INVERSE KINEMATIC PROBLEM FOR A RANDOM GRADIENT MEDIUM IN GEOMETRIC OPTICS APPROXIMATION

被引：8

作者：

PETERSEN, NV

机构：

[1] Institute of Physics of the Earth, USSR Academy of Sciences, Moscow

来源：

PURE AND APPLIED GEOPHYSICS | 1990年 / 132卷 / 1-2期

关键词：

inversion; random inhomogeneities; Scattering; travel time;

D O I：

10.1007/BF00874372

中图分类号：

P3 [地球物理学]; P59 [地球化学];

学科分类号：

0708 ; 070902 ;

摘要：

Scattering at random inhomogeneities in a gradient medium results in systematic deviations of the rays and travel times of refracted body waves from those corresponding to the deterministic velocity component. The character of the difference depends on the parameters of the deterministic and random velocity component. However, at great distances to the source, independently of the velocity parameters (weakly or strongly inhomogeneous medium), the most probable depth of the ray turning point is smaller than that corresponding to the deterministic velocity component, the most probable travel times also being lower. The relative uncertainty in the deterministic velocity component, derived from the mean travel times using methods developed for laterally homogeneous media (for instance, the Herglotz-Wiechert method), is systematic in character, but does not exceed the contrast of velocity inhomogeneities by magnitude. The gradient of the deterministic velocity component has a significant effect on the travel-time fluctuations. The variance at great distances to the source is mainly controlled by shallow inhomogeneities. The travel-time flucutations are studied only for weakly inhomogeneous media. © 1990 Birkhäuser Verlag.

引用

页码：417 / 437

页数：21

共 13 条

[1]

Chernov L.A., Waves in Randomly Inhomogeneous Media, (1975)

[2]

Golynsky S.M., Gusev V.D., The Most Probable Raypath in a Horizontally Stratified Medium. I. The Linear Layer, Geomagnetism i aeronomiya, 22, 6, pp. 960-965, (1982)

[3]

Koarov V.M., Ray Statistics in a Horizontally Stratified Medium with a Random Inhomogeneity, Izv. Vuzov. Radiofizika, 9, 1, pp. 292-302, (1966)

[4]

Kushnir G.S., Pruchkina P.M., Numerical determination of rays and travel times in 3-D inhomogeneous media, Vychislitel'anya Seismologiya, pp. 106-117, (1974)

[5]

Mereu R., Ojo S., The Scattering of Seismic Waves Through a Crust and Upper Mantle with Random Lateral and Vertical Inhomogeneities, Phys. Earth Planet. Inter., 26, 4, pp. 233-240, (1981)

[6]

Nikolaev A.V., Seismics of Inhomogeneous and Turbulent Media, (1973)

[7]

Nikolaev A.V., Tregub F.S., A Statistical Model of the Earth's Crust

[8]

Method and Results, Tectonophysics, 10, pp. 573-578, (1970)

[9]

Ojo S., Mereu R., The Effect of Random Velocity Functions on the Travel Times and Amplitudes of Seismic Waves, Geophys. J. Roy. Astron. Soc., 84, 3, pp. 607-618, (1986)

[10]

Petersen N.V., Wave Kinematics in Inhomogeneous Media, Izv. AN SSSR, Fizika Zemli, 3, pp. 34-43, (1983)

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