包头6.4级地震前后地下水位固体潮加卸载响应比的变化     

张昭栋  刘庆国  魏焕  耿杰  王忠民 《高原地震》1998,(4)

将加卸载响应比的理论和方法引入到地下水位潮汐资料计算中来,从岩石的应变与应力的非线性响应分析了井水位固体潮加卸载响应比的物理机理,从理论上论证可以应用地下水位观测资料来计算加卸载响应比,并研究出利用地下水位对固体潮响应来计算加卸载响应比的方法。经此方法计算了河北省万全、昌黎和河间３口水井多年的Ｂ井水位的固体潮加卸载响应比,分析了１９９６年包头６．４级地震前后地下水位固体潮加卸载响应比的变化特征。  相似文献   

技术方法的进步与地球科学的发展     

丁悌平 《地学前缘》1998,5(1):9-15

地球科学作为自然科学的一大门类,其发展速度十分惊人。地球科学的迅速发展一方面反映了人类生产的发展对资源和环境方面愈来愈高的要求,一方面得益于科学技术的普遍发展为地球科学研究提供的越来越有利的条件。关于技术方法对地球科学研究的推动作用,人们早有认识,而现在更为深刻。当今对地球科学研究影响最大的关键技术,包括空间技术,深部探测技术,高新分析测试技术和数据综合分析技术,均来源于现代科学技术的最新发展。为了推动地球科学研究,不但要注意引进各种高新技术,还要注意将这些技术与地学研究相结合,发展和创造适合于地学研究的高新技术,并善于综合应用它们,使它们在地学研究中发挥最有效的作用。  相似文献   

Inversion of free oscillation data for an elliptical rotating earth in source moment tensor studies     

Jorge A. Mendiguren 《Pure and Applied Geophysics》1980,118(2):1192-1208

It is shown, through numerical experiments, that the effect of ignoring ellipticity and rotation of the earth when inverting free oscillation data in moment tensor studies, is to introduce spurious spectral components in the solution. For numerical simulation of the data conditions of the 1970 deep Colombian event the spurious part has isotropic and deviatoric components, besides a distortion in the phase spectra which may lead to artificial precursive source in the solution. The magnitude of the artificial isotropic component is of the order of 10% of the real source moment tensor, depending on the data set used in the inversion. Measuring the excitation of each mode at each station using the technique of integrating over the spectral peaks does not cancel completely the effect of multiplet splitting, in particular that splitting due to rotation of the earth. The effect of lateral heterogeneities was simulated by introducing arbitrary splitting parameters which produced scattering in the eigenperiods compatible with those observed. For that splitting the inversion rendered additional isotropic components.We conclude that the observed implosive precursor the the 1970 Colombian event could have been artificially introduced by ignoring rotation, ellipticity and lateral heterogeneities of the earth.A procedure to invert free oscillation data for an elliptical rotating earth is proposed. It could be applied to a laterally inhomogeneous earth if the excitation for that model could be computed. Its application to real data for the deep Colombian event indicates that we will need to improve our knowledge on the effect of rotation, ellipticity, lateral heterogeneities and anelasticity on free oscillation and their excitation in order to solve accurately for the six components of the moment tensor independently.  相似文献   

本世纪青藏高原气候的三次突变及与天文因素的相关   总被引：39，自引：9，他引：30  

汤懋苍  白重瑗 《高原气象》1998,17(3):250-257

用给出了的划分气候阶段的标准对本世纪高原的气温,降水和季风的阶段性变化进行了分析,发现本世纪高原气候在２０年代初,５０－６０年代和８０年代初发生了三次突变,与北半球的气候变化一致。高原气温突长数年后我国和北半球温度突升,接着高原季节增强,高原“季风多雨区”变温,“季风少雨区”变干,反之则相反,进一步分析表明,地球自转速度和太阳黑子周期长度的变化对高原及北半球本世纪气候的突变和阶段性变化起着重要的作  相似文献   

Antarctic dry valleys: Microclimate zonation, variable geomorphic processes, and implications for assessing climate change on Mars     

David R. Marchant  James W. Head III 《Icarus》2007,192(1):187-222

The Antarctic Dry Valleys (ADV) are generally classified as a hyper-arid, cold-polar desert. The region has long been considered an important terrestrial analog for Mars because of its generally cold and dry climate and because it contains a suite of landforms at macro-, meso-, and microscales that closely resemble those occurring on the martian surface. The extreme hyperaridity of both Mars and the ADV has focused attention on the importance of salts and brines on soil development, phase transitions from liquid water to water ice, and ultimately, on process geomorphology and landscape evolution at a range of scales on both planets. The ADV can be subdivided into three microclimate zones: a coastal thaw zone, an inland mixed zone, and a stable upland zone; zones are defined on the basis of summertime measurements of atmospheric temperature, soil moisture, and relative humidity. Subtle variations in these climate parameters result in considerable differences in the distribution and morphology of: (1) macroscale features (e.g., slopes and gullies); (2) mesoscale features (e.g., polygons, including ice-wedge, sand-wedge, and sublimation-type polygons, as well as viscous-flow features, including solifluction lobes, gelifluction lobes, and debris-covered glaciers); and (3) microscale features (e.g., rock-weathering processes/features, including salt weathering, wind erosion, and surface pitting). Equilibrium landforms are those features that formed in balance with environmental conditions within fixed microclimate zones. Some equilibrium landforms, such as sublimation polygons, indicate the presence of extensive near-surface ice; identification of similar landforms on Mars may also provide a basis for detecting the location of shallow ice. Landforms that today appear in disequilibrium with local microclimate conditions in the ADV signify past and/or ongoing shifts in climate zonation; understanding these shifts is assisting in the documentation of the climate record for the ADV. A similar type of landform analysis can be applied to the surface of Mars where analogous microclimates and equilibrium landforms occur (1) in a variety of local environments, (2) in different latitudinal bands, and (3) in units of different ages. Documenting the nature and evolution of the ADV microclimate zones and their associated geomorphic processes is helping to provide a quantitative framework for assessing the evolution of climate on Mars.  相似文献   

The theory of the nutation for the rigid earth model at the second order   总被引：6，自引：0，他引：6  

Hiroshi Kinoshita  Jean Souchay 《Celestial Mechanics and Dynamical Astronomy》1990,48(3):187-265

We perform a complete reconstruction of the series of the nutation for a rigid Earth model with the use of the very accurate theories ELP2000 and VSOP82 for the motion of the Moon and the planets respectively, in such a way that all the individual contributions up to 0.005 mas should be taken. This implies the introduction of the planetary effects, of the influence of second-order parts of the potential of the Earth (J3, triaxiality), and some improvements due to an extension of the theory at the second order. All this increase notably the number of coefficients to be taken in account, and modifies also in a significant way the value of some of them.  相似文献   

A New Protocol for the Astrometric Follow-up of Near Earth Asteroids     

A. Boattini  G. D’Abramo  G. B. Valsecchi  A. Carusi 《Earth, Moon, and Planets》2007,100(1-2):31-41

A new protocol was devised to improve the efficiency of astrometric follow-up observations of Near Earth Asteroids for the accurate determination of their orbits. It was implemented in the activities of the Spaceguard Central Node (SCN, a facility of the Spaceguard Foundation, established with the support of the European Space Agency) in the form of a Priority List. Here we describe this protocol and results obtained during five years of activity (2000–2004).  相似文献   

形变地球对不同驱动力的响应     

张捍卫  铁琼仙  杨磊 《天文学报》2007,48(4):449-455

地球形变位移场和重力场的时空变化无论在基础理论研究,还是在地理空间信息建设中都具有重要的意义.地球在各种力学机制的作用下产生了形变,形变又导致地球引力位的变化,即形变附加位或Euler引力位增量.基于矢量球函数的基本理论,讨论了引潮力、负载力和地表应力对地球形变和引力位增量的影响,给出了均匀不可压缩地球模型的Euler引力位增量的具体表达式和Love数的理论关系.可为地球形变的理论研究提供参考和依据.  相似文献   

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杨兆  孙和平  雷湘鄂 《大地测量与地球动力学》2007,27(4):38-43

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The fortnightly and monthly zonal tides in the Earth's rotation from 1962 to 1988     

J. Hefty  N. Capitaine 《Geophysical Journal International》1990,103(1):219-231

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