Results 261 to 270 of about 4,956 (290)

Shear Wave Splitting in Himalaya

Chinese Journal of Geophysics, 2007
AbstractWe analyze the records of 56 stations in Himalaya area with the method of minimizing the eigenvalue. Splitting was observed at thirty‐nine stations of them. The average splitting time is about 0.8s. The parameters of splitting vary not only from south to north, but are also different on the two sides of the line joining the station GAIG and ...
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Bootstrapping shear-wave splitting errors

Bulletin of the Seismological Society of America, 1994
Abstract We have developed a bootstrap method to estimate errors associated with inverting SKS waveforms for shear-wave splitting parameters. Although presented for shear-wave splitting inversions, this method is suitable for any waveform inversion procedure.
Eric Sandvol, Thomas Hearn
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Shear-wave splitting near Guam

Physics of the Earth and Planetary Interiors, 1992
Abstract Polarities of shear waves from intermediate-focus events underneath Guam are studied. For records from a group of ten events, shear-wave splitting with faster-arriving E-W components are observed. This event group occurred within, or above, one geographic portion of the Wadati-Benioff zone, with depths ranging between 57 and 148 km.
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Amplitude effects associated with shear‐wave splitting

SEG Technical Program Expanded Abstracts 2009, 2009
Shear-wave anisotropy results in a time delay between two different shear-wave polarizations S1 and S2. If there are associated differences in attenuation of the amplitudes, then simple time shifting is insufficient to match the S1 and S2 images. This ―differential‖ attenuation leads to both an additional time delay and a frequency dependent amplitude ...
Bruno Gratacos, Richard Bale, Pierre‐Yves Granger   +2 more
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Evaluation of anisotropy by shear-wave splitting

Geophysics, 1985
Abstract The polarizations of three-component shear wave-trains carry unique information about the internal structure of the rock through which they pass: specifically, commonly observed shear-wave splitting may contain information about the orientation of crack distributions.
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Error in shear‐wave polarization and time splitting

Geophysical Prospecting, 2004
ABSTRACTShear‐wave polarization and time delay are attributes commonly used for fracture detection and characterization. In time‐lapse analysis these parameters can be used as indicators of changes in the fracture orientation and density. Indeed, changes in fracture characteristics provide key information for increased reservoir characterization and ...
Gwénola Michaud, Roel Snieder
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Multichannel analysis of shear wave splitting

Journal of Geophysical Research: Solid Earth, 2000
A multichannel analysis is introduced to constrain seismic anisotropy from the shear wave splitting of SKS and SKKS. This technique utilizes simultaneously a set of records coming from different azimuths. The splitting intensity of SKS waves, measured by the amplitude of the transverse component, depends on the angle between the back azimuth of the ...
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Shear-wave splitting observations on Milos, Greece

Geothermics, 1989
Abstract Seismograms from local earthquakes recorded on Milos have been analysed for shear-wave splitting diagnostic of seismic anisotropy. Many complex P- and shear-wave trains were observed, indicating the presence of much heterogeneity, but shear-wave splitting was identified in most shear-wave arrivals within the shear-wave window.
D.C. Booth, S. Schleper, S. Crampin, N. Ochmann, J. Wohlenberg   +4 more
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Making Reliable Shear-Wave Splitting Measurements

Bulletin of the Seismological Society of America, 2013
Shear-wave splitting (SWS) analysis using SKS, SKKS, and PKS (here- after collectively called XKS) phases is one of the most commonly used techniques in structural seismology. In spite of the apparent simplicity in performing SWS measure- ments, large discrepancies in published SWS parameters (fast direction and splitting time) suggest that a ...
K. H. Liu, S. S. Gao
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Implications of temporal changes in shear‐wave splitting

SEG Technical Program Expanded Abstracts 1988, 1988
Details of the behaviour of shear-wave splitting have been observed to change before and after earthquakes and before and after hydraulic fracturing. The observations before earthquakes can be interpreted as the increasing aspect ratio (dilatation) of stress-aligned EDA-cracks, and the return to thin cracks after the earthquake has released the stress.
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