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The clays involved in the 1963 Vajont landslide: Genesis and geomechanical implications
Full text linkThe catastrophic Vajont landslide that occurred on 9 October 1963 caused about 2000 deaths when 270–300 Mm3 of rock and debris slid from the northern slope of Mt. Toc into the newly created artificial reservoir, displacing some huge water waves that flooded the nearby villages. The 1963 slide was an en-block remobilisation of a prehistoric rockslide lying on the southern reservoir bank. Basal sliding took place within a complex lithostratigraphic sequence of cherty–marly limestones and clay interbeds belonging to the Fonzaso Formation of Upper Jurassic age. In this work, we investigate the geological origin and provenance of the Vajont clays according to the results of mineralogical and geochemical analyses performed on several clay samples which were collected from the landslide failure surface and the same limestone sequence in the surrounding area. The sampled clayey materials contained variable amounts of clay minerals (36–96%), calcite (4–64%) and quartz (0–6%). The dominant clay minerals were illite/smectite (I/S) mixed layers with a high illite content (85–50%), which was consistent with the high percentage of K2O (1.17–5.77%). The Vajont clays included in the Fonzaso Fm. can be referred to as K-bentonites and can be interpreted as distinct deposits of volcanoclastic materials (tephra), representing the sedimentary inputs of volcanic ashes that interrupted the “normal” calcareous sedimentation during the late Oxfordian–upper Tithonian (158–145 Ma). The soft clay interbeds played a different mechanical role in the occurrence of the prehistoric rockslide and the 1963 en-block remobilisation. When referring to the ancient slope failures, distinct clay-rich layers that were concentrated within some specific lithostratigraphic intervals of the Jurassic cherty limestone sequence caused a localised decrease in the available shear strength, allowing for relative shear displacements along the dip-slope bedding planes. This caused additional shear/tensile fracturing of limestone beds and the formation of a stepped basal failure surface. During the 1963 remobilisation, the clay layers contributed to the average shear strength decrease of the debris material forming the basal shear zone of the slide, but the main triggering factor was the increase in pore pressures caused by the reservoir-induced groundwater inflow
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
An interdisciplinary approach for the characterisation of the clays involved in the catastrophic 1963 Vajont landslide
No full textHigh-plasticity clay levels played a decisive role in the catastrophic 1963 Vajont slide, as also emphasised by Hendron
& Patton (1985) in the detailed geological survey of the large upper detachment surface. However, many geological and
geomechanical issues still remain open, because the geological context of these clay layers was not described in detail.
This lack prevents full understanding of the clay influence on the catastrophic slope failure and on the subsequent high
velocity sliding into the Vajont reservoir. A specifically-addressed geomechanical survey has been performed over the
recent years (2006–2015) and many clay levels have been sampled (Paronuzzi & Bolla, 2012). On the basis of this new
data, an updated engineering-geological map of the Vajont landslide has been implemented (Paronuzzi & Bolla, 2015).
The clays involved in the 1963 rupture were analysed according to an interdisciplinary approach that considers
lithostratigraphical, mineralogical and geotechnical aspects. This work presents the main results of this interdisciplinary
characterisation. The clay samples (20) belong to three distinct units: 1) the main rupture surface involving the cherty
limestone bedrock (Fonzaso Formation: Upper Jurassic); 2) the basal shear zone of the Vajont slide (angular gravel with
contorted clay lenses and sheared off rock masses); and 3) the upper part of the Fonzaso Formation outcropping on the
opposite valley flank. Field evidence confirms the occurrence of discontinuous clay lenses having a thickness ranging
from 0.5 to 5 cm, in most cases. Clay materials exhibit variable colours: greenish grey, pale olive, pale yellow, light grey,
and even white. XRD analysis revealed a rather constant mineralogical composition, including calcite, quartz and
montmorillonite (19 samples), whereas plagioclase have occasionally been identified (2 samples). Montmorillonite shows
both a well-crystallised structure (class A) and a poor-crystallised structure (class E), thus influencing the shear strength
characteristics. Laboratory investigations on the clay samples testify to a great variability of their geotechnical properties.
The clay fraction ranges from about 10% to 60%. Three main groups of clay materials can be identified on the basis of
their plasticity properties: low-medium, medium and high plasticity clays. The liquid limit varies considerably, ranging
from 30% up to 90%. Clay samples were also tested in the laboratory through ring shear test apparatus to investigate their
shear strength. The results of the shear tests emphasize a notable variation in the characteristic residual friction angle
(φres) that ranges from very low (6.7–9.7°) to considerably higher values (25.1–26.7°), thus denoting a remarkable (and
previously not pointed out) geotechnical variability of the clay levels involved in the catastrophic 1963 slope failure
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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