A lithospheric seismic refraction profile in the western North Atlantic Ocean     

R. B. Whitmarsh  C. E. Keen  L. Steinmetz§  J. Tomblin¶  R. B. Whitmarsh  M. Donegan  R. C. Lilwall  B. D. Loncarevic  B. Nichols  J. Shepherd¶ 《Geophysical Journal International》1983,75(1):23-69

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Upper mantle structure beneath the Mid-Atlantic Ridge north of the Azores based on observations of compressional wave     

L. Steinmetz  R. B. Whitmarsh  V. S. Moreira 《Geophysical Journal International》1977,50(2):353-380

Summary. Four seismic refraction profiles have been interpreted which serve to indicate the structure of the lithosphere near the Mid-Atlantic Ridge close to the Azores. An east–west profile which crosses the ridge axis yields a crustal structure. Although energy is propagated across the ridge axis within the crust the axial region marks a clear barrier to propagation within the mantle. A profile parallel to the axis (4 my isochron) shows, below a 7.6 km/s layer, a low-velocity zone underlain by an 8.3 km/s refractor 9 km below the sea bed. On profies normal to the ridge axis higher velocities, which are observed on lines shot towards the ridge, can be attributed to this refractor if it has a dip of several degrees away from the ridge. On another profile parallel to the axis (9 my isochron) a velocity of about 8.3 km/s is only found to exist much deeper at about 30 km depth. These observations are interpreted in the light of seismic refraction results recently obtained by Lewis & Snydsman and of quantitative petrological models, such as that of Bottinga & Allègre. A velocity model based on Bottinga & Allègre's model allows us to understand our results qualitatively. In particular the two 8.3 km/s refractors at 9 and 30 km depth correspond to two different residual peridotite layers. The upper layer contains 1.5–2 wt per cent water and as the lithosphere moves away from the ridge axis the temperature in this layer becomes low enough to start hydration reactions. These cause the low-velocity zone observed at 4 my and the total disappearance of the shallow level refractor before 9 my.  相似文献   

The economic sustainability of artisanal fisheries: the case of the trawl ban in the Gulf of Castellammare, NW Sicily     

David Whitmarsh  Carlo Pipitone  Fabio Badalamenti  Giovanni D&#x;Anna 《Marine Policy》2003,27(6):489-497

Small-scale fisheries and the communities they support are often given the protection of designated fishing zones from which non-artisanal vessels are excluded. This paper looks at one example of this approach, the trawl ban introduced in the Gulf of Castellammare (NW Sicily), focussing on the economic sustainability of the artisanal fishery currently operating within the protected area. The consequences of lifting the trawl ban and how far this would jeopardise the sustainability of the artisanal fishery are explored via an analysis of the financial viability of trammel net vessels under alternative assumptions concerning catch rates. The paper also investigates fishermen's attitudes towards the trawl ban and their predisposition either to remain in the fishery or to quit in the event of the ban being removed.  相似文献   

The crustal structure beneath Porcupine Ridge as determined by explosion seismology     

R.B. Whitmarsh  J.J. Langford  J.S. Buckley  R.J. Bailey  D.J. Blundell 《Earth and Planetary Science Letters》1974,22(3):197-204

A 200 km long reversed seismic refraction line shot over Porcupine Ridge, a shoal area in the northeast Atlantic jutting out from the continental margin off Ireland, shows that the ridge has a crustal thickness of about 28 km. This result confirms the continental nature of this feature. The seismic data can be interpreted in two ways, one of which suggests the presence of a 6.7-km/sec refractor within the main crustal layer.  相似文献   

Barriers perceived to engaging with climate change among the UK public and their policy implications   总被引：6，自引：2，他引：6  

Irene Lorenzoni  Sophie Nicholson-Cole  Lorraine Whitmarsh 《Global Environmental Change》2007,17(3-4):445-459

This paper reports on the barriers that members of the UK public perceive to engaging with climate change. It draws upon three mixed-method studies, with an emphasis on the qualitative data which offer an in-depth insight into how people make sense of climate change. The paper defines engagement as an individual's state, comprising three elements: cognitive, affective and behavioural. A number of common barriers emerge from the three studies, which operate broadly at ‘individual’ and ‘social’ levels. These major constraints to individual engagement with climate change have implications for achieving significant reductions in greenhouse gases in the UK. We argue that targeted and tailored information provision should be supported by wider structural change to enable citizens and communities to reduce their carbon dependency. Policy implications for effective engagement are discussed.  相似文献   

Public engagement with carbon and climate change: To what extent is the public ‘carbon capable’?   总被引：1，自引：0，他引：1  

Lorraine Whitmarsh  Gill SeyfangSaffron O’Neill 《Global Environmental Change》2011,21(1):56-65

The relevance of climate change for society seems indisputable: scientific evidence points to a significant human contribution in causing climate change, and impacts which will increasingly affect human welfare. In order to meet national and international greenhouse gas (GHG) emissions reduction targets, there is an urgent need to understand and enable societal engagement in mitigation. Yet recent research indicates that this involvement is currently limited: although awareness of climate change is widespread, understanding and behavioral engagement are far lower. Proposals for mitigative ‘personal carbon budgets’ imply a need for public understanding of the causes and consequences of carbon emissions, as well as the ability to reduce emissions. However, little has been done to consider the situated meanings of carbon and energy in everyday life and decisions. This paper builds on the concept of ‘carbon capability’, a term which captures the contextual meanings associated with carbon and individuals’ abilities and motivations to reduce emissions. We present empirical findings from a UK survey of public engagement with climate change and carbon capability, focusing on both individual and institutional dimensions. These findings highlight the diverse public understandings about ‘carbon’, encompassing technical, social, and moral discourses; and provide further evidence for the environmental value-action gap in relation to adoption of low-carbon lifestyles. Implications of these findings for promoting public engagement with climate change and carbon capability are discussed.  相似文献   

Fisheries and failing states: The case of Sierra Leone     

Andy Thorpe  David Whitmarsh  Ernest Ndomahina  Andrew Baio  Miatta Kemokai  Thomas Lebbie 《Marine Policy》2009

Marine fisheries play an important role in the economy of Sierra Leone, supporting livelihoods and contributing significantly to food security. This paper looks in detail at how the performance of fisheries was impacted by the ten year civil war, an event which contributed to the country's reputation for being a “failed state”. The paper focuses mainly on the artisanal fisheries sector, which employs the majority of the country's coastal population, and demonstrates how the conflict caused major social dislocation to fishing communities as well as reducing the productive capacity of the fleet. The paper concludes with a discussion of the policy challenges now facing Sierra Leone, particularly the prevention of resource looting through illegal fishing of the offshore stocks and the development of strategies to enable the potential wealth of these fisheries to be captured.  相似文献   

Inferring the lithology of borehole rocks by applying neural network classifiers to downhole logs: an example from the Ocean Drilling Program   总被引：3，自引：0，他引：3  

D. Benaouda  G. Wadge  R. B. Whitmarsh  R. G. Rothwell  & C. MacLeod 《Geophysical Journal International》1999,136(2):477-491

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The ocean–continent boundary off the western continental margin of Iberia—I. Crustal structure at 40°30'N     

R. B. Whitmarsh  P. R. Miles  A. Mauffret 《Geophysical Journal International》1990,103(2):509-531

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The Aegir Rift: Crustal Structure of an Extinct Spreading Axis     

Grevemeyer  Ingo  Weigel  Wilfried  Dehghani  G. Ali  Whitmarsh  Robert B.  Avedik  Felix 《Marine Geophysical Researches》1997,19(1):1-23

Two seismic refraction and gravity lines were obtained along and normal to the axis of the Aegir Rift, an extinct spreading centre in the Norway Basin. Velocity-depth solutions and crustal structure models are derived from ocean-bottom records using two-dimensional ray tracing and synthetic seismogram modelling techniques. Gravity data are used to generate models consistent with the lateral variations in thickness of the layers in the crustal models. The resulting models require considerable degree of lateral inhomogeneity along and perpendicular to the rift axis. Crust within the extinct spreading centre is found to be thinner and of low P-wave velocity when compared with the crust sampled off-axis. To explain reduced velocities of the lower crust we suggest that, due to the relationship between fracturing and seismic velocity, the decreasing spreading rate leading up to extinction let the mechanically strong layer thicken, so that faulting and fracturing extended to greater depths . Low velocities are also observed in the uppermost mantle underlying the extinct spreading ridge. This zone is attributed to hydrothermal alteration of upper mantle peridotites. Furthermore, after spreading ceased 32-26 my ago, ongoing passive hydrothermal circulation was accompanied by the precipitation of alteration products in open void spaces, thereby decreasing the porosity and increasing the velocity. Consequently the typical low velocities of layer 2 found at active mid-ocean ridges have been replaced by values typical of mature oceanic crust.  相似文献