Synthesis of body wave seismograms from point sources in anisotropic media

Conference · Tue Jul 10 00:00:00 EDT 1990 · Journal of Geophysical Research; (United States)

OSTI ID:5386979

Tsvankin, I D; Chesnokov, E M ^[1]

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1. Institute of Physics of the Earth, Moscow (USSR)

A method of synthetic seismogram calculation in arbitrary anisotropic media is developed. A solution in the frequency domain is derived in the form of a double integral with respect to horizontal slowness and azimuthal angle. Approximation of the influence of azimuthal anisotropy by Fourier series expansions makes it possible to carry out the integration over azimuthal angle analytically using series coefficients derived from simultaneous linear equations. As a result the double contour integral is reduced to a Fourier-Bessel integral over horizontal slowness which retains information about azimuthal anisotropy. Numerical evaluation of this integral enables one to compute body wave seismograms with allowance for nongeometrical effects. This approach can be applied to reflection-transmission problems or to the calculation of individual wavelet propagation in multilayered anisotropic media. The influence of anisotropy on point source radiation in a homogeneous medium is analyzed. Comparison of numerical results with high frequency asymptotic solution provides a reasonable physical interpretation for wave propagation anomalies. Synthetic data for a medium of orthorhombic symmetry show that the radiation pattern and the polarization of shear waves are very sensitive to the presence of anisotropy. The most pronounced amplitude distortions are caused by focusing of energy near velocity maxima and by defocusing near velocity minima. Numerical modeling reveals significant nongeometrical phenomena in anisotropic media. In some cases deviations from geometrical seismics are substantial even in the far field.

• OSTI ID: 5386979
• Report Number(s): CONF-880531-; CODEN: JGREA
• Journal Information: Journal of Geophysical Research; (United States), Vol. 95:B7; Conference: 3. international workshop on seismic anisotropy, Berkeley, CA (United States), 31 May - 4 Jun 1988; ISSN 0148-0227
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
SEISMIC SURVEYS
DATA ANALYSIS
AMPLITUDES
ANISOTROPY
CALCULATION METHODS
FOURIER ANALYSIS
MATHEMATICAL MODELS
POLARIZATION
REFLECTIVITY
SEISMIC S WAVES
SEISMIC SOURCES
SEISMIC WAVES
SEISMOGRAPHS
SIMULATION
TRANSMISSION
WAVE PROPAGATION
GEOPHYSICAL SURVEYS
MEASURING INSTRUMENTS
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
SEISMIC ARRAYS
SEISMIC DETECTORS
SURFACE PROPERTIES
SURVEYS
580000* - Geosciences