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  • Articles  (26)
  • 1985-1989  (16)
  • 1975-1979  (10)
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  • 1
    Electronic Resource
    Electronic Resource
    Synthetic body wave seismograms for laterally varying media containing thin transition layers (1989)
    Oxford, UK : Blackwell Publishing Ltd
    Geophysical journal international 99 (1989), S. 0 
    Details
    ISSN: 1365-246X
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences
    Notes: An approximate hybrid approach to computing high-frequency body wave synthetic seismograms in 2-D and 3-D laterally varying layered structures containing thin transition layers is suggested. It combines the ray method with the matrix (reflectivity) method. The ray method is applied to thick layers with smooth variations of velocity and the reflectivity method is applied to thin transition layers. Alternatively, the method of summation of Gaussian beams is used instead of the ray method in the hybrid code. An algorithm and the relevant program package BEAM87, designed for such hybrid computations in 2-D laterally varying layered structures containing one laterally varying thin transition layer, are briefly described. The thin transition layer may represent a region of a high velocity gradient, a laminated region, a region of a low Q, etc. It is simulated by a stack of very thin layers. The accuracy of the hybrid computations is tested on 1-D models by the comparison with reflectivity-method computations. The hybrid method yields sufficiently accurate results for transition layers, the thickness of which is smaller than one half of the prevailing wavelength of the wavefield under consideration, particularly for small angles of incidence. For reflected waves, the best accuracy is obtained for subcritical reflections, but the accuracy is lower for critical and overcritical reflections. The accuracy in the critical region is improved, if the Gaussian beam summation method is used instead of the ray method in the hybrid scheme. Numerical examples of synthetic body wave seismograms for a laterally varying model containing thin transition layers of various types are presented.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-246X.1989.tb01692.x
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  • 2
    Electronic Resource
    Electronic Resource
    Ray tracing in factorized anisotropic inhomogeneous media (1989)
    Oxford, UK : Blackwell Publishing Ltd
    Geophysical journal international 99 (1989), S. 0 
    Details
    ISSN: 1365-246X
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences
    Notes: A concept of a factorized anisotropic inhomogeneous (FAI) medium is introduced. In the FAI medium, the position dependent density normalized elastic parameters aijkl(Xi) can be factorized in the following sense: aijkl(Xi) =f2(xi)Aijkl, where Aijkl are constants, independent of Cartesian coordinates xi, and f(xi) is an arbitrary continuous function of xi. Thus, all the density normalized elastic parameters aijkl(xi) in the FAI medium depend on the coordinates xi in the same way, but the generality of anisotropy and of inhomogeneity is not restricted. The factorization of aijkl(xi) leads to a factorization of certain important ray theory expressions and equations (eikonal equation, etc.), and to particularly simple ray tracing and dynamic ray tracing. For certain types of FAI media, these equations may even be solved analytically or semianalytically.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-246X.1989.tb02017.x
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  • 3
    Electronic Resource
    Electronic Resource
    Transmitted waves in the vicinity of the interface beyond the critical point (1977)
    Springer
    Studia geophysica et geodaetica 21 (1977), S. 137-142 
    Details
    ISSN: 1573-1626
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Geosciences , Physics
    Notes: Summary The space (time) delay of transmitted waves in the vicinity of the interface beyond the critical point is investigated on two-dimensional seismic models of a low velocity channel; results of laboratory experiments are compared with the conclusions of the theory. The effect of the time delay in field measurements is demonstrated by means of two typical geological formations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01634824
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  • 4
    Electronic Resource
    Electronic Resource
    Computation of ray amplitudes in inhomogeneous media with curved interfaces (1978)
    Springer
    Studia geophysica et geodaetica 22 (1978), S. 248-258 
    Details
    ISSN: 1573-1626
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Geosciences , Physics
    Notes: Summary This paper is a continuation of[1]. It is mainly devoted to problems connected with the application of the method of determination of geometrical spreading in laterally inhomogeneous media with curved interfaces based on the solution of eight (in a three-dimensional medium) or two (in a two-dimensional medium) linear ordinary differential equations of the first order. The method of determination of the partial derivatives of velocity with respect to the special coordinates, connected with the ray under investigation, and the methods of determination of the initial values for the system of differential equations at the source and at the interfaces are proposed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01627902
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  • 5
    Electronic Resource
    Electronic Resource
    The effect of local geological conditions onP-wave amplitudes (1979)
    Springer
    Studia geophysica et geodaetica 23 (1979), S. 381-387 
    Details
    ISSN: 1573-1626
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Geosciences , Physics
    Notes: Summary At two observation sites located in different geological conditions seismic waves from borehole shots and from quarry blast were recorded with a three-component broadband instrument. The analysis of dynamic characteristics, based on the experimental investigation of the displacement amplitudes, is presented.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01633243
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  • 6
    Electronic Resource
    Electronic Resource
    Wave phenomena on blocks — A schlieren model study (1975)
    Springer
    Studia geophysica et geodaetica 19 (1975), S. 350-357 
    Details
    ISSN: 1573-1626
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Geosciences , Physics
    Notes: Summary The aim of performed experiments was to visualize, record and analyse the P wave pattern connected with simple block structures. Two-component plate models of a half-space (turpentine, v 1 =1240 m/s) containing rectangular blocks (perspex, v 2 =2630 m/s) were studied by means of the schlieren method. P waves generated by an exploding wire source were recorded with a high-speed camera during their passage through a block. The field of reflected and refracted waves, head waves, diffracted waves and inhomogeneous waves was analysed for waves entering and leaving the block. Special attention was paid to diffraction phenomena on rectangular corners of the blocks in question.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01615809
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  • 7
    Electronic Resource
    Electronic Resource
    Bicubic spline smoothing of two-dimensional geophysical data (1976)
    Springer
    Studia geophysica et geodaetica 20 (1976), S. 168-177 
    Details
    ISSN: 1573-1626
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Geosciences , Physics
    Notes: Summary A computational method for fitting smoothed bicubic splines to data given in a regular rectangular grid is suggested. The one-dimensional spline fit has well defined smoothness properties. These are duplicated for a two-dimensional approximation by solving the corresponding variational problem. The complete algorithm for computing the functional values and its derivatives at arbitrary points is presented. The posibilities of the method are demonstrated on an example from geomagnetic surveys.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01626049
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  • 8
    Electronic Resource
    Electronic Resource
    Relation between the field of surface heat flow and the distribution ofP n -wave velocities for continents (1988)
    Springer
    Studia geophysica et geodaetica 32 (1988), S. 287-299 
    Details
    ISSN: 1573-1626
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Geosciences , Physics
    Description / Table of Contents: Summary The dependence between Pn-wave velocities and the surface heat flow, temperature at the core-mantl boundary and thickness of the Earth's crust for continents (Europe, Asia, North America and Australia) was investigated statistically in connection with the problem of lateral inhomogeneities in the upper mantle. The relations obtained were compared with those determined under laboratory conditions. The conclusion is that temperature and pressure effects may provide additional explanations of the regional variations of Pn-wave velocities observed in most continents.
    Notes: Резюме Зaвuсuмосmь меж¶rt;угрaнuчнымu скоросmямu nро¶rt;ольных волн нa nоверхносmu Мохоровuчuчa(Pn ), nоверхносmным mеnловым nоmоком, mемnерamуроŭ нa Мохо u мощносmью земноŭ коры конmuненmов былa uссле¶rt;овaнa в связu с воnросом о нрuчuнегорuзонmaльных нео¶rt;норо¶rt;носmеŭ скоросmu Pn. Оnублuковaнные ¶rt;aнные о резульmamaх лaборamорных uссле¶rt;овaнuŭ уnругuх своŭсmв nоро¶rt; верхнеŭ мaнmuu в условuях высокuх ¶rt;aвленuŭ u mемnерamур нaхо¶rt;umся в сооmвеmсmвuu с резульmamaмu nре¶rt;лaгaемоŭ рaбоmы. Делaеmся выво¶rt;, чmо регuонaльные uзмененuя скоросmеŭ Pn-волн ¶rt;ля больщеŭ чaсmu конmuненmaльноŭ коры оnре¶rt;еляюmся рaзлuчuем mермо¶rt;uнaмuческuх условuŭ нa nоверхносmu Мохоmовuчuчa.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01637886
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  • 9
    Electronic Resource
    Electronic Resource
    Approximative ray tracing and the accuracy of earthquake localization in media approximated by block structures (1989)
    Springer
    Studia geophysica et geodaetica 33 (1989), S. 164-176 
    Details
    ISSN: 1573-1626
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Geosciences , Physics
    Description / Table of Contents: Summary Localization errors made by approximating a given medium by a homogeneous rectangular block model and due to the approximative solution of two-point ray tracing are estimated for four different structures. The separate influence of the individual characteristics of the medium is discussed. The iterative Geiger method supplemented by a generalized inversion of the damped least-squares and Marquardt algorithm is used for localizating five hypothetical hypocentres using 9 stations. Travel times in the original structures, used as input data for localization, are calculated using a special ray tracing system.
    Notes: Резюме В рaбоmе оценены ошuбкu локaлuзaцuu вызвaнные annроксuмaцuеŭ реaльноŭ сре¶rt;ы мо¶rt;елеŭ сосmaвленноŭ uз орmогонaлных о¶rt;норо¶rt;ных блоков u annроксuмaцuеŭ mочного лучa ¶rt;вумя munaмu nрuблuзumельных лучеŭ.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01646582
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  • 10
    Electronic Resource
    Electronic Resource
    Computation of synthetic seismograms in 2-D and 3-D media using the Gaussian beam method (1989)
    Springer
    Studia geophysica et geodaetica 33 (1989), S. 213-229 
    Details
    ISSN: 1573-1626
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Geosciences , Physics
    Description / Table of Contents: Summary The Gaussian beam method is applied to vertical seismic profiling in 2-D and 3-D models. A simple approach to the computation of Gaussian beam seismograms in the vicinity of structural interfaces is proposed. The effects of (a) the radiation pattern of a point source, (b) noncausal attenuation, (c) transverse inhomogeneities in synthetic seismograms are studied on numerical examples.
    Notes: Резюме Меmо¶rt; Гaуссевых nучков uсnользуеmся ¶rt;ля верmuкaльно о сеŭсмuческо о nрофuлuровaнuя в ¶rt;вух u mрехмерных мо¶rt;елях сре¶rt;ы. Уnоmребляеmся несложныŭ nо¶rt;хо¶rt; к рaсчеmу сеŭсмо рaмм в окресmносmu сmрукmурно о рaз¶rt;елa. Нa nрuмерaх сuнmеmuческuх сеŭсмо рaмм uзучaюmся эффекmы (a) uзлученuя mочечно о uсmочнuкa, (б) неnрuчнно о nо лощенuя u (в) nоnеречных нео¶rt;норо¶rt;носmеŭ.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01633525
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