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P waves was determined. Surface wave$ in an iso-tropie linear elastic half-space with piane materiał (boundary) (35). free boundary waves at a piane interface between a half-space and a compressible nonviscous liquid (36]. and normal wave propaga-tion through an unbounded materiał that is mildly stratif ied or periodic (37) have been analyzed.

An edge wave traveling along a Continental shelf with a sloping region sandwiched by a fiat shelf and an ocean bottom has been investigated (38]. A model experiment has been performed to investi-gate Rayleigh waves transmitted across a trench (39]. Characteristics of surface-wave propagation in an ocean basin have been examined numerically (40. 41]. A stochastic perturbation theory has been used to study the propagation of piane seismic waves in a medium iri which random fluctuations in local density and elastic shear modulus were considered

(42] . Surface-wave distribution along the piane boundary of a fluid and a prestressed body interface

(43]    as well as shear modes in a system consisting of a liquid and a prestressed half-space (44] have been examined Propagation of Rayleigh and Love waves in a multilayered nonhomogeneous viscoelastic half-space has been studied (45].

Conditions under which the equations of motion in a nonhomogeneous isotropic medium can be approximated by the scalar wave equation. and under which the scalar wave equation can be approxi-mated by a ray equation. have been discussed (46]. The discrete wave number method has been used to study motions due to an arbitrary tensile source (47). A model for a strike-slip fault has been pro-posed in which an instability such as an earthquake or stable fault slip has been produced by strain softening of the fault zonę (48]. A method to obtain the displacement field of a Haskell model of an earthquake source. based on the well-known equivalence of seismic dislocations and body force. has been described (49]. A model, based on fracture mechanics concepts. of the behavior of an earthquake source prior to the occurrence of an earthquake has been presented (50] Disturbances in a medium due to torsional motion of a circular ring source (51 ] and transient forces and twists on the surface of a spheri-cal and a buried cyłindrical source have been studied 152]

An unstable constitutive model has been constructed to represent a fault medium (53].A generał constitu-tive equation of an ełastic-plastic rock medium was used; the coefficient of internal friction and cohesion of the fault medium were assumed to vary with deformation. Teleseismic P_n waves have been mod-eled as a sum of whispering gallery waves (54J; these waves propagate in a waveguide composed of a simple high-velocity mantle lid underlain by a low-vełocity zonę. A plane-geometry model has been used to illustrate the effects of a fluid confined in a borę hole on surface and body waves travełing along the borę hole in an elastic solid (55]. The effects of a eon-tacting layer and oscillation polarization on trans-verse wave propagation along a nonrigid contact between identical half-spaces has been considered (56].

The propagation of energy in half-spaces with the passage of a Stoneley wave (57] and the behavior of a non-steady surface wave in a nonhomogeneous linearly deformable elastic medium [58] have been studied. A numerical approach to surface-wave propagation across vertical discontinuities has been discussed (59]; computational results for Love wave propagation across the vertical boundary between two layered-quarter spaces were demonstrated. A pair of semi-linear hyperbolic partial differential equations governing slow variations in amplitudę and phase of quasi-monochromatic finite amplitudę Love waves on a layered half-space has been derived (60] using the method of multiple scales. The be-havior of waves in a nonhomogeneous composite medium with after effect has been studied (61).

The effect of initial stress on the propagation of Love waves has been examined 162], as has the same problem in a half-space with a double superficiał layer 163]. The propagation of such waves in nonhomogeneous layers lying over a prestressed half-space has also been demonstrated (64]. Seismic radiation from an arbitrarily growing spherical source in a nonhomogeneously prestressed medium (65] has been analyzed.

The propagation of seismic phases. P_n. P_g. S_n. and L_g from earthquake and explosion sources (66] and of seismic waves in the Earth's crust (67] has been studied. The propagation of shot-generated Stoneley waves as well as ambient background noise (68] have been discussed; Stoneley waves were observed propa-gating at velocities of 20 to 50 ms^-1. Fundamental modę Love and Rayleigh waves generated by some