排序方式： 共有6条查询结果，搜索用时 15 毫秒
1
1.
Hristopulos Dionissios T. Pavlides Andrew Agou Vasiliki D. Gkafa Panagiota 《Mathematical Geosciences》2021,53(8):1907-1949
Mathematical Geosciences - Classical geostatistical methods face serious computational challenges if they are confronted with large spatial datasets. The stochastic local interaction (SLI) approach... 相似文献
2.
3.
Aikaterini Rogkala Petros Petrounias Petros Koutsovitis Panagiota P. Giannakopoulou Panagiotis Pomonis Paraskevi Lampropoulou Konstantin Hatzipanagiotou 《Chemie der Erde / Geochemistry》2022,82(2):125860
In the Veria-Naousa ophiolitic complex (north Greece), rodingite appears mainly in the form of cross cutting dykes within serpentinised peridotites. It is distinguished into three types, based upon the provenance of its protoliths, textural characteristics, mineralogical assemblages and geochemical affinities. Type I rodigites were derived from boninitic diabasic protoliths and their mineralogical assemblage include garnet + clinopyroxene + chlorite. Type II rodingites were formed at the expense of gabbroic precursors, comprising clinopyroxene + garnet + vesuvianite ± quartz, whereas Type III rodingites replaced diabasic tholeiitic protoliths comprising of garnets + vesuvianite + clinopyroxene + chlorite. Rodingitisation resulted in desilification, decrease of alkalies, Al, Fe, Mg and increase in Ca contents. In Type I rodingites the MREE (middle rare earth elements) and HREE (heavy rare earth elements) were slightly reduced. Type II rodingites experienced LREE (light rare earth elements) depletions, whereas MREE and HREE remained fairly stable. Restricted mobility of REE in Type III rodingites is assigned to shallow-level rodingitisation under decreasing pH.Rodingitisation occured in two distinct stages at fore-arc settings. The first stage occured under mildly oxidising conditions and enhanced CO2/H2O ratios. This stage affected the protoliths of all rodingite types. The second rodingitisation stage occured under more oxidising conditions and lower CO2/H2O ratios, which corresponds to the exhumation stage of the serpentinite-rodingite formations. Types II and III rodingites were subjected to further rodingitisation under the increasing influence of slab-derived hydrous phases at shallower depths, leading to the formation of late-stage andradite and vesuvianite. All stages of rodingitisation are estimated to have occurred under relatively moderate temperatures and pressure (~300 to 450 °C; ~2–6 kbar respectively). 相似文献
4.
Christos Makris Panagiota Galiatsatou Konstantia Tolika Christina Anagnostopoulou Katerina Kombiadou Panayotis Prinos Kondylia Velikou Zacharias Kapelonis Elina Tragou Yannis Androulidakis Gerasimos Athanassoulis Christos Vagenas Ioannis Tegoulias Vassilis Baltikas Yannis Krestenitis Theodoros Gerostathis Kostantinos Belibassakis Eugen Rusu 《Ocean Dynamics》2016,66(12):1603-1635
5.
P. Galiatsatou P. Prinos 《Stochastic Environmental Research and Risk Assessment (SERRA)》2011,25(2):165-183
In the present paper a statistical model for extreme value analysis is developed, considering seasonality. The model is applied
to significant wave height data from the N. Aegean Sea. To build this model, a non-stationary point process is used, which
incorporates apart from a time varying threshold and harmonic functions with a period of one year, a component μ
w(t) estimated through the wavelet transform. The wavelet transform has a dual role in the present study. It detects the significant
“periodicities” of the signal by means of the wavelet global and scale-averaged power spectra and then is used to reconstruct
the part of the time series, μ
w(t), represented by these significant features. A number of candidate models, which incorporate μ
w(t) in their location and scale parameters are tried. To avoid overparameterisation, an automatic model selection procedure
based on the Akaike information criterion is carried out. The best obtained model is graphically evaluated by means of diagnostic
plots. Finally, “aggregated” return levels with return periods of 20, 50 and 100 years, as well as time-dependent quantiles
are estimated, combining the results of the wavelet analysis and the Poisson process model, identifying a significant reduction
in return level estimation uncertainty, compared to more simple non-stationary models. 相似文献
6.
Wavelet analysis for relating soil amplification and liquefaction effects with seismic performance of precast structures 
下载免费PDF全文
下载免费PDF全文 Precast concrete structures are preferred for facilities with large open areas due to easiness in construction. Such structures are typically composed of individual columns and long‐span beams, and are quite flexible and of limited redundancy. In this paper, nonlinear dynamic analyses of a typical such structure are conducted using as excitation 54 ground motions recorded on top of a variety of soils (hard, soft, and liquefied soil sites). The results show that liquefaction‐affected level‐ground motions systematically impose a greater threat to precast‐concrete structures in terms of seismic demand, even when low values of elastic spectral acceleration prevail, as opposed to soft‐soil records and even more to hard‐soil ones. Thus, elastic spectral acceleration appears to be an insufficient engineering demand parameter for design. Soil effects, the “signature” of which is born on ground motions, are first uncovered using wavelet analysis to detect the evolution of the energy and frequency content of the ground motion in the time domain. From this, the changes in effective (“dominant”) excitation period are noted, persuasively attributed to the nature of the soil, and finally correlated with the observed structural behavior. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
1