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earthquakes have been analyzed (69]; the disperslon of such waves has been used to determłne models of sheer vełocity agalnst depth for crustal ages (70). The group veloclty disperslon characteristlcs of fundamental modę Rayleigh waves (T * 20 to 100 sec) have been determined from movlng window analyses of selsmograms (71J.

A solution for surface displacements due to burled dlslocation sources (72]. formulas for catculating travel times In tran$versely isotropic Earth models (73], equatlons descrlblng the rełatlon between pressure and wave-propagatlon vełoclty In fracture and porous rock (74]. and equatlons of motion describing the llnear magneto-elastic behavlor of a continuum (75] have been considered. The problem of crack propagation (76) as well as selsmic waves and the spectrum generated by a dynamlcal rupture process [77] and dlsplacement spectra from micro-earthquakes (78) have been studled. A perturbation method has been used to study the effect of weak nonhomogeneities on the propagation of selsmic rays through a layer of fixed thlckness (79].

The Airy function often appears as a part of Solutions in theoretical seismology (80]. The rangę of problems in applications of statistics to seismology has been $urveyed [81J. An analytic solution of the problem of propagation of a longitudinal slnusoidal wave has been considered [82]. Wave-induced stress in a porous elastic medium has been studied on the basis of Biot's linearized theory [83]. Finite dif-ference techniques have been used to study the re-sponse of a sedimentary basin In an isotropic half-space to vertically incident compressional and shear sources [84]. Displacements on the surface of a traction-free half-space have been studied (85. 86].

The splitting matrix method has been used (87) to derive two parabollc-approximation partial differen-tial equations to a three-dimensional llnear wave equation nonhomogeneous media. A numerical technique for attaining the SH-wave contribution to tangential displacements due to point dislocation sources in a piane layered Earth has been shown [88].

The behavior of Green's functions for Biots equa-tion in the neighborhood of wave fronts has been discussed [89]. A method to derive the coefficients in the strain energy functional of Biot's theory for elastic waves In fluid-saturated porous media has been proposed (90). For a stratified elastic half-space Green's tensor has been used to give a spectraI representatlon for coupled selsmic waves (91]. The finite element method has been used to obtain a disperslon curve for fundamental-mode Love waves (92).

A scalar potentlal representatlon for a P wave In a nonhomogeneous medium has been developed from ray theory (93] and shown to be applicable to both P and S waves. Spontaneous cracks spreading over a fault piane in an infinite medium have been studied as an earthquake source model [94]; the boundary Integra! equation technique was used. The Somigliana dislocation theory has been applied [95] to the study of strlke-slip faultlng in an Isotropic. homo-geneous half-space in the presence of localized dlstributions of strain nuctei.

Equations governing the propagation of random Rayleigh wave$ in isotropic viscoelastic solids have been derlved [96]. The propagation of elastic spheri-cal waves emltted by a source point placed outside a glven finite set of concentric spherical layers has been studied in an infinite space [97]. Green's functions for a layered medium can be expressed as a double Integra) over frequency and horizontal wave number; the wave number integral can be represented by a discrete summation [98]. An equation for waves on an anisotropic haJf-space has been examined [99]. Partial derivatives of Love wave phase velocities with respect to sheer velocities in a spherical Earth have been computed (100).

The theory of micropolar continua has been used to study some earthquake problems (101]; changes in Earth's inertia tensor due to earthquake faulting have been calculatęd using a reciprocal relation. The frequency equation of Rayleigh waves in a thermo-elastic half-space under initial stresses [102], the influence of gravity on wave propagation in a thermo-elastlc layer [1031. a Rayleigh wave velocity equa-tion in a micropolar medium with stretch (104). and propagation of magneto-elastic Love waves [105] have been discussed. The solution for a problem of connected thermo-elasticity on surface wave propagation in the isotropic half-space formed by regular alternation of several layers with different thermo-mechanical properties (106] has been studied The damping and dispersion of Rayleigh waves by the