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V. I. Ulomov T. I. Danilova N. S. Medvedeva T. P. Polyakova L. S. Shumilina 《Izvestiya Physics of the Solid Earth》2007,43(7):559-572
The seismicity of the North Caucasus is the highest in the European part of Russia. The detection of potential seismic sources here and long-term prediction of earthquakes are extremely important for the assessment of seismic hazard and seismic risk in this densely populated and industrially developed region of the country. The seismogenic structures of the Iran-Caucasus-Anatolia and Central Asia regions, adjacent to European Russia, are the subjects of this study. These structures are responsible for the specific features of regional seismicity and for the geodynamic interaction with adjacent areas of the Scythian and Turan platforms. The most probable potential sources of earthquakes with magnitudes M = 7.0 ± 0.2 and 7.5 ± 0.2 in the North Caucasus are located. The possible macroseismic effect of one of them is assessed. 相似文献
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Vladyslav V. Khlebovich Vladimir V. Ivanov Vyacheslav M. Makeyev 《Marine pollution bulletin》1997,35(7-12):222-225
Estuarine ecosystem may be considered as ‘pulse-targets’ where information about contamination of all-river basin and about scale and forms of contaminants input to the seas is concentrated. The nucleus of the estuarine processes of contaminants transformation and sedimentation is the critical salinity zone. In the real natural conditions of the Arctic the salinity dependent processes are masked by hydrodynamic effect. The tasks of effective chemical and biological monitoring of Russian Arctic estuarine ecosystems are formulated. 相似文献
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芦山地震震后次生滑坡灾害风险评价研究 总被引：2，自引：2，他引：0
以北京时间2013年4月20日8时02分四川省雅安市芦山县7.0级地震为例,对研究区进行震后次生滑坡灾害风险评价.研究在利用芦山地震受灾区航空影像对震后次生滑坡灾害隐患点解译的基础上,选择坡度、坡向、震后累计降雨量和危险植被指数4个评价因子,利用统计分级法对各因子进行敏感性分析,采用层次分析法（Analytic Hierarchy Process,AHP）对评价因子进行权重量化,最后综合运用GIS空间分析技术对芦山地震震后次生滑坡灾害进行风险评价,研究结果将研究区划分为次生滑坡灾害高危险区、中危险区和低危险区. 相似文献
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Concentrations of heavy metals (Cu, Ni, Cd, Pb, Cr, and Zn) in bottom sediments, water, snow, and biota of the Uvod Reservoir,
as well as of rare-earth elements (Ce, Dy, Er, Eu, Gd, Ho, La, Lu, Nd, Pr, Sm, Tb, Y, and Yb) in its water are assessed. Geochemical
studies of concentrations of Cu, Ni, Cd, Pb, Cr, and Zn in soils, water, and snow allow us to state that the metals enter
the reservoir mostly from natural sources; however, some part of them are of anthropogenic origin. The sum of concentrations
of light rare-earth elements (La, Ce, and Nd) make almost the total of all rare-earth elements in the reservoir—from 70 to
97%, depending on the sampling site. The highest concentrations of metals (and the highest percentage of their labile forms)
are recorded in the Priplotinnyi and Kolbaskinskii (in macrophite deposits) pools and at the site of water inflow from the
Volga-Uvod canal. There is also reason to suppose a secondary entry of the elements under study into the water mass. The largest
variations in metals’ concentrations are observed during the periods of spring and autumn floods, when a great quantity of
terrigenous suspended matter enters the water body. The distribution of the above metals and rare-earth elements in water
is uneven; their highest concentrations are observed in the site of water inflow from the canal and in the Uvod River (the
latter is likely to be due to the effect of the settlement of Pistsovo). The analysis of biota (fennel-leaved pondweed and
zooplankton) has shown that the Uvod Reservoir is polluted with heavy metals. 相似文献
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The Indian Ocean is one of the most tsunamigenic regions of the world and recently experienced a mega-tsunami in the Sumatra region on 26 December 2004 (M W 9.2 earthquake) with tsunami intensity I (Soloviev-Imamura intensity scale) equal to 4.5, causing heavy destruction of lives and property in the Indian Ocean rim countries. In this study, probabilities of occurrences of large tsunamis with tsunami intensities I ≥ 2.0 and I ≥ 3.0 (average wave heights H ≥ 2.83 m and H ≥ 5.66 m, respectively) during a specified time interval were calculated using three stochastic models, namely, Weibull, gamma and lognormal. Tsunami recurrence was calculated for the whole Indian Ocean and the special case of the Andaman-Sumatra-Java (ASJ) region, excluding the 1945 Makran event from the main data set. For this purpose, a reliable, homogeneous and complete tsunami catalogue with I ≥ 2.0 during the period 1797–2006 was used. The tsunami hazard parameters were estimated using the method of maximum likelihood. The logarithm of likelihood function (ln L) was estimated and used to test the suitability of models in the examined region. The Weibull model was observed to be the most suitable model to estimate tsunami recurrence in the region. The sample mean intervals of occurrences of tsunamis with intensity I ≥ 2.0 and I ≥ 3.0 were calculated for the observed data as well as for the Weibull, gamma and lognormal models. The estimated cumulative and conditional probabilities in the whole Indian Ocean region show recurrence periods of about 27–30 years (2033–2036) and 35–36 years (2039–2040) for tsunami intensities I ≥ 2.0 and I ≥ 3.0, respectively, while it is about 31–35 years (2037–2041) and 41–42 years (2045–2046) for a tsunami of intensity I ≥ 2.0 and I ≥ 3.0, respectively, in the ASJ region. A high probability (>0.9) of occurrence of large tsunamis with I ≥ 2.0 in the next 30–40 years in the Indian Ocean region was revealed. 相似文献
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Many past studies have verified numerical simulations of tsunamis using only qualitative and subjective methods. This paper investigates the relative merits of several indices that can be used to objectively verify tsunami model performance. A number of commonly used indices, such as error in the maximum amplitude and root-mean-square error, are considered, as well as some further indices that have been developed for other specific applications. Desirable qualities of the indices are presented and these include computational efficiency, invariance when applied to tsunamis of any size or to time series of varying length (including relatively short series), and the ability to clearly identify a single best prediction from within a set of simulations. A scenario from the T2 tsunami scenario database is chosen as the control. From this, time series of sea-level elevations are extracted at designated test points located at a range of distances from the tsunami source region. Parameters of the T2 database are perturbed in order to examine the performance of the indices. Of the indices examined, several performed better than others, with Wilmott’s Index of Agreement and Watterson’s transformed Mielke index found to be the best. Combining data from multiple locations was shown to improve the performance of the indices. This study forms the basis for future evaluation of the indices using real observations of tsunamis. 相似文献
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Assessment of the vertical distribution on seismic ground motion 总被引：1，自引：0，他引：1
It is very important for the facilities such as nuclear power plants to infer seismic force loading on the earthquake stability assessment of the building foundation and the surrounding slope. The purpose of this paper was to propose a method to evaluate underground seismic coefficients, taking into account dynamic response along the depth in horizontally multi-layered ground. The dynamic property of the seismic coefficient was analyzed on the basis of earthquake records observed at hard and soft rock sites mostly found in Tertiary deposits and sedimentary ground sites of the Pleistocene and Holocene epoch. The evaluation methods of a vertical distribution on underground seismic coefficients were proposed for a few calculation methods on the classified layered ground. Extended evaluation for underground seismic coefficients was confirmed with respect to some multi-layered ground during strong motion. 相似文献
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Assessment of marine debris on the Belgian Continental Shelf 总被引：2，自引：0，他引：2
Lisbeth Van Cauwenberghe Michiel Claessens Michiel B. Vandegehuchte Jan Mees Colin R. Janssen 《Marine pollution bulletin》2013
A comprehensive assessment of marine litter in three environmental compartments of Belgian coastal waters was performed. Abundance, weight and composition of marine debris, including microplastics, was assessed by performing beach, sea surface and seafloor monitoring campaigns during two consecutive years. Plastic items were the dominant type of macrodebris recorded: over 95% of debris present in the three sampled marine compartments were plastic. In general, concentrations of macrodebris were quite high. Especially the number of beached debris reached very high levels: on average 6429 ± 6767 items per 100 m were recorded. Microplastic concentrations were determined to assess overall abundance in the different marine compartments of the Belgian Continental Shelf. In terms of weight, macrodebris still dominates the pollution of beaches, but in the water column and in the seafloor microplastics appear to be of higher importance: here, microplastic weight is approximately 100 times and 400 times higher, respectively, than macrodebris weight. 相似文献
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Robert C. Knox 《Ground water》1984,22(3):279-284
Currently, one of the most popular methods of containing contaminated ground water is through use of subsurface impermeable barriers. These barriers can take one of three forms: slurry walls, grout curtains, or steel sheet piles. Successful operation of these barrier systems is dependent upon three basic criteria. First, the barrier must be truly impermeable and remain so over time even upon exposure to the contaminated ground water. Second, there must exist an underlying impermeable formation, at a reasonable depth, to which the barrier can be connected. Third, an adequate connection between the barrier and the underlying formation must be assured. This paper presents the results of the analysis of the movement of contaminated ground water under or through an imperfect barrier. The first phase of the analysis consists of the development of an analytical solution for the flow of ground water under a barrier and a simple numerical integration technique for developing concentration breakthrough curves. This simple solution algorithm was applied to the cases of variable recharge rates and lengths, variable depths of penetration of the barrier, and anisotropic soils. The second phase of the analysis involves applying a numerical solute transport model to analyze the performance of a barrier with and without the effects of hydrodynamic dispersion, and in the presence of a layered soil, and finally the performance of a fully penetrating but partially permeable barrier. 相似文献
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Comprehensive assessment of ecotoxicological situation in the Volga River basin is presented. Concentrations of organic and inorganic toxic substances are cited. Basic clinic and postmortem symptoms of intoxication in fish are described; changes in the cellular structure of their organs and tissues, as well as disturbances in hemogenesis, developing under the effect of toxic agents, are characterized. Based on the dose-effect dependences, calculated according to the values of the total concentration of toxic substances, standardized to MPC, and criteria of the physiological state of fish, cases of exceedance of the critical concentrations of pollutants are demonstrated for the investigated river sections.__________Translated from Vodnye Resursy, Vol. 32, No. 4, 2005, pp. 410–424.Original Russian Text Copyright © 2005 by Moiseenko, Gashkina, Sharova, Pokoeva. 相似文献
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Antonio Di Cesare Felice Carlo Ponzo Domenico Nigro 《Bulletin of Earthquake Engineering》2014,12(6):2777-2796
The advantages of passive supplemental dampers for performance enhancement of new and existing structures have been demonstrated extensively in the past. The big amount of experimental tests carried out all over the world on framed structures upgraded by energy dissipating bracing (EDB) systems based on hysteretic dampers (HDs), have shown their effectiveness in reducing seismic effects on buildings. The mechanical characteristics of the HDs in some cases may be different from those arising by the design procedure due to industrial tolerance or because of some damage suffered during previous earthquakes. In order to assess the robustness of this technique, in terms of capacity of seismic vibrations control even for significant changes in the mechanical characteristics of the EDB system respect to the design ones, in this paper experimental tests and parametric nonlinear time history analysis have been carried out changing the characteristics of the HD stiffness and strength. The experimental results refer to the shaking table tests performed at the Structural Laboratory of the University of Basilicata within a wide research program, named Joint Experimental Testing on Passive and semiActive Control Systems. The program has been completely funded by the Italian Department of Civil Protection within the activity of the Research Line 7 of the ReLUIS (Italian Network of University Laboratories of Earthquake Engineering) 2005–2008 project. A displacement-focused design procedure has been considered to evaluate the mechanical characteristics of the dissipating system, with the aim of limiting inter-storey drifts after frame yielding. From the experimental point of view, two design solutions have been tested for chevron braces equipped with HD, assuming the same stiffness but different values of both ductility demand and yield strength of the HDs. Moreover, parametric studies have been performed through numerical simulations. This paper provides an overview of the experimental set up and briefly summarizes the experimental outcomes and the comparison with the results of numerical nonlinear time history analysis. Moreover, the results of the parametric analysis for the assessment of the performances of the dissipating system in controlling structural response are presented. 相似文献
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G. B. Warburton 《地震工程与结构动力学》1990,19(3):457-467
In the Newmark and other approximate step-by-step methods, having introduced assumptions in order to transform the differential equations, which are characteristic of response problems, into simultanéous equations, successive solutions lead to a response-time history. In this paper numerical results and formulae are given for the errors which are generated by this procedure. These errors are oscillatory in nature and, in general, the oscillations increase in magnitude as the number of time steps increases. Recommendations for upper limits on the time step, which will provide acceptable accuracy for a wide range of system and excitation parameters, are presented. 相似文献
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The present study was aimed at comparing zooplankton composition and abundance between the western shore of the shallow lake
Setúbal, on which the city of Santa Fe is founded, and the eastern shore, whose environmental impact is scarce or null. Five
samplings were carried out in 14 stations, under different seasonal conditions, hydrometric levels, and volumes of previous
rainfalls. The values of conductivity, pH, transparency, specific richness, and abundance of macro and microzooplankton showed
significant differences between both shores. The highest zooplankton density, with a proportion of Bdelloid rotifers of up
to 20% of the total abundance, was associated with the urbanization of the impacted shore. The volume of the lake and its
fast turnover rate would buffer the impact of contamination, as indicated by a certain degree of eutrophication, which is
more evident at lower hydrometric levels and higher temperatures.
Published in Russian in Vednye Resursy, 2006, Vol. 33, No. 6, pp. 728–736.
The article was translated by the author. 相似文献