668 research outputs found

    NEW SEISMIC SOURCE ZONE MODEL FOR PORTUGAL AND AZORES

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    The development of seismogenic source models is one of the first steps in seismic hazard assessment. In seismic hazard terminology, seismic source zones (SSZ) are polygons (or volumes) that delineate areas with homogeneous characteristics of seismicity. The importance of using knowledge on geology, seismicity and tectonics in the definition of source zones has been recognized for a long time [1]. However, the definition of SSZ tends to be subjective and controversial. Using SSZ based on broad geology, by spreading the seismicity clusters throughout the areal extent of a zone, provides a way to account for possible long-term non-stationary seismicity behavior [2,3]. This approach effectively increases seismicity rates in regions with no significant historical or instrumental seismicity, while decreasing seismicity rates in regions that display higher rates of seismicity. In contrast, the use of SSZ based on concentrations of seismicity or spatial smoothing results in stationary behavior [4]. In the FP7 Project SHARE (Seismic Hazard Harmonization in Europe), seismic hazard will be assessed with a logic tree approach that allows for three types of branches for seismicity models: a) smoothed seismicity, b) SSZ, c) SSZ and faults. In this context, a large-scale zonation model for use in the smoothed seismicity branch, and a new consensus SSZ model for Portugal and Azores have been developed. The new models were achieved with the participation of regional experts by combining and adapting existing models and incorporating new regional knowledge of the earthquake potential. The main criteria used for delineating the SSZ include distribution of seismicity, broad geological architecture, crustal characteristics (oceanic versus continental, tectonically active versus stable, etc.), historical catalogue completeness, and the characteristics of active or potentially-active faults. This model will be integrated into an Iberian model of SSZ to be used in the Project SHARE seismic hazard assessment

    Global distribution of material inflows to in-use stocks in 2011 and its implications for a circularity transition

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    Around 40% of global raw materials that are extracted every year accumulate as in-use stocks in the form of buildings, infrastructure, transport equipment, and other durable goods. Material inflows to in-use stocks are a key component in the circularity transition, since the reintegration of those materials back into the economy, at the end of the stock's life cycle, means that less extraction of raw materials is required. Thus, understanding the geographical, material, and sectoral distribution of material inflows to in-use stocks globally is crucial for circular economy policies. Here we quantify the geographical, material, and sectoral distributions of material inflows to in-use stocks of 43 countries and 5 rest-of-the-world regions in 2011, using the global, multiregional hybrid units input-output database EXIOBASE v3.3. Among all regions considered, China shows the largest amount of material added to in-use stocks in 2011 (around 46% of global material inflows to in-use stocks), with a per capita value that is comparable to high income regions such as Europe and North America. In these latter regions, more than 90% of in-use stock additions are comprised of non-metallic minerals (e.g., concrete, brick/stone, asphalt, and aggregates) and steel. We discuss the importance of understanding the distribution and composition of materials accumulated in society for a circularity transition. We also argue that future research should integrate the geographical and material resolution of our results into dynamic stock-flow models to determine when these materials will be available for recovery and recycling. This article met the requirements for a Gold-Gold JIE data openness badge described in http://jie.click/badgesIndustrial Ecolog

    Incorporating Descriptive Metadata into Seismic Source Zone Models for Seismic Hazard Assessment: A case study of the Azores-West Iberian region

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    In probabilistic seismic-hazard analysis (PSHA), seismic source zone (SSZ) models are widely used to account for the contribution to the hazard from earth- quakes not directly correlated with geological structures. Notwithstanding the impact of SSZ models in PSHA, the theoretical framework underlying SSZ models and the criteria used to delineate the SSZs are seldom explicitly stated and suitably docu- mented. In this paper, we propose a methodological framework to develop and docu- ment SSZ models, which includes (1) an assessment of the appropriate scale and degree of stationarity, (2) an assessment of seismicity catalog completeness-related issues, and (3) an evaluation and credibility ranking of physical criteria used to delin- eate the boundaries of the SSZs. We also emphasize the need for SSZ models to be supported by a comprehensive set of metadata documenting both the unique character- istics of each SSZ and the criteria used to delineate its boundaries. This procedure ensures that the uncertainties in the model can be properly addressed in the PSHA and that the model can be easily updated whenever new data are available. The pro- posed methodology is illustrated using the SSZ model developed for the Azores–West Iberian region in the context of the Seismic Hazard Harmonization in Europe project (project SHARE) and some of the most relevant SSZs are discussed in detail

    Revisiting the Local Scaling Hypothesis in Stably Stratified Atmospheric Boundary Layer Turbulence: an Integration of Field and Laboratory Measurements with Large-eddy Simulations

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    The `local scaling' hypothesis, first introduced by Nieuwstadt two decades ago, describes the turbulence structure of stable boundary layers in a very succinct way and is an integral part of numerous local closure-based numerical weather prediction models. However, the validity of this hypothesis under very stable conditions is a subject of on-going debate. In this work, we attempt to address this controversial issue by performing extensive analyses of turbulence data from several field campaigns, wind-tunnel experiments and large-eddy simulations. Wide range of stabilities, diverse field conditions and a comprehensive set of turbulence statistics make this study distinct

    QCD Corrections to QED Vacuum Polarization

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    We compute QCD corrections to QED calculations for vacuum polarization in background magnetic fields. Formally, the diagram for virtual eeˉe\bar{e} loops is identical to the one for virtual qqˉq\bar{q} loops. However due to confinement, or to the growth of αs\alpha_s as p2p^2 decreases, a direct calculation of the diagram is not allowed. At large p2p^2 we consider the virtual qqˉq\bar{q} diagram, in the intermediate region we discuss the role of the contribution of quark condensates \left and at the low-energy limit we consider the π0\pi^0, as well as charged pion π+π−\pi^+\pi^- loops. Although these effects seem to be out of the measurement accuracy of photon-photon laboratory experiments they may be relevant for Îł\gamma-ray burst propagation. In particular, for emissions from the center of the galaxy (8.5 kpc), we show that the mixing between the neutral pseudo-scalar pion π0\pi_0 and photons renders a deviation from the power-law spectrum in the TeVTeV range. As for scalar quark condensates \left and virtual qqˉq\bar{q} loops are relevant only for very high radiation density ∌300MeV/fm3\sim 300 MeV/fm^3 and very strong magnetic fields of order ∌1014T\sim 10^{14} T.Comment: 15 pages, 4 figures; Final versio
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