1,720,969 research outputs found
Role of precursor joints in the contractional deformation of a granite pluton, Machu Picchu batholith, Eastern Cordillera, Peru
No full textIntegration of geophysical investigation to landslide analysis in the archaeological site of Stabiae (Italy)
No full textThe complex of the Roman villas of the ancient Stabiae is located over a morphological terrace near the edge of a steep slope that separates the archaeological site from the urban area of Castellammare di Stabia (Gulf of Naples). The hill is being affected by debris and earth flows that have endangered some ancient structures of the complex. The present work has reconstructed the slope dynamics and causes by means of a geomorphological and geotechnical approach coupled with geophysical investigation. A slope stability modelling, calibrated with landslide historical information and direct survey, has provided main failure mode and magnitude of recent events. Geophysical investigation has permitted to analyse the state of superficial terrains under prominent archaeological structures, providing important information on potential failure surfaces that can be mobilised in the near future in the lack of urgent mitigation measures in the most hazardous sectors of the slope.The complex of the Roman villas of the ancient Stabiae is located over a morphological terrace near the edge of a steep slope that separates the archaeological site from the urban area of Castellammare di Stabia (Gulf of Naples). The hill is being affected by debris and earth flows that have endangered some ancient structures of the complex. The present work has reconstructed the slope dynamics and causes by means of a geomorphological and geotechnical approach coupled with geophysical investigation. A slope stability modelling, calibrated with landslide historical information and direct survey, has provided main failure mode and magnitude of recent events. Geophysical investigation has permitted to analyse the state of superficial terrains under prominent archaeological structures, providing important information on potential failure surfaces that can be mobilised in the near future in the lack of urgent mitigation measures in the most hazardous sectors of the slope
Geological and geophysical investigation in the North Stelae Park of Aksum (Ethiopia) as contribution for the re-erection of the Roma Stela
No full textMultidisciplinary approach were used in the characterization of archaeological park of Axum. The study was for the return of stelae to Asum
Geo-structural modelling for potential large rock slide in Machu Picchu
No full textThe monumental complex of the Historical Sanctuary of Machu Picchu, declared as World Heritage Site by UNESCO in 1983, is located in the Andean chain at approx. 80 km from Cuzco (Peru) and at an elevation of 2430 m a.s.l. along the Urubamba River Valley. From a geological point of view, the Machu Picchu granitoid pluton, forming part of the larger "Quillabamba granite", is one of a series of plutons intruded along the axial zone of the high Eastern Cordillera Permo-Liassic rift system including a variety of rock types, dominantly granites and granodiorites. The most evident structures at the outcrop scale consist of planar joint sets that may be variably reactivated and exhibiting 4 main orientations. At present, the site is affected by geological risk due to frequent landslides that threaten security and tourist exploitation. In the last years, the international landslide scientific community has promoted a multi-discipline joint programme mainly finalised to slope deformation monitoring and analysis after the warning, launched in 2001, of a potential collapse of the citadel, caused by a huge rock slide. The contribute of the Italian research team was devoted to implement a landslide risk analysis and an innovative remote sensing techniques. The main scope of this work is to present the implementation of a geo-structural modelling aimed at defining present and potential slope stability conditions of the Machu Picchu Citadel. Data have been collected by geological, structural and geomechanical field surveys and laboratory tests in order to reconstruct the geomorphological evolution of the area. Landslide types and evolution are strictly controlled by regional tectonic uplift and structural setting. Several slope instability phenomena have been identified and classified according to mechanism, material involved and state of activity. Rock falls, debris flows, rock slides and debris slides are the main surveyed landslide types. Rock slides and rock falls may produce blocks with dimensions variable from 10-1 to 102m3 that form the toe accumulation on steeper slopes. The area of the citadel has also been interpreted as affected by a deep mass movement (>100m) that, if confirmed by the present day monitoring systems, could be referred to a deep-seated gravitational slope deformation (DSGSD), probably of the type of the compound bi-planar sagging (CB) described by Hutchinson (1988). The analysis of active strain processes (e.g. tension cracks) along with the damage pattern surveyed on archaeological structures (e.g. sinking, swelling, tilting) suggest that the potential failure of a large rock slide may be located at a depth of ca. 30m. The various data sets have been integrated in order to obtain a general geo-structural and geotechnical model (strength and deformation parameters, seismic input) of the citadel at the slope scale. This represents a first step in implementing a slope stability analysis capable of reconstructing present and potential landslide evolution under static and dynamic conditions. This multi-discipline study, based on geological and structural analysis integrated with geotechnical and geomechanical interpretation, will aid defining actual landslide hazard and risk levels, indispensable for the design of low impact mitigation measures to be applied at Machu Picchu Citadel
“STABILITY AND SEISMIC VULNERABILITY OF THE STYLITE TOWER AT UMM AR-RASAS„
Full text linkThe stability and vulnerability analyses carried out on the Stylite tower at Umm ar−Rasas, Jordan, are presented in this paper. The tower is a unique example of this kind of structure still existing. The soil and the structural material were analyzed by means of in situ ex− perimental tests. These consisted of Schmidt−hammer tests on stone blocks and passive seismic measurements. The stability of the tower was first analyzed, assuming an elastic – perfect plastic behavior in compression for masonry. Then the push−over seismic analysis was carried out, which was based on a single−mode approach and a finite solid element modelling with a Drucker−Prager yield criterion for masonry. The work is propaedeutic to the design of a retrofit intervention
Seismic analysis of the Stylite Tower at Umm ar-Rasas
No full textA seismic vulnerability analysis carried out on the Stylite Tower at Umm ar-Rasas, Jordan, which is a UNESCO World Heritage Site, is presented in this paper. The monument, a unique survived example of stylite towers in the Middle East, presents evidence of structural damage due to earthquakes. The study was based on preliminary investigations, which consisted in Schmidt-hammer tests executed on stone blocks and passive tromography tests on the ground. Two models were implemented for the tower. In the first one, the tower was considered as a rigid structure supported by means of an elasto-perfect plastic cushion at the base. In the second one, a finite element model was setup, with solid elements characterized by a Drucker-Prager yield criterion. In both cases a push over analysis was performed, which resulted in a very low resistance of the tower to seismic actions. The work is part of a preservation effort which will include the design of a retrofit intervention
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
An inventory-based approach to landslide susceptibility assessment and its application to the Virginio River Basin, Italy
No full textAn inventory-based method for the assessment of landslide susceptibility is presented in this article. The method has been tested in the Virginio River Basin, a tributary of the Arno River whose confluence is located about 20 km downstream from Florence (Italy). The scope of this study includes setting up a procedure for landslide hazard zoning to be applied by those urban planners typically working on small areas at large scale. The proposed method deals with traditional and well-known landslide hazard analyses, based on geomorphological tools, and its most original contribution is represented by the attempt to carry out and apply a technique for landslide hazard assessment that takes into account two different scales of analysis. The basis of a detailed landslide inventory and the first phase of this research was an in-depth geomorphological investigation at basin scale (1: 25,000-1:10,000). This was aimed at indicating the most important factors influencing the landslide processes within the area, which also turned out to be the most generally accepted factors: a) slope gradient in which the landslide originated, b) lithology, and c) land cover. Once those factors were defined as thematic vector data, they were expressed using GIS overlay mapping, allowing the identification, for the entire Virginio River basin, of first-order homogeneous domains (Unique Condition Units, UCUs) that contain, for each landslide type, unique combinations (domains) of the selected hillslope stability factors. The domains are the basic Terrain Units for the subsequent landslide susceptibility assessment and mapping, which was carried out at slope scale (1: 10,000-1:2,000). Landslide factors not identified in the first phase of analysis, but considered to have played an important role in contributing to the activation of the mass movements, so-called second-order landslide preparatory factors, have been taken into account in the second phase of the analysis. Once mapped and spatially referenced, these factors were overlain by vector-based GIS techniques to define second-order UCUs which, in turn, constituted the basis of a landslide susceptibility function. Essentially, this is a logic function based on the presence/absence of preparatory factors and slope instability indicators within previously selected Unique Condition Terrain Units. The final mapping of the areas characterized by different landslide susceptibility levels was performed by vector- and raster-based GIS techniques on the basis of the number and rank of the preparatory factors. The final landslide susceptibility classes, defined by a logical and easily replicable procedure, are considered to be useful in the decision-making procedures associated with territorial planning
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
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