Systems of colliding bodies in a gravitational field: Impact velocity,inelasticity and sizes distributions     

Sonia Clairemidi 《Earth, Moon, and Planets》1987,38(3):237-248

We study numerically the dynamical evolution of a system of colliding bodies. Collisions are inelastic and the coefficient of rebound is a function of the impat velocity. Various functions are used. The system can reach an equilibrium state characterized by a finite thickness independently on the sense of variation of the functions. Within the frame of various distributions of the body sizes we observe a segregation rather than equipartition of the kinetic energy of random motions.  相似文献   

Mantle and crustal processes in the magmatism of the Campania region: inferences from mineralogy, geochemistry, and Sr–Nd–O isotopes of young hybrid volcanics of the Ischia island (South Italy)     

Massimo D’Antonio  Sonia Tonarini  Ilenia Arienzo  Lucia Civetta  Luigi Dallai  Roberto Moretti  Giovanni Orsi  Mariachiara Andria  Alberto Trecalli 《Contributions to Mineralogy and Petrology》2013,165(6):1173-1194

Ischia, one active volcano of the Phlegraean Volcanic District, prone to very high risk, is dominated by a caldera formed 55 ka BP, followed by resurgence of the collapsed area. Over the past 3 ka, the activity extruded evolved potassic magmas; only a few low-energy explosive events were fed by less evolved magmas. A geochemical and Sr–Nd–O isotope investigation has been performed on minerals and glass from products of three of such eruptions, Molara, Vateliero, and Cava Nocelle (<2.6 ka BP). Data document strong mineralogical, geochemical, and isotopic heterogeneities likely resulting from mingling/mixing processes among mafic and felsic magmas that already fed the Ischia volcanism in the past. Detailed study on the most mafic magma has permitted to investigate its origin. The mantle sector below Ischia underwent subduction processes that modified its pristine chemical, isotopic, and redox conditions by addition of ≤1 % of sediment fluids/melts. Similar processes occurred from Southeast to Northwest along the Apennine compressive margin, with addition of up to 2.5 % of sediment-derived material. This is shown by volcanics with poorly variable, typical δ¹⁸O mantle values, and ⁸⁷Sr/⁸⁶Sr progressively increasing toward typical continental crust values. Multiple partial melting of this modified mantle generated distinct primary magmas that occasionally assimilated continental crust, acquiring more ¹⁸O than ⁸⁷Sr. At Ischia, 7 % of Hercynian granodiorite assimilation produced isotopically distinct, K-basaltic to latitic magmas. A SW–NE regional tectonic structure gave these magmas coming from large depth the opportunity to mingle/mix with felsic magmas stagnating in shallower reservoirs, eventually triggering explosive eruptions.  相似文献   

Yields of suspended sediment and dissolved solids from the Andean basins of Ecuador     

Elisa Armijos  Alain Laraque  Sonia Barba  Luc Bourrel  Catalina Ceron  Christelle Lagane 《水文科学杂志》2013,58(7):1478-1494

Abstract

Water discharge and suspended and dissolved sediment data from three rivers (Napo, Pastaza and Santiago) in the Ecuadorian Amazon basin and a river in the Pacific basin (Esmeraldas) over a 9-year period, are presented. This data set allows us to present: (a) the chemical weathering rates; (b) the erosion rates, calculated from the suspended sediment from the Andean basin; (c) the spatio-temporal variability of the two regions; and (d) the relationship between this variability and the precipitation, topography, lithology and seismic activity of the area. The dissolved solids load from the Esmeraldas basin was 2 × 10⁶ t year^-1, whereas for the Napo, Pastaza and Santiago basins, it was 4, 2 and 3 × 10⁶ t year^-1, respectively. For stations in the Andean piedmont of Ecuador, the relationship between surface sediment and the total sediment concentration was found to be close to one. This is due to minimal stratification of the suspended sediment in the vertical profile, which is attributed to turbulence and high vertical water speeds. However, during the dry season, when the water speed decreases, sediment stratification appears, but this effect can be neglected in the sediment flux calculations due to low concentration rates. The suspended sediment load in the Pacific basin was 6 × 10⁶ t year^-1, and the total for the three Amazon basins was 47 × 10⁶ t year^-1. The difference between these contributions of the suspended sediment load is likely due to the tectonic uplift and the seismic and volcanic dynamics that occur on the Amazon side.

Editor Z.W. Kundzewicz

Citation Armijos, E., Laraque, A., Barba, S., Bourrel, L., Ceron, C., Lagane, C., Magat, P., Moquet, J.-S., Pombosa, R., Sondag, F., Vauchel, P., Vera, A., and Guyot, J.L., 2013. Yields of suspended sediment and dissolved solids from the Andean basins of Ecuador. Hydrological Sciences Journal, 58 (7), 1478–1494.  相似文献   

Performance of the L’Aquila (central Italy) gas distribution network in the 2009 (\mathrm{{M}}_\mathrm{{w}} 6.3) earthquake     

Simona Esposito  Sonia Giovinazzi  Ludovica Elefante  Iunio Iervolino 《Bulletin of Earthquake Engineering》2013,11(6):2447-2466

Despite the seismic vulnerability of gas systems and the significance of the direct and indirect consequences that loss functionality might have on large communities, the analysis of the earthquake performance and of post-earthquake management for this kind of distribution networks appears under-represented in the international literature, with respect to other lifeline systems. To contribute on this matter, the study presented comprises an investigation of the impact of L’Aquila 2009 earthquake ( $\text{ M }_\mathrm{w}$ 6.3) on the performance of the local medium- and low-pressure gas distribution networks. The assessment of the physical impact of the earthquake to the buried components of network, namely pipes, valves, and demand nodes, was carried out when processing post-earthquake repair activity reports. Repair data, along with geometrical and constructive features, were collected in a geographic information system linked to the digitized maps of the network, and compared with the interpolated map of recorded transient ground motion, measured in terms of peak ground velocity (i.e., a $Shakemap^\mathrm{TM}$ ). The impact of permanent ground deformation was also investigated and found to be limited in the study area. The resulting observed repair rates (number of repairs per km), presented for different pipeline materials, were compared with repair ratio fragility functions available in literature, showing relatively agreement especially to those for steel pipes, likely also because of the uncertainties in the estimations. Finally, the management of the L’Aquila gas system in the emergency phase and the resilience (functionality recover versus time) of the system was discussed.  相似文献   

Parameterization of historical earthquakes in Switzerland   总被引：1，自引：1，他引：0  

Sonia álvarez-Rubio  Philipp K?stli  Donat F?h  Souad Sellami  Domenico Giardini 《Journal of Seismology》2012,16(1):1-24

Macroseismic earthquake parameters of historical events have been reassessed in the framework of the update of the Earthquake Catalogue of Switzerland ECOS-09. The Bakun and Wentworth method (Bakun and Wentworth 1997) has been used to assess location, magnitude, and, when possible, focal depth. We apply a two-step procedure. Intensity attenuation is assessed first by fitting a model with a logarithmic and a linear term, using a set of 111 earthquakes. The magnitude range is 3 and 5.8. Then, intensity to magnitude relation is developed. A subset of the 111 events, all having an instrumental moment magnitude, was used to perform this intensity to magnitude calibration. Five final calibration strategies were developed based on different intensity calibration datasets, regionalized or non-regionalized models, and fixed or variable source depth. The final assessment of the macroseismic earthquake parameters is based on an expert judgment procedure, using the results derived from all five strategies, and taking into consideration the historical knowledge available for the particular earthquake. A bootstrap procedure has been applied to assess the uncertainty of parameters. Indicative lower and upper bounds of uncertainty are derived from distributions of location and magnitude for a number of events, obtained through bootstrap sampling of the intensity field and of the single intensity values. The final uncertainties are given in terms of parameter uncertainty classes already used in previous versions of the earthquake catalogue of Switzerland.  相似文献   

Forest biodiversity assessment in Peruvian Andean Montane cloud forest     

Alicia Ledo  Sonia Condés  Iciar Alberdi 《山地科学学报》2012,9(3):372-384

Cloud forests are unusual and fragile habitats, being one of the least studied and least understood ecosystems. The tropical Andean dominion is considered one of the most significant places in the world as regards biological diversity, with a very high level of endemism. The biodiversity was analysed in an isolated remnant area of a tropical montane cloud forest known as the "Bosque de Neblina de Cuyas", in the North of the Peruvian Andean range. Composition, structure and dead wood were measured or estimated. The values obtained were compared with other cloud forests. The study revealed a high level of forest biodiversity, although the level of biodiversity differs from one area to another: in the inner areas, where human pressure is almost inexistent, the biodiversity values increase. The high species richness and the low dominance among species bear testimony to this montane cloud forest as a real enclave of biodiversity.  相似文献   

Response spectra for the deep sediment-filled Rhône Valley in the Swiss Alps     

Hans-Balder Havenith  Donat Fäh  Sonia Alvarez-Rubio  Daniel Roten 《Soil Dynamics and Earthquake Engineering》2009

We present numerical modeling of earthquake ground motion for various profiles across the Swiss Rhône Valley and characterize the seismic response in terms of spectral acceleration. First, we evaluate the relative amplification of 2D with respect to 1D response. Then, we show how the selected bedrock spectrum influences the response spectra of the valley sites. Particular attention is paid to how the internal sediment structure and the often weakly constrained Q-factor shape the seismic response. Results obtained for the different profiles are compared with reference spectra (Swiss building code and Eurocode 8) and for one profile with recorded data as well. From this comparison, we infer that the surficial layer strongly influences spectral acceleration values between 0.1 and 1 s. The total thickness of sediments significantly affects the seismic response at longer periods around the fundamental period of the studied valley sections between 1.8 and 3.6 s.  相似文献   

From climate change impacts to the development of adaptation strategies: Challenges for agriculture in Europe   总被引：1，自引：0，他引：1  

Ana Iglesias  Sonia Quiroga  Marta Moneo  Luis Garrote 《Climatic change》2012,112(1):143-168

This study links climate change impacts to the development of adaptation strategies for agriculture in Europe. Climate change is expected to intensify the existing risks, particularly in southern regions, and create new opportunities in some northern areas. These risks and opportunities are characterised and interpreted across European regions by analysing over 300 highly relevant publications that appeared in the last decade. The result is a synthesis of the reasons for concern for European agricultural regions. The need to respond to these risks and opportunities is addressed by evaluating the costs and benefits of a number of technical and policy actions. The results highlight the importance of enhanced water use efficiency as a critical response to climate risks and the need for a more effective extension service. These results aim to assist stakeholders as they take up the adaptation challenge and develop measures to reduce the vulnerability of the sector to climate change.  相似文献   

The effect of climate change on the mobility and stability of coastal sand dunes in Ceará State (NE Brazil)     

Haim Tsoar  Noam Levin  Luis P. Maia  Sonia H. Tatumi 《Quaternary Research》2009,71(2):217-397

The coast of Ceará State in NE Brazil is covered by vast fields of active and stabilized coastal sand dunes. Its tropical climate is characterized by two seasons, wet and dry, with wind intensity determined by the meridional shift of the Intertropical Convergence Zone. The wind power is negatively correlated with precipitation, and precipitation is negatively correlated with the difference between sea surface temperatures of the tropical Atlantic north and south of the equator. We present a model suggesting that during the Late Pleistocene wind power determined the mobility and stability of the dunes. Sand dunes accumulated during periods of high wind power (as it is today) and stabilized when wind power was low. Once the dunes were stabilized by vegetation they could not be activated even by increased wind power. Samples that were taken for luminescence dating from 25 stabilized dunes along the coasts of Ceará gave ages ranging from135 ka to < 100 yr. We postulate that these luminescence ages fall at the beginning of wet periods in NE Brazil characterized by low wind power. These paleoclimatic wet periods correlate well with the cold periods of stades in Greenland ice-core records.  相似文献   

Probabilistic relationships between wind and surface water circulation patterns in the SE Bay of Biscay     

Lohitzune Solabarrieta  Anna Rubio  Mar Cárdenas  Sonia Castanedo  Ganix Esnaola  Fernando J. Méndez  Raúl Medina  Luis Ferrer 《Ocean Dynamics》2015,65(9-10):1289-1303

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