Eigenfunction Expansion of SH Wave-Fields for a Layered Medium Having an Irregular Interface

Abstract A method based on a discrete horizontal wave-number representation of seismic-source wave fields is developed and applied to the study of the near-field of a seismic source embedded in a layered medium. The discretization results from a periodicity assumption in the description of the source. The problem is basically two-dimensional but its extension to three dimensions is sometimes feasible. The source is quite general and is represented through its body-force equivalents. Tests of the accuracy of the method are made against Garvin's (1956) analytical solution (a buried line source in a half-space) and against Niazy's (1973) results for a propagating fault in an infinite medium. In both cases, a remarkably good agreement is found. The method is applied to the modeling of the San Fernando earthquake, and to the computation of synthetic seismograms at short distance from a complex source in a layered medium. In particular, we show that the high acceleration-high frequency phase of the Pacoima Dam records is due to the Rayleigh wave from the point of ground breakage. Other high-acceleration phases, predicted by our model, are associated with the shear-wave arrival from the hypocenter or result from changes in the fault orientation.

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The study of perfectly matched layer absorbing boundaries for SH wave fields

Applied Geophysics ◽

10.1007/s11770-009-0023-0 ◽

2009 ◽

Vol 6 (3) ◽

pp. 267-274 ◽

Cited By ~ 8

Author(s):

Jiong Liu ◽

Jian-wei Ma ◽

Hui-zhu Yang

Keyword(s):

Perfectly Matched Layer ◽

Sh Wave ◽

Wave Fields ◽

Absorbing Boundaries

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Cylindrical love waves, leaking modes and transient SH wave fields along borehole

10.1190/1.1815923 ◽

2000 ◽

Author(s):

Kexie Wang ◽

Guijin Yao ◽

Jun Ma ◽

Xianyun Wu

Keyword(s):

Love Waves ◽

Sh Wave ◽

Wave Fields

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Computation of multi-attribute seismic wavefields by solution of the elastodynamic equations

Bulletin of the Seismological Society of America ◽

10.1785/bssa0820021134 ◽

1992 ◽

Vol 82 (2) ◽

pp. 1134-1143

Author(s):

How-Wei Chen ◽

George A. McMechan

Keyword(s):

Shear Stress ◽

Particle Acceleration ◽

Wave Equations ◽

Layered Medium ◽

Normal Strain ◽

Particle Displacement ◽

Seismic Modeling ◽

Wave Fields ◽

Single Piece ◽

Explosive Source

Abstract By using the elastodynamic equations rather than wave equations for seismogram synthesis, multi-attribute wave fields can be computed in a single execution of one program. In the present implementation, for 2-D models, the wave fields and seismograms produced include any or all of the following: two components of each of particle acceleration, particle velocity, and particle displacement; two components of normal strain; shear strain; two components of normal stress; shear stress; and the dilatation and curl of the particle displacement. If flexible source and receiver configurations are also included, a single piece of software can be used for most seismic modeling applications. This significantly reduces the need for development and maintenance of separate programs. The algorithm is illustrated using waves synthesized for an explosive source in a layered medium. Snapshots and seismograms at both surface and borehole arrays are presented.

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SH-wave propagation in heterogeneous media: Velocity‐stress finite‐difference method

Geophysics ◽

10.1190/1.1441605 ◽

1984 ◽

Vol 49 (11) ◽

pp. 1933-1942 ◽

Cited By ~ 516

Author(s):

Jean Virieux

Keyword(s):

Wave Propagation ◽

Finite Difference ◽

Layered Medium ◽

Heterogeneous Media ◽

Heterogeneous Medium ◽

Head Wave ◽

Sh Wave ◽

Quarter Plane ◽

Discrete Grid ◽

Lateral Propagation

A new finite‐difference (FD) method is presented for modeling SH-wave propagation in a generally heterogeneous medium. This method uses both velocity and stress in a discrete grid. Density and shear modulus are similarly discretized, avoiding any spatial smoothing. Therefore, boundaries will be correctly modeled under an implicit formulation. Standard problems (quarter‐plane propagation, sedimentary basin propagation) are studied to compare this method with other methods. Finally a more complex example (a salt dome inside a two‐layered medium) shows the effect of lateral propagation on seismograms recorded at the surface. A corner wave, always in‐phase with the incident wave, and a head wave will appear, which will pose severe problems of interpretation with the usual vertical migration methods.

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