Aspects of landslide activity in the Mercantour Massif and the French Riviera, southeastern France     

Maurice Julian  Edward Anthony   《Geomorphology》1996,15(3-4)

Landslides pose serious hazards in the Mercantour Massif and the French Riviera in southeastern France. The context for landslide development is a particularly favourable one, both in terms of the geomorphic and structural setting of this Alpine region, and of the climatic, hydrologic and seismic factors that trigger such failures. High mountain relief and steep slopes constitute a very favourable setting for failures affecting massive basement rocks and a very heterogeneous sedimentary cover whose resistance has been weakened by weathering, tectonic stresses, and cambering due to gravity. Among trigger factors, the important appears to be the precipitation regime. Rainfalls are commonly concentrated into short high-intensity downpours or into bursts of sustained falls over periods of several days, leading to soil saturation and lubrication of potential failure planes. Snowmelt also contributes to these lubrication processes. Earthquakes affecting this region are also a potentially important landslide trigger. However, while a lot of work has been done on the relationship between extreme climatic events and landslide activity, much less is known of the trigger effects of earthquakes.Both the background factors that promote landslide development and the factors that trigger such failures are discussed within a time frame of landslide development. Progressive changes in soil strength due to weathering, rock cambering and shattering processes lead to long-term reduction in resistance. Superimposed on these progressive changes are episodic triggerings related to rainfall and snowmelt episodes or earthquakes. Landslides may occur as shallow, low-volume “one-time” events or may be part of a progressive long-term failure. The former generally affect unconsolidated or clay-rich sedimentary rocks, especially on the coastal hillslopes of the French Riviera. A notable exception of a major, voluminous “one-time” event was the submarine landslide of the Var Delta in 1979. This landslide, like numerous other smaller subaerial landslides onland, was largely a result of human activities. This landslide occurred following extensive modification of the Var Delta and, notably, reclamation of the steep, fine-grained delta front. Deforestation, quarrying, urbanisation and road network developments are various ways in which human activity has destabilized the coastal hillslopes, favouring the development of numerous shallow landslides following each episode of heavy rainfall.Progressive landslides on the upper hillslopes of the Mercantour Massif have developed over long time spans (order of 10¹ to 10⁵ yrs) and have involved more complex interactions between lithological controls, slope characteristics and trigger factors. The Collelongue and Bois de Malbosc landslides have evolved into now stable failures buttressed by resistant migmatitic diorites or amphibolites. The more voluminous and well monitored Clapière landslide is a relatively simple rotational landslide of the toe-failure type. This active landslide poses a serious to inhabitants and infrastructure in the Tinée Valley. The importance of continued field monitoring, modelling and mapping of landslides and their hazards is emphasised.  相似文献   

Carbon Sequestration, Soil Conservation, and the Kyoto Protocol: Summary of Implications   总被引：1，自引：0，他引：1  

Julian Dumanski 《Climatic change》2004,65(3):255-261

This paper discusses relationships between soil conservation, carbon sequestration, and the Kyoto Protocol. The Kyoto Protocol is the first attempt to use the flexibility of the global market place to stabilize and reduce GHG emissions, mitigate climate change, and promote sustainable development. The protocol emerged first as a framework agreement, but through international negotiations it is progressing into sets of legal articles. These impose obligations on all signatories, but they also identify opportunities for improved environmental land management at local, national and international levels. This is particularly true for soil conservation, where the sequestration of carbon above and below ground increases soil organic matter, enhances soil fertility, and improves production, while concomitantly reducing atmospheric CO₂. It is a classic `win-win' situation. Both the evolving opportunities and the obligations under the Kyoto Protocol are discussed in the paper.  相似文献   

'Just sustainability': the emerging discourse of environmental justice in Britain?   总被引：1，自引：0，他引：1  

Julian Agyeman  Bob Evans 《The Geographical journal》2004,170(2):155-164

Environmental justice is both a vocabulary for political opportunity, mobilization and action, and a policy principle to guide public decision making. It emerged initially in the US, and more recently in the UK, as a new vocabulary underpinning action by community organizations campaigning against environmental injustices. However, as the environmental justice discourse has matured, it has become increasingly evident that it should play a role in the wider agendas for sustainable development and social inclusion. The links between sustainability and environmental justice are becoming clearer and more widely understood in the UK by NGOs and government alike, and it is the potential synergy between these two discourses which is the focus of this paper. This paper argues that the concept of 'just sustainability' provides a discourse for policymakers and activists, which brings together the key dimensions of both environmental justice and sustainable development.  相似文献   

The effective number of cycles of earthquake ground motion     

Jonathan Hancock  Julian J. Bommer 《地震工程与结构动力学》2005,34(6):637-664

The seismic response of any system that accumulates damage under cyclic loading is dependent not only on the maximum amplitude of the motion but also its duration. This is explicitly recognized in methods for estimating the liquefaction potential of soil deposits. Many researchers have proposed that the effective number of cycles of the ground motion is a more robust indicator of the destructive capacity of the shaking than the duration. However, as is the case with strong‐motion duration, there is no universally accepted approach to determining the effective number of cycles of motion, and the different methods that have been proposed can give widely varying results for a particular accelerogram. Definitions of the effective number of cycles of motion are reviewed, classified and compared. Measurements are found to differ particularly for accelerograms with broad‐banded frequency content, which contain a significant number of non‐zero crossing peaks. The key seismological parameters influencing the number of cycles of motion and associated equations for predicting this quantity for future earthquakes are identified. Correlations between cycle counts and different duration measures are explored and found to be rather poor in the absence of additional parameters. Copyright © 2004 John Wiley & Sons, Ltd.  相似文献   

The impact of epistemic uncertainty on an earthquake loss model     

Helen Crowley  Julian J. Bommer  Rui Pinho  Juliet Bird 《地震工程与结构动力学》2005,34(14):1653-1685

Models capable of estimating losses in future earthquakes are of fundamental importance for emergency planners, for the insurance and reinsurance industries, and for code drafters. Constructing a loss model for a city, region or country involves compiling databases of earthquake activity, ground conditions, attenuation equations, building stock and infrastructure exposure, and vulnerability characteristics of the exposed inventory, all of which have large associated uncertainties. Many of these uncertainties can be classified as epistemic, implying—at least in theory—that they can be reduced by acquiring additional data or improved understanding of the physical processes. The effort and cost involved in refining the definition of each component of a loss model can be very large, for which reason it is useful to identify the relative impact on the calculated losses due to variations in these components. A mechanically sound displacement‐based approach to loss estimation is applied to a test case of buildings along the northern side of the Sea of Marmara in Turkey. Systematic variations of the parameters defining the demand (ground motion) and the capacity (vulnerability) are used to identify the relative impacts on the resulting losses, from which it is found that the influence of the epistemic uncertainty in the capacity is larger than that of the demand for a single earthquake scenario. Thus, the importance of earthquake loss models which allow the capacity parameters to be customized to the study area under consideration is highlighted. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   

Sustainability schizophrenia or “actually existing sustainabilities?” toward a broader understanding of the politics and promise of local sustainability in the US     

Rob Krueger  Julian Agyeman 《Geoforum》2005,36(4):410-417

As an approach to development, many see capitalism as reaching across an enormous range of scholarly domains and political interests. For some time geographers and others have begun to conceptualize capitalism as less of a system of intrinsic economic logic and more a collection of social and discursive relationships. By bringing capitalism into the “discursive world” these commentators and others have provided the theoretical ground for an exploration of alternative economic forms, especially those that are more socially and ecologically just. This paper makes an argument for putting sustainable development through the same theoretical scrutiny. Drawing on examples from the US we recruit the concept of “actually existing sustainabilities” from Altvater’s concept “actually existing socialisms” as an entry point to this conversation. Our purpose is to show that the potential for sustainability in the US exists in current local policies and practices if we rethink how we frame it.  相似文献   

Merged dust climatology in Phoenix,Arizona based on satellite and station data     

Hang Lei  Julian X. L. Wang  Daniel Q. Tong  Pius Lee 《Climate Dynamics》2016,47(9-10):2785-2799

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Variable Nitrification Rates Across Environmental Gradients in Turbid,Nutrient-Rich Estuary Waters of San Francisco Bay     

Julian Damashek  Karen L. Casciotti  Christopher A. Francis 《Estuaries and Coasts》2016,39(4):1050-1071

Understanding rates of nitrogen cycling in estuaries is crucial for understanding their productivity and resilience to eutrophication. Nitrification, the microbial oxidation of ammonia to nitrite and nitrate, links reduced and oxidized forms of inorganic nitrogen and is therefore an important step of the nitrogen cycle. However, rates of nitrification in estuary waters are poorly characterized. In fall and winter of 2011–2012, we measured nitrification rates throughout the water column of all major regions of San Francisco Bay, a large, turbid, nutrient-rich estuary on the west coast of North America. Nitrification rates were highest in regions furthest from the ocean, including many samples with rates higher than those typically measured in the sea. In bottom waters, nitrification rates were commonly at least twice the magnitude of surface rates. Strong positive correlations were found between nitrification and both suspended particulate matter and ammonium concentration. Our results are consistent with previous studies documenting high nitrification rates in brackish, turbid regions of other estuaries, many of which also showed correlations with suspended sediment and ammonium concentrations. Overall, nitrification in estuary waters appears to play a significant role in the estuarine nitrogen cycle, though the maximum rate of nitrification can differ dramatically between estuaries.  相似文献   

Optimizing Ore–Waste Dig-Limits as Part of Operational Mine Planning Through Genetic Algorithms     

Julian Ramirez Ruiseco  Jacob Williams  Mustafa Kumral 《Natural Resources Research》2016,25(4):473-485

Dig-limit optimization is an operational decision making problem that significantly affects the value of open-pit mining operations. Traditionally, dig-limits have been drawn by hand and can be defined as classifying practical ore and waste boundaries suiting equipment sizes in a bench. In this paper, an optimization approach based on a genetic algorithm (GA) was developed to approximate optimal dig-limits on a bench, given grade control data, equipment constraints, processing, and mining costs. A case study was conducted on a sample disseminated nickel bench, in a two destination and single ore-type deposit. The results from using the GA are compared to hand-drawn results. The study shows that GA-based approach can be effectively used for dig-limit optimization.  相似文献   

The reserves of extracted resources: Historical data     

Julian L. Simon  Guenter Weinrauch  Stephen Moore 《Natural Resources Research》1994,3(4):325-340

The available data on known reserves of extracted resources have not previously been tabulated and graphed. In this article we compile the reserves data in one place for the first time. This serves to (1) show the trends in the reserves series, (2) make the series available to others, and (3) place the reserves data in the context of price data for which longer series have been available, and with which they can now be seen to be consistent in both showing increasing availability rather than increasing scarcity.  相似文献