Long-term volcanic hazard forecasts based on Somma-Vesuvio past eruptive activity     

Lucio Lirer  Paola Petrosino  Ines Alberico  Immacolata Postiglione 《Bulletin of Volcanology》2001,63(1):45-60

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Macrofauna associated to Mycale microsigmatosa (Porifera, Demospongiae) in Rio de Janeiro State, SE Brazil     

Suzi M. Ribeiro  Elianne P. Omena  Guilherme Muricy   《Estuarine, Coastal and Shelf Science》2003,57(5-6):951-959

The macrofauna (endo- and epi-biotic) associated to the sponge Mycale (Carmia) microsigmatosa Arndt, 1927 was studied at three sites in Rio de Janeiro State, Brazil (Arraial do Cabo, Niterói, and Rio de Janeiro). A total of 2235 individuals (over 1 mm long) of 75 invertebrate species were found associated to 19 specimens of the sponge. The most abundant and diverse taxa were the crustaceans (83%, 31 spp.), polychetes (10%, 18 spp.), and molluscs (3.7%, 15 spp.). Cnidarians, platyhelminthes, ascidians, echinoderms, pycnogonids, bryozoans, and sponges were also represented. Amphipod crustaceans were the dominant group, comprising 61% of all individuals collected. Species richness and abundance of associated fauna were highly correlated with sponge volume, but diversity and evenness were not. The site of collection influenced the species composition of the fauna associated to M. microsigmatosa but did not change significantly its diversity, abundance, richness, and dominance patterns of higher taxa. Pregnant females and juvenile stages of 29% of the species associated, including crustaceans, molluscs, echinoderms, and pycnogonids were frequently found inside M. microsigmatosa. Although many of these organisms do occur and reproduce in other habitats outside the sponge as well, M. microsigmatosa is also important for their reproduction and survivorship, thus contributing for the maintenance of biodiversity in Southwestern Atlantic sublittoral rocky shores.  相似文献   

The Serra da Graciosa A-type Granites and Syenites, southern Brazil: Part 2: Petrographic and mineralogical evolution of the alkaline and aluminous associations     

Guilherme A.R. Gualda  Silvio R.F. Vlach 《Lithos》2007,93(3-4):310-327

The Serra da Graciosa Granites and Syenites comprise five distinct plutons in the Brasiliano/Pan-African Graciosa A-type Province, southern Brazil. Six petrographic series can be identified in these plutons: (1) Alkaline series 1, composed of amphibole-bearing alkali feldspar syenites with varied mafic mineralogy and quartz contents, from alkali feldspar syenites with calcic amphibole, clinopyroxene, olivine and allanite to alkali feldspar quartz syenites with sodic–calcic amphibole and chevkinite–perrierite and to alkali feldspar granites with sodic amphibole; (2) Alkaline series 2, characterized by amphibole-bearing alkali feldspar granites, with limited modal variations but amphibole compositions also varying from calcic to sodic; (3) Alkaline series 3, of limited occurrence, which includes alkali feldspar syenites with olivine and clinopyroxene and no amphibole; (4) Aluminous series 1, of widespread occurrence, with various petrographic facies of biotite granites with amphibole; (5) Aluminous series 2, characterized by alkali feldspar granites with biotite and only minor amphibole; (6) Monzodiorites, typically with biotite, calcic amphibole and augitic clinopyroxene, partially mingled with granitic magmas. The mafic minerals present are, in general, Fe-rich with correspondingly low Mg and Al contents. In Alkaline series 1, amphiboles crystallized in progressively more oxidizing and alkaline conditions, while in Alkaline series 2, the initial conditions were somewhat more oxidizing and shifted to reducing in the final stages. In Aluminous series 1 and Aluminous series 2, amphiboles are calcic and comparatively homogeneous. The amphiboles in the monzodioritic rocks, while also homogeneous, are more Mg-rich and show compositions quite distinct from the calcic varieties in the other associations, and this is also the case for clinopyroxene. Mg# in biotite decreases from the monzodioritic rocks to Aluminous series 1 and further to Aluminous series 2. Contrasting evolution of the various associations suggests that several coeval magmatic series are present in the Serra da Graciosa granites.  相似文献   

Early Warning Systems: Feasibility and End-Users' Point of View     

C. S. Oliveira  F. Mota de Sá  M. Lopes  M. A. Ferreira  I. Pais 《Pure and Applied Geophysics》2015,172(9):2353-2370

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The role of the urban system dysfunction in the assessment of seismic risk in the Mt. Etna area (Italy)     

F. Meroni  G. Zonno  R. Azzaro  S. D’Amico  T. Tuvè  C. S. Oliveira  M. A. Ferreira  F. Mota de Sá  C. Brambilla  R. Rotondi  E. Varini 《Bulletin of Earthquake Engineering》2016,14(7):1979-2008

A procedure for seismic risk assessment is applied to the Mt. Etna area (eastern Sicily, Italy) through assessment of urban system dysfunction following the occurrence of an earthquake. The tool used is based on the Disruption Index as a concept implemented in Simulator QuakeIST, which defines urban disruption following a natural disaster. The first element of the procedure is the definition of the seismic input, which is based on information about historical seismicity and seismogenic faults. The second element is computation of seismic impact on the building stock and infrastructure in the area considered. Information on urban-scale vulnerability was collected and a geographic information system was used to organise the data relating to buildings and network systems (e.g., building stock, schools, strategic structures, lifelines). The central idea underlying the definition of the Disruption Index is identification and evaluation of the impact on a target community through the physical elements that most contribute to severe disruption. The procedure applied in this study (i.e., software and data) constitutes a very useful operational tool to drive the development of strategies to minimise risks from earthquakes.  相似文献   

The concept of a disruption index: application to the overall impact of the July 9, 1998 Faial earthquake (Azores islands)   总被引：2，自引：1，他引：1  

Carlos Sousa Oliveira  Mónica Amaral Ferreira  Francisco Mota de Sá 《Bulletin of Earthquake Engineering》2012,10(1):7-25

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Evaluation of pseudostatic active earth pressure coefficient of cantilever retaining walls     

Aldo Evangelista  Anna Scotto di Santolo  Armando Lucio Simonelli 《Soil Dynamics and Earthquake Engineering》2010

A stress plasticity solution is proposed for evaluating the gravitational and dynamic active earth pressures on cantilever retaining walls with long heel. The solution takes into account the friction angle of the soil, wall roughness, backfill inclination and horizontal and vertical seismic accelerations. It is validated by means of the comparison with both traditional limit equilibrium methods (e.g. Mononobe–Okabe equations) and static and pseudostatic numerical FLAC analyses. For numerical analyses the soil is modelled as an elasto-plastic non-dilatant medium obeying the Mohr–Coulomb yield criterion, while the wall is elastic. The solutions for the horizontal and vertical seismic coefficients are proposed, which allow one to determine the intensity of the active thrust and its inclination δ with respect to the horizontal. It is demonstrated that the latter also depends on the soil friction angle φ. The inclination in seismic conditions δ_E is greater than the one in static conditions, δ_S, usually adopted in both cases. As a matter of fact, since wall stability conditions improve with the increase of inclination δ, the present method gives solutions that are less onerous than traditional ones, producing less conservative wall designs. Finally pseudostatic results are compared with proper dynamic analyses (by FLAC code) performed utilising four Italian accelerometric time-histories as input ground motion.  相似文献   

A Study of the Solar-Like Properties of β Hydri     

Maria Pia Di Mauro  Jørgen Christensen-Dalsgaard  Lucio Paternò 《Astrophysics and Space Science》2003,284(1):229-232

We investigate properties of the internal structure of HR2021, better known as Hydri, a G2 IV subgiant with mass close to solar and for which observations by Bedding et al. (2001) have shown the presence of solar-like oscillations.We have computed models of Hydri,based on updated global parameters,and compared the computed frequencies for the models with the observed oscillation spectrum.  相似文献   

Evidence of oil leakage from the Bahía Paraíso wreck in Arthur Harbour, Antarctica     

Janiot LJ  Sericano JL  Marcucci O 《Marine pollution bulletin》2003,46(12):1619-1622

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Convection in a rotating deep compressible spherical shell: Application to the Sun     

Gaetano Belvedere  Lucio Paternò 《Solar physics》1977,54(2):289-312

In this paper we study the interaction of rotation with convection in a deep compressible spherical shell as the Sun's convection zone. We examine how the energy transport and the large scale motions can be affected by rotation. In particular we study how a large scale meridional circulation can give rise to variations of angular velocity with latitude and depth.It is assumed that the energy transport is only due to convection and that the mixing-length theory gives an adequate representation of it. Furthermore we assume that rotation acts as a perturbation of the turbulent convective flux through its transport coefficient.The equations involved in the model are integrated numerically in the limit of large viscosity and slow rotation. After having expanded all physical quantities to the first order in terms of Legendre polynomials, the fitting with the observed solar differential rotation gives the expansion parameter, which represents the coupling constant between rotation and convection.The results show a three-cell circulation extending from the poles to the equator. The first one is located in the lower half of the convection zone with the fluid rising at the equator and sinking at the poles. In the second one the direction of the motion is reversed while the third one, located in a thin upper layer, shows the same characteristics of the first one. The meridional velocities at the surface are directed towards the poles and are about 20 cm s^-1. In the other cells the meridional velocities are typically of a few cm s^-1 while the radial velocities are of the order of a few tenths of cm s^-1.The heat flux relative variation at the surface is about 10^-4 (3 × 10^-3 at the bottom) with a polar excess. The temperature variation at the surface is of the same order, with an equatorial excess however. The convection seems to be stabilized stronger at the equator. The angular velocity increases inwards and varies about 6% between the surface and the bottom of the convection zone.An attempt is made for explaining the picture which emerges. In particular the negligible flux and temperature variations at the surface are explained in terms of equalization by the particular structure of the latitudinal flow. This configuration of large scale circulation is attributed to the high stratification of the convection zone with depth.  相似文献