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51.
Tiziana Rossetto 《Bulletin of Earthquake Engineering》2018,16(4):1657-1660
52.
Katsuichiro?GodaEmail author Crescenzo?Petrone Raffaele?De?Risi Tiziana?Rossetto 《Stochastic Environmental Research and Risk Assessment (SERRA)》2017,31(9):2337-2355
This study conducts coupled simulation of strong motion and tsunami using stochastically generated earthquake source models. It is focused upon the 2011 Tohoku, Japan earthquake. The ground motion time-histories are simulated using the multiple-event stochastic finite-fault method, which takes into account multiple local rupture processes in strong motion generation areas. For tsunami simulation, multiple realizations of wave profiles are generated by evaluating nonlinear shallow water equations with run-up. Key objectives of this research are: (i) to investigate the sensitivity of strong motion and tsunami hazard parameters to asperities and strong motion generation areas, and (ii) to quantify the spatial variability and dependency of strong motion and tsunami predictions due to common earthquake sources. The investigations provide valuable insights in understanding the temporal and spatial impact of cascading earthquake hazards. Importantly, the study also develops an integrated strong motion and tsunami simulator, which is capable of capturing earthquake source uncertainty. Such an advanced numerical tool is necessary for assessing the performance of buildings and infrastructure that are subjected to cascading earthquake–tsunami hazards. 相似文献
53.
The recognition of the economic value of nature and the services it provides to humanity has become increasingly essential in the context of coastal zone management. In this paper we review the progress to date on both the necessary conceptual framework and empirical valuation studies required to bolster decision support systems (DSS) targeted at integrated coastal zone management goals. We highlight the importance of using an ecosystem services approach and recommend some basic sequential, although overlapping, analytical steps for appropriate environmental valuation and policy assessment: spatial explicitness; marginal changes; double counting; non-linearities; and threshold effects. We illustrate the practical use of the DSS by reviewing an existing UK case study on managed coastal realignment along the Eastern coast of England, and a new UK case study on managed realignment implemented in a southern area on the same coast. Comparing the two studies, the importance of spatial explicitness and the need for a sequential decision support system when dealing with ecosystem services valuation and project policy appraisal become particularly evident. 相似文献
54.
Fabrizio Nestola Tiziana Boffa Ballaran Haruo Ohashi 《Physics and Chemistry of Minerals》2008,35(8):477-484
Two synthetic single-crystals with composition Li(Al0.53Ga0.47)Si2O6 and LiGaSi2O6 and space group C2/c at room conditions have been studied under pressure by means of X-ray diffraction using a diamond anvil cell. The unit-cell
parameters were determined at 12 and 10 different pressures up to P = 8.849 and P = 7.320 GPa for Li(Al0.53Ga0.47)Si2O6 and LiGaSi2O6, respectively. The sample with mixed composition shows a C2/c to P21/c phase transformation between 1.814 and 2.156 GPa, first-order in character. The transition is characterised by a large and
discontinuous decrease in the unit-cell volume and by the appearance of the b-type reflections (h + k = odd) typical of the primitive symmetry. The Ga end-member shows the same C2/c to P21/c transformation at a pressure between 0.0001 and 0.39 GPa. The low-pressure value at which the transition occurred did not
allow collecting any data in the C2/c pressure stability field except that on room pressure. Our results compared with those relative to spodumene (LiAlSi2O6, Arlt and Angel 2000a) indicate that the substitution of Al for Ga at the M1 site of Li-clinopyroxenes strongly affects the transition pressure
causing a decrease from 3.17 GPa (spodumene) to less than 0.39 GPa (LiGaSi2O6) and decreases the volume discontinuity at the transition. As already found for other compounds, the C2/c low-pressure phases are more rigid than the P21
/c high-pressure ones. Moreover, the increase of the M1 cation radius causes a decrease in the bulk modulus K
T0. The axial compressibility among the Li-bearing clinopyroxenes indicates that the c axis is the most rigid for the C2/c phases while it becomes the most compressible for the P21
/c phases. 相似文献
55.
This article describes a methodology to analyse debris-flow risk in the torrential watersheds of the southern hillside of
Gargano (Puglia—Italy). The approach integrates a stability model that identifies the areas of potential shallow landslides
in different meteorological conditions with a two-dimensional flood routing model that allows hazard mapping and GIS interface.
The results were combined with a susceptibility map that was defined by analyzing the vulnerability conditions and the exposure
of the alluvial fan. The models were calibrated on the 1972, July catastrophic event for which the distribution of rainstorm
intensity was available. The geo-mechanical properties of the debris were studied by field surveys and laboratory tests while
the sediment source areas and the shape of the alluvial cone were obtained using photo-aerial interpretation. The risk conditions
of the areas under consideration were also investigated in order to plan and guide measures aimed at limiting the damage such
hazards may cause. 相似文献
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57.
Laura?Uenver-ThieleEmail author Alan?B.?Woodland Nobuyoshi?Miyajima Tiziana?Boffa?Ballaran Daniel?J.?Frost 《Contributions to Mineralogy and Petrology》2018,173(3):20
Experiments at high pressures and temperatures were carried out (1) to investigate the crystal-chemical behaviour of Fe4O5–Mg2Fe2O5 solid solutions and (2) to explore the phase relations involving (Mg,Fe)2Fe2O5 (denoted as O5-phase) and Mg–Fe silicates. Multi-anvil experiments were performed at 11–20 GPa and 1100–1600 °C using different starting compositions including two that were Si-bearing. In Si-free experiments the O5-phase coexists with Fe2O3, hp-(Mg,Fe)Fe2O4, (Mg,Fe)3Fe4O9 or an unquenchable phase of different stoichiometry. Si-bearing experiments yielded phase assemblages consisting of the O5-phase together with olivine, wadsleyite or ringwoodite, majoritic garnet or Fe3+-bearing phase B. However, (Mg,Fe)2Fe2O5 does not incorporate Si. Electron microprobe analyses revealed that phase B incorporates significant amounts of Fe2+ and Fe3+ (at least ~?1.0 cations Fe per formula unit). Fe-L2,3-edge energy-loss near-edge structure spectra confirm the presence of ferric iron [Fe3+/Fetot?=?~?0.41(4)] and indicate substitution according to the following charge-balanced exchange: [4]Si4+?+?[6]Mg2+?=?2Fe3+. The ability to accommodate Fe2+ and Fe3+ makes this potential “water-storing” mineral interesting since such substitutions should enlarge its stability field. The thermodynamic properties of Mg2Fe2O5 have been refined, yielding H°1bar,298?=???1981.5 kJ mol??1. Solid solution is complete across the Fe4O5–Mg2Fe2O5 binary. Molar volume decreases essentially linearly with increasing Mg content, consistent with ideal mixing behaviour. The partitioning of Mg and Fe2+ with silicates indicates that (Mg,Fe)2Fe2O5 has a strong preference for Fe2+. Modelling of partitioning with olivine is consistent with the O5-phase exhibiting ideal mixing behaviour. Mg–Fe2+ partitioning between (Mg,Fe)2Fe2O5 and ringwoodite or wadsleyite is influenced by the presence of Fe3+ and OH incorporation in the silicate phases. 相似文献
58.
Serena C. Tarantino Michele Zema Tiziana Boffa Ballaran 《Physics and Chemistry of Minerals》2010,37(10):769-778
The structural evolution of two columbites under pressure, one ferrocolumbite from Raode (Africa) and one manganocolumbite
from Kragero (Norway), has been determined by single-crystal X-ray diffraction. Structural investigations at high pressure
have been carried out on samples which were preliminarily annealed to attain the complete cation-ordered state. For each crystal,
five complete datasets have been collected from room pressure up to ca. 7 GPa. Structure refinements converged to final discrepancy
factors R ranging between 5.2 and 5.8% for both the crystals. Structure refinements of X-ray diffraction data at different pressures
allowed characterisation of the mechanisms by which the columbite structure accommodates variations in pressure. A and B octahedral
volumes in both samples decrease linearly as pressure increases, with a larger compression of the larger A site. The difference
in polyhedral bulk moduli of the A sites for the two samples does not appear to relate directly to the octahedral sizes, the
A site being more compressible in the Fe-rich sample than in the Mn-rich one. By far the most compressible direction in both
the analysed samples is along b. The cations are in fact free to move along this direction, thus allowing the octahedral chains to slide over each other;
this effect is particularly evident in the manganocolumbite sample which shows a steep shortening of interchain A–B distances
along b. 相似文献
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Magnetite is one of the most important end member of iron corrosion products under a reducing environment; therefore, it may be one of the first products interacting with radionuclides in a radioactive waste disposal after the canister failure.Nanocrystalline magnetite was synthetised in the laboratory and its main physico-chemical properties (microstructure, surface area, surface charge) were analysed. The stability of the oxide was also investigated under the experimental conditions used in sorption studies. The sorption behaviour of UVI onto magnetite was analysed under O2- and CO2-free conditions in a wide range of pH, ionic strengths and radionuclide concentrations.The uranyl binding to magnetite is characterised by a sorption edge between pH 4 and 5.5, and sorption was found to be independent on the electrolyte concentration, which indicates the formation of inner sphere complexes. The sorption isotherms showed a linear behaviour up to the saturation of the sorption sites with a Langmuir-type behaviour.One of the aims of this work was to find the simplest model capable to reproduce the experimental data. Sorption data were fitted using a classical approximation (diffuse double layer model), considering only one type of surface site and evaluating two different options: the first one involving two different monodentate complexes, and the second one a single binuclear bidentate complex. A highly satisfactory fit of the experimental data was obtained by both approaches in the range of the experimental conditions investigated. 相似文献