1,720,964 research outputs found
Seismic Imaging of Fractured Reservoirs in the Scansano-Amiata area, Southern Tuscany
No full textFresh water availability has recently become a serious concern in the Italian Apennines as various activities rely on a predictable supply. In southern Tuscany along the Scansano-Amiata ridge the situation is further complicated because of the contamination of the nearby alluvial aquifers. Locally aquifers consist of thin fractured reservoirs, generally within low-permeability formations, and planning exploitation of resources, based on conventional techniques, could be complicated. An integrated investigation program, based on remote sensing, structural geology and geophysical exploration, was initiated in 2002 to associate tectonics and groundwater circulation and better define the hydrological model. After the regional identification of fault and fracture patterns a major structure has been investigated in detail to accurately map the spatial position, and understand the associated aquifer geometry and properties to assess exploitation potentials. The subsurface around the fault zone was clearly imaged with Ground Probing Radar, 2D and 3D resistivity tomography and more recently with 3D shallow seismic. The vertical and the horizontal contacts between the different geological units of the Ligurian and of the Tuscan Series were resolved with a high degree of spatial accuracy. 3D high-resolution geophysical imaging proved to be very effective in small-scale fractured reservoir characterisation
Passive seismic exploration in an urban environment along the projected route of an underground railway
No full textWe utilised the Refraction Microtremors (ReMi) seismic technique to conduct a survey in the city of Malaga in Spain to support a project for the construction of a new subway line in the vicinity of the coast.
The ReMi technique was chosen to carry out the survey because of the expected difficulties of conventional seismic operations in a densely populated urban area with its logistical and administrative restrictions and with a very high level of background noise.
A total of about 1400 m of profiles were collected in two days of field work. The correlation of shear wave maps with the available borehole stratigraphy was generally good. In a few areas, probably because of structural complexity, ReMi interpretation of the data was not definitive. Poor ReMi performance was seen as an indicator of zones of geological complexity requiring either further geophysical investigation or special attention during tunnel excavation.
The ReMi technique proved to be adequate for characterising the shallow subsurface in the study site in terms of geometry and shear wave velocity down to a depth of 5070
meters. The bandwidth andamplitude of the spectrum of the traffic and urban noise were sufficient to generate usable surface waves
3D Seismic Imaging of a Deep Landslide in the Eastern Alps (Northern Italy)
No full textThe Lamosano Town in the Eastern Alps, was built on the top of a ridge, involved in a slow landslide movement that caused several damages to various buildings. Former studies, conducted in the early eighties, suggested of classify the town as a centre to be relocated.
The Italian Government recently funded a new investigation program aimed to better understand the landslide dynamics and assess the possibility of mitigating the surface effects avoiding the need of transferring part of the local population to a different site.
In this context was undertaken an integrated 3D seismic refraction tomography / reflection survey targeting the geological structure of the ridge. The subsurface below the ridge was clearly imaged by the seismic and the major contacts between the different units were resolved with an adequate degree of horizontal and vertical resolution.
The high-resolution acoustic image of the subsurface led to the formulation of new hypotheses about the major cause of the soil movements and the possible relationship between groundwater circulation and surface displacements.
3D high-resolution seismic imaging proved to be very effective in the characterisation of areas affected by deep landslide phenomena
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
3D-imaging of shallow fractured aquifers along the Scansano-Amiata ridge (Tuscany, Italy)
No full textA series of high-resolution geophysical surveys including 3D seismic refraction and resistivity tomography, 2D resistivity tomography and Ground Probing Radar, were recently conducted in three sites of the Scansano-Amiata ridge in southern Tuscany (Italy). The goal of the survey was to clearly image the geometry and the properties of some small scale aquifers hosted in high-angle faulted and fractured zones. In the recent years fresh water availability has become a major issue in the Italian peninsula as various agricultural and industrial activities as well as urban settlements depend on a constant and predictable supply. In the Appennine area, aquifers very often consist of fractured reservoirs within low-permeability formations, where established alluvial aquifer modeling techniques appear inadequate to protect the resource from pollutants or plan new extracting plants. The existing well distribution was compared with the fault network revealed by satellite image interpretation. The most productive aquifers resulted invariably located along major faults, thus pointing out the importance of secondary (tectonic) permeability. A prominent sub-vertical fault system ("Patrignone" fault), oriented north-south was investigated with high-resolution geophysical methods and direct excavation at three different sites: "Aione", "Ripacci" and "Poderino". We report here some of the results obtained at the "Poderino" site where 3D-geophysical data have been also collected (Figure 1). The different geophysical images clearly outlined the structural framework of the subsurface down to a depth greater than 100 m and the final synthesis provided a comprehensive insight into the architecture of faulted and fractured zones and in the overall permeability structure
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Regional Mapping of the Average Shear Wave Velocity for Geotechnical Applications - An Example in North-eastern Italy
No full textWe utilised the Refraction Microtremors (ReMi) seismic technique to conduct a regional survey targeting the average shear wave velocity in the uppermost 30 m in the Province of Treviso in north-eastern Italy. The ReMi technique was chosen because of its cost effectiveness as the field operations can be easily conducted by single person The data acquisition grid was optimised using a multidisciplinary approach. Each VS recording station was precisely located based on a high-resolution depositional model of the entire venetian plain. A total of 250 recording stations, scattered over an area of 2000 square km, were collected in a time window of a month in the early 2006. Data processing faced some problems as in some cases spectral quality was not satisfying and the dispersion curve could not be identified with an adequate degree of confidence. A percentage of 10% of the collected were discarded. The final VS map showed a surprisingly correlation with the alluvial and fluvio-glacial depositional model acting during late Pleistocene and Holocene. The ReMi technique and more generally the surface wave based techniques proved to be a valuable tool for the regional mapping of average values of VS in the near surface strata
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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