SANARIS Project: A Satellite Network for Natural Risk Monitoring     

Tárraga  Marta  Garcia  Alicia  Ortiz  Ramon  Abella  Rafael  Peña  Javier 《Natural Hazards》2001,23(2-3):417-429

A new satellite communication system specificallydesigned for low-rate data applications has beendeveloped and prototyped. A validation project isproposed to install a pilot network to be operated for6 months. One of the target markets related tovolcanoes, has been selected, so that a group of usersis integrated in the project. A specific applicationfor this market will be developed regarding dataacquisition, processing, storage and dissemination todistant users. The feasibility of using the newsatellite system to provide a new Eutelsat service forlow-rate data applications, will be evaluated from theperformance of the pilot network. The system ofautomatic acquisition, field storage and communicationwith the local control center is already functioning,as well as the circulation of information viaInternet. The development of the application andtransmission via satellite to distant users is stillin an evaluation phase for the volcanoes of Timanfaya(Lanzarote, Canary Island), Vesuvius (Naples) and SeteCidades Caldera (Sao Miguel, Azores Islands).  相似文献   

MacWateqf: The Classic Speciation and Saturation Program Adapted to Macintosh Computers     

F. Javier Sánchez San Román 《Ground water》1995,33(5):829-831

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Designing river water quality policy interventions with scarce data: the case of the Middle Tagus Basin,Spain     

Antonio Bolinches  Lucia De Stefano  Javier Paredes-Arquiola 《水文科学杂志》2020,65(5):749-762

ABSTRACT

Anthropic pressures deteriorate river water quality, so authorities need to identify their causes and define corrective actions. Physically based water quality models are a useful tool for addressing physicochemical pollutants, but they must be calibrated with an amount of data that is often unavailable. In this study, we explore the characterization of a model to design corrective interventions in a context of sparse data. A calibration indicator that is both simple and flexible is proposed. This approach is applied to the Middle Tagus Basin in central Spain, where the physicochemical concentration of pollutants is above legal standards. We quantify the effects of the main existing pressures (discharge from wastewater treatment plants, agricultural diffuse pollution and a major inter-basin water transfer) on the receiving waters. In particular, the study finds that wastewater treatment plant effluent concentrations should be reduced to up to 0.65 mg/L of ammonium and 0.55 mg/L of phosphate to achieve the environmental goals. We propose and prioritize a set of policy actions that would contribute to the good status of surface water bodies in the region.  相似文献   

Electrical conductivity of igneous rocks: Composition and temperature relations     

R. Alvarez  J. Perez Reynoso  L. Javier Alvarez  M. Lopez Martinez 《Bulletin of Volcanology》1978,41(4):317-327

The conductivity of four igneous rocks with, 49, 65, 77, and 84% SiO₂ was measured as a function of temperature in the interval from 20° to 1280°C; measurements were made in a vacuum of 10^?3 torr. No simple relationships were found between conductivity and SiO₂ content or versus major element groupings such as Na₂O=K₂O=CaO and TiO₂=Cr₂O₃=Al₂O₃=Fe₂O₃=FeO. An analytical expression was obtained between conductivity and the albite-quartz ratio, valid for temperatures between 300° and 1200°C. It was necessary to compute the CIPW norm in order to obtain the albite and quartz percentages. The onset of melting apparently occurred between 600° and 700°C. Petrography performed on two samples after cooling showed 70 and 85% partial melting. Three conduction regions were identified: 1) below 300°C, 2) between 300°C and 600°C, and 3) above 600°C. Different activation energies obtained for the heating and cooling intervals confirm that the sample undergoes textural changes in the heating-cooling cycle. Activation energy increments of 0.1 and 0.2 eV per decade of albite-quartz ratio were obtained.  相似文献   

New data (U–Pb, K–Ar) on the geochronology of the alkaline-carbonatitic association of Fuerteventura, Canary Islands, Spain     

Mercedes Muoz  Juana Sagredo  Cristina de Ignacio  Javier Fernndez-Surez  Teresa E. Jeffries 《Lithos》2005,85(1-4):140-153

Zircons from a nepheline-syenite of the Fuerteventura Basal Complex were dated by Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS). The age obtained from a total of 21 U–Th–Pb analyses is 25.4 ± 0.3 Ma (2σ) indicating a late Oligocene–early Miocene crystallization. This age is consistent with new K–Ar ages on nepheline-syenites and pyroxenites, and contradicts previously published ³⁹Ar–⁴⁰Ar (feldspar) ages that were interpreted to represent a late Cretaceous–early Paleocene, pyroxenitic–syenitic magmatic episode. These new geochronological data are consistent with both field observations and most of the previously published ages on alkaline silicate rocks and associated carbonatites of Fuerteventura. Therefore, they strongly support the existence of a single, late Oligocene–early Miocene event of alkaline–carbonatitic magmatism in the Basal Complex of Fuerteventura, taking place at approximately 25 Ma and comprising: alkaline-pyroxenites, melteigites-ijolites, nepheline-syenites and carbonatites, as well as their volcanic equivalents and associated dykes.

These new data provide an estimate for the length of time that it took the island to grow, thus eliminating one of the major problems in explaining its development by a hot-spot model.  相似文献   

Visualization of Volcanic Rock Geochemical Data and Classification with Artificial Neural Networks   总被引：1，自引：0，他引：1  

Juan Pablo Lacassie  Javier Ruiz del Solar  Barry Roser  Francisco Hervé 《Mathematical Geology》2006,38(6):697-710

An unsupervised neural network technique, Growing Cell Structures (GCS) was used to visualize geochemical differences between four different island arc volcanic rock types: basalts, andesites, dacites and rhyolites. The output of the method shows the cluster structure of the dataset clearly, and the relevant geochemical patterns and relationships between its variables. The data can be separated into four clusters, each associated with a specific volcanic rock type (basalt, andesite, dacite and rhyolite), according to a unique combination of major element concentrations. Following clustering, performance of the trained GCS network as a classifier of volcanic rock type was tested using two test datasets with major element concentration data for 312 and 496 island arc volcanic rock samples of known volcanic type. Preliminary classification results are promising. In the first test dataset 94% of basalts, 76% of andesites, 83% of dacites and 100% of the rhyolites were classified correctly. Successful classification rates in the second dataset were 100%, 80%, 77%, and 98% respectively. The success of the analysis suggests that neural networks analysis constitutes a useful analytical tool for identification of natural clusters and examination of the relationships between numeric variables in large datasets, and that can be used for automatic classification of new data.  相似文献   

Secular Climatic Oscillations as Indicated by Catastrophic Floods in the Spanish Mediterranean Coastal Area (14th–19th Centuries)     

Mariano Barriendos Vallve  Javier Martin-Vide 《Climatic change》1998,38(4):473-491

Historical documentation describing events on the Mediterranean coast of the Iberian Peninsula allows us to reconstruct the record of catastrophic floods. Through this information, it is possible to identify and to date three climatic oscillations within the so-called Little Ice Age: 1570–1630, 1760–1800 and 1830–1870, which coincide with advances in some Alps glaciers.  相似文献   

Pleistocene and Holocene aeolian facies along the Huelva coast (southern Spain): climatic and neotectonic implications     

Zazo  C.  Dabrio  C.J.  Borja  F.  Goy  J.L.  Lezine  A.M.  Lario  J.  Polo  M.D.  Hoyos  M.  Boersma  J.R. 《Geologie en Mijnbouw》1998,77(3-4):209-224

The stratigraphic relationships, genesis and chronology, including radiocarbon dating, of the Quaternary sandy deposits forming the El Asperillo cliffs (Huelva) were studied with special emphasis on the influence of neotectonic activity, sea-level changes and climate upon the evolution of the coastal zone. The E-W trending normal fault of Torre del Loro separates two tectonic blocks. The oldest deposits occur in the upthrown block. They are Early to Middle Pleistocene fluviatile deposits, probably Late Pleistocene shallow-marine deposits along an E-W trending shoreline, and Late Pleistocene and Holocene aeolian sands deposited under prevailing southerly winds. Three Pleistocene and Holocene aeolian units accumulated in the downthrown block. Of these, Unit 1, is separated from the overlying Unit 2 by a supersurface that represents the end of the Last Interglacial. Accumulation of Unit 2 took place during the Last Glacial under more arid conditions than Unit 1. The supersurface separating Units 2 and 3 was formed between the Last Glacial maximum at 18 000 ¹⁴C yr BP and ca. 14 000 ¹⁴C yr BP, the latter age corresponding to an acceleration of the rise of sea level. Unit 3 records wet conditions. The supersurface separating Units 3 and 4 fossilised the fault and the two fault blocks. Units 4 (deposited before the 4th millennium BC), 5 (> 2700 ¹⁴C yr BP to 16th century) and 6 (16th century to present) record relatively arid conditions. Prevailing wind directions changed with time from W (Units 2–4) to WSW (Unit 5) and SW (Unit 6).  相似文献   

Evaluation of interaction effects on the system period and the system damping due to foundation embedment and layer depth   总被引：1，自引：0，他引：1  

Javier Avilés  Luis E. Pérez-Rocha 《Soil Dynamics and Earthquake Engineering》1996,15(1):11-27

On the basis of some simplifying assumptions, a parametric analysis is made of the interaction effects on the effective period and damping of structures with embedded foundation in a soil layer. A simplified three-dimensional interaction model is used, in which the depth of a cylindrical foundation, the degree of contact between the ground and the footing walls and the depth of a homogeneous stratum over rigid rock are considered variable. The soil is replaced with impedance functions that are taken from a data base obtained with an appropriate numerical technique, so that suitable springs and -pots dependent on the excitation frequency are used. The system period and system damping are determined from the steady-state response of an equivalent single oscillator with flexible base subjected to a harmonic motion with constant amplitude, by equating its resonant response with that of a replacement oscillator with rigid base excited with the same motion. The influence of the foundation embedment and soil layer is investigated for several depths of both the footing and the stratum.It is confirmed that the system period decreases and the system damping increases with the foundation embedment only for sidewalls extending along the entire foundation depth. For embedded footings without sidewall or with sidewall in null contact with the surrounding soil, the effective system parameters behave opposite to those corresponding to the interface condition of total contact. Also, the system damping increases significantly with the layer depth, while the system period is practically insensitive to variations of this characteristic parameter. Finally, introducing additional permissible simplifications, an improved approximate solution for the effective period and damping of coupled systems is presented, which differs from previous analogous approximations in that damping factors of second order are not neglected and the foundation depth is explicitly considered.  相似文献   

Modeling Sea-Water Intrusion with Open Boundary Conditions   总被引：1，自引：0，他引：1  

Francisco Padilla  Javier Cruz-Sanjulián 《Ground water》1997,35(4):704-712

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