1,720,980 research outputs found
Inherited structures and lateral variability along a plate boundary shear zone in a convergent margin: The Sestola-Vidiciatico Tectonic Unit and the Subligurian Units of the Northern Apennines of Italy
No full textInternal architecture of the frontal part of subduction accretionary prism: the role of folding in brittle diffuse deformation
No full textFluid history related to the early Eocene-middle Miocene convergent system of the Northern Apennines (Italy). Constraints from structural and isotopic studies
Full text linkThe late Eocene-middle Miocene erosive plate boundary between the European and
the Adriatic plates is exhumed in the Northem Apennines of Italy. The fossil fault zone is
500 m thick and the outcropping portion exposes the :first 5 km of its depth. At this
plate boundary basai and frontal tectonic erosion incorporated unlithified, fluid-rich sediments
into the fault zone. The deformation and nature of the material along the plate boundary define a
fossil subduction channel. Here we couple a detailed structural analysis of the Apennine subduction
channel, focusing, in particular, on calcite veins, with a stable isotope analysis to characterize
the fluid regime along an active subduction channel.
The 13C and 180 composition of calcite vein and host rock samples within the fault zone
indicates that there is a deep metamorphic source of fluids migrating upward along the subduction
channel, in addition to locally derived fluid components. Dewatering of subducting turbidites
contributes significantly only in the shallowest part of the channel. Structural observations
indicate fluid flow along and across the subduction channel. At deep levels fluid flow is
associated with discrete deformation events on shear faults offset by dilational jogs :filled with
implosion breccias. At intennediate levels deformation is stili cyclic and associated with repeated
crack-and-seal events. At the shallowest levels deformation occurred, while portions of the
subducting material were stili unlithi:fied. Here the deformation was quasicontinuous, without
associated vein development. Both isotope and structural analyses indicate that this erosive
subduction channel behaved as a weak: fault with a vertical maximum principal stres
Mechanical behavior of the shallow part of megathrusts: hints from the Sestola Vidiciatico tectonic Unit (Northern Apennines, Italy)
No full textDoes subduction of mass transport deposits (MTDs) control seismic behavior of shallow–level megathrusts at convergent margins?
No full textWe present a critical appraisal of the role of subducted, medium (10–1000 km2) to giant (≥1000 km2) and heterogeneous, mud-rich mass transport deposits (MTDs) in seismic behavior and mechanisms of shallow earthquakes along subduction plate interfaces (or subduction channels) at convergent margins. Our observations from exhumed ancient subduction complexes around the world show that incorporation of mud-rich MTDs with a “chaotic” internal fabric (i.e., sedimentary mélanges or olistostromes) into subduction zones strongly modifies the structural architecture of a subduction plate interface and the physical properties of subducted material. The size and distribution of subducted MTDs with respect to the thickness of a subduction plate interface are critical factors influencing seismic behavior at convergent margins. Heterogeneous fabric and compositions of subducted MTDs may diminish the effectiveness of seismic ruptures considerably through the redistribution of overpressured fluids and accumulated strain. This phenomenon possibly favors the slow end-member of the spectrum of fault slip behavior (e.g., Slow Slip Events, Very Low Frequency Earthquakes, Non-Volcanic Tremors, creeping) compared to regular earthquakes, particularly in the shallow parts (T < 250 °C) of a subduction plate interface
New thermal constraints on a shallow fossil subduction channel from the Northern Apennines of Italy
No full textGoing 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
- …
