1,720,980 research outputs found
Glossary of normal faults
No full textIncreased interest in normal faults and extended terranes has led to the development of an increasingly complex terminology. The most important terms are defined in this paper, with original references being given wherever possible, along with examples of current usage
The nature and tectonic significance of fault-zone weakening: An introduction
No full textFault zones control the location, architecture and evolution of a broad range of geological features, act as conduits for the focused migration of economically important fluids and, as most seismicity is associated with active faults, they also constitute one of the most important global geological hazards. In general, the repeated localization of displacements along faults and shear zones, often over very long time scales, strongly suggests that they are weak relative to their surrounding wall rocks. Geophysical observations from plate boundary faults such as the San Andreas fault additionally suggest that this fault zone is weak in an absolute sense, although this remains a controversial issue. Out understanding of fault-zone structure and mechanical behavior derive from three main sources of information: (1) Studies of natural fault zones and their deformation products (fault rocks); (2) seismological and neotectonic studies of currently active natural fault systems; (3) laboratory-based deformation experiments using rocks or rock-analogue materials. These provide us with a basic understanding of brittle faulting in the upper crust of the Earth where the stress state is limited by the frictional strength of networks of faults under the prevailing fluid-pressure conditions, under the long-term loading conditions typical of geological fault zones, poortly understood phenomena sucha as subcritical crack growth in fracture process zones are likely to be a major importance in controlling both fault growth and strength. Grain-size reduction in highly strained fault rocks produced in the plastic-viscous and deeper parts of frictional regime can lead to changes in deformation mechanisms and relative weakening that can account for the localization of deformation and repeated reactivation of crustal faults. Our understanding the interactions between deformation mechanism, metamorphic processes and the flow of chemically active fluids is a key area for future study. An improved understanding of how fault- or shear-zone linkages, stregth and microstructure evolve over large changes in finite strain will ultimately lead to the development of geologically more realistic numerical models of lithosphere depormation that incorporate displacements concentrated into narrow, weaker fault zones
Large lateral ramps in the Eocene Valkyr shear zone: extensional ductile faulting controlled by plutonism in southern British Columbia: discussion
No full text
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Convergence - related 'dynamic spreading' in a mid-crustal ductile thrust zone: a possible orogenic wedge model.
No full textDispelling the Myths Behind First-author Citation Counts
Get PDFWe 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
- …
