Observed and calculated short-periodPKIKP/PKP1 amplitude ratio     

Jaromír Janský  Jan Zedník  Reviewer J. Zahradník 《Studia Geophysica et Geodaetica》1989,33(1):22-28

Summary The ratio of short-period PKIKP and PKP1 amplitudes of deep earthquakes in the Tonga region observed at the seismological station KHC is compared with the theoretical ratio computed for the probable geometry of the Tonga subduction zone and the Preliminary Reference Earth Model. Quantitatively good agreement of observed and calculated values was attained. The influence of the period of the signal and of a broad range of the source parameter rake on the calculated PKIKP/PKP1 amplitude ratio is investigated.

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Резюме С?rt;елaно срaвненuе оmнощенuŭ aмnлumу?rt; короmкоnерuо?rt;ных волн PKIKP u PKP1 оm лубокuх землеmрясенuŭ Тон a, зanuсaнных сеŭсмuческоŭ сmaцuеŭ HKC, с сооmвеmсmвующuмu mеореmuческuмu велuчuнaмu, рaссчumaннымu ?rt;ля верояmноŭ еомеmрuu зоны суб?rt;укцuu в рaŭоне Тон a u мо?rt;елu PREM. Нaблю?rt;енные u рaссчumaнные велuчuны ?rt;aюm колuчесmвенно хорощее со лaсuе. Обсуж?rt;aеmся влuянuе вaрuaцuŭ nерuо?rt;ов Т u уклонa л нa велuчuны рaссчеmных aмnлuму?rt; PKIKP u PKP1.

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The mechanism of small mining tremors from amplitude inversion     

Jan Šílený 《Pure and Applied Geophysics》1989,129(3-4):309-324

A method of inverting seismic wave amplitudes from mining tremors is proposed to reveal their mechanism. A simple shear-implosive model of a mechanism is proposed. The shapes of theoretical and observed radiation patterns are compared in the least squares norm and the parameters describing the shear-slip together with the ratio of implosive and shear dislocations are optimized. The efficiency of the method, even in the case of a small number of stations, is demonstrated by applying it to weak mining tremors from two mine regions in Czechoslovakia.The weak mining tremors are found to be of a predominantly shear mechanism with a clear coincidence of nodal planes to local tectonics, which could imply their tectonic nature.  相似文献   

Fast computation of ray synthetic seismograms in vertically inhomogeneous media     

Vlastislav Červený  Jaromír Janský  Reviewer I. Pšenčík 《Studia Geophysica et Geodaetica》1985,29(1):49-67

Summary A procedure of fast computation of body-wave ray synthetic seismograms in vertically inhomogeneous media is suggested. The procedure uses a special approximation of the velocitydepth distribution which guarantees continuity of the first and second derivatives of velocity and does not generate false low-velocity layers (oscillations in the velocity-depth function). The ZESY82 program package, which is based on the suggested procedure, is described. The point source with an arbitrary radiation pattern may be situated at any points of the model, the receivers are situated regularly or irregularly along any profile on the Earth's surface, containing the epicentre. Numerical examples of the synthetic record sections for a model of the Earth's crust and the uppermost mantle are given.

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¶rt;aam m¶rt; m ama ummuu a mua ¶rt;¶rt; ¶rt;, u¶rt; u nua annuauu m aa, ma nuam nm mu u n u m nu¶rt; u nu¶rt;um aau um nu mu. am nua aumn na ZESY82, a a m m¶rt;. umu aamumu uu an m ¶rt;u; nuuu ¶rt; m an¶rt; ¶rt; nu, ¶rt;a num. u¶rt; nu ummuu a ¶rt; ¶rt; ¶rt;u u amuu.

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Geomorphological processes and landforms in the southern part of the Polická vrchovina Highland (Czech Republic)     

J. Demek  J. Kopecký 《GeoJournal》1994,32(3):231-240

The paper examines relations among geomorphological processes and the landforms of the Polická vrchovina Highland in the Bohemian Massif. Geologically, the Polická vrchovina Highland is a part of the Intra-Sudetic Basin on the boundary between Bohemia and Poland. The basin structure of the Highland developed during the neotectonic period. In the outer parts of the Highland, Mesozoic rocks dip gently to the centre of the basin to form cuestas. In the central part, layers are horizontal or subhorizontal. Mesas (Hejda and Osta Mesa) provide evidence of the erosion of the Mesozoic deposits. The relative uplift of the Highland resulted in the incision of the Metuje River and its tributaries. Unloading of rocks and erosion initiated typical geomorphological processes such as deep- seated creep, cambering, rockfalls, landslides and pseudokarst processes. These processes produced some typical forms controlled by rock properties, jointing, relative differences in height and climatic changes in the Tertiary and Quaternary.  相似文献   

Reflection/transmission laws for slowness vectors in viscoelastic anisotropic media     

V. Červený 《Studia Geophysica et Geodaetica》2007,51(3):391-410

The reflection/transmission laws (R/T laws) of plane waves at a plane interface between two homogeneous anisotropic viscoelastic (dissipative) halfspaces are discussed. Algorithms for determining the slowness vectors of reflected/transmitted plane waves from the known slowness vector of the incident wave are proposed. In viscoelastic media, the slowness vectors of plane waves are complex-valued, p = P + iA, where P is the propagation vector, and A the attenuation vector. The proposed algorithms may be applied to bulk plane waves (A = 0), homogeneous plane waves (A ≠ 0, P and A parallel), and inhomogeneous plane waves (A ≠ 0, P and A non-parallel). The manner, in which the slowness vector is specified, plays an important role in the algorithms. For unrestricted anisotropy and viscoelasticity, the algorithms require an algebraic equation of the sixth degree to be solved in each halfspace. The degree of the algebraic equation decreases to four or two for simpler cases (isotropic media, plane waves in symmetry planes of anisotropic media). The physical consequences of the proposed algorithms are discussed in detail. vcerveny@seis.karlov.mff.cuni.cz  相似文献   

Electric conductivity in the inhomogeneous photosphere and sunspots     

M. Kopecký 《Solar physics》1970,14(1):136-137

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Uranus and the Outer Planets     

Zdeněk Pokorný 《Earth, Moon, and Planets》1982,27(1):139-139

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Preface     

I. Pšenčík  V. Červený 《Pure and Applied Geophysics》2002,159(7-8):1401-1402

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Allocution     

V. Pokorný 《Precambrian Research》1981,15(1):3-4

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Formaldehyde polymers in comets     

V. Vanýsek  N. C. Wickramsinghe 《Astrophysics and Space Science》1975,33(2):L19-L28

The possibility that crystalline formaldehyde polymers are present in cometary dust is discussed. In common with most other parent molecules proposed for comets, (H₂CO) _n is difficult to detect, even if it is present in relatively high concentrations. The optical properties of these polymers in the visual and infrared regions are similar to those of silicate grains, and crystalline formaldehyde polymers provide no emission at 6 cm wavelength. The lifetime of gaseous H₂CO in the solar radiation field is too short, and the expected transitions in the microwave region would be too weak to be detected. However, the available data concerning the physical properties of comets indicate that polymerized formaldehyde cannot be ruled out as a major constituent of cometary material.  相似文献