Time variation of earthquake activity in the Balkan region     

Vít Kárník  Cornel Radu  Reviewer J. Buben 《Studia Geophysica et Geodaetica》1977,21(3-4):285-293

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   

Dynamic loading of the boundaries in the finite-difference study of diffraction     

Jiří Zahradník  Reviewer J. Vaněk 《Studia Geophysica et Geodaetica》1977,21(3-4):255-259

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   

Mechanism of solar-terrestrial relations and changes of atmospheric circulation     

Václav Bucha  Reviewer F. Rein  Reviewer J. Bochníček 《Studia Geophysica et Geodaetica》1977,21(3-4):350-360

Summary As a result of investigating the relations between the variations of geomagnetic activity and meteorological factors [1, 2] a mechanism of solar-terrestrial relationships and a model of the changes of atmospheric circulation in the Northern Hemisphere are proposed; this provides an explanation of the causes of the fluctuation of the climate, of dry and cold periods and differing vegetation conditions in various years in dependence on the intensity of geomagnetic activity.  相似文献   

On one generalization of trochoidal waves     

Dagmar Novotná  Vojtěch Vítek  Reviewer O. Zikmunda 《Studia Geophysica et Geodaetica》1977,21(1):81-84

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   

Secondary vorticity centres as centres of secondary (streamwise) vorticity     

Pavla Kočíková  Reviewer O. Zikmunda 《Studia Geophysica et Geodaetica》1977,21(2):185-194

Summary The theory of secondary vorticity is used to explain the essence of so-called secondary or upper vorticity centres, discovered on satellite photographs. The general equation of vorticity, which is then adjusted by means of the equations of state and motion, is transformed into a specially selected intrinsic co-ordinate system. Three-component equations of vorticity are discussed for cases important meteorologically. The conclusion could be drawn that the secondary vorticity centres may be identified with centres of so-called secondary vorticity and that the theoretical facts about their origin and occurrence may be used, together with satellite photographs, to improve weather forecasts.  相似文献   

Radiocarbon dates and late-Quaternary stratigraphy from Mamontova Gora,unglaciated central Yakutia,Siberia, U.S.S.R.     

Troy L. Péwé  André Journaux  Robert Stuckenrath 《Quaternary Research》1977,8(1):51-63

A fine exposure of perennially frozen ice-rich silt and associated flora and vertebrate fauna of late-Quaternary age exists at Mamontova Gora along the Aldan River in central Yakutia, Siberia, U.S.S.R. The silt deposit caps a 50-m-high terrace and consists of three units. An upper layer 1–2 m thick overlies a 10–15-m-thick brownish to black silt layer. The lower silt layer is greenish to gray and about 15 m thick. All the silt is well sorted with 60% of the particles falling between 0.005 and 0.5 mm in diameter and is generally chemically and mineralogically homogeneous. The middle unit contains may extinct vertebrate mammal remains and ice wedges. The lower unit contains little vegetation and no ice wedges. The silt is widespread and exists as a loamy blanket on terraces at various elevations on both sides of the lower Aldan River. The origin of the silt blanket of late-Quaternary age in central Yakutia has long been controversial. Various hypotheses have been suggested, including lacustrine and alluvial, as well as frost-action origins. It is sometimes referred to as loess-like loam. Péwé believes the silt at Mamontova Gora is loess, some of which has been retransported very short distances by water. The silt probably was blown from wide, braided, unvegetated flood plains of rivers draining nearby glaciers. The silt deposits are late Quaternary in age and probably associated with the Maximum glaciation (Samarov) and Sartan and Syryan glaciations of Wisconsinan age. On the basis of biostratigraphy, 10 radiocarbon dates, and their relation to the nearby glacial record, it is felt that the upper unit at Mamontova Gora is Holocene and the middle unit is Wisconsinan. The youngest date available from the middle unit at this particular location is 26,000 years. Dates greater than 56,000 years were obtained in the lower part of the middle unit. The lower unit is definitely beyond the range of radiocarbon dating and probably is older than the last interglacial. The sediment, fauna, ice wedges, stratigraphy, and age of perennially frozen slit deposits in central Alaska are remarkably similar to those of the deposits exposed in central Yakutia. Both areas consist of unglaciated rolling lowlands and river terraces surrounded by high mountains that were extensively glaciated in Pleistocene time. The glaciers extended from the high mountains to the edges of the ranges. In both regions, extensively braided, silt-charged rivers drained the mountains and flowed through the lowlands on their way to the sea. It follows that there should be a similar late-Quaternary history.  相似文献   

Frequency limitation to the theoretical investigation of the transmission of hm waves through the ionosphere     

Josef Bochníček  Reviewer M. Hvoždara 《Studia Geophysica et Geodaetica》1974,18(4):405-408

Summary As a result of investigating the energy flow, transmitted by short-period HM waves, the existence of a frequency limitation was found at the theoretical investigation of the propagation of these HM waves.  相似文献   

A note on the equatorial anticyclogenesis     

Vojtěch Vítek  Rewiever O. Zikmunda 《Studia Geophysica et Geodaetica》1974,18(1):83-84

Summary The formative stage of low-latitude anticyclones is studied in terms of the simplified divergence theorem and vorticity equation.  相似文献   

The problem of the system of height reference in determining the settling of foundations and buildings     

Peter Marčák  Lubomír Kubáček  Reviewer J. Kašpar 《Studia Geophysica et Geodaetica》1974,18(1):33-46

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On the possibilities of studying impulsive elastic waves in an inhomogeneous medium by the finite difference method     

Jiří Zahradník  Reviewer J. Vaněk 《Studia Geophysica et Geodaetica》1974,18(4):339-358

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