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331.
Earthquake‐induced pounding of adjacent structures can cause severe structural damage, and advanced probabilistic approaches are needed to obtain a reliable estimate of the risk of impact. This study aims to develop an efficient and accurate probabilistic seismic demand model (PSDM) for pounding risk assessment between adjacent buildings, which is suitable for use within modern performance‐based engineering frameworks. In developing a PSDM, different choices can be made regarding the intensity measures (IMs) to be used, the record selection, the analysis technique applied for estimating the system response at increasing IM levels, and the model to be employed for describing the response statistics given the IM. In the present paper, some of these choices are analyzed and evaluated first by performing an extensive parametric study for the adjacent buildings modeled as linear single‐degree‐of‐freedom systems, and successively by considering more complex nonlinear multi‐degree‐of‐freedom building models. An efficient and accurate PSDM is defined using advanced intensity measures and a bilinear regression model for the response samples obtained by cloud analysis. The results of the study demonstrate that the proposed PSDM allows accurate estimates of the risk of pounding to be obtained while limiting the number of simulations required. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
332.
333.
Daily sea level variability in the Adriatic Sea is studied from different data sets using Empirical Orthogonal Functions, in connection with atmospheric pressure and wind stress. The first mode explains 56–69% of total variance and consists of uniform sea level variability all over the basin, correlated with atmospheric pressure through the inverse barometer effect. The second mode explains 13–16% of variance and accounts for an along-basin sea level gradient, which is correlated with the meridional wind stress component. The first two Principal Components are used as proxies to pressure- and wind-induced components of storm surges in the northern Adriatic. The analysis of the frequency of the most intense events in the 1957–2005 period shows that the wind contribution to storm surges has decreased, while no significant trends are found in the contribution of atmospheric pressure. 相似文献
334.
PGA and structural dynamics input motion at a given site 总被引:1,自引:1,他引:0
The computation of the representative ground motions, to be used as input for the dynamic analyses of a structure at a particular
site, can be approached by several methods. The choice of the approach depends on two factors : the data available and the
type of problem to be solved. This paper reports the experience of the authors in approaching a specific case study: the Southern
Memnon Colossus, located in Luxor, Egypt. The results are of interest when the hazard analysis estimation in developing countries
and the safeguard of cultural heritage are concerned. Monuments have to be treated as important structures, due to their historical
and economical value. Hence, standard procedures of probabilistic seismic hazard analysis for the seismic classification of
common buildings have to be disregarded. On the other hand, the consequences of the collapse of a monument are not comparable
to those related to structures such as nuclear power plants and large dams, for which the deterministic seismic hazard analysis
provides a straightforward framework for evaluation of the worst case ground motions. An “intermediate” approach, which requires
a lower amount of input data with respect to the deterministic one, is adopted. Its stochastic component can capture significant
characteristics of earthquakes, primarily the frequency contents which depend on the magnitude (often referred to as the earthquake
scaling law).
Supported by: European Union-ICA3-1999-00006 相似文献
335.
Benedetto?Badalamenti Nicola?Bruno Tommaso?Caltabiano Fabio?Di Gangi Salvatore?GiammancoEmail author Giuseppe?Salerno 《Bulletin of Volcanology》2004,66(1):80-89
Continuous monitoring of soil CO2 dynamic concentration (which is proportional to the CO2 flux through the soil) was carried out at a peripheral site of Mt. Etna during the period November 1997–September 2000 using an automated station. The acquired data were compared with SO2 flux from the summit craters measured two to three times a week during the same period. The high frequency of data acquisition with both methods allowed us to analyze in detail the time variations of both parameters. Anomalous high values of soil CO2 dynamic concentration always preceded periods of increased flux of plume SO2, and these in turn were followed by periods of summit eruptions. The variations were modeled in terms of gas efflux increase due to magma ascent to shallow depth and its consequent depressurization and degassing. This model is supported by data from other geophysical and volcanological parameters. The rates of increase both of soil CO2 dynamic concentration and of plume SO2 flux are interpreted to be positively correlated both to the velocity of magma ascent within the volcano and to lava effusion rate once magma is erupted at the surface. Low rates of the increase were recorded before the nine-month-long 1999 subterminal eruption. Higher rates of increase were observed before the violent summit eruption of September-November 1999, and the highest rates were observed during shorter and very frequent spike-like anomalies that preceded the sequence of short-lived but very violent summit eruptions that started in late January 2000 and continued until late June of the same year. Furthermore, the time interval between the peaks of CO2 and SO2 in a single sequence of gas anomalies is likely to be controlled by magma ascent velocity.Editorial responsibility: H. Shinohara 相似文献
336.
The Eddington mission was given full approval by the European Space Agencyon the 23rd May 2002, as part of the new `Cosmic Vision' Science programme, with launch scheduled for 2007/8. Its twin scienceobjectives are asteroseismology and planet finding.In its current design it consists of 4 × 60 cm folded Schmidt telescopes, eachwith 6° × 6° field of view and its own CCD array camera.The current observing plan is to spend 2 years primarily devoted to asteroseismologywith 1–3 months on different target fields monitoring up to 50,000 stars per field,and 3 years continuously on asingle target field monitoring upwards of 100,000 stars as required for planetsearching. The asteroseismic goal is to be able to detect oscillationsfrequencies with a precision 0.1–0.3 Hz. 相似文献
337.
Luigi Caputi Fabio Crocetta Francesco Toscano Paolo Sordino Paola Cirino 《Marine Ecology》2015,36(1):118-128
Ciona intestinalis sp. A (Tunicata, Ascidiacea) is a marine invertebrate with a widespread distribution and high invasive potential, yet little is known about its ecology. Here, the macrodynamics of demographic and reproductive trends were first determined using archive data covering 2002–2012. Species abundance in the central Tyrrhenian Sea (Campania, Italy ‐ NW Mediterranean) displayed Poisson distribution across 2002–2008, massive die‐off in 2009/2010 and population recovery in 2011/2012. We defined the seasonal ranges of sea surface temperature in which sampling size, animal size and reproductive status reached their highest values. In 2003/2004, self and non‐self fertilization appeared to follow reverse trends across the year. The long‐term recording run here on Ciona intestinalis sp. A provides novel insights into its population biology and ecology, and represents a valuable tool for sampling management and research planning. 相似文献
338.
Scribano Vittorio Carbone Serafina Manuella Fabio C. Hovland Martin Rueslåtten Håkon Johnsen Hans-K. 《International Journal of Earth Sciences》2017,106(7):2595-2608
International Journal of Earth Sciences - Worldwide marine salt deposits ranging over the entire geological record are generally considered climate-related evaporites, derived from the... 相似文献
339.
The NCEP twentieth century reanalyis and a 500-year control simulation with the IPSL-CM5 climate model are used to assess the influence of ocean-atmosphere coupling in the North Atlantic region at seasonal to decadal time scales. At the seasonal scale, the air-sea interaction patterns are similar in the model and observations. In both, a statistically significant summer sea surface temperature (SST) anomaly with a horseshoe shape leads an atmospheric signal that resembles the North Atlantic Oscillation (NAO) during the winter. The air-sea interactions in the model thus seem realistic, although the amplitude of the atmospheric signal is half that observed, and it is detected throughout the cold season, while it is significant only in late fall and early winter in the observations. In both model and observations, the North Atlantic horseshoe SST anomaly pattern is in part generated by the spring and summer internal atmospheric variability. In the model, the influence of the ocean dynamics can be assessed and is found to contribute to the SST anomaly, in particular at the decadal scale. Indeed, the North Atlantic SST anomalies that follow an intensification of the Atlantic meridional overturning circulation (AMOC) by about 9 years, or an intensification of a clockwise intergyre gyre in the Atlantic Ocean by 6 years, resemble the horseshoe pattern, and are also similar to the model Atlantic Multidecadal Oscillation (AMO). As the AMOC is shown to have a significant impact on the winter NAO, most strongly when it leads by 9 years, the decadal interactions in the model are consistent with the seasonal analysis. In the observations, there is also a strong correlation between the AMO and the SST horseshoe pattern that influences the NAO. The analogy with the coupled model suggests that the natural variability of the AMOC and the gyre circulation might influence the climate of the North Atlantic region at the decadal scale. 相似文献
340.
Marco Maffione Stefano Pucci Leonardo Sagnotti Fabio Speranza 《International Journal of Earth Sciences》2012,101(3):849-861
Anisotropy of magnetic susceptibility (AMS) represents a valuable proxy able to detect subtle strain effects in very weakly
deformed sediments. In compressive tectonic settings, the magnetic lineation is commonly parallel to fold axes, thrust faults,
and local bedding strike, while in extensional regimes, it is perpendicular to normal faults and parallel to bedding dip directions.
The Altotiberina Fault (ATF) in the northern Apennines (Italy) is a Plio-Quaternary NNW–SSE low-angle normal fault; the sedimentary
basin (Tiber basin) at its hanging-wall is infilled with a syn-tectonic, sandy-clayey continental succession. We measured
the AMS of apparently undeformed sandy clays sampled at 12 sites within the Tiber basin. The anisotropy parameters suggest
that a primary sedimentary fabric has been overprinted by an incipient tectonic fabric. The magnetic lineation is well developed
at all sites, and at the sites from the western sector of the basin it is oriented sub-perpendicular to the trend of the ATF,
suggesting that it may be related to extensional strain. Conversely, the magnetic lineation of the sites from the eastern
sector has a prevailing N–S direction. The occurrence of triaxial to prolate AMS ellipsoids and sub-horizontal magnetic lineations
suggests that a maximum horizontal shortening along an E–W direction occurred at these sites. The presence of compressive
AMS features at the hanging-wall of the ATF can be explained by the presence of gently N–S-trending local folds (hardly visible
in the field) formed by either passive accommodation above an undulated fault plane, or rollover mechanism along antithetic
faults. The long-lasting debate on the extensional versus compressive Plio-Quaternary tectonics of the Apennines orogenic
belt should now be revised taking into account the importance of compressive structures related to local effects. 相似文献