贺兰山寒武系研究新进展

贺兰山寒武系早期苏屿口组为砂、砾混杂和不等粒结构的水下冲积扇沉积;五道塘组为下古生界碳酸盐台地沉积,其下部为含泥中、细粒砂屑和生物碎屑,中、上部为含不同形态的核形石碳酸盐岩组成;陶思沟组为发育水下流动波痕和水上暴露泥裂构造碳酸盐岩与细碎屑岩系的混合沉积;胡鲁斯台组和阿不切亥组为陆表海与“风暴海”沉积.根据该区与华北地台的对比,首次提出贺兰山寒武纪早期的苏屿口组古地理面貌应是西低东高,而非传统认为的西高东低;寒武纪早期的五道塘组、陶思沟组古地理面貌则为西高东低.     

Nonlinearity in the response of soils in the 1995 Kobe earthquake in vertical components of records

Strong motion records provided by seismic vertical arrays allow estimation of stress–strain relations in soils at depths from the surface to the location of the deepest device. As an example, time-dependent nonlinear soil behavior was estimated in vertical components of records obtained in the epicentral area of the 1995 Kobe earthquake. Degradation of the rigidity of soils in the strong motion was observed. The constructed nonlinear models of the soil behavior were used for estimating the nonlinear parts in the ground response by the nonlinear system identification technique. Nonlinear parts in the ground response were found to be as high as 50% at 2 km from the fault and 10% at 6–15 km from the fault plane. Odd types of nonlinearity, such as cubic, the fifth, seventh, etc. order, were found to be typical for soils, whereas, nonlinearities of even types are usually weak, but increase in liquefied soils.     

The QBO effect on the solar signal in the global stratosphere in the winter of the Northern Hemisphere

This paper contains correlations between the NCEP/NCAR global stratospheric data below 10 hPa and the 11-year solar cycle. In the north summer the correlations between the stratospheric geopotential heights and the 11-year solar cycle are strong and positive on the Northern Hemisphere and as far south as 30°S, whereas they are weak in the north winter all over the globe. If the global stratospheric heights and temperatures in the north winter are stratified according to the phase of the QBO in the lower stratosphere, their correlations with the solar cycle are large and positive in the Arctic in the west years of the QBO but insignificantly small over the rest of the earth, as far as the South Pole. In the east years, however, the arctic correlations with the solar cycle are negative, but to the south they are positive and strong in the tropical and temperate regions of both hemispheres, similar to the correlations with the full series of stratospheric data in the other seasons. The influence of the solar cycle in the Arctic is stronger in the latter half of the winter. The global difference, in the northern winter, in the sign and strength of the correlations between the stratospheric heights and temperatures and the solar cycle in east and west years of the QBO can be ascribed to the fact that the dominant stratospheric teleconnection and the solar influence work in the same direction in the east years, but oppose each other in the west years.     

Convection currents in the Earth's mantle and the spherical harmonic development of the topography of the earth

Summary A system of simple principles concerning the kinematics of the convection currents in the Earth's mantle was postulated as the starting point. The mantle is supposed to become more and more homogeneous downward. Here it is essential, for the reason of symmetry, that the current system has a degree of regularity as high as possible and is modified only in the upper part, mainly due to the distribution of continents and oceans. The adequate system is chosen by the help of the theory of point groups. Evaluating the distribution to be expected of the coefficients of the spherical harmonic development of the Earth's theoretical topography by means of electronic computers, accordance is found for the extrema to the 31 st order, i.e. as far as they have been determined until now. — The system yields the seismic discontinuities of the Earth's mantle as a secondary product. That does not mean that the system explains them, but it is absolutely consistent with them. That seems to be aquantitative proof of the system regarded as probable on the strength of group-theoretic considerations.Report No. 74, lectured in Potsdam, May 7, 1970.     

Problem of the nature of the sunrise effect in diurnal variations in the electric field in Kamchatka: 1. Time variations in the electric field

The effect of sunrise in time variations in the electric field in the near-Earth atmosphere at the Kamchatka Paratunka observatory has been studied. Twenty-nine records under fair-weather conditions have been selected. It has been indicated that the estimated effect parameters—the times of the effect’s onset and field strength maximum relative to the sunrise time, as well as the ratio of the strength maximum to its value before sunrise and the effect duration—coincide with the previously published data. Thereby, the conclusion is confirmed that the sunrise effect in diurnal variations in the electric field in the near-Earth atmosphere is related to the turbulence and convection processes in the atmospheric boundary layer at a change in atmospheric temperature.     

印度洋8.7级特大地震后川滇地区地震活动趋势判定

2004年12月26日发生了印尼Ms8．7特大地震,我国川滇地区震时和震后有明显响应,如小震活动加强、流体各种前兆异常突出等。为了判定我国大陆地震活动的趋势,2005年1月对川滇地区进行了紧急GPS应急加测。此前,中国地壳运动观测网络分别于1999、2001、2004年进行了三期GPS复测。在这三期复测资料的基础上,对此次紧急复测资料和相关的几个GPS连续观测站的资料进行了分析,认为：①川滇地区的地壳形变主要为机械形变所致,且在8．7级地震震时和震后呈相对松驰变化,这有利于短期内5～6级地震的发生;②若大幅度压缩与拉张反复交替出现,也不排除孕育更强地震的可能性。     

On the maintenance of the axisymmetric part of the flow in the atmosphere

Summary The maintenance of the axisymmetric component of the flow in the atmosphere is investigated by means of a steady-state, quasi-geostrophic formulation of the meteorological equations. It is shown that the meridional variations in the time-averaged axisymmetric variables can be expressed as the sum of three contributions, one being due to the eddy heat transport, another to the eddy momentum transport, and a third to the convective-radiative equilibrium temperature which enters the problem through the specification of a Newtonian form of diabatic heating. The contributions by the large scale eddies are evaluated through the use of observed values for the eddy heat and momentum transports.The contributions from each of the three forcing mechanisms to the temperature and zonal wind fields are invstigated individually and found to be of about equal importance. The sum of the three contributions are also presented for the temperature, the zonal wind, the stream function associated with the mean meridional circulation and the corresponding vertical motion. Although the results fail to reproduce the main observed features of the lower stratosphere, they are found to be in good agreement with observations in the middle latitude troposphere. At any pressure level, for example, the computed mean zonal wind has a jet-like profile and the axis of the jet is found to slope to the south with height, as observed in the atmosphere.Based in part on a thesis submitted by the first author as partial fulfillment of the requirements for the Ph.D. degree at the University of Michigan. — Publication No. 194 from the Department of Meteorology and Oceanography, The University of Michigan.     

On the solution stability in the problem of determining the time variations of the tidal responses of a medium in the vicinity of the sources of severe earthquakes

In (Molodenskii M.S. et al., 2016), the data from horizontal pendulums recording the tilts in the closest vicinity of the Great Tohoku earthquake of March 11, 2011 in Japan were analyzed. A significantly improved method for statistical analysis of the observational data enabled the authors to reveal a slow growth in tidal tilts during a period of six years before the earthquake, which was superseded by an instantaneous drop in the amplitudes at the time of the earthquake. After this, during the subsequent four years, the tidal amplitudes have remained at a significantly lower level than their average values before the earthquake. These changes in tidal amplitudes testify to the nonlinear character of the tidal response of the medium in the presence of large tectonic stresses: as is well known, the linear relationship between stresses and strains in a real medium is only the case for stresses that are far below the yield stress. When the stresses approach the failure limit, two counteracting effects come into play: (1) the shear moduli in some areas decrease as a result of the avalanche growth of the crack formation processes, and (2) the moduli increase due to the compression in the other areas. Irrespective of which particular effect of these two is predominant, in either case the linearity of the relationship between the stresses and strains should be violated. This violation cannot but affect the amplitudes of the tidal tilts and strains characterizing this relationship in the presence of fairly low additional tidal stresses (i.e., the derivative of the off-diagonal stress tensor components with respect to the same components of the strain tensor). Since there is presently a sufficiently dense network of the horizontal pendulums recording the tilts (the global IRIS network and the particularly dense F-NET network in Japan), monitoring the changes in the amplitudes of tidal tilts can be considered as a key instrument for capturing the signs of the approach of tectonic stresses to their critical values. The increase in tidal amplitudes before the Tohoku earthquake and their drop at the moment of the earthquake, which were revealed by us, as well as the constancy of the amplitudes during four years after the event, unambiguously indicate that the accumulation of tectonic stresses caused the growth in tidal amplitudes, whereas the stress release by the earthquake caused their diminution. This does not however mean that stress accumulation is accompanied by a decrease in the elastic moduli and that the release of stresses is accompanied by the growth of elastic moduli all over the source area. As was shown in (Molodenskii M.S. et al., 2012), even in the simplest model of spatially homogeneous variations of elastic modules, the variations in tidal tilts are an odd function of the distance from the epicenter. Therefore, irrespective of whether the elastic moduli decrease or increase, the amplitudes of tidal tilts should decrease in some areas and increase in other areas. Hence, the very fact of the growth of tidal tilt amplitudes with time cannot be considered as a sign of the growth of tectonic stresses. To be positive about the latter, one should make sure that the consistent (unidirectional) changes have been observed during a sufficiently long time interval and that their magnitudes were significantly larger than the measurement errors. Hence, it is important to reliably estimate the errors of the observational data.     

Transfer of organic contaminants to the Baltic in the Odra Estuary

This paper describes the transfer of organic contaminants to the sea, using PAHs (12 compounds) and PCBs (11 congeners) as examples, through a eutrophicated coastal lagoon (Szczecin Lagoon, on the Polish-German border). The transfer of contaminants study was based on their concentration in recent sediments (0-10 cm), in relation to different environmental conditions such as temperature, salinity, turbidity, oxygen and nutrients in water, hydrological conditions, organic carbon and biomarkers (pigments and their derivatives) in sediments. Results include the data obtained between 1994 and 2000, also those on before and afterwards the great flood in July 1997, at different stations in the Lagoon and the adjacent Pomeranian Bay. The results indicated that the eutrophic estuary of the shape of lagoon acts as an effective trap for the hydrophobic organic pollutants. The abundance and taxonomy of plankton as well as detritus derived from it play an important role in bonding the studied compounds. The salinity gradient in the lagoon has a significant influence upon deposition of the pollutants from the water column to the sediments and the residence time of the compounds there depends strongly on oxic-anoxic status of the sediments and the strength of interaction with sediments resulting from polarity, the type and stability of associates formed, as well as on hydrological conditions. We conclude that eutrophication in this area prevents pollution of the sea to some extent.     

Some questions of geomechanics of the faults in the continental crust

We present the results of laboratory experiments on studying the formation of different slip modes on the interfaces in a rock massif such as aseismic creep, stick-slip, and periodic slow-slip events. It is shown that the way of releasing the accumulated elastic energy is determined by the mesoscale structure of the gouge rather than by its macroscopic strength characteristics. The evolution of the stress chains which are formed and broken during the displacement on the fracture, as well as the length and number of these chains, completely determines the regularities of the deformation. The role of these load-bearing elements in nature can be played, e.g., by the “contact spots,” which determine the regularities of stress concentration near the interblock boundary. We consider the effects of low-amplitude vibrations on stressed fractures. It is shown that, depending on the mode of deformation, the vibration impact can either reduce or boost the amplitude of separate events and the fraction of energy that is released dynamically. In the conclusion of the paper, we discuss the possibility of using the shear strength of the fault zone as a geomechanical parameter controlling the mode of deformation.     

Spatio-temporal variations in the structure of the attenuation field of the S-wave in the region of Nevada nuclear test site

The characteristics of the attenuation field of short-period shear waves in the region of Nevada nuclear test site (NNTS) are studied. The seismograms of underground nuclear explosions (UNEs) and earthquakes recorded by three seismic stations in 1975–2012 at the epicentral distances of up to 1000 km are processed by the methods based on the analysis of the amplitude ratios of Sn to Pn and Lg to Pg waves, as well as the S-coda envelopes for close events. It is shown that the structure of the attenuation field in the Earth’s crust and upper mantle in the NNTS region experienced significant temporal variations during the interval of nuclear operations. The strongest variations were associated with UNEs conducted in the Pahute Mesa area, which held about two-thirds of the most intense explosions. Our data indicate that temporal variations in the structure of the attenuation field are related to the migration of deep fluids. A comparison of the general characteristics of the attenuation field in the regions of the three large nuclear test sites is presented.     

Evaluation of the possibility for phytoplankton monitoring frequency reduction in the coastal waters of the Community of Valencia, in the scope of the Water Framework Directive

The Water Framework Directive, under the European Legislation, requires that all European waters, should reach a good ecological status by 2015. To achieve this goal, a phytoplankton monitoring network with monthly water samplings was established to evaluate the ecological quality, in the coastal waters of the Community of Valencia, and the collected data have allowed us to study the efficiency of the monthly campaigns of the monitoring network. With the results obtained in this research, we have designed a new monitoring strategy for the coastal waters of Valencia that for certain water bodies can mean lower sampling frequency. The new monitoring policy provides results as reliable as the previous strategy and allows a precise ecological classification of water bodies at a lower cost. The methodologies we have developed can be used in other monitoring networks and are not limited by geographic location or by the type of water body.     

On the cold wave of January 1954 in the Far East

Summary A synoptic study is made based primarily on 10-day and 5-day mean maps on an unusually cold spell which appeared all over the Far East in the end of January, 1954, following an abnormal warmth. It is found that while it is warm in Japan, cold air is accumulated in Siberia to the north of the climatological jet stream and is confined in the northern latitudes by the latter as long as the high index pattern prevails. But once the index drops, with the southward displacement of the jet stream, the permanent trough of the Far East deepens and the cold air so far accumulated is allowed to penetrate into southern latitudes. Some characteristic features of contour pattern and frontal activity preceding and following the cold air outbreak are described. Further, it is shown that the blocking wave directly related to the cold air outbreak in the Far East can be traced from as far east as North America or possibly the eastern Atlantic.     

Dynamics of the large-scale ULF electromagnetic wave structures in the ionosphere

The present article displays the results of theoretical investigation of the planetary ultra-low-frequency (ULF) electromagnetic wave structure, generation and propagation dynamics in the dissipative ionosphere. These waves are stipulated by a spatial inhomogeneous geomagnetic field. The waves propagate in different ionospheric layers along the parallels to the east as well as to the west and their frequencies vary in the range of (10–10⁻⁶) s⁻¹ with a wavelength of order 10³ km. The fast disturbances are associated with oscillations of the ionospheric electrons frozen in the geomagnetic field. The large-scale waves are weakly damped. They generate the geomagnetic field adding up to several tens of nanotesla (nT) near the Earth's surface. It is prescribed that the planetary ULF electromagnetic waves preceding their nonlinear interaction with the local shear winds can self-localize in the form of nonlinear long-living solitary vortices, moving along the latitude circles westward as well as eastward with a velocity different from the phase velocity of the corresponding linear waves. The vortex structures transfer the trapped particles of medium, as well as energy and heat. That is why such nonlinear vortex structures can be the structural elements of the ionospheric strong macro-turbulences.     

Seismogenic deformations in the walls of the late medieval Yeni-Kale fortress in Eastern Crimea

The results of a macroseismic study of the late medieval Turkish Yeni-Kale fortress in Eastern Crimea are described. Despite the fact that the fortress’ structures were considerably affected by local landslide activity, military operations during the Crimean War, the Civil War, and the WWII, as well as by anthropogenic factors, such as railroads, etc., numerous specific deformations in the fortress walls suggest that the existing destruction and damage might be explained by strong seismic impacts. The local intensity of seismic oscillations could be I = (VIII)–IX points according to the MSK-64 macroseismic scale, and the direction of the combined maximum seismic impact could have a NW–SE strike. It is likely that the Turks abandoned the fortress without a battle because of its significant seismic damage and destruction in the 18th century, which had not yet been repaired by the time the Russian army arrived.     

地震应急现场网络传输方案的选择

地震现场的通讯环境极为复杂,公共的网络接入模式在地震时往往很难保证现场与后方指挥中心之间的实时文件传输和视频通信。本文根据地震带来的破坏程度的不同,针对地震现场的具体通信情况,以及地震应急工作中现场网络通信的需求,提出多项确保地震现场局域网络和后方指挥中心之间通信畅通的解决方案。     

城市群地震灾害特点与防震减灾对策

城市群是我国经济迅速发展的产物。我国东部地区已经涌现了大量的城市群。城市群地震灾害比单个城市的地震灾害更为复杂、严重。地震对社会经济的影响更大。本文首次对城市群的地震灾害特点、防震减灾对策进行了系统的讨论，并着重指出了城市群防震减灾研究的重点领域。     

Scale-to-scale stabilization of the magnetic field in the dynamo models

The three-dimensional dynamo model in the fast-rotating plane layer heated from below is considered. The transition from the linear generation of the magnetic field to the nonlinear generation is studied. With the use of the wavelet analysis, it is demonstrated how the spatial spectra of the kinetic and magnetic energies, as well as the hydrodynamic, magnetic, cross-, and current helicity, vary in time. The scenarios of the suppression of α-effect (α-quenching) by the magnetic field are suggested.     

高速公路路面厚度探地雷达检测

探讨了探地雷达检测高速公路路面厚度的物理前提,并根据我国公路工程建设的实际情况,建立了高等级公路路面结构地球物理模型.系统地介绍了雷达检测路面厚度的方法原理,并对检测中技术参数的选择,如:采样频率、时窗、检测速度进行了详细的说明.介绍了自制的高速公路路面厚度雷达探测解释系统各个模块,如:数据预处理中的时、空域滤波,偏移等方法,并总结面层与基层的反射波三个重要特征,为辅助计算机自动识别反射波打下基础.应用SIR-3000型探地雷达于益常高速公路路面厚度交工验收检测中,通过55个钻孔抽样对比表明,雷达检测能很好地达到了评价路面厚度的目的,为工程质量评价提供了可靠的科学依据.     

Comparative hydrochemical assessment of the current state of some water bodies in the Upper Volga

Results of field studies of water chemistry in the Upper Volga and some its tributaries in the reach between the Volga source and Tver City, as well as in lakes Sterzh, Vselug, Peno, and Volgo, which are constituent parts of the Verkhnevolzhskoe Reservoir, as well as Selizharovskii Pool of Lake Seliger. The year-to-year and season-to-season dynamics of the hydrochemical regime of the examined water bodies and their variations downstream the Volga under the effect of natural and anthropogenic factors are analyzed.