1,720,965 research outputs found
Modelling tectonic deformation along the North-Anatolian Fault in the Sea of Marmara
Full text linkUsing analogue techniques, we attempted to model the complex tectonic deformation pattern observed along the North-Anatolian Fault in the Sea of Marmara from morpho-bathymetry and seismic reflection images. In particular this paper focuses on the so-called Cinarcik segment of the fault connecting the eastern Izmit segment, which entirely ruptured during the Mw 7.4, 1999 earthquake, to the western segment of the Central High. The Çınarcık segment, potentially loaded after the Izmit earthquake, is expected to rupture during an earthquake occurring in the near future, possibly the next decades, with a high potential to affect the Istanbul metropolitan area. Our analysis suggests that the development of the observed structures accommodating strike-slip, transtensional and transpressional deformations, could be explained by changes in the geometry of fault segments within a right-lateral strike-slip tectonic regime. Tectonic deformations were reproduced in the analogue model by imposing a small (about 10°) and sharp difference in the relative orientations of the strike-slip segments at the edges of a major releasing bend. In the model slower strain accumulation occurs along the analogue of the Çınarcık segment than along the analogue of the Izmit segment of the fault. This would predict a delay for earthquakes triggered by stress transfer between the Izmit and Çınarcık segments. The model further predicts that most of the deformation in the Çınarcık basin is controlled by the sharp changes in the geometry of the fault itself
Centrifuge modelling of thrust systems in the brittle crust: Role of frictional décollement geometry
No full textCentrifuge analogue modelling has provided significant insights into the evolution and architecture of fold and thrust systems. However, all previous works focused on the deformation of viscous and/or plastic layers, and did not analyze the development of structures in the brittle crust. In this work, we present the results of analogue centrifuge models reproducing compression of purely brittle upper crustal layers. We run enhanced gravity models investigating the role exerted by frictional décollements on the evolution and architecture of thrusting and compared the results with new normal-gravity models with similar set-up. In line with the results of previous experimental works, our models show that the presence of a low-friction basal décollement significantly influences the evolution and pattern of thrust systems. By reducing the basal friction of the experimental wedge or the sector of the wedge where the low-friction décollement is located, this layer promotes experimental wedges with low tapers and low heights in the inner portion. Moreover, when a low-friction basal décollement occurs, the tectonic wedge is characterized by an increase in wavelength of thrust sheets toward the foreland, compared to the purely brittle models. Results show a good comparison between centrifuge and normal gravity models, indicating that the centrifuge technique can be successfully used to model shortening in the brittle crust and therefore to analyze the evolution and architecture of thrust systems
Messinian halite and residual facies in the Crotone Basin (Calabria, Italy)
No full textThe Neogene Crotone basin in eastern Calabria contains extensive Messinian evaporite deposits, including thick gypsarenite and halite bodies. The halite deposit reaches a maximum thickness of ~300 m and in some areas forms relatively small diapirs piercing late Messinian and Pliocene sediments. Halite is strongly modified by folding and recrystallisation, but a few primary features are preserved. Four primary halite facies have been recognised: (a) banded halite consisting of folded white and dark bands deposited in a salt pan and/or saline mudflat; (b) white facies, massive halite containing anhydrite nodules, probably formed in a variably desiccating saline lake; (c) clear facies made up of a mosaic of large blocky halite crystals separated by mud, possibly the product of displacive halite growth in a saline mudflat; and (d) breccia facies, a product of dissolution of halite/mudstone/siltstone layers;Residual facies formed from halite dissolution are present as both, weld- and cap-rocks. Weld-rocks are thick, undeformed, and composed only of insoluble phases originally included in the salt, whereas cap-rocks are thin, strongly sheared and include clasts from the cover rocks
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
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
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
- …
