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991.
Seismic moment tensor of Pribaikalye earthquakes from the surface-wave amplitude spectra 总被引:2,自引:0,他引:2
The method of surface-wave amplitude spectra inversion for the seismic moment tensor (SMT) is implemented and tested in the Pribaikalye region. The SMTs are calculated for 39 events with M w = 4.4–6.3, which occurred in the region in 2000–2011. Based on the obtained data, the seismotectionic deformations of the crust are estimated in two seismically active areas-the Northern Pribaikalye and northeastern Baikal rift zone. It is found that on a level of moderate-magnitude events, the region is dominated by the regimes of subhorizontal northwestern extension and strike-slip faulting, which reflects the long-term trends in the stress field of the crust in these parts of the rift. 相似文献
992.
aam mam uu mn¶rt;muaamuu n¶rt; u u nua ua —aam auumu m mnam (200–1000°, 2 10–1 a). aa¶rt;u, m um na¶rt;a uu a n¶rt;u auumu mn¶rt;mu m mnam, u¶rt;m auumu ¶rt;a mn¶rt;mu mnam u n¶rt;m mu mnam uma. 相似文献
993.
Maria Giovanna Durante Luigi Di Sarno George Mylonakis Colin A. Taylor Armando Lucio Simonelli 《地震工程与结构动力学》2016,45(7):1041-1061
An effective way to study the complex seismic soil‐structure interaction phenomena is to investigate the response of physical scaled models in 1‐g or n‐g laboratory devices. The outcomes of an extensive experimental campaign carried out on scaled models by means of the shaking table of the Bristol Laboratory for Advanced Dynamics Engineering, University of Bristol, UK, are discussed in the present paper. The experimental model comprises an oscillator connected to a single or a group of piles embedded in a bi‐layer deposit. Different pile head conditions, that is free head and fixed head, several dynamic properties of the structure, including different masses at the top of the single degree of freedom system, excited by various input motions, e.g. white noise, sinedwells and natural earthquake strong motions recorded in Italy, have been tested. In the present work, the modal dynamic response of the soil–pile–structure system is assessed in terms of period elongation and system damping ratio. Furthermore, the effects of oscillator mass and pile head conditions on soil–pile response have been highlighted, when the harmonic input motions are considered. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
994.
M. N. Berdichevsky N. S. Golubtsova Iv. M. Varentsov P. Yu. Pushkarev A. K. Rybin E. Yu. Sokolova 《Izvestiya Physics of the Solid Earth》2010,46(8):698-706
The paper presents the results of 2D inversion of deep magnetotelluric (MT) and magnetovariational (MV) soundings along the
Naryn Line. The method of partial (sequential) inversions is used. According to this method, at the first stage, magnetovariation
responses are used for the localization of deep anomalies of electrical conductivity, and then the magnetotelluric sounding
data are invoked to refine the structure of the host medium and the structural details in the upper part of the section. It
is shown that this approach enables one to estimate the informativeness of separate components of the electromagnetic field,
to reduce the distorting influence of the near-surface geoelectric inhomogeneities, and to increase the stability of the final
solution of the inverse problem. 相似文献
995.
Grain-size trends, basin subsidence and sediment supply in the Campanian Castlegate Sandstone and equivalent conglomerates of central Utah 总被引:1,自引:1,他引:1
Reconstructions of grain-size trends in alluvial deposits can be used to understand the dominant controls on stratal architecture in a foreland basin. Different initial values of sediment supply, tectonic subsidence and base-level rise are investigated to constrain their influence on stratal geometry using the observed grain-size trends as a proxy of the goodness of fit of the numerical results to the observed data. Detailed measurements of grain-size trends, palaeocurrent indicators, facies and thickness trends, channel geometries and palynological analyses were compiled for the middle Campanian Castlegate Sandstone of the Book Cliffs and its conglomerate units in the Gunnison and Wasatch plateaus of central Utah. They define the initial conditions for a numerical study of the interactions between large-scale foreland basin and small-scale sediment transport processes. From previous studies, the proximal foreland deposits are interpreted as recording a middle Campanian thrusting event along the Sevier orogenic belt, while the stratal architecture in the Book Cliffs region is interpreted to be controlled by eustatic fluctuation with local tectonic influence. Model results of stratal geometry, using a subsidence curve with a maximum rate of ≈45 m Myr?1 for the northern Wasatch Plateau region predict the observed grain-size trends through the northern Book Cliffs. A subsidence curve with a maximum rate of ≈30 m Myr?1 in the Gunnison–Wasatch Plateaus best reproduces the observed grain-size trends in the southern transect through the southern Wasatch Plateau. Eustasy is commonly cited as controlling Castlegate deposition east of the Book Cliffs region. A eustatic rise of 45 m Myr?1 produces grain-size patterns that are similar to the observed, but a rate of eustatic rise based on Haq et al. (1988) will not produce the observed stratal architecture or grain-size trends. Tectonic subsidence alone, or a combined rate of tectonic subsidence and a Haq et al. (1988) eustatic rise, can explain the stratal and grain-size variations in the proximal and downstream regions. 相似文献
996.
克里雅河下游及圆沙古城脊椎动物考察记录 总被引:1,自引:0,他引:1
克里雅河发源于昆仑山脉,位置在新疆的南部。2001年10月18-11月22日,中法联合考察队对克里雅河下游进行了深入的调查。根据标本采集与资料统计,克里雅河流域的野生脊椎动物约有98种(包括已绝迹的几种),隶属于5纲,24目,48科。其中,鱼类约4种;两柄类1种;爬行类约4种;鸟类70种;兽类约19种。有一些动物的遗骸发掘自圆沙古城及附近的古墓地。本文探讨了物种绝迹的原因。 相似文献
997.
U. Kastrup N. Deichmann A. Fröhlich D. Giardini 《Geophysical Journal International》2007,169(3):1273-1288
998.
999.
R. P. Malik A. V. Shanwal H. S. Iyer 《Journal of the Indian Society of Remote Sensing》1984,12(2):59-64
Salinity is creating great problems in the Yamuna Alluvial Plain. State Government is taking steps for reclaiming these lands to increase agricultural production. Impeded drainage, excess canal irrigation, topography parent material, shallow depth and bad quality of ground water are the main factors which are responsible for the genesis of saline soils in the alluvial plains of Haryana. On the arial photographs tonal differences on account of salt concentration in the soil are clearly seen. These differences are aslo associated with physiography and soil conditions which can be easily delineated. The information thus; collected can be used for reclamation of saline soils. 相似文献
1000.
S.?PetitEmail author A.?Decarreau F.?Martin R.?Buchet 《Physics and Chemistry of Minerals》2004,31(9):585-592
The aim of this paper is to determine a relationship between the wavenumbers of the first OH-stretching overtones (W2OH) and the wavenumbers of the OH-stretching fundamentals (WOH) to help to interpret the near-infrared (NIR) spectra. The first overtone (2OH) bands appear at wavenumbers less than twice those of the fundamental bands (OH), due to the anharmonic character of vibrations, X = W2OH/2 - WOH, with X being the anharmonicity constant. Talc samples with various crystal chemistries are used to solve the equation and the experimental data are well fitted with X = –85.6 cm–1. As far as the authors are aware, it is the first time that the anharmonicity constant for the OH-stretching vibrations is determined for phyllosilicates. The anharmonicity constant remains almost unchanged for several types of clay samples. Therefore the relation, established from talc samples because their absorption bands are narrow and their wavenumber range of OH vibrations is wide, can be used for any other clay minerals. 相似文献