In Situ Multi-Element Analysis of the Mount Pinatubo Quartz-Hosted Melt Inclusions by NIR Femtosecond Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry     

Anastassia Yu. Borisova  Rémi Freydier  Mireille Polvé  Stefano Salvi  Frederic Candaudap  Thierry Aigouy 《Geostandards and Geoanalytical Research》2008,32(2):209-229

Microscopic melt inclusions found in magmatic minerals are undoubtedly one of the most important sources of information on the chemical composition of melts. This paper reports on the successful application of near-infrared (NIR) femtosecond laser ablation (LA) - inductively coupled plasma-mass spectrometry to in situ determination of incompatible trace elements (Li, Rb, Sr, Y, Zr, Nb, Cs, Ba, REE, Ta, Th, U) and ore metals (As, Mo, Pb) in individual melt inclusions hosted in quartz from the Mount Pinatubo dacites, Philippines. The determined elements cover a concentration range of five orders of magnitude. Femtosecond LA-ICP-MS analyses of twenty-eight individual melt inclusions demonstrate the efficiency of the microanalytical technique and suggests a spectacular homogeneity of the entrapped melt, at least with respect to the following incompatible trace elements: Rb, Sr, Nb, Cs, Ba, La, Ce, Pr, Nd, Pb, Th. The analytical precision (1s) for Na, Ca, Rb, Sr, Y, Nb, Ba and LREE ranged from 3 to 20%. Comparison of trace element concentrations in Mt. Pinatubo melt inclusions determined by femtosecond LA-ICP-MS with those of melt inclusions previously analysed by secondary ion mass spectrometry analysis (SIMS) and those of matrix glasses previously determined by nanosecond LA-ICP-MS showed an agreement typically within 30–40%. The homogeneity of trace element concentrations of the Mt. Pinatubo melt inclusions and the matrix glasses is consistent with the melt inclusion origin as homogeneous rhyolitic melt that was trapped in quartz phenocrysts at the final crystallisation stages of the host adakite (dacite) magma.  相似文献   

Impact of methane seeps on the local carbon‐isotope record: a case study from a Late Jurassic hemipelagic section     

Beat Louis‐Schmid  Pauline Rais  Dmitry Logvinovich  Stefano M. Bernasconi  Helmut Weissert 《地学学报》2007,19(4):259-265

An Oxfordian (Late Jurassic) hemipelagic succession from Beauvoisin (SE France) contains a pronounced, short‐lived negative excursion in the bulk‐carbonate carbon‐isotope record, with an amplitude of 4‰. It was shown previously that the Beauvoisin paleoenvironment was impacted by hydrocarbon seepage. New isotopic data corroborate that methane was a significant constituent of these hydrocarbons. The negative excursion was caused by transient enhanced precipitation of ¹³C‐depleted carbonate, mediated by anaerobic oxidation of methane. Despite its local diagenetic origin, the Beauvoisin excursion is similar in shape and duration to globally recognized negative C‐isotope excursions that have been related to catastrophic, massive dissociation of methane hydrate. Shape and duration of negative excursions therefore cannot be used as an argument when determining their origin if they have not been shown to represent a global perturbation of the carbon cycle.  相似文献   

Spectral measurements of aerosol particle extinction in the 0.4–3.7 μm wavelength range, performed at Sagres with the IR‐RAD sun‐radiometer     

Vito Vitale  Claudio Tomasi  Wolfgang Von Hoyningen&#;huene  Ubaldo Bonafe  Stefano Marani  Angelo Lupi  Alessandra Cacciari  Pietro Ruggeri 《Tellus. Series B, Chemical and physical meteorology》2000,52(2):716-733

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Effects of the filtering action exerted by piles on the seismic response of RC frame buildings     

Luca de Sanctis  Raffaele Di Laora  Nicola Caterino  Giuseppe Maddaloni  Stefano Aversa  Alessandro Mandolini  Antonio Occhiuzzi 《Bulletin of Earthquake Engineering》2015,13(11):3259-3275

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Seismic Modal Contribution Factors   总被引：1，自引：0，他引：1  

Michele Palermo  Stefano Silvestri  Giada Gasparini  Tomaso Trombetti 《Bulletin of Earthquake Engineering》2015,13(10):2867-2891

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Seismic design of yielding structures on flexible foundations          下载免费PDF全文

Masoud Moghaddasi  Gregory A. MacRae  J.  G. Chase  Misko Cubrinovski  Stefano Pampanin 《地震工程与结构动力学》2015,44(11):1805-1821

This paper introduces a simple method to consider the effects of inertial soil–structure interaction (SSI) on the seismic demands of a yielding single‐degree‐of‐freedom structure. This involves idealizing the yielding soil–structure system as an effective substitute oscillator having a modified period, damping ratio, and ductility. A parametric study is conducted to obtain the ratio between the displacement ductility demand of a flexible‐base system and that of the corresponding fixed‐base system. It is shown that while additional foundation damping can reduce the overall response, the effects of SSI may also increase the ductility demand of some structures, mostly being ductile and having large structural aspect ratio, up to 15%. Finally, a design procedure is provided for incorporation of the SSI effects on structural response. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

Motion control-based seismic retrofit solutions for a R/C school building designed with earlier Technical Standards     

Stefano Sorace  Gloria Terenzi 《Bulletin of Earthquake Engineering》2014,12(6):2723-2744

The study of two motion control-based seismic retrofit solutions for a low-rise reinforced concrete school building is presented in this paper. The building was assumed as a benchmark structure for a Research Project financed by the Italian Department of Civil Protection, and is representative of several similar public edifices designed with earlier Technical Standards editions, in Italy as well as in other earthquake-prone European countries. The two solutions refer to the alternative earthquake protection strategies based on the concepts of supplemental damping and seismic isolation, respectively. Namely, they consist in the installation of: (1) a dissipative bracing system incorporating pressurized fluid viscous spring-dampers; and (2) a base isolation system including double friction pendulum sliding bearings. The structural characteristics of the building, and a synthesis of the investigation campaigns developed on it, are initially presented. The mechanical parameters, dimensions, locations and installation details of the constituting elements of the two protective systems are then illustrated, along with the performance assessment analyses carried out in original and rehabilitated conditions according to a full non-linear dynamic approach. The results of the analyses show a remarkable enhancement of the seismic response capacities of the structure for both retrofit hypotheses. This allows reaching the mutual high performance levels postulated in the two rehabilitation designs with remarkably lower costs and architectural intrusion as compared to traditional rehabilitation interventions designed for the same objectives.  相似文献   

Geodetic GPS-based analysis of recent crustal motions in Victoria Land (Antarctica)   总被引：1，自引：0，他引：1  

Antonio Zanutta  Luca Vittuari  Stefano Gandolfi   《Global and Planetary Change》2008,62(1-2):115-131

GPS measurements were collected within the framework of the VLNDEF (Victoria Land Network for DEFormation control) project, which was started in 1999 with the aim of detecting crustal deformation in Northern Victoria Land (Antarctica). The network was established in 1999 and is composed of one permanent station (TNB1), which has been observing since 1998, and 28 periodically surveyed control points. Three complete campaigns and some partial surveying of the network have been carried out to date.Data processing and analysis have been performed using an undifferenced approach for the network position within the ITRF. A double-differences-based strategy has been applied for movement detection. The data processing and analysis of results have been carried out for all available data, both periodically acquired and long time series.GPS measurements collected between December 1999 and February 2006 indicate a mean “absolute” motion of the region of v_e = 11.3 mm/yr and v_n = − 11.1 mm/yr and rock uplift rates of v_u = 2.8 mm/yr. These values are consistent with Antarctic plate motion and the general postglacial rebound models of the region. The relative motions within VLNDEF are small and only few points show velocities greater than the confidence levels.  相似文献   

Testing a new sampler for measuring plot soil loss          下载免费PDF全文

Francesco G. Carollo  Costanza Di Stefano  Vito Ferro  Vincenzo Pampalone  Francesco Sanzone 《地球表面变化过程与地形》2016,41(7):867-874

In order to measure soil loss in equipped plots the estimate of the weight of solid material intercepted at their lower end is required. At the experimental area of Sparacia, Sicily, the runoff produced by an erosive event is collected within storage tanks with a capacity of about 1 m³. In this paper, the use of a new sampler is proposed to measure easily the weight of solid material eroded from an experimental plot and collected into a storage tank. The sampler is a cylinder having a closing valve at the bottom. Two different series of runs were carried out both to test the reliability of the sampler and to establish a sampling procedure, respectively. An analysis of various sampling configurations usable in the field differentiated by the number and location of sampling verticals in the tank cross‐section was finally carried out. The results of the present investigation are that the concentration measurement by the sampler was more accurate than that obtained by other methods involving a collection tank, agitation and sampling of the suspension. This sampler is cheap and usable in combination with a quick field sampling procedure which is particularly advisable when the number of plots equipped at an experimental area is large. The sampler was tested using a clay soil contained within cylinders and a cubic tank, but it appeared also to be usable with coarser sediment than clay and in combination with tanks having a different shape. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

Erratum to: Peak velocities estimation for a direct five-step design procedure of inter-storey viscous dampers     

Michele Palermo  Stefano Silvestri  Luca Landi  Giada Gasparini  Tomaso Trombetti 《Bulletin of Earthquake Engineering》2016,14(2):621-621

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