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根据新疆及苏联天山地区的地震目录和古地震研究成果,将整个天山地区的地震韵律划分为地震世、地震亚世、地震期、地震幕、地震阶五级,探讨了各级韵律的特征。估计了我国天山地区未来地震活动趋势。 相似文献
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概述了2002年7月23日南黄海Ms4.9地震的地震参数、地震影响、地震应急、地震预测，以及震源区地质构造及历史地震等情况。 相似文献
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地震目录是地震学中最基础的资料,具有丰富的地震信息,它不仅被用于地球内部构造和地震地质的研究,在地震活动性研究、地震预报研究、地震危险性分析和震害损失预测研究中也被广泛使用。同时地震目录还是编制地震烈度区划图的主要信息源及国民经济建设和国土开发的重要基础资料。因此,编制地震目录受到地震科技工作者的高度重视。 １ 新疆地震目录点析新疆是我国多震省区,地震强度大,频度高,地震信息丰富。自１９７０年新疆组建地震机构以来,在地震目录的编制上投入了大量的人力和物力,先后编撰出版了下列地震目录。（１）《地震… 相似文献
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随着社会及学科的发展,越来越多的地震知识应用于社会领域,对社会的发展具有极大的促进作用,为此有必要进一步探讨地震科学的影响。从地震预报、工程地震、震害预测、震灾评估、地震宣传和地震速报与应急等方面讨论了地震科学对社会发展的影响。结果表明,地震科学具有重要手社会价值和广泛的应用前景。在此基础上,提出应进一步加强地震震源、地球内部结构和地震预报等学科的研究,并展望了共应用前景。 相似文献
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从分析地震活动性参数变化特征的角度出发,结合实际的地震活动观测资料,对张北６．２级地震前河北省及邻区地震活动性参数的变化,地震序列的衰减特征进行了分析,结果表明张北６．２级地震前在震源区附近１００ｋｍ和大范围地震活动性参数有长、中、短期的异常变化。张北６．２级地震强余震前地震活动性参数有短、临变化。 相似文献
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《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
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新生代火山岩中的幔源包体可以提供有关上地幔的直接信息。通过对采自甘肃宕昌县好梯乡的幔源橄榄岩包体的详细研究 ,探讨该地区上地幔的热结构和流变学特征 ,并与华北地区进行对比。研究结果表明 ,该区自壳幔边界以下至 75km深处的上地幔主要由尖晶石二辉橄榄岩组成 ,75km以下则主要由石榴石二辉橄榄岩组成 ,方辉橄榄岩只占少数 ;与华北地区没有明显的差异。由包体平衡温度、压力建立的上地幔地温线低于华北地区地温线 ;确定的壳幔边界在 5 2km左右 ,莫霍界面附近为下地壳物质与尖晶石二辉橄榄岩的过渡带 ;岩石圈底界深度约为 12 0km左右。根据包体的研究结果建立了研究区上地幔的差异应力、应变速率和等效黏滞度剖面。结果表明 ,该区新生代时期存在软流层的底辟 ,以及相应的岩石圈的减薄 ,但其规模明显小于华北地区。这些结果表明该区处在中国东部大陆裂谷带和中国中部克拉通块体群的过渡带 相似文献
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The results of observations of disturbances in the lower and middle ionosphere and in the geomagnetic field accompanying the partial solar eclipse over Kharkov are presented. The ionospheric effects have been studied with the use of an ionosonde and measurements of the phase and amplitude of a radio signal with a frequency of 66.(6) kHz on the Moscow–Kharkov route, and the effects in the magnetic field have been analyzed with the help of a magnetometer–fluxmeter in the range of periods from 1 to 1000 s. Disturbances in both the lower and middle ionosphere, as well as in the geomagnetic field, have been detected. The observation results have been compared with the results of a simulation of physical processes accompanying the solar eclipse. A good agreement has been found between observational and modeling results. 相似文献
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Drop calorimetry measurements between 900 and 1850 K are reported for amorphous anorthite, andesine, wollastonite, diopside, cordierite and pyrope. The isobaric heat capacities of the glassy and liquid phases of these materials, and the enthalpies of fusion of the minerals have been derived. The calorimetric entropies of fusion of these substances and of other oxide minerals are generally consistent with the calculated volume changes on melting and with the observed pressure dependences of the melting points. The thermodynamics of mixing of liquid plagioclases have been examined, and it is concluded that their enthalpies of mixing are markedly different from the values derived directly from solution calorimetry measurements at 985 K. 相似文献
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Art Raiche 《Surveys in Geophysics》1994,15(2):159-207
Researchers in the field of electromagnetic modelling and inversion have taken advantage of the impressive improvements of new computer hardware to explore exciting new initiatives and solid extensions of older ideas. Finite-difference time-stepping methods have been successfully applied to full-domain 3D models. Another new method combines time-stepping with spatial frequency solutions. The 2D model 3D source (2.5D) problem is also receiving fresh attention both for continental and sea floor applications.The 3D inversion problem is being attacked by several researchers using distorted Born approximation methods. Q-domain inversions using transformation to pseudo-wave field and travel time tomography have also been successfully tested for low contrast problems. Subspace methods have been successful in dramatically reducing the computational burden of the under-determined style of inversion. Static magnetic field interpretation methods are proving useful for delineating the position of closely-spaced multiple targets.Novel (appeals to nature) methods are also being investigated. Neural net algorithms have been tested for determining the depth and offset of buried pipes from EM ellipticity data. Genetic algorithms and simulated annealing have been tested for extremal model construction.The failure of researchers to take adequate account of the properties of the mathematical transformation from algorithms to the number domain represented by the computing process remains a major stumbling block. Structured programming, functional languages, and other software tools and methods are presented as an essential part of the serial process leading from EM theory to geological interpretation. 相似文献
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D. E. Teterin 《Izvestiya Physics of the Solid Earth》2011,47(8):653-668
In 1994–2006, the German research vessel, Polarstern, and the Russian research vessel, Akademik Boris Petrov, carried out marine geologic and geophysical explorations in the Western Antarctic Region within the Bellingshausen, Amundsen,
and Scotia marginal Seas and the Drake Passage. In these expeditions, new unique data on submarine topography have been collected
by a multibeam echosounder, gravity and magnetic measurements have been carried out, multichannel seismic profiling has been
performed, and the collections of rock samples have been acquired. The analysis and interpretation of new evidence together
with previous geologic and geophysical data for the Drake Passage region have shown that end of spreading in the Aluk Ridge
three million years ago resulted in the redistribution of stresses associated with the relative motion of the Antarctic, Scotia,
and Phoenix Plates, which, in turn, caused significant tectonic reconstruction of the entire transition zone of the Drake
Passage. 相似文献
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L. P. Babich A. Yu. Kudryavtsev M. L. Kudryavtseva I. M. Kutsyk 《Geomagnetism and Aeronomy》2008,48(3):378-391
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
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M. Ciccotti N. Negri L. Sassi G. Gonzato F. Mulargia 《Journal of Volcanology and Geothermal Research》2000,98(1-4)
The results of a series of experiments aimed at characterizing the elastic and failure parameters of lava specimens from Mount Etna, Vulcano and Stromboli volcanos is presented. The double torsion—constant configuration—load relaxation method has been employed to obtain the behavior of the stress intensity factor versus mode I subcritical crack velocity. The experimental technique has been optimized in several respects. First, a very stiff machine, expressly designed and built, has been used. Second, all samples have been carefully machined to low tolerance. Third, the experimental conditions have been carefully controlled, with temperature variations within 1°C and humidity within 10%. Fourth, high resolution electronic measuring systems have been used together with a pulse stacking procedure. Fifth, the length of the prefracture has been optically checked. This optimization allowed us to measure the slope of the subcritical fracture propagation curve in the III region, which extends from velocities of 10−7 m/s to catastrophic, with a standard deviation around 20%, suggesting that the results can be effectively used for modeling purposes. As a by-product, we could measure the elastic parameters with an accuracy of a few percent. 相似文献
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Zili Fan Xuncheng Xia Yuling Shen Kurban Alishir Ranghui Wang Shengyu Li Yingjun Ma 《中国科学D辑(英文版)》2002,45(1):102-108
Because of the human exploitation and utilization of water resources in the Tarim Basin, the water resources consumption has changed from mainly natural ecosystem to artificial oasis ecosystem, and the environment has changed correspondingly. The basic changes are: desertification and oasis development coexist, both “the human being advance and the desert retreat” and “the desert advance and the human being retreat” coexist, but the latter is dominant. In the upper reaches, water volume drawing to irrigated agricultural areas has increased, artificial oases have been enlarging and moving from the deltas in the lower reaches of many rivers to the piedmont plains. In the middle and lower reaches of the Tarim River, the stream flow has decreased, old oases have declined, natural vegetations have been degenerating, desertification has been enlarging, and the environment has deteriorated. The transition regions, which consist of forestlands, grasslands and waters between the desert and the oases, have been decreasing continuously, their shelter function to the oases has been weakened, and the desert is threatening the oases seriously. 相似文献