Race and rights at the rock face of change

2021 ◽  
pp. 116-154
Keyword(s):  
Rock Face

INVESTIGATING ROCK-FACE BOUNDARY EFFECTS ON CAPILLARY PRESSURE AND RELATIVE PERMEABILITY MEASUREMENTS

2011 ◽  
Vol 14 (5) ◽  
pp. 395-409 ◽  
Author(s):  
O. A. Al-Omair ◽  
S. M. Al-Mudhhi ◽  
M. M. Al-Dousari
Keyword(s):  
Capillary Pressure ◽  
Relative Permeability ◽  
Boundary Effects ◽  
Rock Face

Patrons and ViewersDura-Europos

2017 ◽  
Author(s):  
Philippa Adrych ◽  
Robert Bracey ◽  
Dominic Dalglish ◽  
Stefanie Lenk ◽  
Rachel Wood
Keyword(s):  
Eastern Europe ◽  
Rock Face ◽  
The Third

The third chapter examines rock-carved tauroctonies in mithraea, and in particular the monumental tauroctony at Bourg-Saint-Andéol, southeast France. Here, the image of Mithras slaying the bull was carved directly into a rock face between two streams. At other sites, particularly in eastern Europe, there are similar instances of tauroctony rock reliefs. While these images may be linked through their material, each has been positioned in a different way within their respective mithraeum, which may suggest differences in the worship of and belief in Mithras between individual communities. This chapter seeks to broaden our ideas of what the tauroctony meant to worshippers by examining the possible impact of the accompanying interior setting and exterior surroundings on the ancient perceptions of, and interactions with, the reliefs.

Implementation of InfraRed Thermographic surveys in complex coastal areas: the case study of Polignano a Mare (southern Italy)

2021 ◽  
Author(s):  
Lidia Loiotine ◽  
Marco La Salandra ◽  
Gioacchino Francesco Andriani ◽  
Eliana Apicella ◽  
Michel Jaboyedoff ◽  
...  
Keyword(s):  
Rock Mass ◽  
Structure From Motion ◽  
Southern Italy ◽  
Thermal Imager ◽  
Rock Masses ◽  
Field Surveys ◽  
Thermal Images ◽  
Thermal Anomalies ◽  
Rock Face

<p><em>InfraRed Thermography</em> (IRT) spread quickly during the second half of the 20<sup>th</sup> century in the military, industrial and medical fields. This technique is at present widely used in the building sector to detect structural defects and energy losses. Being a non-destructive diagnostic technique, IRT was also introduced in the Earth Sciences, especially in the volcanology and environmental fields, yet its application for geostructural surveys is of recent development. Indeed, the acquisition of thermal images on rock masses could be an efficient tool for identifying fractures and voids, thus detecting signs of potential failures.<br>Further tests of thermal cameras on rock masses could help to evaluate the applicability, advantages and limits of the IRT technology for characterizing rock masses in different geological settings.<br>We present some results of IRT surveys carried out in the coastal area of Polignano a Mare (southern Italy), and their correlation with other remote sensing techniques (i.e. <em>Terrestrial Laser Scanning</em> and <em>Structure from Motion</em>). The case study (<em>Lama Monachile</em>) is represented by a 20 m-high cliff made up of Plio-Pleistocene calcarenites overlying Cretaceous limestones. Conjugate fracture systems, karst features, folds and faults, were detected in the rock mass during field surveys. In addition, dense vegetation and anthropogenic elements, which at places modified the natural setting of the rock mass, represent relevant disturbances for the characterization of the rock mass. In this context, IRT surveys were added to the other techniques, aimed at detecting the major discontinuities and fractured zones, based on potential thermal anomalies. <br>IRT surveys were carried out in December 2020 on the east side of the rock mass at <em>Lama Monachile</em> site. Thermal images were acquired every 20 minutes for 24 hours by means of a FLIR T-660 thermal imager mounted on a fixed tripod. Ambient air temperature and relative humidity were measured during the acquisition with a pocketsize thermo-hydrometer. A reflective paper was placed at the base of the cliff to measure the reflected apparent temperature. In addition, three thermocouple sensors were fixed to the different lithologic units of the rock face. These parameters, together with the distance between the FLIR T-660 and the rock face, were used in order to calibrate the thermal imager and correct the apparent temperatures recorded by the device, during the post-processing phase. Successively, vertical profiles showing the temperature of the rock face over time were extracted from the thermograms. Thermal anomalies were correlated with stratigraphic and Geological Strength Index profiles, obtained by means of field surveys and Structure from Motion techniques. The presence of fracture and voids in the rock mass was also investigated.</p>

scholarly journals The role of frost cracking in local denudation of steep Alpine rockwalls over millennia (Eiger, Switzerland)

2020 ◽  
Vol 8 (3) ◽  
pp. 637-659
Author(s):  
David Mair ◽  
Alessandro Lechmann ◽  
Romain Delunel ◽  
Serdar Yeşilyurt ◽  
Dmitry Tikhomirov ◽  
...  
Keyword(s):  
Swiss Alps ◽  
Rock Fall ◽  
Temperature Changes ◽  
Rock Face ◽  
Temperature Conditions ◽  
Denudation Rates ◽  
Reconstructed Temperature ◽  
Cryogenic Processes

Abstract. Denudation of steep rockwalls is driven by rock fall processes of various sizes and magnitudes. Rockwalls are sensitive to temperature changes mainly because thermo-cryogenic processes weaken bedrock through fracturing, which can precondition the occurrence of rock fall. However, it is still unclear how the fracturing of rock together with cryogenic processes impacts the denudation processes operating on steep rockwalls. In this study, we link data on long-term rockwall denudation rates at the Eiger (Central Swiss Alps) with the local bedrock fabric and the reconstructed temperature conditions at these sites, which depend on the insolation pattern. We then estimate the probability of bedrock for failure through the employment of a theoretical frost cracking model. The results show that the denudation rates are low in the upper part of the NW rockwall, but they are high both in the lower part of the NW rockwall and on the SE face, despite similar bedrock fabric conditions. The frost cracking model predicts a large difference in cracking intensity from ice segregation where the inferred efficiency is low in the upper part of the NW rockwall but relatively large on the lower section of the NW wall and on the SE rock face of the Eiger. We explain this pattern by the differences in insolation and temperature conditions at these sites. Throughout the last millennium, temperatures in bedrock have been very similar to the present. These data thus suggest the occurrence of large contrasts in microclimate between the NW and SE walls of the Eiger, conditioned by differences in insolation. We use these contrasts to explain the relatively low denudation rates in the upper part of the NW rockwall and the rapid denudation in the SW face and in the lower part of the NW rock face where frost cracking is more efficient.

scholarly journals Modern Death. La critique rock face à Blackstar

Miranda ◽  
2018 ◽  
Author(s):  
Claude Chastagner
Keyword(s):  
Rock Face

On Dynamic Fracture of Rock Under Bit Impact Loads

1982 ◽  
Vol 104 (2) ◽  
pp. 105-107 ◽  
Author(s):  
I. E. Eronini
Keyword(s):  
Rock Fracture ◽  
Laboratory Data ◽  
Essential Elements ◽  
Dynamic Force ◽  
Rock Face ◽  
Time Histories ◽  
Drop Tests ◽  
Force Time ◽  
Indiana Limestone

A characterization of the dynamic interaction between an impacting tool and rock is presented. The analysis is based on the concept of rock fracture energy and on simple representations of the amount of fracturing and energy storage in the rock during fracture propagation. The governing equations are not complicated. They contain a small number of parameters and impose minimum restrictions on the form or sophistication of the model of the impacting tool. Simulation results are shown for bit-tooth drop tests on Indiana limestone under different values of the differential pressure across the rock face and for various heights of drop. The predicted dynamic force-penetration curves, force-time, displacement-time and velocity-time histories agree well with reported Laboratory data and demonstrate that the essential elements of tooth drop loading are adequately represented by the model.

Prehistoric Cave Art: From Image to Graphic Narration

Paragraph ◽  
2021 ◽  
Vol 44 (3) ◽  
pp. 379-393
Author(s):  
Marc Azéma
Keyword(s):  
Flickering Light ◽  
Rock Face ◽  
Bande Dessinee ◽  
Cave Art

This article examines cave art in France, arguing that the images created at many sites, but particularly Chauvet, can be analysed in terms of animation, storytelling, lighting and sound. Through superimposition and juxtaposition, and using the contours of the rock face, Palaeolithic artists invented a form of narration based on images, often then animated by the flickering light of lamps and torches. Drawing on semiological work by Philippe Sohet and his terms ‘narrative image’ and ‘iconic narration’, the article sees panels of cave art as constituting scenes and actions that can be discussed in relation to both bande dessinée and cinema. Finally, evidence suggests that the spectacles produced in these spaces, whatever their elusive meaning, also depended on sound and acoustics.

High alpine rock-wall retreat rates over millennia through thermo-cryogenic pre-conditioned rock fall (Mt. Eiger, Switzerland)

2021 ◽  
Author(s):  
David Mair ◽  
Alessandro Lechmann ◽  
Romain Delunel ◽  
Serdar Yeşilyurt ◽  
Dmitry Tikhomirov ◽  
...  
Keyword(s):  
Swiss Alps ◽  
Rock Fall ◽  
Rock Wall ◽  
Rock Face ◽  
Depth Profiles ◽  
Weathering Processes ◽  
Temperature Conditions ◽  
Low Efficiency ◽  
Cryogenic Processes

<p>Rock fall processes of various size and magnitude control retreat rates of high alpine rock-walls. For millennial time scales, these retreat rates can be quantified in-situ from concentrations of cosmogenic nuclides along bedrock depth profiles (Mair et al., 2019). We measured cosmogenic <sup>36</sup>Cl and <sup>10</sup>Be along several such profiles at Mt Eiger in the Central Swiss Alps to study the local rock-wall retreat on this time scale (Mair et al., 2019; 2020). The resulting spatial pattern shows that rock-wall retreat rates are low (0.5 to 0.6 ± 0.1 mm/yr) in the higher region of the NW rock-wall, in contrast to both the lower part of the NW rock-wall and the SE face, where rates are high (1.7 ± 0.4 to 3.5 ± 1.4 mm/yr). We link these retreat rates to differences in local temperature conditions, because the patterns of faults and fractures and the lithology of the bedrock are similar at all sites, and thermo-cryogenic processes are known to weaken the bedrock through fracturing, thereby preconditioning the occurrence of rock fall (e.g., Draebing and Krautblatter, 2019). However, it is still unclear how effective and at which rate individual thermo-cryogenic processes contribute to the preconditioning through fracturing. Therefore, we investigate several processes and estimate the probability of bedrock fracturing through the employment of a theoretical frost-cracking model, which predicts cracking intensity from ice segregation. The model results infer a low efficiency in the higher region of the NW rock-wall, but a relatively high one in the lower section of the NW wall and on the SE rock face of Mt. Eiger. Although the model is rather generic, the results disclose a significant control of temperature conditions on the erosional processes and rates. Furthermore, temperature conditions for the last millennia have been similar to present day conditions, as our reconstructions disclose, therefore the cosmogenic-nuclide-based long-term differences in rock-wall retreat rates predominantly stem from large contrasts in the microclimate between the NW and SE walls of Mt. Eiger. Accordingly, the site-specific differences in microclimate conditions could explain the lower retreat rates in the upper part of the NW rock-wall and the rapid retreat in the SW face and in the lower part of the NW rock face.</p><p>References</p><p>Draebing, D. and Krautblatter, M.: The Efficacy of Frost Weathering Processes in Alpine Rockwalls, Geophys. Res. Lett., 46, 6516–6524, doi:10.1029/2019GL081981, 2019.</p><p>Mair, D., Lechmann, A., Yesilyurt, S., Tikhomirov, D., Delunel, R., Vockenhuber, C., Akçar, N. and Schlunegger, F.: Fast long-term denudation rate of steep alpine headwalls inferred from cosmogenic 36Cl depth profiles, Sci. Rep., 9, 11023, doi:10.1038/s41598-019-46969-0, 2019.</p><p>Mair, D., Lechmann, A., Delunel, R., Yeşilyurt, S., Tikhomirov, D., Vockenhuber, C., Christl, M., Akçar, N. and Schlunegger, F.: The role of frost cracking in local denudation of steep Alpine rockwalls over millennia (Eiger, Switzerland), Earth Surf. Dyn., 8, 637–659, doi:10.5194/esurf-8-637-2020, 2020.</p>

A landslide-generated tsunami and outburst flood at Elliot Creek, coastal British Columbia  

2021 ◽  
Author(s):  
Marten Geertsema ◽  
Brian Menounos ◽  
Dan Shugar ◽  
Tom Millard ◽  
Brent Ward ◽  
...  
Keyword(s):  
British Columbia ◽  
Rock Avalanche ◽  
Lake Basin ◽  
Outburst Flood ◽  
Coast Mountains ◽  
Rock Face ◽  
Valley Fill ◽  
Causative Relationship ◽  
Displacement Wave ◽  
Steep Slopes

<p>On 28 November 2020, about 18 Mm<sup>3</sup> of quartz diorite detached from a steep rock face at the head of Elliot Creek in the southern Coast Mountains of British Columbia. The rock mass fragmented as it descended 1000 m and flowed across a debris-covered glacier. The rock avalanche was recorded on local and distant seismometers, with long-period amplitudes equivalent to a M 4.9 earthquake. Local seismic stations detected several earthquakes of magnitude <2.4 over the minutes and hours preceding the slide, though no causative relationship is yet suggested. More than half of the rock debris entered a 0.6 km<sup>2 </sup>lake, where it generated a huge displacement wave that overtopped the moraine at the far end of the lake. Water that left the lake was channelized along Elliot Creek, deeply scouring the valley fill over a distance of 10 km before depositing debris on a 2 km<sup>2</sup> fan in the Southgate River valley. Debris temporarily dammed the river, and turbid water continued down the Southgate River to Bute Inlet, where it produced a 70 km turbidity current and altered turbidity and water chemistry in the inlet for weeks. The landslide followed a century of rapid glacier retreat and thinning that exposed a growing lake basin. The outburst flood extended the damage of the landslide far beyond the limit of the landslide, destroying forest and impacting salmon spawning and rearing habitat. We expect more cascading impacts from landslides in the glacierized mountains of British Columbia as glaciers continue to retreat, exposing water bodies below steep slopes while simultaneously removing buttressing support.</p>

scholarly journals Dawes Point

2010 ◽  
Vol 2 (2) ◽  
pp. 45-46
Author(s):  
Shirley Fitzgerald
Keyword(s):  
Aboriginal People ◽  
Young Girl ◽  
African Studies ◽  
Local Language ◽  
Rock Face ◽  
The University ◽  
Nevil Maskelyne

The promontory at the western end of Circular Quay was known to the Aboriginal people as Tar-Ra. It was chosen as the site for an observatory by Lieutenant William Dawes, who arrived with the first Europeans. Dawes came with a recommendation from the Astronomer Royal, Dr Nevil Maskelyne, and some instruments from the Board of Longitude, with which to study the heavens. The point was initially named Maskelyne Point, but as Dawes lived there while he was in the colony from 1788 until 1791, the area became known as Dawes Point.Dawes kept the colony's first meteorological records here, and it was also here that Dawes pinned the town's first clock to a rock face. He encouraged friendship with local Aboriginal people, including a young girl Pategarang, from whom he learned some of the language of the Cadigal people. Dawes's notebooks, held in the School of Oriental and African Studies at the University of London, remain one of the most precious records of the local language.

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