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171.
One of the main purposes of the International Seismological Centre (ISC) is to collect, integrate and reprocess seismic bulletins provided by agencies around the world in order to produce the ISC Bulletin. This is regarded as the most comprehensive bulletin of the Earth’s seismicity, and its production is based on a unique cooperation in the seismological community that allows the ISC to complement the work of seismological agencies operating at global and/or local-regional scale. In addition, by using the seismic wave measurements provided by reporting agencies, the ISC computes, where possible, its own event locations and magnitudes such as short-period body wave m b and surface wave M S . Therefore, the ISC Bulletin contains the results of the reporting agencies as well as the ISC own solutions. Among the most used seismic event parameters listed in seismological bulletins, the event magnitude is of particular importance for characterizing a seismic event. The selection of a magnitude value (or multiple ones) for various research purposes or practical applications is not always a straightforward task for users of the ISC Bulletin and related products since a multitude of magnitude types is currently computed by seismological agencies (sometimes using different standards for the same magnitude type). Here, we describe a scheme that we intend to implement in routine ISC operations to mark the preferred magnitudes in order to help ISC users in the selection of events with magnitudes of their interest. 相似文献
172.
The 2013 European Seismic Hazard Model: key components and results 总被引:11,自引:5,他引:6
Jochen Woessner Danciu Laurentiu Domenico Giardini Helen Crowley Fabrice Cotton Gottfried Grünthal Gianluca Valensise Ronald Arvidsson Roberto Basili Mine Betül Demircioglu Stefan Hiemer Carlo Meletti Roger W. Musson Andrea N. Rovida Karin Sesetyan Massimiliano Stucchi The SHARE Consortium 《Bulletin of Earthquake Engineering》2015,13(12):3553-3596
173.
Correlation between nitrate concentration in groundwater and parameters affecting aquifer intrinsic vulnerability 总被引:3,自引:0,他引:3
This paper is the result of a study which was carried out in order to verify if the traditional methods to evaluate the intrinsic
vulnerability or vulnerability related parameters, are able to clarify the problem of nitrate pollution in groundwater. In
particular, the aim was to evaluate limitations and problems connected to aquifer vulnerability methods applied to nitrate
contamination prevision in groundwater. The investigation was carried out by comparing NO3
− concentrations, measured in March and November 2004 in the shallow aquifer, and the vulnerability classes, obtained by using
GOD and TOT methods. Moreover, it deals with a comparison between NO3
− concentrations and single parameters (depth to water table, land use and nitrogen input). The study area is the plain sector
of Piemonte (Northern Italy), where an unconfined aquifer nitrate contamination exists. In this area the anthropogenic presence
is remarkable and the input of N-fertilizers and zootechnical effluents to the soil cause a growing amount of nitrates in
groundwater. This approach, used in a large area (about 10,000 km2) and in several monitoring wells (about 500), allowed to compare the efficiency of different vulnerability methods and to
verify the importance of every parameter on the nitrate concentrations in the aquifer. Furthermore it allowed to obtain interesting
correlations in different hydrogeological situations. Correlations between depth to water table, land use and nitrogen input
to the soil with nitrate concentrations in groundwater show unclear situations: in fact these comparisons describe the phenomenon
trend and highlight the maximum nitrate concentrations for each circumstance but often show wide ranges of possible nitrate
concentrations. The same situation could be observed by comparing vulnerability indexes and nitrate concentrations in groundwater.
These results suggest that neither single parameters nor vulnerability methods (GOD and TOT) are able to describe individually
the complex phenomena affecting nitrate concentrations in soil, subsoil and groundwater. In particular, the traditional methods
for vulnerability analysis do not analyze physical processes in aquifers, such as denitrification and nitrate dilution. According
to a recent study in the shallow unconfined aquifer of the Piemonte plain, dilution can be considered as the main cause for
nitrate attenuation in groundwater. 相似文献
174.
A numerical study adopting the 2D δ-SPH model is performed to compare the hydrodynamic characteristics of a single pontoon floating breakwater and a double pontoon floating breakwater. Numerical simulations are performed using the δ-SPH model and experimental tests are conducted to validate the numerical model. The numerical results of both the free surface elevations and motions of the floating breakwater are in good agreement with the experimental results. Numerical results show that when the ... 相似文献
175.
176.
Domenico Altieri Enrico Tubaldi Marco De Angelis Edoardo Patelli Andrea Dall’Asta 《Bulletin of Earthquake Engineering》2018,16(2):963-982
Viscous dampers are widely employed for enhancing the seismic performance of structural systems, and their design is often carried out using simplified approaches to account for the uncertainty in the seismic input. This paper introduces a novel and rigorous approach that allows to explicitly consider the variability of the intensity and characteristics of the seismic input in designing the optimal viscous constant and velocity exponent of the dampers based on performance-based criteria. The optimal solution permits controlling the probability of structural failure, while minimizing the damper cost, related to the sum of the damper forces. The solution to the optimization problem is efficiently sought via the constrained optimization by linear approximation (COBYLA) method, while Subset simulation together with auxiliary response method are employed for the performance assessment at each iteration of the optimization process. A 3-storey steel moment-resisting building frame is considered to illustrate the application of the proposed design methodology and to evaluate and compare the performances that can be achieved with different damper nonlinearity levels. Comparisons are also made with the results obtained by applying simplifying approaches, often employed in design practice, as those aiming to minimize the sum of the viscous damping constant and/or considering a single hazard level for the performance assessment. 相似文献
177.
Domenico Giardini Laurentiu Danciu Mustafa Erdik Karin Şeşetyan Mine B. Demircioğlu Tümsa Sinan Akkar Levent Gülen Mehdi Zare 《Bulletin of Earthquake Engineering》2018,16(8):3567-3570
The collaborative project Earthquake Model of the Middle East (EMME, 2010–2015) brought together scientists and engineers from the leading research institutions in the region and delivered state-of-the-art seismic hazard assessment covering Afghanistan, Armenia, Azerbaijan, Cyprus, Georgia, Iran, Iraq, Jordan, Lebanon, Palestine, Pakistan, Syria and Turkey. Their efforts have been materialized in the first homogenized seismic hazard model comprising earthquake catalogues, mapped active faults, strong motions databank, ground motion models and the estimated ground motion values for various intensity measure types and relevant return periods (e.g. 475–5000 years). The reference seismic hazard map of the Middle East, depicts the mean values of peak ground acceleration with a 10% chance of exceedance in 50 years, corresponding to a mean return period of 475 years. A full resolution poster is provided with this contribution. 相似文献
178.
Shake table testing on restoring capability of double concave friction pendulum seismic isolation systems 下载免费PDF全文
Felice Carlo Ponzo Antonio Di Cesare Gianmarco Leccese Domenico Nigro 《地震工程与结构动力学》2017,46(14):2337-2353
After an earthquake, non‐negligible residual displacements may affect the serviceability of a base isolated structure, if the isolation system does not possess a good restoring capability. The permanent offset does not affect the performance unless the design is problematic for utilities, also considering possible concerns related to the maintenance of the devices. Starting from experimental and analytical results of previous studies, the restoring capability of Double Concave Friction Pendulum bearings is investigated in this paper. A simplified design suggestion for the estimation of maximum expected residual displacements for currently used friction pendulum systems is then validated. The study is based on controlled‐displacement and seismic input experiments, both performed under unidirectional motion. Several shaking table tests have been carried out on a three‐dimensional isolated specimen structure. The same sequence of seismic inputs was applied considering three different conditions of sliding surfaces corresponding to low, medium and high friction. The accumulation of residual displacements is also investigated by means of nonlinear dynamic analysis. Copyright © 2017 John Wiley & Sons, Ltd. 相似文献
179.
180.
Raffaella De Luca Domenico Miriello Alessandra Pecci Salvador Domínguez‐Bella Dario Bernal‐Casasola Daniela Cottica Andrea Bloise Gino Mirocle Crisci 《Geoarchaeology》2015,30(4):330-351
This paper presents the results of the compositional study of 29 samples of mortar from the so‐called “Garum Shop” (I, 12, 8) at Pompeii in Southern Italy. The characterization of the samples yielded information on the raw materials used in the mixtures, the production technology of mortars, and the building phases. It was carried out through polarized optical microscopy, X‐ray powder diffraction, X‐ray fluorescence, microanalysis energy‐dispersive X‐ray spectroscopic microanalysis, and image analysis through the JMicroVision software. The resultant data show great compositional homogeneity among the samples, suggesting the presence of a principal construction phase, probably associated with the first phase of the house. Apart from this main construction phase, there are some samples that show differences related either to their different function or to the fact that they come from different construction phases or restoration works. The raw materials used are related to the geology of the area and are fully compatible with the pyroclastic deposits of Vesuvius. 相似文献