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1.
The dynamics of anthropogenic activity and anthropogenic sources of nutrients in the Republic of Bashkortostan have been analyzed. Statistical analysis of many-year data of hydrochemical monitoring have been used to establish the year-to-year and annual regularities in the variations of N compound concentrations in watercourses. Maps of the mean annual N concentration in its forms (ammonium, nitrites, and nitrates) have been constructed. The fitness of river water to different types of water use have been assessed. Probability distributions of the concentrations of hydrochemical components have been constructed for different phases of stream water regimes. The exceedance probabilities have been evaluated for MAC values of N compounds in watercourses.  相似文献   

2.
本文处理了张掖地区数字微震监测台网资料,求得了小震的震源参数,对中小地震相对比较集中的肃南地区部分地震进行了谱分析,估计了震源的谱参数。用振幅比方法反演了肃南地区小震的震源机制解及错动参数,分析了它们的构造意义和预报意义。  相似文献   

3.
In this study the seismic risks of northern Iraq have been evaluated by a probabilistic method. The data contain about 500 earthquakes which occurred between 1840 and 1978. The epicentral locations and magnitudes of the included earthquakes have been presented. A linear relationship between magnitude and frequency has been assumed. The attenuation of intensities has been presented as a function of magnitude and epicentral distance. The seismic risk has been calculated for 225 points of the analysed area. The equiseismal maps related to a certain risk level have been plotted by using these point values of intensities, and assuming a linear variation between the points. The significance of the standard deviation of the attenuation law and the strict lower bound intensity has been investigated by sensitivity analyses. The intensity contours related to the annual return period of 50, 100 and 200 years have been presented, and also the intensity contours with an occurrence probability of 10 per cent during 50, 100 and 200 years have been drawn.  相似文献   

4.
《Continental Shelf Research》2006,26(17-18):2319-2334
Instrumented bottom tripods have provided important data on sediment transport processes on continental shelves and in estuaries for four decades. Since the initial deployment in a tidal channel in Puget Sound, WA, in 1965 numerous tripods have been constructed to investigate bottom boundary layer and sediment dynamics worldwide. Tripod data have led to new understanding of near-bottom wave and current flows in the coastal ocean, and have been crucial to the development of shelf circulation and sediment transport models. Calculations of bottom stress, bottom roughness, and sediment flux that resulted directly from tripod data have been compared to bottom boundary layer model results. Where these have differed, new or revised model components have been developed to improve the skill of the models. The many discoveries that have been made from tripod experiments include dense, near-bottom fluid mud layers that transport large quantities of suspended sediment offshore into deeper regions of the continental shelf. This process has been linked to the seaward progradation of subaqueous deltas and to the boundaries of mid-shelf mud deposits off rivers with high fine-sediment discharge.  相似文献   

5.
井间地震资料精细解释方法研究与应用   总被引:1,自引:0,他引:1       下载免费PDF全文
井间地震资料分辨率很高,但是缺乏成熟的解释方法,本文针对井间地震资料的特点,借鉴地面地震解释技术对井间地震资料开展了精细解释方法研究.首先在深度域资料特点分析的基础上,利用区域速度和层析成像速度将深度域井间地震资料转换到时间域进行研究,并通过粗化降频建立起井间地震资料与地面地震资料之间的相似性联系,得到对井间地震低频反射特征的认识,结合井旁道合成地震记录标定建立起井间地震资料的反射特征,准确的解释了井间地震的反射层位.采用地震瞬时属性分析和时频属性分析得到了对沉积环境的认识,进一步通过波阻抗反演更好的认识井间储层特征.在实际应用中综合多种方法进行解释,并结合测井资料对比落实了井间砂体展布特征,得到对井间储层的精细描述结果,解决了两口井之间储层分布范围、横向连通性及厚度变化等问题,取得了较好的应用效果.  相似文献   

6.
2009年2月福州乌鸦嘴泉水氡与该泉流量同时出现异常。为此观测人员进行了多次相关检查,在排除了观测人员、观测仪器以及该泉历史上曾经出现的干扰因素后,认为此次乌鸦嘴泉异常可能是受到位于该泉西南方向的鼓楼老年公寓内工地施工的影响,并对该异常的成因进行了分析。  相似文献   

7.
Lake Baikal: Extreme level as a rare hydrological event   总被引:1,自引:0,他引:1  
The optimal boundaries of water level variation range in Lake Baikal have been determined under the conditions of runoff regulation at the Irkutsk HPP and the extremely low water abundance in lake basin in recent years. The properties of the time series of level regime and the characteristics of runoff from its drainage basin have been studied. The formation of long-term dry periods in the region has been studied, and the regularities in level regime variations in the lake have been estimated for both natural and runoff-regulation conditions, and the specifics of runoff regulation and level drawdown in dry years have been considered.  相似文献   

8.
地电场观测中若干问题的讨论   总被引:4,自引:0,他引:4  
“九五”期间在全国陆续建设了二十来个地电场观测场地,经过几年的观测,已经观测到了一些地电场的基本特征,但在观测中也发现存在很多问题。现就一些主要问题展开讨论,并提出建议,供地电场的观测和建设参考。  相似文献   

9.
Gigantic upward atmospheric discharges have been numerically simulated. The space-time distributions of the self-consistent electric field strength and charged particle densities have been obtained. The brightness, color, and evolution in the space and time of fluorescence above a thundercloud, which agree with the data of field observations of such high-altitude optical phenomena as blue jets and red sprites, have been calculated. It has been indicated that large duration of blue jets results from the emission of a decaying ion plasma of the air. The yields of hard gamma rays and neutrons, generated by upward discharges, have been calculated.  相似文献   

10.
Variations in the characteristics of the annual, dry-season, and minimal monthly runoff in rivers of European Russia for the recent 35 years (1975?C2005) have been estimated and analyzed in comparison with a period of approximately the same duration (1935?C1969). The genesis of runoff for different river basins and the major causes of current changes in runoff characteristics have been studied. Regional regularities in the hydrological and geohydrological processes have been identified, and zoning of the territory has been performed with identification of specific features in the formation of river runoff in the European North and the basins of the Volga, Don, Ural, etc. The natural resources of surface and subsurface waters over 1970?C2005 have been re-estimated with the construction of appropriate maps. Water availability and load on water resources have been analyzed.  相似文献   

11.
Data on diatom complexes from bottom deposits of Lake Karakel’ (the Karachayevo-Cherkessian Republic) have been analyzed. The principle of unification of bioindication methods has been applied. The hydrological parameters of lake water (temperature, pH, and saprobithy) have been reconstructed over a period of 2000 years. The results of isotopic dating of bottom sediments have been used. For the first time for the Central Caucasus, the current and Late Holocene diatom alga complexes have been described. Photographs of the most abundant and significant lower taxa of diatom algae are given.  相似文献   

12.
Inundatios on the Black Sea coast of Krasnodar krai between 1945 and 2013 have been analyzed. The main genetic types of inundations on the coast have been identified. The specific features and regularities of inundation wave transformation along the rivers and over time have been studied. Seasonal and maximal runoff of Black Sea rivers has been analyzed over a long-term period. Regularities in the variations of the number of inundatios and their characteristics over the coastal area have been revealed both at the annual and long-term scales. Quantitative estimates are given to the hazard and damage to the population and economic activity due to inundations in the valleys of Black Sea rivers.  相似文献   

13.
自相似地震活动特征的提取   总被引:1,自引:0,他引:1  
本文研究了强震前的地震活动前兆。为定量描述这组前兆,我们研究了一组自相似地震活动函数。在此基础上进行了自相似地震活动特征的提取。然后利用直方图法对每一特征作了特征选择,如此共选取了21个特征。这些特征反映了强震活动水平增高,地震活化,地震活动偏离正常值及b值异常等地震活动前兆现象。  相似文献   

14.
Levels of seven marker polychlorinated biphenyls (PCBs) have been determined in five species of Baltic fish collected during 1997-2006. Downward time trends in the concentrations of heavier congeners of PCBs in different Baltic fish, with the exception of cod, have been observed between 1997 and 2001. In case of sprat and herring samples, the statistical significance of the time trends of the PCBs: 101, 118, 153, 138 and 180 concentrations has been proved. Species-specific bioaccumulation of PCBs has been indicated, and the lowest and highest levels of PCBs (expressed on the basis of lipid weight) have been observed in sprat and salmon samples, respectively. PCB profiles have been found to be similar in all the fish species tested. Sampling location has not been a crucial factor for the observed levels of various PCBs. In some fish species, PCB concentrations are negatively correlated with the fat content but have no relation with the fish length.  相似文献   

15.
The dynamics and fine structure of auroras before and during 60 auroral breakups, including pseudobreakups and breakups at moderate and high auroral activity, have been studied using the developed method for processing television images. The IMAGE and POLAR satellite and simultaneous ground images of auroras, ground magnetic data, and measurements of IMF and solar wind plasma parameters have been analyzed. The signatures that can be precursors of breakup have been found out in the auroral dynamics and morphology in the spatial—temporal vicinity of breakup. The morphological characteristics of auroral structures have been analyzed statistically. The directions of motion of weak subvisual structures have been determined. The velocities of motion of such structures are presented. The relation of the initial auroral arc bright-ening during breakups and pseudobreakups to the beginning of magnetic activation and formation of rayed structures has been analyzed.  相似文献   

16.
The main data have been summarized, and the results, achieved using data from the worldwide network during the entire period of ground-based observations of solar cosmic rays (SCRs) from February 28, 1942, when they were discovered, have been generalized. The methods and equipment for registering SCRs have been described. The physical, methodical, and applied aspects, related to the SCR generation, as well as the SCR interaction with the solar atmosphere, transport in the IMF, motion in the Earth’s magnetosphere, and the affect on the Earth’s atmosphere, have been discussed. It has been indicated that the fundamental results were achieved in this field of space physics during 70 years of studies. Special attention has been paid to up-to-date models and concepts of ground-level enhancement (GLE). The most promising tendencies in the development and application of this effective method of solar-terrestrial physics have been outlined.  相似文献   

17.
俞维贤  王晋南 《地震研究》1993,16(4):350-358
本文利用滇西地区近些年来的地震地质、地球物理及地壳形变等方面的资料,经深入研究分析,最终选定了12个较理想的特征参数,通过综合图像识别,在64个研究对象中得到了28个D类对象,占研究区总面积的43%。其中有16个对象历史上已有6级以上地震的记载;12个为新判定的中强地震潜在震源区;1个为判定不稳定对象。最后给出了云南滇西地震重点监视防御区中强地震潜在震源区预测图。  相似文献   

18.
Summary A one-dimensional numerical model has been developed which gives the vertical profiles of the electron and ion concentrations at altitudes between 50 and 100 km. The model has been constructed for day-time ionization conditions in midlatitudes and yields a slightly abbreviated scheme of ion-molecular reactions. Neutral species concentrations have been compiled from various authors. Seasonal variations of temperature and the most important neutral species have been taken into account. For the purpose of this paper moderate solar fluxes in all required radiation bands have been considered.  相似文献   

19.
Results of the continuous ground-based monitoring of the cosmic ray flux by neutron monitors are used as an experimental material for many works devoted to studying cosmic ray variations. Long-term stability of detectors is the problem of an extreme importance. Two independent methods for estimating long-term stability of neutron monitor operation have been proposed. The quantitative estimates have been obtained for 90 detectors that operated and have been operating during more than one solar cycle. The conditions responsible for long-term stability of a detector and the causes of instability have been considered.  相似文献   

20.
概述了太旧高速公路周缘地区(19个县市)的地震灾害。在寻建筑物的类型进行划分的基础上,用地震安全性评定的综合概率法计算每个单元遭遇烈度的概率,得到了各类建筑物的易损性矩阵,最后计算得出19个计算单元所有建筑物的破坏数量和预期经济损失,并对计算结果进行了分析和比较,最后提出防震减灾对策。  相似文献   

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