1,721,011 research outputs found
A geophysical approach to the enviromental study of a coastal plain. Journal of Applied Geophysics, September 2003, Volume 68, Iusse 5, pp. 14461459 BALIA R.,GAVAUDO? E.,ARDAU F. & GHIGLIERI G. (2003)
No full textin the study of coastal plains affected by soil and water salination, a knowledge of several geological aspects, such as structural features, depth to basement, stratigraphy of sedimentary cover, relationships between the phreatic aquifer and underlying aquifers, and the latter's structure, is basic to gaining an adequate understanding of both the causes and possible evolution of salination. In this framework, geophysical techniques can play a very important role.
To improve the available geophysical information about the Muravera coastal plain, Sardinia, Italy, which is affected by severe soil and water salination, previously acquired electrical resistivity, reflection seismic and gravity data have been reprocessed, and a new seismic reflection survey has been conducted. Moreover, in order to give better support to the geological and hydrogeological interpretation of geophysical data, three boreholes were drilled. Reprocessed electrical data indicate the presence of a wide, electrically homogeneous low-resistivity zone associated with salination phenomena. Reprocessed reflection data provide useful information on the near-surface stratigraphy. The combined interpretation of resistivity and seismic results, supported by one calibration borehole, elucidates the relationships between the phreatic aquifer and the underlying confined aquifer. A new seismic reflection survey gives information on the depth to, and structure of, the Paleozoic basement, as well as on stratigraphic conditions of Pleistocene-Holocene sediments. Finally, the combined interpretation of seismic, gravity, and well data results in a geological section containing most of the information considered essential, such as the interface between Holocene alluvium and Pleistocene alluvium, the thickness of the latter, and the structure and composition of the Paleozoic basement.
The work as a whole shows how the combined application of geophysical techniques can in this specific situation provide wide-ranging and high-quality information that is essential for the realistic mathematical modeling of aquifer contamination, and can enable the rational planning of exploratory drillings
Verso un protocollo d’indagine pluridisciplinare: la cortina di Santa Chiara a Cagliari
No full textIl contributo mostra l’impostazione di una ricerca pluridisciplinare che analizza un settore della città storica, interessato a partire dal Cinquecento da importanti modificazioni di assetto urbano.
L’impiego di metodologie di diagnostica non distruttiva affianca e supporta la ricerca storica ed il rilevamento delle architetture presenti nell’area, con l’obiettivo di fornire un quadro completo delle dinamiche costruttive che hanno interessato un particolare segmento di tale area, compreso tra il bastione di Santa Croce e la torre dell’Elefant
Tau-p mapping based filtering techniques for linear noise attenuation in reflection data
No full textApplication of the cross-hole seismicc tomography to the study of slope stability in a complex rock formation
No full textDecomposing Training Data to Improve Network Intrusion Detection Performance
No full textAnyone working in the field of network intrusion detection has been able to observe how it involves an everincreasing number of techniques and strategies aimed to overcome the issues that affect the state-of-the-art solutions. Data unbalance and heterogeneity are only some representative examples of them, and each misclassification made in this context could have enormous repercussions in different crucial areas such as, for instance, financial, privacy, and public reputation. This happens because the current scenario is characterized by a huge number of public and private network-based services. The idea behind the proposed work is decomposing the canonical classification process into several sub-processes, where the final classification depends on all the sub-processes results, plus the canonical one. The proposed Training Data Decomposition (TDD) strategy is applied on the training datasets, where it applies a decomposition into regions, according to a defined number of events and features. The reason that leads this process is related to the observation that the same network event could be evaluated in a different manner, when it is evaluated in different time periods and/or when it involves different features. According to this observation, the proposed approach adopts different classification models, each of them trained in a different data region characterized by different time periods and features, classifying the event both on the basis of all model results, and on the basis of the canonical strategy that involves all data
Hydrogeological and geophysical investigations for groundwater in the Arumeru District (Northen Tanzania)
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Modelling of the Campidano graben (Sardinia, Italy) by combined geophysical data
No full textThe present study reports on a telluric profile, carried out over the Campidano graben, which is one of the most interesting structures in Sardinia. The telluric data, which were interpreted together with magnetotelluric, gravity, electrical and magnetic data, depict the form of the graben with a remarkable degree of mutual consistency and reliability. The results confirm the value of a combined interpretation in solving complex problems, where the application of a single method may give only an ambiguous or incomplete solution. © 1991
Prospecting for safe (low fluoride)groundwater in the eastern African Rift :the Arameru District (Northern Tanzania)
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