Reanalysis of in situ permeability measurements in the Barbados décollement

A cased and sealed borehole in the Northern Barbados accretionary complex was the site of the first attempts to measure permeability in situ along a plate boundary décollement. Three separate efforts at Hole 949C yielded permeability estimates for the décollement spanning four orders of magnitude. An analysis of problems encountered during installation of the casing and seals provides insights into how the borehole conditions may have led to the wide range of results. During the installation, sediments from the surrounding formation repeatedly intruded into the borehole and casing. Stress analysis shows that the weak sediments were deforming plastically and the radial and tangential stresses around the borehole were significantly lower than lithostatic. This perturbed stress state may explain why the test pressure records showed indications of hydrofracture at pressures below lithostatic, and permeabilities rose rapidly as the estimated effective stress dropped below 0.8 MPa. Even after the borehole was sealed, the plastic deformation of the formation and relatively large gap of the wire wrapped screen allowed sediment to flow into the casing. Force equilibrium calculations predict sediment would have filled the borehole to 10 cm above the top of the screen by the time slug tests were conducted 1.5 years after the borehole was sealed. Reanalysis of the slug test results with these conditions yields several orders of magnitude higher permeability estimates than the original analysis which assumed an open casing. Overall the results based on only the tests with no sign of hydrofracture yield a permeability range of 10^?14–10^?15 m² and a rate of increase in permeability with decreasing effective stress consistent with laboratory tests on samples from the décollement zone.     

Book-in-a-box to Xbox: materiality and the contemporary textual object

Book-in-a-box to Xbox is a discussion of developments in the material form of contemporary textual objects and of the impact this has on user/reader experience. The article formulates itself as a contemporary book history, situating the texts in question within the broader sphere of digital culture, and analyses textual function, reception, form and user interaction, presenting a cultural theorising of contemporary textual objects. The article conducts these discussions via a consideration of Marc Saporta's Composition No. 1 (a key example of materially experimental literature); recent developments in e-reading and the implications of these developments; designing interactivity in massively multiplayer online gaming; and emerging forms of sociality, or shared experience, in virtual reading and playing communities.     

Le Conte de deux cités1 : Analyse comparative des conflits urbains de Montréal et Valence, 1995–2010

A tale of two cities: 9 Comparative analysis of urban conflicts of Montreal and Valencia, 1995–2010 Metropolization processes at work in contemporary societies produce social and spatial change, which can raise strong opposition from a variety of urban actors, leading to acts of dissent. While such urban conflict has been examined in the past, geographical analysis of urban conflicts as sociospatial processes is more recent. Systematic quantitative research on urban conflict is virtually nonexistent in terms of comparative analysis conducted with an international perspective. Systematic comparative analysis sheds light on the existing relationship between urban conflicts and the socio‐territorial contexts in which conflicts emerge and evolve. This article presents a comparative analysis of urban conflict that occurred in a selection of boroughs in two cities characterized by different geographical realities, Valencia (Spain) and Montreal (Canada), between 1995 and 2010. Spatial autocorrelation techniques applied to a conflict database show a significant relationship between the emergence of urban conflict and the spatial distribution of some contextual variables. Indeed, for Montreal as for Valencia, the concentration of urban conflict is the greatest in the most deprived neighbourhoods. Also, regarding the management and regulation of urban conflict, results shed light on important differences between Montreal and Valencia. These differences include the outcome of urban conflicts, repertoire of action of actors involved in conflict activity, and the type of contestation faced by actors who promote the challenged urban projects.