On the reliability of long‐period response spectral ordinates from digital accelerograms     

Roberto Paolucci  Antonio Rovelli  Ezio Faccioli  Carlo Cauzzi  Daniela Finazzi  Manuela Vanini  Carola Di Alessandro  Giovanna Calderoni 《地震工程与结构动力学》2008,37(5):697-710

Using records from co‐located broadband and digital strong motion (SM) instruments, it is first shown that the displacement waveforms obtained by double integration of the accelerogram need not be free of unrealistic baseline drift to yield reliable spectral ordinates up to at least 10 s. Secondly, to provide objective criteria for selecting reliable digital SM records for ground motion predictions at long periods, a set of synthetic accelerograms contaminated by random long‐period noise has been used, and the difference between the original accelerograms and the spurious ones in terms of response spectra has been quantified, by introducing a noise index that can be easily calculated based on the velocity waveform of the record. The results of this study suggest that high‐pass filtering the digital acceleration record from a cutoff period selected to suppress baseline drifts on the displacement waveform appears to be in most cases too conservative and unduly depletes reliable information on long‐period spectral ordinates. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

2D numerical simulations of earthquake ground motion: examples from the Marche Region,Italy     

Giovanna Laurenzano  Enrico Priolo  Emanuele Tondi 《Journal of Seismology》2008,12(3):395-412

A detailed numerical simulation of the ground motion and a site response analysis for two towns in the Marche Region (Treia and Cagli) is carried out on the basis of structural models deduced from available geological and geophysical data. In both cases, the reference event is an M = 5.7 earthquake associated with a normal fault located beneath each town. The ground motion is computed using the 2D spectral element method (SPEM 2D). The method solves the propagation of the seismic field through complex geological structures and enables an estimate of the effects of deep crustal structure, superficial geology, and topography on ground motion. Numerical simulations of the seismic field are performed along 2D vertical planes containing the seismic source. Strong ground motion has not been yet recorded in the two towns; therefore, the numerical simulation of ground motion represents a way to overcome the lack of instrumental data. The simulations carried out for Treia show that ground motion is influenced by both source mechanism and effects due to propagation through the geological structure, while ground motion in Cagli features strong local effects, caused by the presence of alluvial deposits under a large area of the town.  相似文献   

Short-term,linear, and non-linear local effects of the tides on the surface dynamics in a new,high-resolution model of the Mediterranean Sea circulation     

Palma  Massimiliano  Iacono  Roberto  Sannino  Gianmaria  Bargagli  Andrea  Carillo  Adriana  Fekete  Balazs M.  Lombardi  Emanuele  Napolitano  Ernesto  Pisacane  Giovanna  Struglia  Maria Vittoria 《Ocean Dynamics》2020,70(7):935-963

Ocean Dynamics - The tides in the Mediterranean Sea are generally weaker than in other regions of the world ocean, but are locally intensified in passages with complex bathymetry, such as the...  相似文献   

A new multi‐proxy investigation of Late Quaternary palaeoenvironments along the north‐western Barents Sea (Storfjorden Trough Mouth Fan)          下载免费PDF全文

Romana Melis  Katia Carbonara  Giuliana Villa  Caterina Morigi  María A. Bárcena  Giovanna Giorgetti  Andrea Caburlotto  Michele Rebesco  Renata G. Lucchi 《第四纪科学杂志》2018,33(6):662-676

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Application of the MoniFLaIR early warning system for rainfall-induced landslides in Piedmont region (Italy)   总被引：2，自引：2，他引：0  

Giovanna Capparelli  Davide Tiranti 《Landslides》2010,7(4):401-410

Landslides triggered by rainfall can be foreseen by modeling the relationship between the time occurrence of landslides and rainfall. This paper deals with the argument by adopting a hydrological model called Forecasting of Landslides Induced by Rainfall (FLaIR). The model is applicable for forecasting recurrent landslides and it is based on the identification of a mobility function Y(.) that links the occurrence of a slope movement to the antecedent rainfall. Once the mobility function is defined, it is possible to define its critical values, the exceeding of which indicates that new mobilizations could occur. The FLaIR model has been used to study some phenomena that happened in Lanzo Valleys, a Western Alps sector of the Piedmont region (Northern Italy) where slope debris flows are the predominant landslide type. The study has led to the development of an early warning system, called MoniFLaIR, for real-time monitoring and forecasting of slope hazard. This article describes some details of the system and its performance.  相似文献   

An atmosphere–ocean regional climate model for the Mediterranean area: assessment of a present climate simulation     

Vincenzo Artale  Sandro Calmanti  Adriana Carillo  Alessandro Dell’Aquila  Marine Herrmann  Giovanna Pisacane  Paolo M. Ruti  Gianmaria Sannino  Maria Vittoria Struglia  Filippo Giorgi  Xunqiang Bi  Jeremy S. Pal  Sara Rauscher 《Climate Dynamics》2010,35(5):721-740

We present an atmosphere–ocean regional climate model for the Mediterranean basin, called the PROTHEUS system, composed by the regional climate model RegCM3 as the atmospheric component and by a regional configuration of the MITgcm model as the oceanic component. The model is applied to an area encompassing the Mediterranean Sea and compared to a stand-alone version of its atmospheric component. An assessment of the model performances is done by using available observational datasets. Despite a persistent bias, the PROTHEUS system is able to capture the inter-annual variability of seasonal sea surface temperature (SST) and also the fine scale spatio-temporal evolution of observed SST anomalies, with spatial correlation as high as 0.7 during summer. The close inspection of a 10-day strong wind event during the summer of 2000 proves the capability of the PROTHEUS system to correctly describe the daily evolution of SST under strong air–sea interaction conditions. As a consequence of the model’s skill in reproducing observed SST and wind fields, we expect a reliable estimation of air–sea fluxes. The model skill in reproducing climatological land surface fields is in line with that of state of the art regional climate models.  相似文献   

Petrology and Sr–Nd–Hf isotope geochemistry of gabbro xenoliths from the Hyblean Plateau: a MARID reservoir beneath SE Sicily?     

Giovanna T. Sapienza  William L. Griffin  Suzanne Y. O’Reilly  Lauro Morten 《Contributions to Mineralogy and Petrology》2009,157(1):1-22

In situ trace-element and isotopic (⁸⁷Sr/⁸⁶Sr) data and whole-rock Sr–Nd–Hf data on 12 gabbro xenoliths from the Hyblean Plateau (south-eastern Sicily) illustrate the complex petrogenetic evolution of this lithospheric segment. The gabbros formed by precipitation of plagioclase + clinopyroxene from a HIMU-type alkaline melt, then were cryptically metasomatized by a low-Rb, high-⁸⁷Sr/⁸⁶Sr fluid, and finally infiltrated by an exotic, late Fe–Ti-rich melt with ⁸⁷Sr/⁸⁶Sr ~ 0.7055, carrying high concentrations of Sr, Rb and HFSE. The geochemical and isotopic features of both the metasomatizing fluid and the Fe–Ti-rich melt are compatible with their common derivation by the progressive melting of an amphibole–phlogopite–ilmenite metasomatic domain (MARID-type?) that probably resided within the subcontinental lithospheric mantle. Therefore, both the astenosphere and the lithosphere underneath the Hyblean Plateau contributed to the petrogenesis of the gabbros. Sm–Nd dating yields an age of 253 ± 60 Ma for the cumulitic pile, roughly coinciding with a hydrothermal event recorded by crustal zircons in the area. We suggest that the Hyblean Plateau suffered a thermal event—probably related to lithospheric thinning and upwelling and melting of the asthenosphere—in Permo-Triassic time (the opening of the Ionian Basin?). The induced perturbation in the lithosphere caused consequent melting of some previously metasomatised portions.  相似文献   

The L��Aquila earthquake��A view of site effects and building behavior from temporary networks     

Giovanna Cultrera  Marco Mucciarelli  Stefano Parolai 《Bulletin of Earthquake Engineering》2011,9(3):691-695

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Trace elements and REE fractionation in subsoils developed on sedimentary and volcanic rocks: case study of the Mt. Vulture area,southern Italy     

Giovanni Mongelli  Michele Paternoster  Giovanna Rizzo  Rosa Sinisi 《International Journal of Earth Sciences》2014,103(4):1125-1140

There is an increasing interest in the distribution of rare earth elements (REEs) within soils, primarily as these elements can be used to identify pedogenetic processes and because soils may be future sources for REE extraction, despite much attention should be paid to the protection and preservation of present soils. Here, we evaluate the processes that control the distribution of REEs in subsoil horizons developed over differing lithologies in an area of low anthropogenic contamination, allowing estimates of the importance of source rocks and weathering. Specifically, this study presents new data on the distribution of REEs and other trace elements, including transition and high-field-strength elements, in subsoils developed on both Quaternary silica-undersaturated volcanic rocks and Pliocene siliciclastic sedimentary rocks within the Mt. Vulture area of the southern Apennines in Italy. The subsoils in the Mt. Vulture area formed during moderate weathering (as classified using the chemical index of alteration) and contain an assemblage of secondary minerals that is dominated by trioctahedral illite with minor vermiculite. The REEs, high-field-strength elements, and transition metals have higher abundances in subsoils that developed from volcanic rocks, and pedogenesis caused the Mt. Vulture subsoils to have REE concentrations that are an order of magnitude higher than typical values for the upper continental crust. This result indicates that the distribution of REEs in soils is a valuable tool for mineral exploration. A statistical analysis of inter-elemental relationships indicates that REEs are concentrated in clay-rich fractions that also contain significant amounts of low-solubility elements such as Zr and Th, regardless of the parent rock. This suggests that low-solubility refractory minerals, such as zircon, play a significant role in controlling the distribution of REEs in soils. The values of (La/Yb)_N and (Gd/Yb)_N fractionation indices are dependent on the intensity of pedogenesis; soils in the study area have values that are higher than typical upper continental crust ratios, suggesting that soils, especially those that formed during interaction with near neutral to acidic organic-rich surface waters, may represent an important source of both light REEs and medium REEs (MREEs). In comparison, MREE/heavy REE fractionation in soils that form during moderate weathering may be affected by variations in parent rock lithologies, primarily as MREE-hosting minerals, such as pyroxenes, may control (La/Sm)_N index values. Eu anomalies are thought to be the most effective provenance index for sediments, although the anomalies within the soils studied here are not related to the alteration of primary minerals, including feldspars, to clay phases. In some cases, Eu/Eu* values may have a weak correlation with elements hosted by heavy minerals, such as Zr; this indicates that the influence of mechanical sorting of clastic particles during sedimentary transport on the Eu/Eu* values of siliciclastic sediments needs to be considered carefully.  相似文献   

The influence of petrography,mineralogy and chemistry on burnability and reactivity of quicklime produced in Twin Shaft Regenerative (TSR) kilns from Neoarchean limestone (Transvaal Supergroup,South Africa)     

Vola  Gabriele  Sarandrea  Luca  Della Porta  Giovanna  Cavallo  Alessandro  Jadoul  Flavio  Cruciani  Giuseppe 《Mineralogy and Petrology》2018,112(4):555-576

Mineralogy and Petrology - This study evaluates the influence of chemical, mineralogical and petrographic features of the Neoarchean limestone from the Ouplaas Mine (Griqualand West, South Africa)...  相似文献