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991.
Alexander Roglinov Ludmil Christoskov Reviewer J. Vaněk 《Studia Geophysica et Geodaetica》1977,21(1):11-18
Summary Aki's spectral 2 model[1] is used to estimate the amplitude field at epicentral distances up to 1000 km in the case of an absorption coefficient of seismic waves which varies with distance. Velocity spectra, the periods of the maximum of these spectra and the maximum velocity amplitudes are obtained. The results are compared with[2] and it is shown that the divergence of the amplitude field decreases if a variable absorption coefficient is used. The theoretical results, obtained in this case, approach the results seen in practice. The possibility of determining the limits of epicentral distances, at which the amplitude field may be considered as linear, is given. 相似文献
992.
Summary Three quantities M, E
1/2
and E
2/3
are used for studying the Balkan earthquake provinces. Most of them show a regular trend of activity, for some of them the observation period of 70 years is too short. Some graphs give evidence of the coincidence or migration of activity. 相似文献
993.
Karel Pěč Jana Pěčová Oldřich Praus Reviewer M. Hvoždara 《Studia Geophysica et Geodaetica》1977,21(3-4):383-393
n ¶rt;a, n¶rt;mau 531 au ¶rt; u aum m u¶rt;uu n mumu ana¶rt;, ¶rt; u -m n, aauum ¶rt;um u u amuaa n¶rt;naa ma ua aama. uu nmam an¶rt;u ¶rt; u aum aam ¶rt;au cuu uP
n
m
, n¶rt;am mn n=1, 2, 3 u 5 (m n). u uua ¶rt;a¶rt;amu uu n¶rt;mauu uum au (a. 1) u u n aumam uu nmu, m n¶rt;mam u¶rt; am uuu ¶rt; u aum (u. 1–4). annuau 2
u 5
mn nm ma am mmmu m (u. 5, 6). ama uuu u m aam amu uu uma. 相似文献
994.
Summary The finite-difference method can be used for obtaining the theoretical seismic response of a block structure to an incident plane wave. Computer time is saved by solving an equivalent problem of dynamic loading of the boundary of the block structure. The loading is performed by means of a set of discrete body forces, replacing the incident wave at the interface. 相似文献
995.
Summary The concept of the generalized trochoidal waves discussed in[1] is revised and modified. A new formula defining the auxiliary function (b, c) was found with the aid of the results derived in[3] and some physical considerations. 相似文献
996.
Summary The motion of a non-viscous liquid medium with an ideal electrical conductivity, enclosed in the ellipsoidal cavity of an envelope subject to precessional motion, is investigated. Inside the cavity there is a toroidal magnetic field. It is proved that the precessional motion of the envelope generates forced oscillations of the medium with a period of 24 hours and two different types of eigen oscillations. Expressions for computing the amplitudes and frequencies of all types of oscillations are derived. The maximum values of disturbance fields are determined for geophysically acceptable parameters. 相似文献
997.
R.W. Van Bemmelen 《Tectonophysics》1977,39(4):T13-T19
The kinematics and mechanics of the seismicity of the Friuli area in northeastern Italy are discussed, especially the focal mechanism of the catastrophic earthquake of May 6, 1976. Alternative solutions are analyzed. A N-S section, down to 60 km below sea-level, across the Alps from the Bavarian foreland to the Adriatic Sea illustrates these possibilities. 相似文献
998.
Twenty-nine Rb-Sr whole-rock isotopic analyses and three U-Pb zircon analyses on foliated granites and largely unfoliated charnockitic rocks indicate that the central part of the Pan-African belt in west Africa was characterised by intense orogenic plutonism. These data and Rb-Sr analyses on muscovite books from late cross-cutting pegmatites indicate that the peak of magmatic activity occurred 610 ± 10 m.y. ago.Initial 87Sr/86Sr ratios for the granitic and charnockitic rocks are in the range 0.7065–0.7125, and indicate a significantly older crustal component in the magmas. 相似文献
999.
Summary The formative stage of low-latitude anticyclones is studied in terms of the simplified divergence theorem and vorticity equation. 相似文献
1000.