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Fluctuations of peak energy and peak frequency o local wavelet energy spectrum for wind wavesTXFluctuationsofpeakenergyandpeak... 相似文献
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J. Zahradník M. Antonini G. Grünthal J. Janský D. Procházková E. Schmedes A. Špičak J. Zedník 《Pure and Applied Geophysics》1990,133(1):53-71
The main shock of the West-Bohemian earthquake swarm, Czechoslovakia, (magnitudem=4.5, depthh=10 km) exhibits an irregular areal distribution of macroseismic intensities 6° to 7° MSK-64. Four lobes of the 6° isoseismal are found and the maximum observed intensity is located at a distance of 8 km from the instrumentally determined epicentre. This distribution can be explained by the energy flux of the directS wave generated by a circular source, the hypocentral location and focal mechanism of which are taken from independent instrumental studies. The theoretical intensity, which is assumed to be logarithmically proportional to the integrated squared ground-motion velocity (i.e.,I=const+log v
2
(t)dt), fits the observed intensity with an overall root-mean-square error less than 0.5°. It is important that the present intensity data can also be equally well explained by the isotropic source. The fit was attained by means of a horizontally layered model though large fault zones and an extended sedimentary basin suggest a significant lateral heterogeneity of the epicentral region. The results encourage a broader application of the simple modelling technique used. 相似文献
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Taoze LIU Yuangen YANG Bangyu LIU Xiangyang BI Feili LI 《中国地球化学学报》2006,25(B08):41-42
It has been found that stream waters were severely contaminated with wastes from a long-time smelting factory in Hezhang, Guizhou, China. The main sources of contamination are the smelting wastes stored in the open air and abandoned in the vicinity of stream. A method of lead isotope was adopted in order to identify relations between tailings and water contamination. Representative samples of tailings and stream sediments were collected. Mineralogical characterizations were conducted using XRD and TEM/SEM, while acid digestion was carried out for determining metal contents. BCR sequential leaching tests were performed in order to assess metal mobility. The tremendous ‘actual' and ‘potential' mobility of heavy metals indicates that the smelting waste and stream sediments present a considerable threat to the environment. Besides the chemical remobilization of heavy metals from the sediments and the reworking of riverbed sediments act as a secondary source of pollution. Also groundwater and stream water were sampled in specific locations and were measured. 相似文献
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The evaluation of seismic site response in the urban area of Catania was tackled by selecting test areas having peculiar lithological
and structural features, potentially favourable to large local amplifications of ground motion. The two selected areas are
located in the historical downtown and in the northern part of Catania where the presence of a fault is evident. Site response
was evaluated using spectral ratio technique taking the horizontal- to-vertical component ratio of ambient noise. Inferences
from microtremor measurements are compared with results from synthetic accelerograms and response spectra computed at all
drillings available for this area. Such method is particularly suitable in urban areas where the nature of the outcropping
geological units is masked by city growth and anthropic intervention on the surface geology. The microtremor H/V spectral
ratios evaluated at soft sites located within the downtown profile tend to be smaller than that usually reported in the literature
for such soils. A tendency for amplifications to peaks near 2 Hz is observed only in some sites located on recent alluvial
deposits. Evidences for amplifications of site effects (frequency range 4–8 Hz) were observed in the sampling sites located
on the fault, with a rapid decrease of spectral amplitude just a few tenths of metres away from the discontinuity. Numerical
simulations evidenced the importance of geolithological features at depth levels even greater than 20–30 m. Besides this,
the results strongly confirm the importance of the subsurface geological conditions, in the estimate of seismic hazard at
urban scale. 相似文献
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Dire financial constraints and the threats of forced structural reform have had the unforeseen effect of forcing municipal councils across Australia to reconsider their operational activities and organisational arrangements. With considerable ingenuity, numerous municipalities have proposed and sometimes adopted new structural formations that embody various forms of co-operative service provision. This remarkable development has unfortunately been largely ignored in the scholarly literature on Australian local government. In a modest effort aimed at remedying this neglect, the present paper seeks to outline the small, rural New South Wales Gilgandra Shire Council's (2004) ‘Co-operative/Local Government Service Company’ model, place it in the broader context of alternative models of local governance suitable for Australian conditions, and evaluate its characteristics. 相似文献