1298378166

Aóstract Tha arieto on aałtmfc wavm dm/s with varioua aapeett of tha propagation of a/att/c wavm on Earth. mathamatkal mathodt,, wavat dna to axploaion and oacUtotbn of tha Earth,, tałtmic pro* pacting, młsmk: rkk, ground motfon and atructuraa, and machanitmt and pradfetion of aarthguakat.

This article Is a continuation of two previous revlews [1, 21 published in the Digest. Surface and gułded waves, mathematlcal methods. waves due to explo-sions and oscillation of the Earth. seismic prospect-ing, seismic risk, and reiated problems are discussed.

SllRFACE AND GUIDED WAYES, MATHEMATICAL METHODS, MODELS

Theories of eiastic wave propagation In fluid and solid layered media [31 and in bodies with initial stresses [4 J as weil as wave motion in anisotropie and cracked elastlc media (51 have been reviewed. The propagation of surface waves In marinę sediments (61. in anelastic media [7], and in a heat-conducting eiastic body [81 have been studied. Characteristics of the propagation of Rayleigh waves through irregu-lar structures [91. of Love waves through laterally heterogeneous structures [101, and of piane harmonie waves in wet granular media [111 have been discussed. The ray theory plays an important role in problems of layered media [7, 12J. A generałized ray theory has been developed to study transient SH waves in a wedge-shaped layer over a half-space [131.

Channeł waves serve as a tool for the detection of discontinuities in coal seams caused. for example, by tectonic faulting; Love waves propagating along discontinuous coal seams have been studied (14). The dispersion relations for Love channeł waves have 7 VTT7 been derłved [15). A numerlcal model of SH-type channeł waves has been presented [16] and utilized to derlve a recompressing fllter to remove dispersion of the waves. Oceanie acoustlc and seismic dlsturb-ances have been modeled as Raylelgh-Stonełey waves in a layered medium consisting of ocean, sediment, and rock [171. The bulk waves observed in longi-tudinal profiles of layered media have been dłvlded into symmetric and antisymmetrlc waves; specific features of the wave twins have been discussed [181 • An acousto-elastic effect for the Rayleigh surface wave [191, a secular equation for Rayleigh waves on the surface of an anisotroplc half-space [201. group velocity dispersion curves of Rayleigh waves [21). and dispersion of leaky compressional (PL) waves [22) have been studied.

A solutlon has been considered to the variance equa-tion for P waves in a soft medium with electrokinetic properties [23]. Rayleigh'$ principle and the concept of iocal wave number have been utilized to determine the dispersion of Love waves [241. Surface SH waves in nonhomogeneous media [251, dispersion-free waves in a medium with a cylindrical cavity [261, and Rayleigh-wave propagation on a gravitating sphericał earth [271 have been studied. Rayleigh and Love waves in an irregular soil layer have been ana-lyzed [281. Solution of a seismic migration problem by Fourier transform in the wave number and fre-quency domain has been presented [291 •

Wave processes in real crystals [301 and in weakly anisotropic media [31] have been described A solution of coupled ełastłc-gravitational field equa-tions has been studied [32]. Wave propagation along a piane boundary sępa rat i ng compressible, previously deformed bodies with eiastic potentlal of arbitrary form has been considered [33]. P-wave propagation

In anisotropic solids has been examined [341; the effect of anlsotropy on the polarizations of quasi-

• National Rmmrch Inatltuta. P.O. Bank kol. Ban kurw. W. Baogal, Indio

T""T

ON SEISMIC WAVES

SanuUuu- De*

3

■    •    •    •    •    «    •    •    •    •    •    •    •    •    •    . • • *    i • • •    • . • «    . i «    •    •-    %    •    •_    •    •

V V V V.- V* .* W yv‘V • vVv'vVvVV' .*• .*• .*•. •    .'w    .% .*•...    \V-*.V s .