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991.
U. Raval 《Pure and Applied Geophysics》1995,145(1):175-192
Recent findings on the Meso-Cenozoic tectonomagmatism and deep-seated anomalous geophysical structures suggest a close linkage between the seismicity of the Koyna region, the Westernghat uplift (WG-U) and associated thermomechanical and fluid activities. The WG-U seems to be the result of late Cretaceous thermal mobilization, erosion of the Deccan trap cover and superposition of compressional stress. The association of seismicity with uplift seems to result from movement of deep-seated heat and fluids/volatiles along the edges (or boundary faults) of the uplift; because the force required for crustal deformation depends on the relief. Observed gradients in relief may be attributed to the differential erosion-rates and heat inputs, due to the time gap of 50 Ma in the break-ups and plume activities on the eastern and western sides and consequence magmatism. Further, the geology and tectonics strongly indicate that the western margin (WM) is a relic of a mobile arm (MA), that included Madagascar, and which formed a part of the Proterozoic mobile belt of greater India (fort>85 Ma). The mobile nature of the WM facilitates mantle upwellings and transient elevation of isotherms at depth, raising the possibility of intermittent metamorphism and greater deformation.Superposition of the ongoing compression and uplift-induced forces make local permeability and pore-fluid pressure vital in triggering the seismic slip over the Peninsular shield. Certain representative model calculations have been carried out to estimate change in the e.m. induction characteristics caused by an intermittent hydraulic connectivity. The results show a drop in the resistivity which could be a useful monitoring index. The close connection of uplift and fluid activity as discussed here seems applicable for other active parts of the South Indian Shield (SIS) also. 相似文献
992.
U. Wegener 《洁净——土壤、空气、水》1983,11(3):279-293
Prerequisite to the nitrogen leaching from agricultural soils in spring is the ecologically optimum control of the first nitrogen fertilizer application. On the basis of investigations having been carried out for some years, a method for determining the optimum time of fertilization with the aid of phenological data is presented. The blossoming data of Anemone nemorosa proved to be a suitable sensitive indicator, their onset of blossoming is the optimum time for the first nitrogen application. In dependence on the height and variation of weather, in the subdued mountains this time is 90 … 116 d after the beginning of the year and corresponds to a temperaturetotal ≥ 5°C of 80 … 120°C or > 0°C: 160 … 230°C. Possibly, the leaf development of Alchemilla vulgaris or the first development of Poa pratensis are suitable as other bioindicators. The boundary conditions and disturbance variables of the bioindication are discussed. By the phenological date-determination of the beginning of fertilization the nitrogen losses can be reduced by 10 … 20% and the nitrate leaching can be considerably reduced especially in drinking-water protection areas. 相似文献
993.
The radial optical depth profile of the Encke ringlet obtained by the occultation experiment of the Voyager photopolarimeter (PPS data) is explained to be caused by the gravitational action of the recently discovered stallite 1981 S13 and a second smaller moonlet orbiting near one of its either libration points — L4 or L5. To this aim the results of previous and new numerical particle simulations as well as an extension of the scattering theory concerning a single moonlet to a pair of satellites have been used leading to a triple-peaked ringlet near the orbits of the moonlets. The width and the shape of that ringlet and its separate peaks depend on the mass ratio of both moonlets and on their orbital eccentricites. The best resemblance between the PPS data and the theoretical profile is obtained if the mass ratio of the either moonlets takes M2/M1981S13 ≈ (0.8 … 3.0) × 10−2 and the eccentricities hold: e1981S13 < h1981S13; e2 ≈ h2 (the values h are the Hill scales of either moonlets defined by h1981S13/2 ≈ (M1981S13/2/3Mh)1/3, Mh = Saturn mass). Furthermore, our results yield a size of 1981 S13 of < 15 km in diameter. 相似文献
994.
M.?CharilaouEmail author J.?F.?L?ffler A.?U.?Gehring 《Physics and Chemistry of Minerals》2012,39(2):87-92
In this study, we present ac susceptibility measurements for a synthetic and a natural hemo-ilmenite (HI) solid solution (x)FeTiO3–(1 − x)Fe2O3 with compositions x = 0.87(1) and 0.88(8), respectively. The focus of the investigation is the magnetic ordering at the Curie temperature T
C and the spin-glass-like freezing at the freezing temperature T
f. The sharpness of T
C for the synthetic solid solution with well-defined structure indicates the chemical homogeneity of the solution, whereas
the disperse magnetic ordering of the natural solid solution reveals inhomogeneities described as spin glass system ofvariations
in composition x. The frequency dispersion of T
f was determined between 10 Hz and 10 kHz and was found to obey a dynamic scaling power law. The relaxation rates deviate by
five orders of magnitude where the synthetic solid solution exhibits ω0 = 3(1) × 104 Hz and the natural one 5.5 × 109 Hz. The strong deviation is attributed to the difference in the ordered state above T
f. These findings provide an insight into the cooling-rate effects of natural solid solutions and how magnetic thermodynamics
can be used to probe the chemical homogeneity of such systems. 相似文献
995.
996.
In this note we observe that a problem of linear approach to Granger causality testing between CO2 and global temperature is that such tests can have low power. The probability to reject the null hypothesis of non-causality when it is false is low. Regarding non-linear Granger causality, based on multi-layer feed-forward neural network, the analysis provides evidence of significant unidirectional Granger causality from CO2 to global temperature. 相似文献
997.
The exact Bianchi type-VI0 stiff-fluid cosmological model is obtained in the Nordtvedt-Barker general scalar-tensor theory of gravitation. Some properties of the model are discussed. 相似文献
998.
199年至1998年伽师地区共出现9次震级为6.1-6.8级的强震. 在一个非常短的时间间隔内和非常小的地区范围内接连出现这么多次震级非常接近的地震,确实非常罕见. 为研究伽师强震区的深部构造背景和孕震机制,本文对伽师地震区的余震观测资料进行了分析处理. 利用联合反演技术同时得到了地震震源位置和地震区地壳三维速度结构. 余震震中沿一北北东向条带分布,与强震分布的两个条带中的北东向条带位置基本重合. 三维反演得到的速度结构结果表明,在地下12 km以下存在一条北北东向和一条北北西向的低速条带. 上述两低速条带与强震分布的两个条带位置很接近. 初步推测,低速条带对应了地壳深部的两条断裂. 在我们观测期间,北北东向断裂有微震活动,北北西向断裂相对平静. 相似文献
999.
K. Shanthi V. U. M. Rao D. R. K. Reddy R. Venkateswarlu 《Astrophysics and Space Science》1991,175(2):241-245
Spatially-homogeneous and anisotropic-vacuum Bianchi type-III cosmological models are obtained in scalar-tensor theories of gravitation proposed by Ross and Dunn. Some physical properties of the models are also discussed. 相似文献
1000.
S. Yu. Gorda Yu. Yu. Balega E. A. Pluzhnik Z. U. Shkhagosheva 《Astrophysical Bulletin》2007,62(4):352-359
A complete set of parameters of the apparent relative orbit of the third body in the SZ Cam system is determined for the first time based on new speckle-interferometric and photometric observations of the eclipsing binary SZ Cam made with the 6-m telescope of the Special Astrophysical Observatory of the Russian Academy of Sciences and 0.5-m telescope of the Astronomical Observatory of Ural State University and published data. The mass of the third body and the distance to SZ Cam are estimated at M 3 = 23.4M ⊙ and d = 1125 kpc, respectively. The binary nature of the third body is confirmed. It is suggested that SZ Cam is possibly not a member of the open star cluster NGC 1502 onto whose center it projects. A total of 16 new times of minima of SZ Cam are reported. 相似文献