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371.
A representation of seismic hazard is proposed for Italy based on the zone-free approach developed by Woo (BSSA 86(2):353–362, 1996a), which is based on a kernel estimation method governed by concepts of fractal geometry and self-organized seismicity, not requiring the definition of seismogenic zoning. The purpose is to assess the influence of seismogenic zoning on the results obtained for the probabilistic seismic hazard analysis (PSHA) of Italy using the standard Cornell’s method. The hazard has been estimated for outcropping rock site conditions in terms of maps and uniform hazard spectra for a selected site, with 10 % probability of exceedance in 50 years. Both spectral acceleration and spectral displacement have been considered as ground motion parameters. Differences in the results of PSHA between the two methods are compared and discussed. The analysis shows that, in areas such as Italy, characterized by a reliable earthquake catalog and in which faults are generally not easily identifiable, a zone-free approach can be considered a valuable tool to address epistemic uncertainty within a logic tree framework. 相似文献
372.
Stephen Serjeant † Alberto Carramiñana † Eduardo Gonzáles-Solares Phillipe Héraudeau Raúl Mújica † Ismael Perez-Fournon Nicola Sedgwick † Michael Rowan-Robinson Alberto Franceschini Thomas Babbedge Carlos del Burgo Paolo Ciliegi reas Efstathiou Fabio La Franca Carlotta Gruppioni David Hughes Carlo Lari Seb Oliver Francesca Pozzi Manfred Stickel Mattia Vaccari 《Monthly notices of the Royal Astronomical Society》2004,355(3):813-818
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374.
Massimiliano Ferronato Giuseppe Gambolati Carlo Janna Pietro Teatini 《国际地质力学数值与分析法杂志》2008,32(6):633-657
The stress variation induced by gas/oil production may activate pre‐existing regional faults. This may enhance the expected land subsidence due to the generation of mechanically weak points close to the producing field. A class of elasto‐plastic interface elements (IE), specifically designed to address the mechanical behaviour of faults over a regional scale, is integrated into a finite element (FE) geomechanical model and used to investigate the role exerted by active faults in anthropogenic land subsidence. The importance of regional faults depends on a variety of factors including depth of the depleted reservoir, fault number, orientation and size, geomechanical properties of porous medium, pore pressure drawdown induced by fluid production, etc. With the aid of some representative examples, a useful indication is provided as to where and how fault activation may influence both magnitude and extent of the land subsidence bowl above producing gas/oil reservoirs, pointing to a generally limited impact on the ground surface. The simulation of a real faulted gas reservoir in a complex 3‐D setting shows that the proposed IE can be simply and efficiently incorporated into a FE geomechanical model, thus improving the quality of the stress and displacement prediction. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
375.
Climate change and warm‐water species at the north‐western boundary of the Mediterranean Sea
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Valeriano Parravicini Luisa Mangialajo Laure Mousseau Andrea Peirano Carla Morri Monica Montefalcone Patrice Francour Michel Kulbicki Carlo Nike Bianchi 《Marine Ecology》2015,36(4):897-909
The effects of global change are particularly serious in areas where range shifts of species are physically constrained such as the Ligurian Sea, which is one of the coldest sectors of the Mediterranean. In this basin, historical information on water temperature (from the sea surface down to 75 m depth) dates back to the 1950s. Early studies also recorded warm‐water species occurrence. Thanks to these data we provide the first detailed characterization of water temperature variation from 1958 up to 2010 in the layer 0–75 m depth. We coupled this analysis with the available information on rocky reef epibenthic communities (literature review from 1955 to 1964 and field data from 1980 to 2010). The analysis of water temperature revealed several patterns of variation: a cooling phase from 1958 to 1980, a phase of rapid warming from 1980 to 1990 and a phase of slower warming from 1990 to 2010. Inter‐annual variation in temperature increased over the entire period for the water layer down to 20 m. Warm‐water native and alien species richness increased during the warming phases. Literature estimates suggest a decrease in warm‐water native species richness during the cooling phase. The analysis of quantitative data collected in the early 1990s and late 2000s indicated a decrease in the cover of warm‐water native species on shallow rocky reefs and an increase in deeper waters. We argue that increased inter‐annual variation in water temperature may disadvantage native warm‐water species in shallow waters. Our results indicate that the effect of temperature rises in cold, constrained basins may be more complex than the simple prediction of species changing their geographical range according to their thermal limits. 相似文献
376.
Cintolesi Carlo Pulvirenti Beatrice Sabatino Silvana Di 《Boundary-Layer Meteorology》2021,180(1):79-104
Boundary-Layer Meteorology - Techniques for improving the removal of pollution from urban canyons are crucial for air quality control in cities. The removal mainly occurs at the building roof... 相似文献
377.
Manzini Carlo Filippo Ottonelli Daria Degli Abbati Stefania Marano Corrado Cordasco Emilia Angela 《Bulletin of Earthquake Engineering》2022,20(4):2045-2084
Bulletin of Earthquake Engineering - The paper presents the comparison of the results of non-linear static analyses performed with different software based on the equivalent frame (EF) modelling... 相似文献
378.
Bernd Wagner Paul Tauber Alexander Francke Niklas Leicher Steven A. Binnie Aleksandra Cvetkoska Elena Jovanovska Janna Just Jack H. Lacey Zlatko Levkov Katja Lindhorst Katerina Kouli Sebastian Krastel Konstantinos Panagiotopoulos Arne Ulfers Dušica Zaova Timme H. Donders Andon Grazhdani Andreas Koutsodendris Melanie J. Leng Laura Sadori Mirko Scheinert Hendrik Vogel Thomas Wonik Giovanni Zanchetta Thomas Wilke 《Boreas: An International Journal of Quaternary Research》2023,52(1):1-26
Studies of the upper 447 m of the DEEP site sediment succession from central Lake Ohrid, Balkan Peninsula, North Macedonia and Albania provided important insights into the regional climate history and evolutionary dynamics since permanent lacustrine conditions established at 1.36 million years ago (Ma). This paper focuses on the entire 584-m-long DEEP sediment succession and a comparison to a 197-m-long sediment succession from the Pestani site ~5 km to the east in the lake, where drilling ended close to the bedrock, to unravel the earliest history of Lake Ohrid and its basin development. 26Al/10Be dating of clasts from the base of the DEEP sediment succession implies that the sedimentation in the modern basin started at c. 2 Ma. Geophysical, sedimentological and micropalaeontological data allow for chronological information to be transposed from the DEEP to the Pestani succession. Fluvial conditions, slack water conditions, peat formation and/or complete desiccation prevailed at the DEEP and Pestani sites until 1.36 and 1.21 Ma, respectively, before a larger lake extended over both sites. Activation of karst aquifers to the east probably by tectonic activity and a potential existence of neighbouring Lake Prespa supported filling of Lake Ohrid. The lake deepened gradually, with a relatively constant vertical displacement rate of ~0.2 mm a−1 between the central and the eastern lateral basin and with greater water depth presumably during interglacial periods. Although the dynamic environment characterized by local processes and the fragmentary chronology of the basal sediment successions from both sites hamper palaeoclimatic significance prior to the existence of a larger lake, the new data provide an unprecedented and detailed picture of the geodynamic evolution of the basin and lake that is Europe’s presumed oldest extant freshwater lake. 相似文献
379.
380.
Parallel computers are potentially very attractive for the implementation of large size geomechanical models. One of the main difficulties of parallelization, however, relies on the efficient solution of the frequently ill‐conditioned algebraic system arising from the linearization of the discretized equilibrium equations. While very efficient preconditioners have been developed for sequential computers, not much work has been devoted to parallel solution algorithms in geomechanics. The present study investigates the state‐of‐the‐art performance of the factorized sparse approximate inverse (FSAI) as a preconditioner for the iterative solution of ill‐conditioned geomechanical problems. Pre‐and post‐filtration strategies are experimented with to increase the FSAI efficiency. Numerical results show that FSAI exhibits a promising potential for parallel geomechanical models mainly because of its almost ideal scalability. With the present formulation, however, at least 4 or 8 processors are required in the selected test cases to outperform one of the most efficient sequential algorithms available for FE geomechanics, i.e. the multilevel incomplete factorization (MIF). Further research is needed to improve the FSAI efficiency with a more effective selection of the preconditioner non‐zero pattern. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献