Numerical model of pore‐pressure diffusion associated with the initiation of the 2010–2011 Guy–Greenbrier,Arkansas earthquakes

We model pore‐pressure diffusion caused by pressurized waste‐fluid injection at two nearby wells and then compare the buildup of pressure with the observed initiation and migration of earthquakes during the early part of the 2010–2011 Guy–Greenbrier earthquake swarm. Pore‐pressure diffusion is calculated using MODFLOW 2005 that allows the actual injection histories (volume/day) at the two wells to diffuse through a fractured and faulted 3D aquifer system representing the eastern Arkoma basin. The aquifer system is calibrated using the observed water‐level recovery following well shut‐in at three wells. We estimate that the hydraulic conductivities of the Boone Formation and Arbuckle Group are 2.2 × 10^?2 and 2.03 × 10^?3 m day^?1, respectively, with a hydraulic conductivity of 1.92 × 10^?2 m day^?1 in the Hunton Group when considering 1.72 × 10^?3 m day^?1 in the Chattanooga Shale. Based on the simulated pressure field, injection near the relatively conductive Enders and Guy–Greenbrier faults (that hydraulically connect the Arbuckle Group with the underlying basement) permits pressure diffusion into the crystalline basement, but the effective radius of influence is limited in depth by the vertical anisotropy of the hydraulic diffusivity. Comparing spatial/temporal changes in the simulated pore‐pressure field to the observed seismicity suggests that minimum pore‐pressure changes of approximately 0.009 and 0.035 MPa are sufficient to initiate seismic activity within the basement and sedimentary sections of the Guy–Greenbrier fault, respectively. Further, the migration of a second front of seismicity appears to follow the approximately 0.012 MPa and 0.055 MPa pore‐pressure fronts within the basement and sedimentary sections, respectively.     

A NEW DATE FOR THE NEANDERTHALS FROM EL SIDRÓN CAVE (ASTURIAS,NORTHERN SPAIN)*

Torres et al. (2010 ) published a series of radiocarbon, AAR, ESR and OSL dates from the site of El Sidrón, northern Spain, which is notable for the discovery of the partial remains of 12 Neanderthals. Whilst the non‐radiocarbon methods suggested an age beyond 32 600–46 300 years, direct radiocarbon dates on the human fossils were inconsistent, ranging between 10 000 and 50 000 bp . This study uses the ultrafiltration pre‐treatment protocol to obtain a date of 48 400 ± 3200 bp (OxA‐21 776) on a bone fragment and confirm the antiquity of the Neanderthal assemblage. Moreover, it demonstrates the comparability of the ultrafiltration and ninhydrin bone radiocarbon pre‐treatment protocols, and highlights the need for appropriate screening methods where valuable collections with poor biomolecular preservation are sampled for collagen extraction.     

Notes & News

Abstract

This paper examines the British Museum unpublished records related to an Early Bronze (EB) Age pithos burial uncovered a century ago in the Inner Town at Carchemish. The grave, cursorily cited and variously dated (Chalcolithic, EB or even LBA) in the final reports, was described in some detail by Hogarth and Thompson; a precise dating is, however, possible today thanks to the information of paramount importance given by T. E. Lawrence who identified and took a picture of the associated finds, which was recently rediscovered in the Carchemish Archives. The pithos can be now ascribed to the third quarter of the third millennium BC and helps to confirm the recent theory according to which the Inner Town of Carchemish, with its massive earthen rampart, had already developed at the time of the second urbanisation in Syria and upper Mesopotamia.     

The Squatters' Movement in Europe: A Durable Struggle for Social Autonomy in Urban Politics

Squatting empty properties for living or to develop public activities has lasted in European cities for more than three decades. Although local and national contexts differ significantly, there are also some general trends and patterns that deserve careful attention. When squatting occasionally appears in public debates, controversy is generated and many gaps open between academic, social and political perceptions. In this article I use evidence from several European cities to argue that the squatters' movement has produced an original impact in urban politics. The main feature of this impact has been to generate a relatively wide autonomous and mainly non‐institutional mode of citizen participation, protest and self‐management. How has this been possible? Which are the specific contributions made by this urban movement? These are questions that both scholars and activists continuously claim to be relevant, so that this research attempts to offer some general answers based on detailed comparisons and experiences.     

Bayesian modelling of an absolute chronology for Egypt's 18th Dynasty by astrophysical and radiocarbon methods

Only a few astrophysical points and synchronisms listed in texts provide anchor points for the absolute chronology of Ancient Egypt. At first we will show how we can re-calculate some of these anchor points by using Sothic dating based on the arcus visionis method, and modelling lunar dates using a Bayesian approach. Then, we will discuss two radiocarbon studies carried out on short-lived Egyptian materials held at the Louvre Museum that could be attributed to particular reigns or other precise periods. Using a Bayesian approach, these dates were combined with the known order of succession and the lengths of reigns. Sothic and lunar dates were integrated as priors in the model. This approach has led to a new proposal for the absolute chronology of Egypt's 18th Dynasty.     

Latest developments in rock art recording: towards an integral documentation of Levantine rock art sites combining 2D and 3D recording techniques

This paper presents a further step in the integral documentation of prehistoric rock art, combining 2D and 3D digital recording techniques. Image processing and digital enhancement techniques are an invaluable aid to obtain high quality and accurate 2D recordings, especially when working with faint motifs or complex superimpositions. But what constitutes a real breakthrough is the possibility of combining 2D digital tracings with metric 3D models, providing a whole set of metric outputs that improve our understanding of the motifs in their context and, at the same time, can be used to deliver accurate metric reproductions.     

D’Arcy Thompson’s Legacy in Contemporary Studies of Patterns and Morphology

Abstract

D’Arcy Thompson’s views on the forms of biomaterials are assessed in the light of current thinking on biomorphology in selected areas of biology. It is clear that his guiding concepts — that biological materials are structured in response to physical forces, and that the biological and abiotic realms share many common features — remain valid. Advances in the physical and biological sciences are discussed, from quantum mechanics and molecular biology to liquid crystalline materials and macroscopic forms. These reveal Thompson’s clear-sighted view of the role of physical and mathematical sciences in biology, as well as his blind-spots.     

Legg–Calvé–Perthes Disease and unifocal eosinophilic granuloma in a visigoth from the Duratón necropolis (Segovia,Spain)

Individual number 12, exhumed at the Duratón Visigoth necropolis (Segovia, Spain), was found in a supine position inside a simple fossa without adornments. He was a very robust adult (∼50/60 years) male presenting two pathologies, independently originated and both occurring in a particular anatomical area: the right hip. The first one has been diagnosed as Legg–Calvé–Perthes Disease, and it affects the right femur and the coxal. The femoral head has a diameter that is much greater than usual, with a porous articular surface, no fovea capitis and a marked arthritic secondary growth which is inserted in the femoral neck; the coxal shows a pathological acetabulum larger than the left one, and having osseous borders. The second disease, considered a unifocal eosinophilic granuloma, is in the inner face of the right ilium, and practically occupies the whole iliac fossa. The development of the two pathologies and their probable repercussions on the individual's mobility, on the basis of the study of both the pathological and normal pieces recovered, are discussed. Copyright © 2010 John Wiley & Sons, Ltd.     

From Corporatism to Public Utilities: Workplace Pensions in the 21st Century

For many Organisation for Economic Cooperation and Development countries, workplace pensions have been an important mechanism for supplementing state‐sponsored social security. Notwithstanding significant differences between developed economies in the significance attached to workplace pensions, provision has been typically encouraged through preferential tax policies on benefits and compensation packages. If relevant for the baby‐boom generation, it is doubtful that these arrangements will be as important for future generations. As state‐sponsored social security has been discounted in terms of promised value and entitlement, traditional workplace pensions have been closing and replaced by retirement saving instruments that are neither as lucrative nor as dependable. Retrenchment in workplace pensions has prompted governments to consider and, in some cases, develop different types of retirement savings institutions. This paper charts the decline of traditional workplace pensions, the apparent inadequacy of alternatives such as money‐purchase (defined contribution) schemes, and the rise of what are referred to as ‘public utilities’: government sponsored savings institutions designed to compensate for the decline (in coverage and promised value) of workplace pensions albeit at a more modest level than that associated with traditional defined benefit schemes. Reference is made to the experience of the USA, the UK, and Australia with passing comments of related developments in Germany and continental Europe. It is argued that the rise of public utilities in this domain is indicative of the transformation of corporate capitalism over the past 25 years and the realisation that the costs of neoliberalism may be so significant that governments have to take responsibility, once again, for underwriting retirement welfare.