Extracting shear wave polarizations from different source orientations: Synthetic modeling

Conference · Tue Jul 10 04:00:00 EDT 1990 · Journal of Geophysical Research; (United States)

OSTI ID:5315992

Igel, H ^[1]; Crampin, S ^[2]

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1. British Geological Survey, Edinburgh (Scotland) Geophysikalisches Institut der Universitaet Karlsruhe (West Germany)
2. British Geological Survey, Edinburgh (Scotland)

Shear wave splitting, diagnostic of some form of seismic anisotropy, has been identified in the past, principally by examining polarization diagrams and by rotating the axes of recordings to separate the shear wave polarizations. The authors introduce a new technique for identifying polarizations of shear waves when the data has been recorded with more than one source orientation. The technique, suitable for vertical seismic profiles (VSPs) or reflection data, averages over an entire shear wavetrain, eliminating source related effects while retaining the anisotropy related polarizations. In shear wave reflection experiments and shear wave VSPs the distribution of displacement directions depends on the elastic properties of the medium (anisotropy), the source orientation, and the effects of scattering. The authors linearly combine seismograms from different source polarizations in order to simulate seismograms for any source polarization. This allows them to show the distribution of displacement directions as a function of source polarization in a high-relief display. The diagrams show characteristic features in the presence of anisotropy which could help to determine the polarizations of the two split shear waves in difficult circumstances. The techniques are tested with synthetic seismograms.

• OSTI ID: 5315992
• Report Number(s): CONF-880531--
• Conference Information: Journal Name: Journal of Geophysical Research; (United States) Journal Volume: 95:B7
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580000* -- Geosciences
ANISOTROPY
BIREFRINGENCE
DATA ANALYSIS
DISTRIBUTION
ELASTICITY
GEOPHYSICAL SURVEYS
MATHEMATICAL MODELS
MEASURING INSTRUMENTS
MECHANICAL PROPERTIES
OPTICAL PROPERTIES
ORIENTATION
PHYSICAL PROPERTIES
POLARIZATION
REFLECTIVITY
REFRACTION
RESERVOIR ROCK
SEISMIC ARRAYS
SEISMIC DETECTORS
SEISMIC S WAVES
SEISMIC SOURCES
SEISMIC SURVEYS
SEISMIC WAVES
SEISMOGRAPHS
SIMULATION
SURFACE PROPERTIES
SURVEYS
TENSILE PROPERTIES