Tidal deformations of viscoelastic body     

Jiří Trešl  Reviewer Z. Šimon 《Studia Geophysica et Geodaetica》1988,32(1):24-31

Summary The tidal deformations of a viscoelastic body are studied using the simple Kelvin-Voigt model. Expressions for the phase lag and amplitude change of the displacement vector are derived. The energy dissipation rate is calculated for the main disturbing bodies and for diurnal and semidiurnal tidal waves.

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am nuu ¶rt;auu n ma ua-ma. ¶rt; au ¶rt; ana¶rt;au a u uu anum¶rt; ma u. aumaa m ¶rt;uunauu uu ¶rt; u a a m u nm .

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The Fourier Integral Method: An efficient spectral method for simulation of random fields   总被引：4，自引：0，他引：4  

E. Pardo-Igúzquiza  M. Chica-Olmo 《Mathematical Geology》1993,25(2):177-217

The Fourier Integral Method (FIM) of spectral simulation, adapted to generate realizations of a random function in one, two, or three dimensions, is shown to be an efficient technique of non-conditional geostatistical simulation. The main contribution is the use of the fast Fourier transform for both numerical calculus of the density spectral function and as generator of random finite multidimensional sequences with imposed covariance. Results obtained with the FIM are compared with those obtained by other classic methods: Shinozuka and Jan Method in 1D and Turning Bands Method in 2D and 3D, the points for and against different methodologies are discussed. Moreover, with the FIM the simulation of nested structures, one of which can be a nugget effect and the simulation of both zonal and geometric anisotropy is straightforward. All steps taken to implement the FIM methodology are discussed.  相似文献   

Dynamic faulting under rate-dependent friction   总被引：2，自引：0，他引：2  

Alain Cochard  Raúl Madariaga 《Pure and Applied Geophysics》1994,142(3-4):419-445

We discuss the effects of rate-dependent friction on the propagation of seismic rupture on active faults. Several physicists using Burridge and Knopoff's box and spring model of faulting have proposed that fault complexity may arise from the spontaneous development of a self-similar stress distribution on the fault plane. If this model proves to be correct, it has important consequences for the origin of the complexity of seismic sources. In order to test these ideas on a more realistic earthquake model, we developed a new boundary integral equation method for studying rupture propagation along an antiplane fault in the presence of nonlinear rate-dependent friction. We study rupture dynamics of models with single and twin asperities. In our models, asperities are places on the fault with a higher value of prestress. Othewise all fault parameters are homogeneous. We show that for models with such asperities, a slip velocity weakening friction leads to the propagation of supersonic healing phases and to the spontaneous arrest of fracture if the prestress outside the asperities is low enough. For models with asperities, we can also observe narrow slip velocity pulses, qualitatively similar to the so-called Heaton pulses observed in some earthquake accelerograms. We also observe a complex distribution of stress after the rupture that depends on details of the initial distribution of asperities and on the details of the friction law.  相似文献   

Seismic activity related to the 1991 eruption of Colima Volcano,Mexico     

Francisco Núñez-Cornú  F. Alejandro Nava  Servando De la Cruz-Reyna  Zenón Jiménez  Carmen Valencia  Rosalía García-Arthur 《Bulletin of Volcanology》1994,56(3):228-237

Ten years after the last effusive eruption and at least 15 years of seismic quiescence, volcanic seismic activity started at Colima volcano on 14 February 1991, with a seismic crisis which reached counts of more than 100 per day and showed a diversity of earthquake types. Four other distinct seismic crises followed, before a mild effusive eruption in April 1991. The second crisis preceded the extrusion of an andesitic scoriaceous lava lobe, first reported on 1 March; during this crisis an interesting temporary concentration of seismic foci below the crater was observed shortly before the extrusion was detected. The third crisis was constituted by shallow seismicity, featuring possible mild degassing explosion-induced activity in the form of hiccups (episodes of simple wavelets that repeat with diminishing amplitude), and accompanied by increased fumarolic activity. The growth of the new lava dome was accompanied by changing seismicity. On 16 April during the fifth crisis which consisted of some relatively large, shallow, volcanic earthquakes and numerous avalanches of older dome material, part of the newly extruded dome, which had grown towards the edge of the old dome, collapsed, producing the largest avalanches and ash flows. Afterwards, block lava began to flow slowly along the SW flank of the volcano, generating frequent small incandescent avalanches. The seismicity associated with the stages of this eruptive activity shows some interesting features: most earthquake foci were located north of the summit, some of them relatively deep (7–11 km below the summit level), underneath the saddle between the Colima and the older Nevado volcanoes. An apparently seismic quiet region appears between 4 and 7 km below the summit level. In June, harmonic tremors were detected for the first time, but no changes in the eruptive activity could be correlated with them. After June, the seismicity decreasing trend was established, and the effusive activity stopped on September 1991.  相似文献   

A continuous kinematic model of plate-tectonic motions     

David Bercovici  Pål Wessel 《Geophysical Journal International》1994,119(2):595-610

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福建滨海木麻黄林下土壤性质的变化及其对林带更新的影响   总被引：4，自引：0，他引：4  

郑达贤  沙济琴 《地理学报》1994,(4)

研究了福建滨海沙地木麻黄防护林Ｍｏ的生物地球化学循环特征和林下土壤ｐＨ的变化，发现因Ｍｏ的生物地球化学循环不平衡引起的土壤微量元素Ｍｏ的耗竭和土壤的酸化是木麻黄林早衰和迹地更新生长不良的重要原因。提出了相应的对策建议。  相似文献   

煤矿地质信息系统     

门桂珍  萨贤春等 《煤田地质与勘探》1994,22(2):32-37

介绍了煤矿地质信息、系统的构成、各模块的性能、功能、自动绘图中各个技术难点的解决方法和途径以及系统的运行环境。该系统是地质测量信息系统中的地质子系统。它是在现有微机环境下开发的集数据管理、统计计算、制表、绘图、辅助决策于一体的计算机地质信息管理系统。  相似文献   

Annual variation of relationship between global radiation and cloud coverage using METEOSAT images     

Dr. A. Rimóczi-Paál 《Theoretical and Applied Climatology》1985,36(1):67-72

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Flocculation of smithsonite and dolomite using polymers containing nitrogen atoms     

A.S. Śláczka  J. Paprotny 《International Journal of Mineral Processing》1985,14(4):319-325

The possibility was investigated of carrying out selective flocculation in the model set smithsonite-dolomite using polymers containing nitrogen atoms, which should interact selectively with zinc minerals.A high activity of flocculants in relation to smithsonite and a low activity towards dolomite was observed. However, the activation of the dolomite surface by Zn²⁺ ions was determined whereby the selective flocculation was not observed in the mixture of smithsonite and dolomite.  相似文献   

Sites occupancy of Fe3+ in Garfield Nontronite: A spectroscopic study     

Dominique Bonnin  Georges Calas  Hélène Suquet  Henri Pezerat 《Physics and Chemistry of Minerals》1985,12(1):55-64

New data on the structure of Garfield nontronite have been produced by the use of different spectroscopic techniques: Mössbauer spectroscopy, optical spectroscopy, X-ray absorption edges and EXAFS and NMR. The tetrahedral iron content is found to be no higher than 1 percent. All iron atoms belong to the octahedral sheet excluding the possibility of the presence of non crystallized phases. Some ambiguities remain about the coherence of the octahedral sheet because of the presence of two doublets in the Mössbauer spectrum and at least two lineshapes in NMR spectra of OH which correspond to different environments.  相似文献