The geomagnetic field in the 20th century

The continuous spatial-temporal model of variations in the main geomagnetic field in the 20th century has been elaborated. All available data—from the navigation to the satellite surveys at the beginning and end of the century, respectively—have been used to construct the model. Since the accuracy of measurements was different during the century and the data are nonuniformly distributed over the Earth’s surface, the methods for regulating solutions based on global parameters of the magnetic field and its secular variation, invariant on the simulation interval, have been used to correct the model. The secular variation model has been represented as the sum of the models obtained by means of expansion in terms of natural orthogonal components. The conclusions that the character of field variations is complex have been made and the spatial and temporal characteristics of the secular variations of different origin have been estimated based on the simulation results.     

Inundatios on the Black Sea coast of Krasnodar krai

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.     

高速屏蔽层下广角地震波场分析及成像方法

在高速玄武岩屏蔽区进行勘探存在一定困难,本文以我国南 方典型靶区为例,提出了解决问题的方法. 首先从理论上探讨了广角地震信号存在的条件以 及在应用过程中所面临的问题. 利用正演理论模型分析了广角地震信号的运动学特征以及噪 声对广角反射的影响. 利用物理模型对广角地震的动力学特征、波场特征及动校拉伸现象进 行了分析. 在上述基础上,对广角地震数据作了精细处理,完成了玄武岩下的地震成像.     

三维地震勘探数据的剩余静校正方法研究与软件实现

剩余静校正的目的是消除地震道中由近地表因素造成的静态剩余时差的影响,通常以时差的四因子分解模型为基础建立剩余静校正方程组,并采用迭代求解方法获得剩余静校正量。但实际上,由于地层的倾斜,时差中还应包含横向和纵向倾角项,因此本文首先对剩余校正的理论模型进行了改进,提出了以扩展面元为计算单元的时差分解六因子模型。又由于地层的走向具有局部线性性,因此剩余动校正项,横向及纵向倾角项系数仅在一些给定的面元上计     

Velocity profiles and incipient motion of frazil particles under ice cover

A series of experiments for the incipient motion of frazil particles under ice cover have been carried out in laboratory under different flow and boundary conditions.Measurements on flow velocities across the measuring cross-section at different water depths have been conducted.Based on these experiments under both ice-covered and open flow conditions,the impacts of solid boundary(such as ice cover and flume sidewall) on the distribution of flow velocity profiles have been discussed.The criteria for the inc...     

地震失稳的滑动弱化模型的有限元分析

本文采用有限元方法,对直立的、无限长的二维走滑断层上的地震不稳定性的滑动弱化模型进行分析,研究断层参数对失稳的影响,从理论上探索当断层强、弱区均有弱化现象时,断层破裂的前兆信息,进而分析摩擦应力弱化规律与地震预报的关系,讨论失稳前后位移场、应变场和应力场的演变过程。     

Mixed boundary value problem in an elastic quarter-space

Summary The stress and displacement throughout a homogeneous, isotropic, elastic quarterspace have been evaluated when the stress is prescribed on one of the plane boundaries and the displacement on the other. The variations of the displacement and stress on the boundaries with time and distance from the origin have been shown graphically.     

震前应变固体潮畸变的物理模式

本文根据岩石力学及固体潮理论，建立了孕震期弹性物体应变固体潮的物理模式，给出了其数学公式。通过分析潮汐应力与寻震应力的合力随潮汐力相位的变化，从物理本质上讨论了不同应力阶段应变固体潮曲线的形态特征；讨论了震前不同异常时期，应变固体潮畸变的不同特．点；并对震例进行了分析，同时，对应变固体潮畸变与地震三要素预报作了初步探讨。     

自相似地震活动特征的提取

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。     

Diatoms from Bottom Sediments of Karakel’ Lake (Central Caucasus) and a Reconstruction of Regional Climate Events in the Late Holocene

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.     

Bottom instrumented tripods: History,applications, and impacts

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.     

b) RAPPORT DU SECRETAIRE SUR LA VIE DE L'ASSOCIATION AU COURS DE LA PERIODE 1957–1960

Summary

The Hooghly is a tidal river and Calcutta one of the most important ports of India is situated on it. The tidal effect stretches to over 175 miles length up to Nabadwip where two nonperennial rivers Bhagirathi and Jalangi, both taking off at different sites from the Gangesmeet and discharge their rain water (freshets) into the Hoogly all through the summer months. Other rivers join it also downstream. Annual tide tables are published for three places on the river viz Sagar, Diamond Harbour and Garden Reach.

In this paper lunitidal intervals, durations of rise and fall, mean high water, mean low water, mean tide level and mean sea level planes and mean ranges have been shown to go through periodic seasonal changes. It has been shown that different tidal planes have changed differently in the intrior of the river indicating changes in tidal regimes and in the river bed. Whereas variations in yearly sea levels since 1882 have not been appreciable at Sagar, these at Garden Reach have changed considerable at indicating sometimes an improvement in the channel, other times worsening of the channel. Four 19 yearly cycles of mean sea-level at Garden Reach have been analysed to give phaselags different from Zero and large variations in amplitudes. To carry this study further one period of 19 years each for Sagar, Madras and Vishakhapatnam on East Coast and 4 periods each for Bombay and Aden in the Arabian Sea have also been analysed to see the possibility of nodal variations being constant in amplitude and phase over large areas of the ocean. 19-yearly cycles in the differences between MTL &; MSL have been examined for Bombay, Madras and Garden Reach. The effects of freshets on various planes have been analysed and the curves of annual freshets and MTLs at Garden Reach are found to run closely parallel. The variations in yearly high water and law water planes above MTLs of the corresponding years after corrections for the longitude of the moons' node have been found to be inappreciable. Theoretical extreme high water and low water planes have been found to be more extreme than actually recorded planes which are very near M.H.W.S. and M.L.W.S. planes indicating there are no predominant effects of winds and storms on the tides in the river. The mean ranges at Garden Reach have been found to be steadily increasing. Theoretical effects of increase in range and lowering of MSL on MHW and MLW plane has been found to agree with actual values. Monthly average temperatures and salinities show distinct annual cycles. High temperatures occur at the same times as low salinities and high mean sea levels. Vertical density structure may be responsible for a large part of annual variation in the sea level at Sagar which is a region of particular interest on account of opposite influences of seasonal monsoons, drainage of rivers and oceanic currents. Seasonal variations in average monthly pressure have been related to variations in mean sea levels and it is found that as the pressures decrease, the height of MSL increases. Tide in Hooghly has been found to be progressive type of wave. Rates of travel of tidal streams outside Sagar and rates of streams in the river have been given also, stating the effects of freshets on tidal streams. Bores in Hooghly have been examined. Shapes of tidal curves and profile of the bore at Garden Reach have been drawn. Rates of propagation of the bore from Doodsons' formulae have been compared with actual values and a remarkable agreement has been found. The rise of tide in 10 minutes and 30 minutes which is the time taken for the steep rise to disappear has been correlated with range of tide and a useful table has been included. Tides in Hooghly are predicted by applying harmonic shallow water corrections to open sea primary predictions at Sagar. As the freshets are unpredictable an approximate relationship has been worked out between the departures of actual freshets from num freshets of the years of analyses and departures of actual from predicted tides. From a knowledge of actual freshets the predictions can be corrected almost, daily.

A large number of tables and only the essential graphs have been included to illustrate the contents.     

Note on transverse vibration of a perfectly conducting viscoelastic infinite plate in a magnetic field

Summary In this note displacement of a thin perfectly conducting viscoelastic plate of Reiss type in contact with vacuum on both sides and in a uniform magnetic field has been discussed. The plate has been assumed to be acted on by an impulsive load. Solutions have been obtained for small and large values of time. Results have also been discussed for some particular cases.     

Apparent resistivity over a three layer earth with an inhomogeneous interstratum

Summary The theory of resistivity sounding on a three layer earth comprising an inhomogeneous interstratum has been presented. The electrical conductivity in the intermediate layer, embedded between two layers of uniform conductivity, is assumed to follow either generalised power law or exponential variation. A point source of current is placed on the surface. The electric potential functions on the ground surface have been obtained. The expressions for apparent resistivity over the above models for the Wenner and Schlumberger electrode configurations have been derived.     

基于MapX控件的地震速报平台开发

介绍了地理信息的一些基本概念和开发的几种方式,并进行了简单比较。着重说明了在VC开发平台上基于MapX控件的电子地图的开发方法,并根据地震速报平台的开发项目,结合程序的源代码,阐述了如何在电子地图中通过经纬度查询地名和显示震中位置的方法。     

Effect of the cryolithic zone electrical properties on the medium-frequency surface wave at high latitudes

Result of the measurements of the cryolithic zone electrical properties by the radio impedance sounding method are presented. The surface impedance and geoelectric section of the Arctic permafrost have been determined. The experiments have been performed near Cherskii in the continental zone. The surface wave attenuation function is considered. The accuracy of the surface wave field calculations at high latitudes has been estimated based on the local electrical characteristics of the underlying cryogenic medium. The effect of the Arctic Ocean on the operating zone of navigation and communication facilities in the kilometer wave band has been experimentally estimated.     

The formation of present-day resources of surface and subsurface waters in European Russia

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.     

The state of a river in pechora basin after an oil spill: Assessment of changes in zooplankton community

The long-term dynamics of zooplankton in a northern river has been studied in the context of its pollution after an oil pipeline break. Oil has been shown to have both negative and stimulating effect on planktonic communities and populations, and the role of the drainage area in river system self-purification is studied. Artificial settling water bodies, which had been formed by regulation of polluted flows in the river, have been found to have additional significance as biological regenerators of aquatic ecosystems.     

The structure of ice and ice cover in lower Amur reaches with branched channel

The study is focused on the specific features of ice regime in Amur lower reaches and the structure of ice surface in branches of different size and dynamic state. The main features of ice stratigraphy in different parts of the river have been identified, and ice cover characteristics have been found to show considerable heterogeneity across the channel. Quantitative data on the concentration of terrigenous material in the ice and its distribution within the ice mass have been collected. The amount of terrigenous material was estimated in the ice in Amur lower reaches, from where it is largely exported into the Sea of Okhotsk during spring ice drift.     

秦岭地区丹风群蛇绿岩古地磁研究及其大地构造意义

本文对秦岭造山带内丹风群蛇绿岩进行了较为详尽的古地磁研究,通过对剩磁分量成因形成时代及变质变形作用对特征分量的影响的讨论,初步确定了丹风群古地磁极位置和古纬度值,并对丹风群的形成演化作了初步探讨