Stresses and displacements in the lithosphere due to terrain topography

Summary The complete two-dimensional theory of stresses and displacements in the loaded elastic floating lithosphere is presented. Analytical expressions are derived describing these quantittes as functions of the physical and geometrical parameters of the model. It is shown that horizontal stresses _xx may considerably exceed the surface load and that values of _xx200 MPa can be generated under certain conditions. Numerical calculations are carried out for geophysically acceptable input parameters.

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am na ¶rt;a mu anu u u a n naa um. ¶rt; aaumuu au, nuau mu uu a uu m uuu umuu naam ¶rt;u. aa, muma anu m aum num anu nm au u m¶rt; a m m n¶rt;a 200 a. n u am ¶rt;uuu ¶rt;nmu ¶rt; naam.

     

Spherical harmonic analysis and Fourier transformation

Summary The paper deals with the computation of spherical harmonic coefficients from surface measurements of the magnetic or gravity field of the Earth when the measurements are distributed regularly. The Fourier representation of associated Legendre functions which this procedure makes use of, then enables the harmonic analysis to be transformed to Fourier analysis which has better numerical properties.

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ama na ama uu uu uum n nm uu aum uuaumau n u a, ¶rt;a mu uu an ammu ma. ¶rt;mau n a¶rt; , m unm mm n¶rt;¶rt;, nm nmauu aau naam aau , m a¶rt;am uu uumu mau.

     

Linear modelling in vertical ionospheric sounding

Summary Applying the methods of computing N(h) profiles to scalar product spaces provides a more general view of the differences between the individual ionospheric models, which enables a better selection of the optimum model.

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u n¶rt; m¶rt;uu ama N(h) nu nmama a nu¶rt;u anauam u ¶rt; a au ¶rt; m¶rt;u uu ¶rt;u, m nm nmm uam nmua ¶rt;.

     

On the role of vertical resolution in the analysis of shallow convective fields

Summary The present paper is an attempt to demonstrate the fact that misleading information about the thermodynamic structure of shallow cumulus fields is obtained when standard isobaric level (SIL) data input is used. The 1-D cumulus model serves as the main tool of examination and the reference input data are those of significant levels (SL) in soundings. The computed cloud tops (SIL) exceeded (SL) tops in nearly 80% of the cases and the excesses are more than 1 kilometre in 25% of the cases. Some discrepancies were also found in potential stability analysis. The local changes in equivalent potential temperature may be seriously affected and even falsified. The important role of high resolution in studies of mesoscale phenomena was again accentuated.

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mam mum ¶rt;aam, m u am u¶rt; ¶rt;a unam ¶rt;a ma¶rt;am uauu (SIL), m num uauu m¶rt;uau mm mu n. ¶rt;m, una nu u¶rt;auu, m ¶rt;a ¶rt; aa, a am n ¶rt; au unm ¶rt;a au ¶rt;aa. auma u a ¶rt; SIL n¶rt;m n au 80% a, a 25% a ¶rt;a a 1 . au ma ma nu aau nmua mumu. aQj uu uam nmua mnam m m aum ua. n¶rt;uam aa aua nmu nu uuu u a.

     

Expansion of a function given over an equipotential surface into spherical harmonics

¶rt;m ¶rt; uuauu uum auu uu, a¶rt;a a nmunmuaa, ¶rt; n uu u. aa, m u u ¶rt;um nmu, uu n¶rt; m nm, u aaaa u aa m nmua.     

The connection between characteristic values of the 11-year cycles of solar and of geomagnetic activity

Summary Using the annual values of the indices of solar and geomagnetic activity for the period 1868–1976, the basic values characterizing the cycle as a whole were determined for the 11-year cycles nos 11–20, (Tab. 1). High values of the coefficients of correlation were found for some pairs of characteristic values of the same and different kinds, given in Tab. 2, which can be utilized for long-term predictions of geomagnetic activity.

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a auu¶rt;u au u¶rt; uaum amumu muu 1868–1976 n¶rt; ¶rt; 11-mu u 11–20 naam aamuu u a (a. 1). u au uuma uu ¶rt; m na naam ¶rt;ua u ¶rt;ua ¶rt;a (a. 2), m m amu nuu nu ¶rt; nuauuaum amumu.

     

On the spiral structure of atmospheric vortices

a au au a ¶rt;am m ¶rt;uauu n¶rt;nu mau nua am u nu uu, m n amu n nua n uau mua mu.     

Anomalous geomagnetic fields of internal origin in Czechoslovakia

Summary The magnetovariational data of 143 stations distributed over the eastern margin of the Bohemian Massif, over the Brunovistulicum and the West Carpathian sector were analysed to obtain transfer functions of the geomagnetic field. Methods of multivariate coherence analysis (spectral domain approach) and of impulse response (time domain approach) were employed. Complex induction vectors were estimated and contour maps of transfer functions were computer generated. Analysing their spatial distribution, we mapped the zones of anomalous induction and interpreted them in terms of electrical conductivity structure with its tectonic implications.

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azumauau ¶rt;a 143 n mau an n amu m au z aua, az a umua u ana anam auma n¶rt;am uu zazumz n m¶rt;au zz zmz aaua (nma n¶rt;¶rt;) u unz mua um ( n¶rt;¶rt;). mu mama n u¶rt;u ma u nm am uuu n¶rt;am u. au nmamz an¶rt;u mu aamumu m aa u¶rt;uu, ¶rt; mm ¶rt;uu u n¶rt;a u zz-zuua umnmau.

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Contribution No. 105/90, Geophysical Institute, Czechosl. Acad. Sci., Prague.     

Modification of the Runcorn's equations on convection flows

Summary Runcorn's equations, which can be used to compute the stresses caused by convection flows from the outer gravity field, were transformed so that gravity anomalies or geoid heights can be employed as input data.

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au aa, m n¶rt;m u n u mmu u anu, a uu nmau, u maua ma, m unam u¶rt; ¶rt; ¶rt;a, aauu u mmu uu mu¶rt;a.

     

Current estimates of the Earth's principal moments of inertia

Summary The principal moments of the Earth's inertia and their differences have been computed and their actual accuracy estimated on the basis of the most recent values of the 2nd degree geopotential parameters (model GEM-T2) and of the parameter H in the precession constant. The contributions due to the zero frequency zonal term in the tidal potential have been determined.

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au m nmnmuaa 2- mnu (¶rt; GEM-T2) u naama nm nuu n¶rt; aua m uuu u u u amu u ¶rt;am u a mmu. u a¶rt; n¶rt; uu nm amu a a nuu nmuaa.

     

On one possible type of upper cyclogenesis

Summary Based on model considerations it is shown that, under certain assumptions, upper cyclogenesis may be expected in the region of the auroral oval as a result of heat released at the time energetic particles of extraterrestrial origin penetrate into the lower stratosphere or even troposphere.

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a auu ¶rt; a¶rt;u naa, m nu m n¶rt;nu u¶rt;am u amu aa aa mam ¶rt;u mna nuu muu amu nu¶rt;u u mam uu mn.

     

Secular variations in the curvature of equipotential surfaces and directions of verticals due to geodynamic phenomena

Summary Formulae and numerical estimates are given for the non-periodical variations in the curvature of equipotential surfaces, horizontal forces and directions of the vertical, caused by the decrease in the second zonal geopotential harmonic, by the decrease in the angular velocity of the Earth's rotation and by secular polar motion.

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am ¶rt; u ua a nu¶rt;uu uu uu nm, maua u u u ma, a u m aauunmuaa, u mu au u u ¶rt;uu n.

     

Some possibilities of predicting radio wave absorption in the lower ionosphere

Summary An attempt is made to show possible ways of predicting radio wave absorption in the midlatitude lower ionosphere using relations between absorption and the intensity of solar ionizing radiation and/or common solar activity indices, and between absorption and f₀F2.

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aa mu nuau nu a¶rt;u ¶rt;um u u a mu ¶rt; nu u umum uuu uu (uu uu u¶rt;au amumu) u ¶rt; nu u f₀F2.

     

Heat flow in the upper-silesian coal basin: Re-evaluation of data with special attention to the lithology

Summary The area of the Upper Silesian Coal Basin was characterized by generally high heat flow ranging from 60 to 120 mWm^–2, mean 82±16 mWm^–2, which has been difficult to explain. Therefore all published data on the heat flow in this region (n=37) were summarized and re-evaluated. Special attention was paid to the detailed assessment of the lithological structure and the contribution of the individual rock types to the characteristic in-situ thermal conductivity. Also the thermal conductivity of the coal bearing layers was estimated and its effect on the temperature-depth distribution was investigated. The application of the data obtained for the representative thermal conductivity profiles of the whole drilled section considerably reduced the mean heat flow to 70±8 mWm^–2. The latter value is fully compatible with the tectonic structure of the northern part of the Carpathian Frontal Foredeep. Slightly increased geothermal activity compared with the heat flow field of the adjacent part of the Bohemian Massif corresponds to certain deep geological rejuvenation during the creation of the Western Carpathians.

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a -uu aa aamum nu uuau mn nma (m 60 ¶rt; 120 m.^–2 nu ¶rt; 82±16 m. ^–2), m ¶rt;a ¶rt u. m u u nm a nua ¶rt;a mn nma (n=37) ¶rt; ¶rt;a ua. ua ¶rt; ¶rt;ma aau umuu aa u u mnn¶rt;mu in situ ¶rt; a¶rt; muna n¶rt;. a a mnn¶rt;m m, a ma, a ma u¶rt;aa an¶rt;u mnam nu. nau n mam ¶rt; nuau mnn¶rt;mu m u amu aa nu am uum ¶rt;u mn nm ¶rt; 70±8 m.^–2. a uua n mam mmu u amu anam a nua. m uumu amumu n au mn n nuaa amu aua mmmmuuau amuuauu nu uauu um ana¶rdt; anam.

     

Seismotectonic model of the upper part of the Earth's crust of Czechoslovakia

Summary A correlation of the earthquake occurrence on the territory of Czechoslovakia and in its close neighbourhood with the data on the neotectonic and geomorphological development of the respective area, the recent movements of the Earth's crust, the courses of photolineations and on the geophysical fields enabled the fundamental structural blocks in the upper part of the Earth's crust to be singled out. The contact zones established between the above blocks exhibit increased long-term movement tendencies particularly in the Neoid period. A seismotectonic model of the upper part of the Earth's crust of Czechoslovakia, compiled with the use of the data mentioned above, is described.

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u m uu mu a mumuu auu u mmu ¶rt;au n mmu,uu, ¶rt;uu , u nmu u uuuu n nua ¶rt;um mm u amu . a a ¶rt; muu au a¶rt;am amau ¶rt; ¶rt;uu, u¶rt; nu¶rt;. m n¶rt;aaa mmua ¶rt; amu aa a au¶rt;uauu n, nu¶rt;u a ua mumuu, u a u u n¶rt;uu au.

     

Topographic effects on tidal strains and tilts

Summary Topographic effects on tidal strains and tilts are studied using a homogeneous elastic spherical model. Expressions for local perturbing strains and tilts are derive das functions of the physical and geometrical parameters of the model. It is demonstrated that tidal tilts are affected more by the topography than tidal strains.

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n ¶rt;¶rt; n u ¶rt;u u¶rt;a uu a mmu a nuu ¶rt;auu u a. ¶rt; au, nuau a uau nuu ¶rt;au u a auumu m uuu umuu naam ¶rt;u. aa, m uau nuu a uau nuu ¶rt;au.

     

Predictions of magnetic fields for Uranus and Neptune

Summary The magnetic moments of Uranus and Neptune have been predicted using different scaling laws of planetary magnetism. The predictions for Uranus cover a broad band of values from very weak magnetic fields (tidal relations) to moderate fields (thermal convection hypothesis). Therefore, the direct measurements of this field by Voyager 2 (January 1986) will be very important for testing the individual hapotheses.

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a m ama a ¶rt; amua nam ¶rt;a n aum m nam a a nm. aa n¶rt;nmu nuu mu, ¶rt;m u¶rt;am a aum n a nmu aa u u a nmu nma.

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Presented at the Fifth Scientific Assembly of IAGA in Prague 1985.     

Tidal evolution of the earth-sun system

Summary The tidal decrease in the Earth's heliocentric longitude generated by the Sun has been computed. It represents the increase in the length of year10^–7 s per century. The resonant angular velocity of the Earth's rotation is approximately equal to the present Earth's mean motion, however, for the model used, i.e., considering the Sun as the point-mass.

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u u zumu ¶rt;m u, a nuuau m a. ¶rt; mmmm uu ¶rt;u z¶rt;a10^–7 a mmu. a za m au u nu aa ¶rt; ¶rt;uu u, u, ¶rt;a, umam ¶rt;a ¶rt;u m a.

     

ТЕОРИЯ ВОЗНИКНОВЕНИЯ КВАЗИДВУХЛЕТНЕГО ЦИКЛА В АТМОСФЕРЕ

a aamaa ¶rt;uaua mu ¶rt;n nauuu a mu mu u ¶rt;uau uma am. m muu mam, m au¶rt;mu u au uuu am a mnuuu nau ¶rt;au. a a mu na an¶rt; aumuu mum ama, m am um m nu¶rt;u au u uu au¶rt;m ua.     

Analysis of the magnetometric vibration method

n¶rt;m mu ¶rt; mu uau aumma. mu aum u mu u m u mu auauu m¶rt;a. u¶rt;m u naam nm nmmuna uau aumma.