the tsunami waves were most violent along the northern and northeastern coastal belt between Punta Frontone and the village of Scari, with maximum runup heights of about 11 m measured on the beach of Spiaggia Longa. Measured runups were observed to decay rapidly with distance from the source, typical of tsunami waves generated by limited-area sources such as landslides.  相似文献   

TRANSALP—A transect through a young collisional orogen: Introduction     

Helmut Gebrande  Alberto Castellarin  Ewald Lüschen  Karl Millahn  Franz Neubauer  Rinaldo Nicolich   《Tectonophysics》2006,414(1-4):1

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The Alpine evolution of the Southern Alps around the Giudicarie faults: A Late Cretaceous to Early Eocene transfer zone     

Alberto Castellarin  Gian Battista Vai  Luigi Cantelli 《Tectonophysics》2006,414(1-4):203

Data supporting relevant Late Cretaceous–Early Eocene sinistral displacement along the Giudicarie fault zone and a minor Neogene dextral displacement along the Periadriatic lineament are discussed. The pre-Adamello structural belt is present only in the internal Lombardy zone, located W of the Adamello massif. This belt is unknown in the Dolomites and surrounding areas located to the E of the Giudicarie lineament. Upper Cretaceous–Early Eocene thick syntectonic Flysch deposits of Lombardy and Giudicarie are well preserved along the southern and eastern border of the pre-Adamello belt (S-vergent Alpine orogen). Towards the E, in the Dolomites and in the Carnic Alps and external Dinarides, only incomplete remnants of Flysch deposits, Aptian–Albian and Turonian–Maastrichtian in age, are present. They can be considered as equivalent to those of Lombardy and Giudicarie formerly in connection to each other along the N-Giudicarie corridor. To the S, the syntectonic Flysch deposits are laterally replaced by the calcareous red pelagites of the Scaglia Rossa and by the carbonate shelf deposits of the Friuli (to the E) and Bagnolo (to the S) carbonate platforms. The different location in the southern structural accretion of the eastern and western opposite blocks (the Dolomites versus the pre-Adamello belt) can be related to the Cretaceous–Eocene convergence. In this frame, the N-Giudicarie fault has been considered as part of a former transfer zone, which produced the sinistral lateral displacement of the Southern Alps front for an amount of some 50 km. During the Late Eocene to Early Oligocene the transfer zone was mostly sealed by the Paleogene Adamello batholith. Oligocene to Neogene compressional evolution inverted the N-Giudicarie fault into a backthrust of the Austroalpine units over the South-Alpine chain.  相似文献   

Groundwater irrigation and its implications for water policy in semiarid countries: the Spanish experience   总被引：1，自引：0，他引：1  

Alberto Garrido  Pedro Martínez-Santos  M. Ramón Llamas 《Hydrogeology Journal》2006,14(3):340-349

Over the last decades, groundwater irrigation has become commonplace in many arid and semiarid regions worldwide, including Spain. This is largely a consequence of the advances in drilling and pumping technologies, and of the development of Hydrogeology. Compared with traditional surface water irrigation systems, groundwater irrigation offers more reliable supplies, lesser vulnerability to droughts, and ready accessibility for individual users. Economic forces influence the groundwater irrigation sector and its development. In Spain's Mediterranean regions, abstraction costs often amount to a very small fraction of the value of crops. In the inner areas, groundwater irrigation supports a more stable flow of farm income than rainfed agriculture. The social (jobs/m³) and economic (€/m³) value of groundwater irrigation generally exceeds that of surface water irrigation systems. However, poor groundwater management and legal controversies are currently at the base of Spain's social disputes over water. A thorough and transparent assessment of the relative socio-economic value of groundwater in relation to surface water irrigation might contribute to mitigate or avoid potential future conflicts. Enforcement of the European Union's Water Framework Directive may deliver better groundwater governance and a more sustainable use.

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Resumen Durante las últimas décadas, la irrigación con agua subterránea se ha vuelto común en muchas regiones áridas y semiáridas alrededor del mundo, incluyendo a España. Ésta es en gran medida una consecuencia de los adelantos en las tecnologías de perforación y bombeo, y del desarrollo de la Hidrogeología. Comparada con los sistemas tradicionales de irrigación con agua superficial, la irrigación con agua subterránea ofrece suministros más fiables, la vulnerabilidad es menor a las sequías, y posee accesibilidad inmediata para los usuarios individuales. Las fuerzas económicas influyen el sector de irrigación con agua subterránea y su desarrollo. En las regiones mediterráneas de España, los costos de extracción suman a menudo una parte muy pequeña del valor de las cosechas. En las áreas internas, la irrigación con agua subterránea constituye un flujo más estable de ingresos para la granja, que la agricultura dependiente del agua lluvia. El valor social (empleos/m³) y económico (€/m³) de la irrigación con agua subterránea, generalmente excede a aquél con sistemas de irrigación de agua superficial. Sin embargo, la gestión pobre del agua subterránea y las controversias legales están actualmente en la base de las disputas sociales en España acerca del agua. Una evaluación completa y transparente del valor socio-económico relativo de agua subterránea respecto a la irrigación con agua superficial, podría contribuir mitigar o evitar los conflictos potenciales del futuro. La entrada en vigor del Marco Reglamentario de Agua de la Unión Europea, puede conllevar a una administración mejor del agua subterránea y a un uso más sostenible.

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Résumé Depuis les dernières décennies, l’irrigation avec l’eau souterraine est devenue commune dans plusieurs régions arides et semi-arides, incluant l’Espagne. Ceci est largement une conséquence due à l’avancement aux technologies de forages et des pompages, et au développement de l’Hydrogéologie. Comparé avec des systèmes traditionnels d’irrigation utilisant l’eau de surface, l’irrigation avec l’eau souterraine offre une technique d’alimentation plus fiable, une vulnérabilité à la sécheresse moins grande, et une accessibilité plus aisée pour chaque utilisateur. Les forces économiques influencent le secteur de l’irrigation par l’eau souterraine et son développement. Dans les régions de l’Espagne Méditerranéenne, les coûts d’exploitation représentent toujours une petite fraction de la valeur des cultures. Dans les régions intérieures, l’irrigation par l’eau souterraine supporte une agriculture plus stable et continue qu’une agriculture reposant sur l’eau de pluie. La valeur sociale (emploi/m³) et économique (€/m³) de l’irrigation avec l’eau souterraine, excède généralement celle des systèmes d’irrigation avec l’eau de surface. Néanmoins, des gestions pauvres de l’eau souterraine et des controverses légales sont couramment à la base de disputes sociales sur l’eau. Un bilan transparent et minutieux des valeurs relatives socio-économiques de l’eau souterraine en relation avec l’eau de surface d’irrigation, devrait contribuer à éviter de potentiels et futurs conflits. Un renforcement de la Directive Cadre de l’Union Européenne devrait apporter une meilleure gouvernance et un usage plus durable.

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Millimetric properties of IRAS galaxies – III. Luminosity functions, sub-mm counts and contributions to the sky background     

Alberto Franceschini  Paola Andreani  & Luigi Danese 《Monthly notices of the Royal Astronomical Society》1998,296(3):709-720

We exploit observations at 1.25 mm with the ESO–SEST telescope of a southern galaxy sample, selected from the IRAS PSC and complete to S ₆₀=2 Jy, to derive the FIR and mm luminosity functions and the conditional probability distributions of FIR and mm luminosity of galaxies. The reliability of these estimates is ensured by the good observed correlation of the far-infrared and mm emissions. This detailed knowledge of the millimetric properties of galaxies is used to simulate the extragalactic sub-mm sky (background intensity, small-scale anisotropy signals and discrete source statistics), which is the target of a variety of ground-based and space observatories. We find, in particular, that a recent tentative detection of a sub-mm background would require, if confirmed, strong evolution with cosmic time of the galaxy long-wavelength emissivity. We finally discuss ways to test such evolution with present and forthcoming facilities: while emphasizing the difficulty of achieving this with large mm telescopes on the ground (because of the poor atmospheric conditions of current sub-mm sites), we mention an interesting opportunity with the long-wavelength camera on ISO . Preliminary results of deep surveys, both from space and from the ground, seem indeed to require excess emission in the past by dusty galaxies with respect to no-evolution predictions.  相似文献   

Forecasting of storm rainfall by combined use of radar, rain gages and linear models     

Paolo Burlando  Alberto Montanari  Roberto Ranzi 《Atmospheric Research》1996,42(1-4)

An integrated approach to real-time prediction of point rainfall is presented. This is based on the assumption that hourly rainfall at a station can be predicted by a Multivariate AutoRegressive Integrated Moving Average (MARIMA) process. The real-time calibration of the multivariate model is performed by combining radar maps and data from rain gages. Accordingly, radar maps provide the basic information for a storm tracking procedure which enables to detect the direction and the speed of storm movement. Storm tracking is used to select those stations which are characterized by the highest Lagrangian cross-correlation of observed precipitation, and which are therefore best suitable for application of the multivariate model. The parameters of the multivariate model are finally estimated using only observed rainfall at the selected stations throughout the current event. Preliminary results of an application to some events which occurred in northern Italy show that the combined use of radar and rain gages allows for an increased efficiency of the MARIMA model performances, as compared with empirical selection of stations to be considered by the multivariate model. The multivariate approach performs better also when it is compared with simple nowcasting procedures based on rain gage data or on radar data used separately. Finally, some considerations are issued in view of a systematic use of this technique to nowcast rainfall intensity in small urban or natural catchments, with a response time of less than 1 or 2 h.  相似文献   

Magnetic stratigraphy of Etan products. I-medieval lavas     

Antimo Angelino  Alberto Incoronato  Patrizia Sarno 《Studia Geophysica et Geodaetica》1996,40(3):217-224

Summary Mean magnetisation directions from 6 lava flows of questionable historical age have been determined. The results, which are based upon very stringent linearity criteria during demagnetisation, point out erroneous dating and the corresponding lavas can be ascribed to medieval activity of Mount Etna, as already suggested for some of the investigated flows, covering a time interval of some centuries around AD 1000. The site mean direction of AD 1536 historically dated lava flow agrees with a previous study (Tanguy et al., 1985), while the site mean directions of AD 1566 and AD 1169/812 differ significantly from those reported earlier. Neither AD 812 nor AD 1169 dating is consistent with the site mean direction of the related flow being compatible with an emplacement age possibly a few decades before AD 1000. The 3 lava flows historically dated AD 1595 exhibit different within site mean directions indicating that they cannot be referred to coeval activity of the volcano; the site mean direction of one of the flows is compatible with an emplacement occurring very close to AD 1000. The resulting SVC is significantly shifted eastwards with respect to that of previous study (Tanguy et al., 1985). However, its older part nearly overlaps the medieval Vesuvius SVC relocated to Etna. This indicates that the strict linearity analysis carried out during demagnetisation has allowed to clearly define the characteristic magnetisations of the investigated lava flows. The adopted procedure is appropriate for performing successful magnetic stratigraphy surveys in volcanic areas.  相似文献   

HYDRO_GEN: A spatially distributed random field generator for correlated properties   总被引：1，自引：0，他引：1  

Alberto Bellin  Yoram Rubin 《Stochastic Environmental Research and Risk Assessment (SERRA)》1996,10(4):253-278

This paper describes a new method for generating spatially-correlated random fields. Such fields are often encountered in hydrology and hydrogeology and in the earth sciences. The method is based on two observations: (i) spatially distributed attributes usually display a stationary correlation structure, and (ii) the screening effect of measurements leads to the sufficiency of a small search neighborhood when it comes to projecting measurements and data in space. The algorithm which was developed based on these principles is called HYDRO_GEN, and its features and properties are discussed in depth. HYDRO_GEN is found to be accurate and extremely fast. It is also versatile: it can simulate fields of different nature, starting from weakly stationary fields with a prescribed covariance and ending with fractal fields. The simulated fields can display statistical isotropy or anisotropy.  相似文献   

Inelastic seismic analysis of a building structure designed by argentine codes     

Victorio E. Sonzogni  Alberto Cardona  Sergio R. Idelsohn 《地震工程与结构动力学》1984,12(6):721-736

A reinforced concrete frame-wall structure of a building designed in accordance to standard practice in Argentina was analysed by the procedures prescribed by current Argentine Codes. In addition, the inelastic step-by-step response of the structure to design spectrum-compatible accelerograms was studied by means of a special element for inelastic dynamic analysis of reinforced concrete frames. Results obtained by the different methods of analysis are presented.  相似文献